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School of Natural Resources: Faculty Publications

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Articles 1501 - 1530 of 1586

Full-Text Articles in Physical Sciences and Mathematics

Respiratory Release Of Co2 In Alfalfa And Soybean Under Field Conditions, S. B. Verma Jan 1986

Respiratory Release Of Co2 In Alfalfa And Soybean Under Field Conditions, S. B. Verma

School of Natural Resources: Faculty Publications

No abstract provided.

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Ectoparasitism As A Cost Of Coloniality In Cliff Swallows (Hirundo Pyrrhonota), Charles R. Brown, Mary Bomberger Brown Jan 1986

Ectoparasitism As A Cost Of Coloniality In Cliff Swallows (Hirundo Pyrrhonota), Charles R. Brown, Mary Bomberger Brown

School of Natural Resources: Faculty Publications

Colonially nesting Cliff Swallows (Passeriformes: Hirundo pyrrhonota) in southwestern
Nebraska, USA, are commonly parasitized by hematophagous swallow bugs (Hemiptera: Cimicidae:
Oeciacus vicarius) and fleas (Siphonaptera: Ceratophyllidae: Ceratophyllus celsus). We examined to
what degree these ectoparasites represent a cost of coloniality for Cliff Swallows. The number of
swallow bugs per nest increased significantly with Cliff Swallow colony size. Body mass of nestling
swallows at 10 d of age declined significantly as the number of bugs per nestling increased. By fumigating
half of the nests in some colonies, killing the bugs, and leaving half of the nests as nonfumigated …

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Middle Miocene To Recent Stratigraphy And Paleogeography Of Western Nebraska, James B. Swinehart, Vernon L. Souders, H. M. Degraw, Robert F. Diffendal Jr. Apr 1985

Middle Miocene To Recent Stratigraphy And Paleogeography Of Western Nebraska, James B. Swinehart, Vernon L. Souders, H. M. Degraw, Robert F. Diffendal Jr.

School of Natural Resources: Faculty Publications

Two generally distinctive suites of sediments occur in western Nebraska, one dominantly volcaniclastic in origin deposited from the Oligocene through Early Miocene, and the other mainly epiclastic in origin deposited from the Middle Miocene through the Holocene. We have combined the epiclastic deposits usually placed in the Hemingford and Ogallala groups into an expanded Ogallala Group and have abandoned the member subdivisions of the Broadwater Formation.

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Oligocene To Middle Miocene (White River And Arikaree Groups) Stratigraphy And Paleogeography Of Western Nebraska, James B. Swinehart, Vernon F. Souders, H. M. Degraw, Robert F. Diffendal Jr. Apr 1985

Oligocene To Middle Miocene (White River And Arikaree Groups) Stratigraphy And Paleogeography Of Western Nebraska, James B. Swinehart, Vernon F. Souders, H. M. Degraw, Robert F. Diffendal Jr.

School of Natural Resources: Faculty Publications

The White River Group traditionally has been divided into three stratigraphic units in western Nebraska, the Chadron, Orella, and Whitney. We also recognize three depositional sequences in the group but these consist of the following stratigraphic intervals (oldest to youngest): 1) the base of the Chadron to the unconformity in the Orella Member; 2) the unconformity to the top of the Whitney; and 3) the Brown Siltstone beds (a new informal unit). We divide the Arikaree into three units; 1) the Gering; 2) Monroe Creek-Harrison formations; and 3) the Upper Harrison beds.

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New Evidence Supporting The Blancan Age Of The Sand And Gravel Sequence Capping The Ash Hollow Formation, Garden, Keith, And Lincoln Counties, Nebraska, Robert F. Diffendal Jr., James W. Goeke, Michael R. Voorhies Mar 1985

New Evidence Supporting The Blancan Age Of The Sand And Gravel Sequence Capping The Ash Hollow Formation, Garden, Keith, And Lincoln Counties, Nebraska, Robert F. Diffendal Jr., James W. Goeke, Michael R. Voorhies

School of Natural Resources: Faculty Publications

Sandwiched between the overlying eolian Quaternary loesses and sands and the underlying beds of the Ash Hollow Formation, Ogallala Group, buried beneath the sliver of Cheyenne Tableland in Keith County and adjacent areas of western Nebraska, is a mass of fluvially deposited sand, gravelly sand, and sandy gravel of previously uncertain age. Some authors assigned these sediments to the Ogallala Group, while others have called them either the Broadwater Formation (Blancan), or a combination of the two rock units.

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Contrasts Among Bidirectional Reflectance Of Leaves, Canopies, And Soils, Elizabeth A. Walter-Shea Jan 1985

Contrasts Among Bidirectional Reflectance Of Leaves, Canopies, And Soils, Elizabeth A. Walter-Shea

School of Natural Resources: Faculty Publications

No abstract provided.

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Microclimate-Plant Architectural Interactions: Influence Of Leaf Width On The Mass And Energy Exchange Of A Soybean Canopy, S. B. Verma Jan 1985

Microclimate-Plant Architectural Interactions: Influence Of Leaf Width On The Mass And Energy Exchange Of A Soybean Canopy, S. B. Verma

School of Natural Resources: Faculty Publications

No abstract provided.

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Manual: Measurement Of Evapotranspiration By The Bowen Ratio Energy Balance Method, Joon Kim, Shashi Verma Jan 1985

Manual: Measurement Of Evapotranspiration By The Bowen Ratio Energy Balance Method, Joon Kim, Shashi Verma

School of Natural Resources: Faculty Publications

The Bowen ratio energy balance method has been widely used by many researchers to estimate the fluxes of water vapor and sensible heat between crops and atmosphere. The energy balance for the crop canopy can be expressed as Rn + G + H + LE + PS + M = 0 (1) where Rn is net radiation, G is soil surface heat flux, H is sensible heat flux and LE is latent heat flux.

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The Inapplicability Of The Concept Of The "Sidney Gravel" To The Ogallala Group (Late Tertiary) In Part Of Southern Banner County, Nebraska, Robert F. Diffendal Jr. Jan 1985

The Inapplicability Of The Concept Of The "Sidney Gravel" To The Ogallala Group (Late Tertiary) In Part Of Southern Banner County, Nebraska, Robert F. Diffendal Jr.

School of Natural Resources: Faculty Publications

A series of geologic maps of counties in western Nebraska was prepared for the Nebraska Geological Survey during the mid-1 930s. These maps showed the distribution of rock units of Tertiary age including a formation designated as the “Sidney.” The Sidney Gravel was described as a widespread sheetlike complex of channel deposits, but with small areas where it is not developed. In southern Banner County, Nebraska, there are several channels filled with sand and gravel that were mapped as Sidney in this series. Recently one of these channel fills has been observed to cut across the other. The fills are …

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Characteristics, Age Relationships, And Regional Importance Of Some Cenozoic Paleovalleys, Southern Nebraska Panhandle, Robert F. Diffendal Jr., James B. Swinehart, J. J. Gottula Jan 1985

Characteristics, Age Relationships, And Regional Importance Of Some Cenozoic Paleovalleys, Southern Nebraska Panhandle, Robert F. Diffendal Jr., James B. Swinehart, J. J. Gottula

School of Natural Resources: Faculty Publications

Few workers have reported previously on features of ancient valleys in western Nebraska. Six sites in the southern Nebraska Panhandle, ranging in age from Oligocene to Middle to Late Pleistocene, illustrate the characteristics and variability of Cenozoic paleovalleys. The dimensions of these paleovalleys vary from less than 0.1 km to more than 1.0 km in width and from less than 1.0 km to more than 100 km in length. Relief is as much as 35 m in outcrop. Four of the examples have valley sides that are nearly vertical. Potholes and other scour features occur at one site. Remnants of …

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Comments On The Geologic History Of The Ogallala Formation In The Southern Panhandle Of Nebraska, Robert F. Diffendal Jr. Jun 1984

Comments On The Geologic History Of The Ogallala Formation In The Southern Panhandle Of Nebraska, Robert F. Diffendal Jr.

School of Natural Resources: Faculty Publications

The southern Panhandle of Nebraska and the adjoining parts of southeastern Wyoming and northeastern Colorado are unusual places to examine the geologic history of the Ogallala Formation because they are much closer to the source areas of much of the sediment which makes up the unit than are other sites along the Ogallala outcrop belt. This study in Nebraska combined with results of earlier work there, in southeastern Wyoming, and ; northeastern Colorado, outlines the complex cut and fill history of the Ogallala close to Rocky Mountain source areas.

Parts of the Ogallala consist of fills of sand and gravel, …

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The Genus: A Macroevolutionary Problem, Cliff A. Lemen, Patricia W. Freeman May 1984

The Genus: A Macroevolutionary Problem, Cliff A. Lemen, Patricia W. Freeman

School of Natural Resources: Faculty Publications

This paper centers on the macroevolutionary problem surrounding the concept of the vertebrate genus. We have been fascinated by the apparent tendency of members of a genus to have the same shape in contrast to the great differences in shape among genera at the family level. If this is true, genera would be considered shape conservative groups. Our initial view of this contrast in shape variation within and among genera leads us to question whether the same evolutionary processes that produce genera can simply be extended to produce families. To approach this question two things need to be done. First, …

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Further Comments On The Nature And Developmental History Of Quaternary Pumpkin Creek, Banner, And Morrill Counties, Nebraska, Robert F. Diffendal Jr. Apr 1984

Further Comments On The Nature And Developmental History Of Quaternary Pumpkin Creek, Banner, And Morrill Counties, Nebraska, Robert F. Diffendal Jr.

School of Natural Resources: Faculty Publications

The occurrence of Quaternary anorthosite-rich sand and gravel deposits in south-central Morrill County, Nebraska, supports the idea that Pumpkin Creek formerly flowed farther east than it does today. This eastern extension of the creek was abandoned when another headward cutting tributary of the North Platte River cut through the divide between Pumpkin Creek and the North Platte just east of Jail and Courthouse rocks and captured Pumpkin Creek.

Unusual clast types found in Quaternary deposits along Pumpkin Creek in Banner County may be used to determine some characteristics of the streams that carried them. For example, armored mud balls and …

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The Effects Of Mowing On The Rodent Community Of A Native Tall Grass Prairie In Eastern Nebraska, Cliff A. Lemen, Mary K. Clausen Apr 1984

The Effects Of Mowing On The Rodent Community Of A Native Tall Grass Prairie In Eastern Nebraska, Cliff A. Lemen, Mary K. Clausen

School of Natural Resources: Faculty Publications

Although fires are an integral part of prairie ecology (Bragg and Hulbert 1976, Daubenmire 1968, Rice and Parenti 1978, Zimmerman and Kucera 1977), there is evidence that mowing can serve at least some of the functions of fire (Hover and Bragg 1981) in prairies. Mowing, in fact, has two major advantages over burning. First there is no need for large crews to control the fire, and second the hay produced can be used as a cash crop. Because mowing is an attractive alternative to burning for prairie preserves it is important to determine the effects of mowing on the prairie. …

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Selection Criteria For Drought Resistance, James R. Brandle Jan 1984

Selection Criteria For Drought Resistance, James R. Brandle

School of Natural Resources: Faculty Publications

No abstract provided.

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Partitioning Solar Radiation Into Direct And Diffuse, Visible And Near-Infrared Components, A. Weiss Jan 1984

Partitioning Solar Radiation Into Direct And Diffuse, Visible And Near-Infrared Components, A. Weiss

School of Natural Resources: Faculty Publications

No abstract provided.

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Kolmogorov Constants For Co2, Wind Velocity, Air Temperature, And Humidity Fluctuations Over A Crop Surface, S. B. Verma Jan 1984

Kolmogorov Constants For Co2, Wind Velocity, Air Temperature, And Humidity Fluctuations Over A Crop Surface, S. B. Verma

School of Natural Resources: Faculty Publications

No abstract provided.

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Evidence For Quaternary Piracy Of Pumpkin Creek, South-Central Morrill County, Nebraska, Robert F. Diffendal Jr. Jan 1984

Evidence For Quaternary Piracy Of Pumpkin Creek, South-Central Morrill County, Nebraska, Robert F. Diffendal Jr.

School of Natural Resources: Faculty Publications

The occurrence of Quaternary anorthosite-rich sand and gravel deposits in south-central Morrill County, Nebraska, southeast of the mouth of Pumpkin Creek and south of the North Platte River suggests that the creek formerly flowed farther east than it does today. This eastern extension of the creek was abandoned when a headward-cutting tributary of the North Platte River eroded through the divide between Pumpkin Creek and the North Platte just east of Jail and Courthouse rocks, and captured Pumpkin Creek.

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Climate Model For Winter Wheat Yield Simulation, Kenneth G. Hubbard, R.J. Hanks Feb 1983

Climate Model For Winter Wheat Yield Simulation, Kenneth G. Hubbard, R.J. Hanks

School of Natural Resources: Faculty Publications

Winter wheat yields were simlulated by a model requiring climatic data as input for estimating crop evapotranspiration and phenological development. An assumed relationship between the winter wheat yields and the amount and timing of crop water use was optimized to simulate yields for two case studies: a single season, irrigated wheat study, and a multi-year, dryland wheat study. The model explained more than 90% of the variance of wheat yields in the irrigated study where total irrigation amounts varied between 0 and 55 cm. About 40% of the variance was explained for annual yields from a 21-year, dryland winter wheat …

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Spatial And Temporal Variations In Long-Term Normal Percent Possible Solar Radiation Levels In The United States, Robert C. Balling, Randall S. Cerveny Jan 1983

Spatial And Temporal Variations In Long-Term Normal Percent Possible Solar Radiation Levels In The United States, Robert C. Balling, Randall S. Cerveny

School of Natural Resources: Faculty Publications

The purpose of this study was to analyze the time and space variations in long-term monthly-averaged daily percent possible solar radiation levels in the United States. Both principal components analysis and harmonic analysis were used to identify the influences of various synoptic-scale climatological phenomena on solar radiation receipt. Generally, an annual cycle was found with maximum percent possible radiation levels occurring in July. In many regions the temporal variance structure deviated from this general annual cycle. The results, which are useful in both theoretical and practical studies, lead to a better understanding of the climatology of solar radiation in the …

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Bird Dispersal Recordings: An Overview, Robert H. Schmidt, Ron J. Johnson Jan 1983

Bird Dispersal Recordings: An Overview, Robert H. Schmidt, Ron J. Johnson

School of Natural Resources: Faculty Publications

Copyright® 1983 by ASTM International. Used by permission.

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Geometries And General Features Of Some Cenozoic Valleys And Valley Fills, Western Nebraska, Robert F. Diffendal Jr. Apr 1982

Geometries And General Features Of Some Cenozoic Valleys And Valley Fills, Western Nebraska, Robert F. Diffendal Jr.

School of Natural Resources: Faculty Publications

Portions of Tertiary and Quaternary valleys and valley fills have been exhumed by recent stream erosion at many sites in western Nebraska. Paleovalleys vary from narrow, steep-sided, high gradient tributary gullies less than 0.1 km wide to broad, flat-floored valleys produced by lateral erosion. Segments of valley floors may be nearly smooth in the case of a Quaternary example, or may be very irregular with potholes and other deep scour features. Paleovalley sides, when exposed, are often steeply sloping, and approaching or possibly going beyond the vertical where the valleys have been eroded into the Brule Formation. Paleovalleys range in …

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A Digital Archive Of Northern Hemisphere Snow Cover, November 1966 Through December 1980, Kenneth F. Dewey, Richard Heim Jr. Jan 1982

A Digital Archive Of Northern Hemisphere Snow Cover, November 1966 Through December 1980, Kenneth F. Dewey, Richard Heim Jr.

School of Natural Resources: Faculty Publications

The purpose of this article is to acquaint the research community with a new data base—a digitized archive of Northern Hemisphere snow cover. Historically, those researchers who needed snow cover data for climatic and atmospheric boundary layer studies have had to rely on the irregularly spaced (and in some regions, sparse) grid of point observations. Northern Hemisphere Weekly Snow and Ice Cover Charts, which are created from analyzed satellite imagery at the National Earth Satellite Service (NESS), have been available on an operational basis since late 1966. Each of these weekly charts for the period November 1966 through December 1980 …

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Influence Of Windbreak-Shelter On Soybean Growth Canopy Structure, And Light Relations, S.N. Ogbuehi, James R. Brandle Jan 1982

Influence Of Windbreak-Shelter On Soybean Growth Canopy Structure, And Light Relations, S.N. Ogbuehi, James R. Brandle

School of Natural Resources: Faculty Publications

No abstract provided.

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Agricultural Meteorology In China, Norman J. Rosenberg Jan 1982

Agricultural Meteorology In China, Norman J. Rosenberg

School of Natural Resources: Faculty Publications

During nearly five weeks in China (May-June 1981), the author visited scientific institutions and experiment stations engaged in agricultural meteorology and climatology research and teaching. The facilities, studies, and research programs at each institution are described and the scientific work in these fields is evaluated. Agricultural meteorology and climatology are faced with some unique problems and opportunities in China and progress in these fields may be of critical importance to that nation in coming years. The author includes culinary notes and comments on protocol in China.

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Teaching Vertebrate Pest Control: A Challenge To Wildlife Professionals, Robert M. Timm Jan 1982

Teaching Vertebrate Pest Control: A Challenge To Wildlife Professionals, Robert M. Timm

School of Natural Resources: Faculty Publications

Vertebrate pest control deals with wild animals that create health hazards, damage resources, or become a general nuisance. Some people prefer the terms "wildlife damage control" or "animal damage control" because they focus on controlling damage rather than controlling animals. This is an important principle. Vertebrate animals that cause damage often have many positive values. In dealing with these situations our objective should always be to reduce or prevent damage; this does not necessarily require the killing of animals. I use the term "vertebrate pest control" because I believe it is less ambiguous than "damage control." When I call an …

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Geology Of Lake Mcconaughy Area, Keith County, Nebraska, Roger K. Pabian, Robert F. Diffendal Jr., Frankie Gould Sep 1981

Geology Of Lake Mcconaughy Area, Keith County, Nebraska, Roger K. Pabian, Robert F. Diffendal Jr., Frankie Gould

School of Natural Resources: Faculty Publications

Rocks cropping out along the North Platte River valley at Lake McConaughy provide a glimpse into Nebraska's geologic past. Here are excellent exposures of the Ogallala Group, which consists of continental sedimentary rocks deposited during the Miocene epoch of the Tertiary period of geologic time. This group of rocks extends throughout much of Nebraska (see geologic bedrock map on outside back cover) but is overlain in most places by younger stream and wind deposits of Pliocene(?) and Pleistocene age. Easily accessible, the Ogallala outcrops contain locally abundant fossils of seeds, casts of pedotubules, and occasional fossils of vertebrate animals such …

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A Test Of Macroevolutionary Problems With Neontological Data, Cliff A. Lemen, Patricia W. Freeman Sep 1981

A Test Of Macroevolutionary Problems With Neontological Data, Cliff A. Lemen, Patricia W. Freeman

School of Natural Resources: Faculty Publications

Ricklefs (1980) suggested the use of neontological data to distinguish between puncuated equilibrium and gradualism as modes of evolution. This paper investigates his model and finds it contains oversimplifications that make any test difficult. We modify his model slightly and use it as a limited test of punctuated equilibrium by large morphological shifts at speciation. This test is applied to a data set of 110 species from two families of bats, the Emballonuridae and the Molossidae. We find no evidence of consistently large morphological shifts at the formation of subspecies, species or genera.

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Review Of Bartlett, Great Surveys Of The American West, And Schubert, Vanguard Of Expansion: Army Engineers In The Trans-Mississippi West, 1819-1879, Robert F. Diffendal Jr. Jul 1981

Review Of Bartlett, Great Surveys Of The American West, And Schubert, Vanguard Of Expansion: Army Engineers In The Trans-Mississippi West, 1819-1879, Robert F. Diffendal Jr.

School of Natural Resources: Faculty Publications

These two books outline the fascinating history of the exploration of the western United States by United States Army topographers and by civilian natural scientists from 1819 to 1879. These two groups, working either together under Army supervision or separately in military and civilian independent surveys, prepared topographic and geologic maps and natural history studies of most of the territory west of the Mississippi River. These maps and studies provided valuable information to settlers and to commercial and government groups involved in opening the west to development, and dispelled many myths concerning previously unexplored regions. They also helped lead to …

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A Comparison Of Reproductive Strategies Among Marine Snakes, Cliff A. Lemen, Harold K. Voris Apr 1981

A Comparison Of Reproductive Strategies Among Marine Snakes, Cliff A. Lemen, Harold K. Voris

School of Natural Resources: Faculty Publications

(1) Gravid females representing fourteen species of marine snakes were collected from four localities along the coast of Malaysia in 1975. The average clutch size ranged from 2.9 to 17.8 but most species had between three and seven young. The number of young produced and the size of gravid Lapemis hardwickii differed significantly at two sites in the Straits of Malacca. Eight species showed a significantly positive relationship between the number of oviducal eggs and female weight. The rate of infertility among ten species ranged from 4.5 to 20%.

(2) Sex ratios in the collections varied significantly through time and …

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