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2005

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Articles 421 - 440 of 440

Full-Text Articles in Physical Sciences and Mathematics

Phytochemical Studies On Stemona Plants: Isolation Of Stemofoline Alkaloids, Thanapat Sastraruji, Araya Jatisatienr, Stephen G. Pyne, Alison T. Ung, Wilford Lie, Morwenna C. Williams Jan 2005

Phytochemical Studies On Stemona Plants: Isolation Of Stemofoline Alkaloids, Thanapat Sastraruji, Araya Jatisatienr, Stephen G. Pyne, Alison T. Ung, Wilford Lie, Morwenna C. Williams

Faculty of Science - Papers (Archive)

Six new stemofoline alkaloids, (2‘R)-hydroxystemofoline (5), (3‘R)-stemofolenol (6), (3‘S)-stemofolenol (7), 1‘,2‘-didehydrostemofoline-N-oxide (8), the first C19 stemofoline alkaloid, methylstemofoline (9), and the first glycosidated Stemona alkaloid, stemofolinoside (10), and three known alkaloids, (2‘S)-hydroxystemofoline (2), (11Z)-1‘,2‘-didehydrostemofoline (3), and (11E)-1‘,2‘-didehydrostemofoline (4), have been isolated from a root extract of an unidentified Stemona species. The structure and relative configuration of these new alkaloids have been determined by spectral data interpretation and …

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Synthesis Of 2-Azaspiro[4.4]Nonan-1-Ones Via Phosphine-Catalysed [3+2]-Cycloadditions, Sarah Yong, Morwenna C. Williams, Stephen G. Pyne, Alison T. Ung, Brian W. Skelton, Allan H. White, P. Turner Jan 2005

Synthesis Of 2-Azaspiro[4.4]Nonan-1-Ones Via Phosphine-Catalysed [3+2]-Cycloadditions, Sarah Yong, Morwenna C. Williams, Stephen G. Pyne, Alison T. Ung, Brian W. Skelton, Allan H. White, P. Turner

Faculty of Science - Papers (Archive)

The phosphine-catalysed [3+2]-cycloaddition of the 2-methylene γ-lactams 4 and 5 and the acrylate 6 with the ylides derived from the ethyl ester, the amide or the chiral camphor sultam derivative of 2-butynoic acid (7a-c) give directly, or indirectly after reductive cyclization, spiro-heterocyclic products. The acid 32 underwent Curtius rearrangement and then acid hydrolysis to give two novel spiro-cyclic ketones, 41 and 42.

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The History Of Aridity In Australia: Chronological Developments, Ed Rhodes, John Chappell, Toshiyuki Fujioka, Kat Fitzsimmons, John Magee, Max Aubert, Dolan Hewitt Jan 2005

The History Of Aridity In Australia: Chronological Developments, Ed Rhodes, John Chappell, Toshiyuki Fujioka, Kat Fitzsimmons, John Magee, Max Aubert, Dolan Hewitt

Faculty of Science - Papers (Archive)

Desert dune-fields are quintessential features of arid landscapes. During arid phases in the recent geological past, such as the global last glacial maximum (LGM) at around 20,000 years ago, many parts of Australia experienced significant sand movement, with sand migrating down-wind and forming linear dunes. Sand entrainment and deposition is controlled by vegetative surface stabilisation, wind speed and direction, which in turn are controlled by regional climate and local factors including ground-water levels. Climate also affects sand supply, through its effects on erosion in the source areas and transport to the dune-building areas.

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Quasi-Static Analysis Of Defected Ground Structure, Nemai C. Karmakar, Sushim Mukul Roy, Isaac Balbin, Gerhard F. Swiegers Jan 2005

Quasi-Static Analysis Of Defected Ground Structure, Nemai C. Karmakar, Sushim Mukul Roy, Isaac Balbin, Gerhard F. Swiegers

Faculty of Science - Papers (Archive)

A quasi-static equivalent circuit model of a dumbbell shaped defected ground structure (DGS) is developed. The equivalent circuit model is derived from the equivalent inductance and capacitance developed due to the perturbed returned current path on the ground and the narrow gap, respectively. The theory is validated against the commercial full-wave solver CST Microwave Studio. Finally, the calculated results are compared with the measured results. Good agreement between the theory, the commercially available numerical analyses and the experimental results validates the developed theoretical model.

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Evidence For Altitude-Dependent Photolysis-Induced 18o Isotopic Fractionation In Stratospheric Ozone, Vanessa E. Haverd, Geoffrey C. Toon, David W. Griffith Jan 2005

Evidence For Altitude-Dependent Photolysis-Induced 18o Isotopic Fractionation In Stratospheric Ozone, Vanessa E. Haverd, Geoffrey C. Toon, David W. Griffith

Faculty of Science - Papers (Archive)

We present vertical profiles of 18O fractionations in ozone, measured by balloon-borne infrared remote sensing between 15 and 40 km. The magnitudes of the 16O16O18O (668O3) and 16O18O16O (686O3) fractionations are 13.5 +/- 2.7% and 7.7 +/- 2.2%, averaged over the 20-35 km altitude range, in good agreement with previous atmospheric measurements by mass spectrometry and both infrared and far infrared remote sensing spectroscopy. We use our fractionation profiles, together with known fractionation effects of the ozone formation reaction, to deduce …

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Tropical Cyclone Disturbance Of Coral Communities Of The Great Barrier Reef, 1969-2003, Marjetta L. Puotinen Jan 2005

Tropical Cyclone Disturbance Of Coral Communities Of The Great Barrier Reef, 1969-2003, Marjetta L. Puotinen

Faculty of Science - Papers (Archive)

The primary building block of coral reef ecosystems, whether an isolated mid-ocean atoll or a complex system of thousands of reefs, are the individual coral colonies that combine to form the reef structures which host coral communities. The state of a coral reef community (i.e. percentage coral coverage, dominant growth forms and size classes), or any other ecosystem, at any given time is the result of interactions between a range of disturbances and routine ecological processes that operate across a continuum of spatial and temporal scales (Gunderson et al 2002). The biological (living coral colonies) and structural (dead coral framework …

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Factors Affecting Metal Releases From Contaminated Marine Sediments, Dianne F. Jolley, Clare A. Atkinson, Stuart L. Simpson Jan 2005

Factors Affecting Metal Releases From Contaminated Marine Sediments, Dianne F. Jolley, Clare A. Atkinson, Stuart L. Simpson

Faculty of Science - Papers (Archive)

In aquatic environments, the depth of oxygen penetration into sediment depends on sediment texture, porosity, permeability and the extent of biological (e.g., bioturbation) and physical (e.g., wave action) processes. Below the oxygen penetration depth (generally 10 mm) anoxic conditions prevail and bacteria use other oxidants such as iron and manganese oxides and sulfate to breakdown organic matter. The bacteria-catalysed reduction of sulfate releases hydrogen sulfide according to Equation 1. The release of H2S into the pore waters SO42- + bacteria → H2S (Equation 1).

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Aboriginal Pastoralism, Social Embeddedness And Cultural Continuity In Central Australia, Nicholas J. Gill Jan 2005

Aboriginal Pastoralism, Social Embeddedness And Cultural Continuity In Central Australia, Nicholas J. Gill

Faculty of Science - Papers (Archive)

Aboriginal people are involved in pastoral enterprises throughout the inland and north of Australia. This has generated difficulties as landowners and policymakers struggled with conflicts between Aboriginal social structures and the demands of running commercial businesses. Problems often arose due to imposition of nonindigenous norms regarding land use. It has been suggested that pastoralism can generate social and cultural benefits for Aboriginal landowners, but these have not been investigated in any detail. Drawing on the concept of social embeddedness and fieldwork with Aboriginal pastoralists, this article identifies, describes, and ranks sociocultural benefits arising from Aboriginal pastoralism. Pastoralism fulfilled uniquely Aboriginal …

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The Genomic Island Sgii, Containing The Multiple Antibiotic Resistance Region Of Salmonella Enterica Serovar Typhimurium Dt104 Or Variants Of It, Is Widely Distributed In Other S-Enterica Serovars, Renee Levings, Diane Lightfoot, Sally R. Partridge, Ruth M. Hall, Steven P. Djordjevic Jan 2005

The Genomic Island Sgii, Containing The Multiple Antibiotic Resistance Region Of Salmonella Enterica Serovar Typhimurium Dt104 Or Variants Of It, Is Widely Distributed In Other S-Enterica Serovars, Renee Levings, Diane Lightfoot, Sally R. Partridge, Ruth M. Hall, Steven P. Djordjevic

Faculty of Science - Papers (Archive)

The global dissemination of the multiply-antibiotic-resistant Salmonella entericaserovar Typhimurium DT104 clone with the resistance genes located in a class 1 integron, here designated In104, within genomic island SGI1 is a significant public health issue. Here, we have shown that SGI1 and variants of it carrying different combinations of resistance genes are found in several Salmonella enterica serovars. These are serovars Cerro, Derby, Dusseldorf, Infantis, Kiambu, and Paratyphi B dT+ isolated from human infections and serovar Emek from sewage effluent. Two new variants, SGI1-I and SGI1-J, both of which include thedfrA1-orfC cassette array, were identified.

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Latitude And Altitude Variability Of Carbon Monoxide In The Atlantic Detected From Ship-Borne Fourier Transform Spectrometry, Model, And Satellite Data, Voltaire A. Velazco, Justus Notholt, Thorsten Warneke, Mark Lawrence, Holger Bremer, James Drummond, Astrid Schulz, Jurgen Krieg, O. Schrems Jan 2005

Latitude And Altitude Variability Of Carbon Monoxide In The Atlantic Detected From Ship-Borne Fourier Transform Spectrometry, Model, And Satellite Data, Voltaire A. Velazco, Justus Notholt, Thorsten Warneke, Mark Lawrence, Holger Bremer, James Drummond, Astrid Schulz, Jurgen Krieg, O. Schrems

Faculty of Science - Papers (Archive)

Carbon monoxide (CO) volume mixing ratio (VMR) profiles have been retrieved from ship-borne solar absorption spectra recorded in the Atlantic between 80°N and 70°S. CO profiles can be retrieved up to 30 km with a maximum altitude resolution of 4 km for a few layers. CO enhancements due to biomass burning have been detected. Recurring enhancements of CO were detected in the upper troposphere (10–15 km) in the equatorial regions and in the southern Atlantic (20°S–30°S). These enhancements could be traced back to African biomass burning sources as well as sources as far as South America. Similar results are observed …

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Planning For Natural Hazards — How Can We Mitigate The Impacts?, Edward A. Bryant, Lesley M. Head, J. Morrison Jan 2005

Planning For Natural Hazards — How Can We Mitigate The Impacts?, Edward A. Bryant, Lesley M. Head, J. Morrison

Faculty of Science - Papers (Archive)

Australia has the same frequency of natural hazards as any other continent; however, the types and impact of hazards are very different. Globally, the deadliest hazards are floods, earthquakes, tropical storms and tsunami. In Australia, the deadliest hazards are heat waves, floods, tropical cyclones and bushfires. Similarly, while the most expensive hazards ranked globally are also floods, earthquakes and tropical cyclones, in Australia, the costliest hazards are tropical storms, floods, wind and bushfires. Our isolated population distribution, together with rugged topography along the eastern and southern coastal fringe where the bulk of the population is concentrated, has lead to a …

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Surface Analyses And Immune Reactivities Of Major Cell Wall-Associated Proteins Of Group A Streptococcus, J. N. Cole, R. D. Ramirez, B. J. Currie, S. J. Cordwell, S. P. Djordjevic, Mark J. Walker Jan 2005

Surface Analyses And Immune Reactivities Of Major Cell Wall-Associated Proteins Of Group A Streptococcus, J. N. Cole, R. D. Ramirez, B. J. Currie, S. J. Cordwell, S. P. Djordjevic, Mark J. Walker

Faculty of Science - Papers (Archive)

A proteomic analysis was undertaken to identify cell-wall associated proteins of Streptococcus pyogenes. Seventy-four distinct cell-wall associated proteins were identified, 66 of which were novel. Thirty-three proteins were immunoreactive with pooled S. pyogenes-reactive human antisera. Biotinylation of the GAS cell-surface identified 23 cellwall associated proteins that are surface exposed.

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An Inventory Of Rangelands In Part Of The Broome Shire, Western Australia, W E. Cotching Jan 2005

An Inventory Of Rangelands In Part Of The Broome Shire, Western Australia, W E. Cotching

Technical Bulletins

The inventory of rangelands in part of the Broome Shire in Western Australia was undertaken by DAFWA between 1989 and 1990. It describes and maps the natural resources of the region’s pastoral leasehold land. This survey report provides a baseline record of the existence and condition of the natural area’s resources, to assist with the planning and implementation of land management practices. The report identified and described the condition of soils, landforms, vegetation, habitat, ecosystems, and declared plants and animals. It also assessed the impact of pastoralism and made land management recommendations. The survey of part of the Broome Shire …

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Comparison Of Phytoplankton And Autotrophic Picoplankton Populations Over A 24-Hour Period From A Pond's Surface And Subsurface Waters, Harold G. Marshall, Lubomira Burchardt, Elżbieta Wilk-Woźniak Jan 2005

Comparison Of Phytoplankton And Autotrophic Picoplankton Populations Over A 24-Hour Period From A Pond's Surface And Subsurface Waters, Harold G. Marshall, Lubomira Burchardt, Elżbieta Wilk-Woźniak

Biological Sciences Faculty Publications

Phytoplankton abundance and composition relationships within the surface layer changed over short time periods (4-6 hours) in comparison with more constant associations at 2 cm below the surface. Both strata had a diverse algal flora (>50 taxa), but no distinct neuston assemblage characterized the surface layer algal composition over the 24-hour study. The similarity between the two strata indicated the floral composition of the surface layer came from the water column algae below the surface. Chlorophytes, diatoms, cyanobacteria, and cryptophytes represented the most abundant algal categories for both strata with a total mean phytoplankton abundance of 3,566 cells ml …

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Population Dynamics Of Oryzomys Palustris And Microtus Pennsylvanicus In Virginia Tidal Marshes, Christopher P. Bloch, Robert K. Rose Jan 2005

Population Dynamics Of Oryzomys Palustris And Microtus Pennsylvanicus In Virginia Tidal Marshes, Christopher P. Bloch, Robert K. Rose

Biological Sciences Faculty Publications

Oryzomys palustris (marsh rice rat) and Microtus pennsylvanicus (meadow vole) cohabit coastal marshes in the mid-Atlantic US. Both were live-trapped for 23 months at two tidal marsh sites in Virginia to assess their demography near the margins of their distributions. In the presence of dense vegetation, population dynamics of the two species were seasonal and positively correlated, with densities declining through the winter. At the more sparsely vegetated site, densities of both species were lower, and densities of M. pennsylvanicus were negatively correlated with those of O. palustris. Patterns of reproduction differed between the species. O. palustris was reproductively …

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Effects Of Human Disturbances On The Behavior Of Wintering Ducks, Melissa L. Pease, Robert K. Rose, Mark J. Butler Jan 2005

Effects Of Human Disturbances On The Behavior Of Wintering Ducks, Melissa L. Pease, Robert K. Rose, Mark J. Butler

Biological Sciences Faculty Publications

Human activity causes wintering waterfowl to expend energy to avoid humans at a time in their annual cycle when energy conservation is important to survival, migration, and breeding reserves. Understanding the effects of recreational activities on waterfowl is important to managing natural resource areas where migratory birds depend on wetland habitat for resting and feeding. We investigated responses of 7 species of dabbling ducks to 5 different experimental human activities, (a pedestrian, a bicyclist, a truck traveling at 2 different speeds, and an electric passenger tram). Responses of ducks depended on type of disturbance, species, and distance from disturbances. Most …

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Phytoplankton Development Within Tidal Freshwater Regions Of Two Virginia Rivers, Usa, Harold G. Marshall, Lubomira Burchardt Jan 2005

Phytoplankton Development Within Tidal Freshwater Regions Of Two Virginia Rivers, Usa, Harold G. Marshall, Lubomira Burchardt

Biological Sciences Faculty Publications

Phytoplankton composition and the range of seasonal patterns of abundance are presented for the tidal freshwater regions in two Virginia rivers based on data accumulated monthly from 1986 through 1999. Diatoms dominated the flora during spring, summer, and fall, whereas, other taxonomic categories were more representative when the river flow rates decreased, allowing for a more stable water system and increased residency time within this tidal region during summer and early fall. This summer/fall period was associated with increased water temperatures, higher productivity rates and chlorophyll levels, increased total phytoplankton abundance and species diversity. The major components of the summer …

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A Review Of Phytoplankton Composition Within Chesapeake Bay And Its Tidal Estuaries, Harold G. Marshall, Lubomira Burchardt, Richard Lacouture Jan 2005

A Review Of Phytoplankton Composition Within Chesapeake Bay And Its Tidal Estuaries, Harold G. Marshall, Lubomira Burchardt, Richard Lacouture

Biological Sciences Faculty Publications

Based on a continuous 20-year data base ofmonthly sampling in Chesapeake Bay and tidal regions of its major tributaries, 1454 phytoplankton taxa have been identified in these waters. They represent a diverse assemblage of species with a dominant diatom flora throughout the year, in addition to large seasonal representation by chlorophytes, cyanobacteria, cryptophytes and dinoflagellates. Included among this flora were 34 potential harmful or toxin producing species. The phytoplankton compositions associated with the seasonal successional patterns are discussed, in addition to characterizing the dominant floral relationships, with comparison to early composition records within the Bay. Several of the present day …

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Demonstration Of Toxicity To Fish And To Mammalian Cells By Pfiesteria Species: Comparison Of Assay Methods And Strains, Joann M. Burkholder, Andrew S. Gordon, Peter D. Moeller, J. Mac Law, Kathryn J. Coyne, Alan J. Lewitus, John S. Ramsdell, Harold G. Marshall, Nora J. Deamer, S. Craig Cary, Jason W. Kempton, Steven L. Morton, Parke A. Rublee Jan 2005

Demonstration Of Toxicity To Fish And To Mammalian Cells By Pfiesteria Species: Comparison Of Assay Methods And Strains, Joann M. Burkholder, Andrew S. Gordon, Peter D. Moeller, J. Mac Law, Kathryn J. Coyne, Alan J. Lewitus, John S. Ramsdell, Harold G. Marshall, Nora J. Deamer, S. Craig Cary, Jason W. Kempton, Steven L. Morton, Parke A. Rublee

Biological Sciences Faculty Publications

Toxicity and its detection in the dinoflagellate fish predators Pfiesteria piscicida and Pfiesteria shumwayae depend on the strain and the use of reliable assays. Two assays, standardized fish bioassays (SFBs) with juvenile fish and fish microassays (FMAs) with larval fish, were compared for their utility to detect toxic Pfiesteria. The comparison included strains with confirmed toxicity, negative controls (noninducible Pfiesteria strains and a related nontoxic cryptoperidiniopsoid dinoflagellate), and P. shumwayae strain CCMP2089, which previously had been reported as nontoxic. SFBs, standardized by using toxic Pfiesteria (coupled with tests confirming Pfiesteria toxin) and conditions conducive to toxicity expression, reliably detected …

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First Record Of An Adult Male Evening Bat From Kansas, Clay R. Davis, Justin G. Boyles Jan 2005

First Record Of An Adult Male Evening Bat From Kansas, Clay R. Davis, Justin G. Boyles

The Prairie Naturalist

The evening bat (Nycticeius humeralis) occurs throughout the eastern and southeastern United States and into extreme northeastern Mexico, approximately 42° to 18° N latitude (Watkins and Shump 1981). Although records of females are common, records of adult male evening bats are rare in the northern portion of the species range (Watkins 1969, Watkins 1972). Jones et al. (1967) suggested that adult males might not accompany females to at least some parts of the parturient range. As part of a larger study (Davis 2003) we surveyed bats on Fort Leavenworth Military Reservation (FLMR), Leavenworth County, Kansas in July 2002 …

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