7 resultados para Local rings and semilocal rings
em DigitalCommons@University of Nebraska - Lincoln
Resumo:
In 2001, the U.S. Geological Survey, as part of the National Water Quality Assessment (NAWQA) Program, initiated a topical study of Transport of Anthropogenic and Natural Contaminants (TANC) to PSW (public-supply wells). Local-scale and regional-scale TANC study areas were delineated within selected NAWQA study units for intensive study of processes effecting transport of contaminants to PSWs. This report describes results from a local-scale TANC study area at York, Nebraska, within the High Plains aquifer, including the hydrogeology and geochemistry of a 108-square-kilometer study area that contains the zone of contribution to a PSW selected for study (study PSW), and describes factors controlling the transport of selected anthropogenic and natural contaminants to PSWs.
Resumo:
In social species, breeding system and gregarious behavior are key factors influencing the evolution of large-scale population genetic structure. The killer whale is a highly social apex predator showing genetic differentiation in sympatry between populations of foraging specialists (ecotypes), and low levels of genetic diversity overall. Our comparative assessments of kinship, parentage and dispersal reveal high levels of kinship within local populations and ongoing male-mediated gene flow among them, including among ecotypes that are maximally divergent within the mtDNA phylogeny. Dispersal from natal populations was rare, implying that gene flow occurs without dispersal, as a result of reproduction during temporary interactions. Discordance between nuclear and mitochondrial phylogenies was consistent with earlier studies suggesting a stochastic basis for the magnitude of mtDNA differentiation between matrilines. Taken together our results show how the killer whale breeding system, coupled with social, dispersal and foraging behaviour, contributes to the evolution of population genetic structure.
Resumo:
Context. Invasive species are a growing global problem. Biological invasions can result in numerous harmful impacts on local ecologies, and non-native herpetofauna are frequently ignored. Nile monitor lizards (Varanus niloticus) and Burmese pythons (Python molurus bivittatus, recently reassessed as Python bivittatus bivittatus), have become established in southern Florida. Both are large, semi-aquatic predators that pose serious threats to a variety of threatened and endangered species, as well as to the unique ecology of the area. Aims. Acetaminophen (CAS#103-90-2), a lethal oral toxicant for the invasive brown treesnake (Boiga irregularis) on Guam, was investigated as a possible toxicant in juvenile Burmese pythons and Nile monitors. Methods. Dead neonatal mouse (DNM) baits containing 0, 10, 20, or 40 mg acetaminophen were force-fed to Nile monitors, whereas DNM containing doses of 0, 20, 40, or 80 mg were freely consumed by Burmese pythons. Subjects were frequently observed post-treatment for general condition and position, with special attention paid to activity (if any), behaviour, respiration, bleeding, emesis, ataxia, and mortality. Key results. In Nile monitors, acetaminophen doses of 10, 20, or 40 mg resulted in 0, 50 and 100% mortality, respectively. In Burmese pythons, doses of 20, 40, or 80 mg resulted in 14.3, 85.7 and 100% mortality, respectively. No mortality was observed in control individuals of either species. A negative correlation between dosage (mg kg–1) and time-to-death was observed in both species. Dosages ranging from 522 to 2438 mg kg–1 and 263 to 703 mg kg–1 were uniformly lethal to monitors and pythons, respectively. Neither species exhibited signs of pain or discomfort following acetaminophen treatment. Conclusions. Acetaminophen is an effective toxicant in juvenile Nile monitors and Burmese pythons. Further investigation into acetaminophen toxicity in adults of these species is merited. Implications. Although further investigation into adult lethal dosages and strategies to optimize bait deployment while minimizing secondary hazards is required, acetaminophen may have a role to play in the control of these invasive species in Florida.
Resumo:
The pathogenesis of South American and North American myxoma viruses was examined in two species of North American lagomorphs, Sylvilagus nuttallii (mountain cottontail) and Sylvilagus audubonii (desert cottontail) both of which have been shown to have the potential to transmit the South American type of myxoma virus. Following infection with the South American strain (Lausanne, Lu), S. nuttallii developed both a local lesion and secondary lesions on the skin. They did not develop the classical myxomatosis seen in European rabbits (Oryctolagus cuniculus). The infection at the inoculation site did not resolve during the 20-day time course of the trial and contained transmissible virus titres at all times. In contrast, S. audubonii infected with Lu had very few signs of disseminated infection and partially controlled virus replication at the inoculation site. The prototype Californian strain of myxoma virus (MSW) was able to replicate at the inoculation site of both species but did not induce clinical signs of a disseminated infection. In S. audubonii, there was a rapid response to MSW characterized by a massive T lymphocyte infiltration of the inoculation site by day 5. MSW did not reach transmissible titres at the inoculation site in either species. This might explain why the Californian myxoma virus has not expanded its host-range in North America.
Resumo:
The development of Crystal Bridges Museum of American Art in Bentonville, Arkansas, by Wal-Mart heiress Alice Walton has prompted diverse coverage from print and online media. This investigation looked at trends in news stories and commentary from 2005-10 to show how the location of a medium affected coverage. Through the author’s own observations and interviews with journalists and other interested parties, several trends emerged. Media outlets outside Arkansas portrayed the museum as trying to plunder the cultural heritage of local communities and relied partly on the museum’s association with Wal-Mart and stereotypes of Arkansas to frame coverage. Arkansas media, faced with limited cooperation from the museum’s public relations apparatus, typically played a cheerleader role, at times overemphasizing the importance of the collection in the art world and showcasing few critical voices in stories about acquisitions and other areas of the museum’s development.
Resumo:
ABSTRACT Nebraska has a veritable wealth of groundwater. The High Plains Aquifer underlies most of the state, and within its sand and gravel deposits, many interconnected aquifers provide fresh water for a variety of uses. One of the most spectacular examples of this resource is the artesian well. Beaver Crossing, Nebraska was once home to one of the most prolific artesian systems in the state before its demise. Founded in the 1880’s, Beaver Crossing soon became known for its many artesian wells, that provided leisure activities and supported profitable business ventures such as small farming, ice production and aquiculture. Eventually these wells would dry up and the town of Beaver Crossing would never see the level of commerce and activity that it saw during its early years. I decided to research this subject because I lived in Beaver Crossing for twelve years. While I lived there I heard stories about the artesian wells, the nationally recognized lily pond, and the large public pool fed by underground water that was plentiful around town. I was interested in knowing what happened to the water, the wells, the pool and businesses. . . And, in the wake of their disappearance, what happened to the town. To research this topic I looked at accounts of the history of Seward County and Beaver Crossing. I also studied the basic geology underlying the Great Plains, as well as local geology and issues pertaining to groundwater levels, such as rainfall amounts, drought and irrigation. As irrigation became a factor in rural Nebraska and through several documented droughts, groundwater levels all over the state declined. At the same time the artesian system in Beaver Crossing all but disappeared.
Resumo:
“Music at the Fair!” gives the daily musical programs for The Trans-Mississippi and International Exposition, held in Omaha, Nebraska, June 1 through October 31, 1898. The Trans-Mississippi and International Exposition brought an unprecedented array of local, national, and international musical acts to Omaha, NE in 1898. This served to designate Omaha, "the gateway to the west" as a musical hub, as well as to incite musical excitement in the region. Some of the more popular acts featured were the Theodore Thomas Orchestra, the U.S. Marine Band, and the Apollo Club of Chicago. Many more groups and their musical programs can be found within the pages of this site. The “Music at the Fair!” website was created by Grace Carey, and last revised on May 19, 2006.It is the result of a two- year research grant funded by an Undergraduate Creative Activities and Research Experiences (UCARE) grant through the University of Nebraska at Lincoln. It is an extension of an ongoing project on music at the TME by Music Professor Peter Lefferts. The primary sources of information for the site are the following newspapers from June – November 1898: The Omaha Daily Bee, the Omaha Evening Bee, and the Omaha World Herald, and the the official programs of the fair located in the archives at the Omaha Public Library. I would like to thank the helpful staff at the Nebraska State Historical Society and the downtown branch of the Omaha Public Library. Site Creator: Grace Carey Project Advisor: Peter Lefferts, Professor of Music History at the University of Nebraska, Lincoln The linked “Document” is a flat PDF version of the interactive website. To download the fully interactive html version, click on the “Related file” to download the zipped folder. When unzipped, click on the file named “index” to enter the website.