Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 71941 - 71970 of 78761

Full-Text Articles in Entire DC Network

Dissection Of An Antibody-Catalyzed Reaction, Jon D. Stewart, Joseph F. Krebs, Gary Siuzdak, Anthony J. Berdis, David B. Smithrud, Stephen J. Benkovic Aug 1994

Dissection Of An Antibody-Catalyzed Reaction, Jon D. Stewart, Joseph F. Krebs, Gary Siuzdak, Anthony J. Berdis, David B. Smithrud, Stephen J. Benkovic

Chemistry Faculty Publications

Antibody 43C9 accelerates the hydrolysis of a p-nitroanilide by a factor of 2.5 x 10(5) over the background rate in addition to catalyzing the hydrolysis of a series of aromatic esters. Since this represents one of the largest rate accelerations achieved with an antibody, we have undertaken a series of studies aimed at uncovering the catalytic mechanism of 43C9. The immunogen, a phosphonamidate, was designed to mimic the geometric and electronic characteristics of the tetrahedral intermediate that forms upon nucleophilic attack by hydroxide on the amide substrate. Further studies, however, revealed that the catalytic mechanism is more complex and involves …

Go to article

Applied Mathematics Should Be Taught Mixed, Gary I. Brown Aug 1994

Applied Mathematics Should Be Taught Mixed, Gary I. Brown

Humanistic Mathematics Network Journal

No abstract provided.

Go to article

Female Voices In Mathematics: A New Course, Shobha Gulati Aug 1994

Female Voices In Mathematics: A New Course, Shobha Gulati

Humanistic Mathematics Network Journal

No abstract provided.

Go to article

Temporal Alternation Between Light- And Nutrient-Limitation Of Phytoplankton Production In A Coastal Plain Estuary., Jonathan Pennock, Jonathan H. Sharp Aug 1994

Temporal Alternation Between Light- And Nutrient-Limitation Of Phytoplankton Production In A Coastal Plain Estuary., Jonathan Pennock, Jonathan H. Sharp

School of Marine Science and Ocean Engineering

ABSTRACT: The potential for Light- and nutrient-limitation of phytoplankton production was examined in the Delaware Estuary, USA, by combining a hierarchy of expenmental approaches including smallscale bioassay experiments, ecosystem-level analysis of nutrient concentration and stoichiometric ratios, and light-limitation modeling. Light was found to be the predominate regulator of phytoplankton growth throughout the estuary during the winter period as a result of high turbidity and a wellmixed water column. However, during late spring, phosphorus (P) was found to limit growth. This observation was confirmed at each of the experimental levels, and was related to several factors, including elevated input ratios (230:l) …

Go to article

The Probe, Issue 146 - August 1994 Aug 1994

The Probe, Issue 146 - August 1994

The Probe: Newsletter of the National Animal Damage Control Association

CONTENTS:
Redefining Wildlife Management As Faunal Resource Management
Wildlife Biologist Position Available at JFK International Airport
CALENDAR OF UPCOMING EVENTS
Bears Attack Hunter in Oregon and German Camper in Canada
U.S. Fish & Wildlife Service to Take Fresh Look at Refuge Uses

Go to article

Surveys Of The Distribution Of Seabirds Found In The Vicinity Of Proposed Geothermal Project Subzones In The District Of Puna, Hawaii, Michelle Reynolds, George Ritchotte, Anthony Viggiano, Jill Dwyer, Bonnie Nielson, James D. Jacobi Aug 1994

Surveys Of The Distribution Of Seabirds Found In The Vicinity Of Proposed Geothermal Project Subzones In The District Of Puna, Hawaii, Michelle Reynolds, George Ritchotte, Anthony Viggiano, Jill Dwyer, Bonnie Nielson, James D. Jacobi

Other Publications in Wildlife Management

In 1993, the U.S. Fish and Wildlife Service (USFWS) entered into an interagency agreement with the Department of Energy (DOE) to conduct specific biological surveys to identify potential impacts of the proposed geothermal development on the natural resources of the East Rift Zone (Figure 1). This report presents information from published literature information and new field data on seabird populations on the island of Hawaii. These data are analyzed with regard to potential impacts of geothermal development on seabird populations in this area. Fifteen species of seabirds, waterbirds, and shorebirds are documented or suspected of being found using habitats within …

Go to article

The Algorithmic Complexity Of Neural Spike Trains Increases During Focal Seizures, P. E. Rapp, I. D. Zimmerman, E. P. Vining, N. Cohn, Alfonso M. Albano, M. A. Jimenez Montano Aug 1994

The Algorithmic Complexity Of Neural Spike Trains Increases During Focal Seizures, P. E. Rapp, I. D. Zimmerman, E. P. Vining, N. Cohn, Alfonso M. Albano, M. A. Jimenez Montano

Physics Faculty Research and Scholarship

The interspike interval spike trains of spontaneously active cortical neurons can display nonrandom internal structure. The degree of nonrandom structure can be quantified and was found to decrease during focal epileptic seizures. Greater statistical discrimination between the two physiological conditions (normal vs seizure) was obtained with,measurements of context-free grammar complexity than by measures of the distribution of the interspike intervals such as the mean interval, its standard deviation, skewness, or kurtosis. An examination of fixed epoch data sets showed that two factors contribute to the complexity: the firing rate and the internal structure of the spike train. However, calculations with …

Go to article

Water Current, Volume 26, No. 4, August 1994 Aug 1994

Water Current, Volume 26, No. 4, August 1994

Water Current Newsletter

CRP Reduces Flood Damage
From the Director
Glossary of Water-Related Terms
Pesticide Fate Vital Factor
California Citrus Production Tied to Groundwater
Research Brief: Pesticide Levels in Storm Runoff From Agricultural Stream Sites with Different Riparian Buffer Strips
Festival of Color
USGS Team Visits Two Projects
Symposium to Take on Water Challenge

Go to article

Hydrogeology And Hydrogeochemistry Of Government Marsh, North St. Joseph County, Michigan, Michael C. Kasenow Aug 1994

Hydrogeology And Hydrogeochemistry Of Government Marsh, North St. Joseph County, Michigan, Michael C. Kasenow

Dissertations

A hydrogeologic and hydrogeochemical investigation was conducted at Government Marsh located in St. Joseph County, Michigan from May, 1988, to November, 1993. Information on glacial geology, topography, drainage patterns, hydraulic conductivity, vegetation, water chemistry, and static water table elevations has been collected and analyzed. Data were collected in order to determine directions of ground water flow and areas of recharge and discharge. Bail-down tests, grain-size analysis, and permeameters were used to determine hydraulic conductivity adjacent to and within the wetland. Water table elevations and chemistry were analyzed from wells adjacent to the wetland perimeter and within the boundaries of the …

Go to article

A Representation Of Approximate Self- Overlapping Word And Its Application, Wojciech Szpankowski Aug 1994

A Representation Of Approximate Self- Overlapping Word And Its Application, Wojciech Szpankowski

Department of Computer Science Technical Reports

No abstract provided.

Go to article

Reply To D. E. Watt, A. S. Alkharam, M. B. Child And M. S. Salikin, “Dose As A Damage Specifier In Radiobiology For Radiation Protection." A Comment On "Dose" (Radiat. Res. 137, 410-413, 1994), Robert Katz Aug 1994

Reply To D. E. Watt, A. S. Alkharam, M. B. Child And M. S. Salikin, “Dose As A Damage Specifier In Radiobiology For Radiation Protection." A Comment On "Dose" (Radiat. Res. 137, 410-413, 1994), Robert Katz

Robert Katz Publications

The authors are generous in observing that "the high degree of success achieved by (Katz's δ-ray theory of track structure) in fits to survival curves for heavy ions, and in analysis and prediction of other biological effects is almost legend." We remind them that the model is physical, and has little to do with biology in an explicit way, except that an oversimplified "bean bag" model of a eukaryotic cell is used, in which the bag represents the cell nucleus and the beans represent internal targets. No explicit biologically mechanistic structure or response is inferred. No reference is made to …

Go to article

Use Of Infrared Spectrometry To Determine The Effect Of Temperature On The Description Rates Of Trichloroethylene From Plastic Clay 98b, Abdellatif Fares Aug 1994

Use Of Infrared Spectrometry To Determine The Effect Of Temperature On The Description Rates Of Trichloroethylene From Plastic Clay 98b, Abdellatif Fares

Theses and Dissertations

This thesis investigated the influence of temperature on the desorption rated of trichloroethylene (TCE) from plastic clay. It was expected that an increase in temperature will cause an increase in both the desorption rates of TCE and in the desorbed quantity. Previous studies on other chemicals indicated a faster decrease in the remaining sorbed concentration with an increase in temperature. This research made use of the infrared optical absorption technique. IR spectroscopy was used to measure the concentration of the vapor TCE that desorbed from the soil. The soil was exposed to liquid TCE for 2 days then placed inside …

Go to article

Modeling Of Ground Water Aquifer Remediation By Pulsed Pumping When Contaminant Transport Is Affected By Physical, Non-Equilibrium Sorption And Desorption, Jeffrey L. Caspers Aug 1994

Modeling Of Ground Water Aquifer Remediation By Pulsed Pumping When Contaminant Transport Is Affected By Physical, Non-Equilibrium Sorption And Desorption, Jeffrey L. Caspers

Theses and Dissertations

This research postulates and demonstrates a modification incorporating rate-limited sorption effects in the USGS SUTRA code for cleanup of a hypothetical sandy aquifer by pump-and-treat remediation methods. Contaminant transport is assumed to be affected by advection, dispersion, and rate-limited sorption/desorption. Sorption is assumed to be either equilibrium or rate-limited, with the rate-limitation described by either a first-order law, or by Fickian diffusion of contaminant through a spherical immobile pore region. Solutions are arrived at by split operator methods for the transport and one-dimensional Galerkin solutions for the solute concentration equations. The resulting model is tested against an analytical Laplace transform …

Go to article

36th Rocky Mountain Conference On Analytical Chemistry Jul 1994

36th Rocky Mountain Conference On Analytical Chemistry

Rocky Mountain Conference on Magnetic Resonance

Program, abstracts, and information about the 36th annual meeting of the Rocky Mountain Conference on Analytical Chemistry, co-sponsored by the Colorado Section of the American Chemical Society and the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Denver, Colorado, July 31 - August 5, 1994.

Go to article

Prairie Dogs, Scott E. Hygnstrom, Dallas R. Virchow Jul 1994

Prairie Dogs, Scott E. Hygnstrom, Dallas R. Virchow

Prevention and Control of Wildlife Damage Handbook

Prairie dogs are stocky burrowing rodents that live in colonies called “towns.” French explorers called them “little dogs” because of the barking noise they make. Their legs are short and muscular, adapted for digging. The tail and other extremities are short. Their hair is rather coarse with little underfur, and is sandy brown to cinnamon in color with grizzled black and buff-colored tips. The belly is light cream to white.
Five species of prairie dogs are found in North America: the black-tailed (Cynomys ludovicianus), Mexican (C. mexicanus), white-tailed (C. leucurus), Gunnison’s (C. gunnisoni), and Utah prairie dog (C. parvidens). The …

Go to article

Belding's, California, And Rock Ground Squirrels, Rex E. Marsh Jul 1994

Belding's, California, And Rock Ground Squirrels, Rex E. Marsh

Prevention and Control of Wildlife Damage Handbook

Twenty-three species and 119 subspecies of ground squirrels exist in the United States (Hall 1981). At least 10 species can be of considerable economic importance to agriculture or have a significant impact on public health. This chapter covers the three species found in the far west and southwest. All three species range over extensive regions. While the California (Spermophilus beecheyi) and the Belding’s (S. beldingi) ground squirrels are considered pests over large agricultural areas, they are not pests throughout their entire range. The rock ground squirrel (S. variegatus) is not a major pest but is important because of its involvement …

Go to article

Mountain Beavers, Dan L. Campbell Jul 1994

Mountain Beavers, Dan L. Campbell

Prevention and Control of Wildlife Damage Handbook

The mountain beaver (Aplodontia rufa) is a medium-sized rodent in the family Aplodontiadae. There are no other species in the family. Average adults weigh 2.3 pounds (1,050 g) and range from 1.8 to 3.5 pounds (800 to 1,600 g). Average overall length is 13.5 inches (34 cm), including a rudimentary tail about 1 inch (2.5 cm) long. The body is stout and compact. The head is relatively large and wide and blends into a large neck with no depression where it joins the shoulders. The eyes and ears are relatively small and the cheeks have long silver “whiskers.” The hind …

Go to article

Muskrats, James E. Miller Jul 1994

Muskrats, James E. Miller

Prevention and Control of Wildlife Damage Handbook

The muskrat (Ondatra zibethicus) is the largest microtine rodent in the United States. It spends its life in aquatic habitats and is well adapted for swimming. Its large hind feet are partially webbed, stiff hairs align the toes, and its laterally flattened tail is almost as long as its body. The muskrat has a stocky appearance, with small eyes and very short, rounded ears. Its front feet, which are much smaller than its hind feet, are adapted primarily for digging and feeding. The overall length of adult muskrats is usually from 18 to 24 inches (46 to 61 cm). Large …

Go to article

Cotton Rats, Donald W. Hawthorne Jul 1994

Cotton Rats, Donald W. Hawthorne

Prevention and Control of Wildlife Damage Handbook

The hispid cotton rat (Sigmodon hispidus) is a moderately large, robust rodent with a scaly, sparsely haired tail that is shorter than the combined head and body. Cotton rats have relatively large eyes. The ears are large but almost hidden in the fur. They have four toes and a small thumb on their front feet and five toes on each hind foot. The cotton rat has very small internal cheek pouches. Distinguishing characteristics are the rough grizzled appearance of the blackish or grayish fur and the rather stiff black guard hairs.
The hispid cotton rat occurs over most of the …

Go to article

Thirteen-Lined Ground Squirrels, Edward C. Cleary, Scott R. Craven Jul 1994

Thirteen-Lined Ground Squirrels, Edward C. Cleary, Scott R. Craven

Prevention and Control of Wildlife Damage Handbook

The thirteen-lined ground squirrel is a slender rat-sized rodent weighing about 8 ounces (227 g) with a length of about 10 inches (25 cm) including a tail of 3 inches (8 cm). As its name implies, 13 stripes run the length of this ground squirrel’s body. Five of the light-colored lines break up into a series of spots as they progress down the back and over the rump. Five light and four dark stripes extend along the top of the head and end between the animal’s eyes. The cheeks, sides of the body, and legs are yellowish, tan, or tan …

Go to article

Beavers, James E. Miller, Greg K. Yarrow Jul 1994

Beavers, James E. Miller, Greg K. Yarrow

Prevention and Control of Wildlife Damage Handbook

The beaver (Castor canadensis) is the largest North American rodent. Most adults weigh from 35 to 50 pounds (15.8 to 22.5 kg), with some occasionally reaching 70 to 85 pounds (31.5 to 38.3 kg). Individuals have been known to reach over 100 pounds (45 kg). The beaver is a stocky rodent adapted for aquatic environments. Many of the beaver’s features enable it to remain submerged for long periods of time. It has a valvular nose and ears, and lips that close behind the four large incisor teeth. Each of the four feet have five digits, with the hind feet webbed …

Go to article

Chipmunks, David E. Williams, Robert M. Corrigan Jul 1994

Chipmunks, David E. Williams, Robert M. Corrigan

Prevention and Control of Wildlife Damage Handbook

Fifteen species of native chipmunks of the genus Eutamias and one of the genus Tamias are found in North America. The eastern chipmunk (Tamias striatus) and the least chipmunk (Eutamias minimas), discussed here, are the two most widely distributed and notable species. Behavior and damage is similar among all species of native chipmunks. Therefore, damage control recommendations are similar for all species.
The eastern chipmunk is a small, brownish, ground-dwelling squirrel. It is typically 5 to 6 inches (13 to 15 cm) long and weighs about 3 ounces (90 g). It has two tan and five blackish longitudinal stripes on …

Go to article

Pocket Gophers, Ronald M. Case, Bruce A. Jasch Jul 1994

Pocket Gophers, Ronald M. Case, Bruce A. Jasch

Prevention and Control of Wildlife Damage Handbook

Thirty-four species of pocket gophers, represented by five genera, occupy the western hemisphere. In the United States there are 13 species and three genera. The major features differentiating these genera are the size of their forefeet, claws, and front surfaces of their chisel-like incisors.
Thomomys have smooth-faced incisors and small forefeet with small claws. Northern pocket gophers (Thomomys talpoides) are typically from 6 1/2 to 10 inches (17 to 25 cm) long. Their fur is variable in color but is often yellowish brown with pale underparts. Botta’s (or valley) pocket gophers (Thomomys bottae) are extremely variable in size and color. …

Go to article

Nutria, Dwight J. Leblanc Jul 1994

Nutria, Dwight J. Leblanc

Prevention and Control of Wildlife Damage Handbook

The nutria (Myocastor coypus) is a large, dark-colored, semiaquatic rodent that is native to southern South America. At first glance, a casual observer may misidentify a nutria as either a beaver (Castor canadensis) or a muskrat (Ondatra zibethicus), especially when it is swimming. This superficial resemblance ends when a more detailed study of the animal is made. Other names used for the nutria include coypu, nutria-rat, South American beaver, Argentine beaver, and swamp beaver.
The original range of nutria was south of the equator in temperate South America. This species has been introduced into other areas, primarily for fur farming, …

Go to article

Porcupines, Sanford D. Schemnitz Jul 1994

Porcupines, Sanford D. Schemnitz

Prevention and Control of Wildlife Damage Handbook

Porcupines (Erethizon dorsatum), sometimes called “porkies” or “quill pigs,” are heavy-bodied, shortlegged, slow, and awkward rodents, with a waddling gait. Adults are typically 25 to 30 inches (64 to 76 cm) long and weigh 10 to 30 pounds (4.5 to 13.5 kg). They rely on their sharp, barbed quills (up to 30,000 per individual) for defense.
The porcupine is a common resident of the coniferous forests of western and northern North America. It wanders widely and is found from cottonwood stands along prairie river bottoms and deserts to alpine tundra.

Exclusion: Fences (small areas). Tree trunk guards.
Cultural Methods: Encourage …

Go to article

Kangaroo Rats, Volney W. Howard Jr. Jul 1994

Kangaroo Rats, Volney W. Howard Jr.

Prevention and Control of Wildlife Damage Handbook

There are 23 species of kangaroo rats (genus Dipodomys) in North America. Fourteen species occur in the lower 48 states. The Ord’s kangaroo rat (D. ordi) occurs in 17 US states, Canada, and Mexico. Other widespread species include the Merriam kangaroo rat (D. merriami), bannertail kangaroo rat (D. spectabilis), desert kangaroo rat (D. deserti), and Great Basin kangaroo rat (D. microps). Kangaroo rats are distinctive rodents with small forelegs; long, powerful hind legs; long, tufted tails; and a pair of external, fur-lined cheek pouches similar to those of pocket gophers. They vary from pale cinnamon buff to a dark gray …

Go to article

Voles, John M. O’Brien Jul 1994

Voles, John M. O’Brien

Prevention and Control of Wildlife Damage Handbook

Voles, also called meadow mice or field mice, belong to the genus Microtus. Voles are compact rodents with stocky bodies, short legs, and short tails. Their eyes are small and their ears partially hidden. Their underfur is generally dense and covered with thicker, longer guard hairs. They usually are brown or gray, though many color variations exist. There are 23 vole species in the United States. This chapter provides range maps, descriptions, and habitat characteristics for seven species that are widespread or cause significant economic damage. Tentative identification of a particular animal may be made using this information. For positive …

Go to article

Franklin, Richardson, Columbian, Washington, And Townsend Ground Squirrels, Leonard R. Askham Jul 1994

Franklin, Richardson, Columbian, Washington, And Townsend Ground Squirrels, Leonard R. Askham

Prevention and Control of Wildlife Damage Handbook

The Franklin ground squirrel (Spermophilus franklinii) is a rather drab grayish brown. Black speckling gives a spotted or barred effect. Head and body average 10 inches (25.4 cm) with a 5- to 6-inch (12.7- to 15.2-cm) tail. Adults weigh from 10 to 25 ounces (280 to 700 g).

The Richardson ground squirrel (S. richardson) is smaller and lighter colored than the Franklin. Some are dappled on the back. The squirrel’s body measures about 8 inches (20.3 cm) with a tail of from 2 to 4 inches (5 to 10 cm). Adults weigh from 11 to 18 ounces (308 to 504 …

Go to article

Rodent-Proof Construction And Exclusion Methods, Rex O. Baker, Gerald R. Bodman, Robert M. Timm Jul 1994

Rodent-Proof Construction And Exclusion Methods, Rex O. Baker, Gerald R. Bodman, Robert M. Timm

Prevention and Control of Wildlife Damage Handbook

The most effective means of limiting rodent damage is rodent-proof construction. New buildings should be designed and built to prevent rodent entry. Rodent-proofing is a good investment. Designing and constructing a rodent-proof building is less expensive than adding rodent-proofing later. Nevertheless, poor maintenance or management practices, such as leaving entry doors and unscreened windows open, will make the bestconstructed building susceptible to rodent entry. Techniques discussed here apply both to new construction and to the modification of existing structures.

Go to article

Norway Rats, Robert M. Timm Jul 1994

Norway Rats, Robert M. Timm

Prevention and Control of Wildlife Damage Handbook

The Norway rat (Rattus norvegicus) is a stocky burrowing rodent, unintentionally introduced into North America by settlers who arrived on ships from Europe. Also called the brown rat, house rat, barn rat, sewer rat, gray rat, or wharf rat, it is a slightly larger animal than the roof rat (Fig. 2). Adult Norway rats weigh an average of 1 pound (454 g). Their fur is coarse and usually brownish or reddish gray above and whitish gray on the belly. Blackish individuals occur in some locations.

Among the diseases rats may transmit to humans or livestock are murine typhus, …

Go to article

First Prev Next Last