Physical Sciences and Mathematics Commons^™

Editorial Board & Iowa Academy Of Science Officers And Directors

Journal of the Iowa Academy of Science: JIAS

No abstract provided.

Semiclassical Scattering Of An Electric Dipole Source Inside A Spherical Particle, James A. Lock

Physics Faculty Publications

Semiclassical scattering phenomena appearing in the far-zone scattered intensity of a point source of electromagnetic radiation inside a spherical particle are examined in the context of both ray theory and wave theory, and the evolution of the phenomena is studied as a function of source position. A number of semiclassical effects that do not occur for plane-wave scattering by the sphere appear prominently for scattering by an interior source. These include a series of scattering resonances and a new family of rainbows in regions of otherwise total internal reflection. Diffractive effects accompanying the semiclassical phenomena are also examined. (C) 2001 …

Introduced Fungi: Some Cause Significant Plant Disease Problems, Lois H. Tiffany

Journal of the Iowa Academy of Science: JIAS

Species of the three groups of fungi characterized here on the basis of their energy source acquisition have differing potentials for becoming problem organisms following introduction as alien fungi new to Iowa. The decomposer group of fungi that obtain an energy supply by action of extracellular enzyme activity on dead plant tissues typically have perennial mycelium, are cosmopolitan in distribution, and are unlikely to become problems even if established. The second group, the mycorrhizal/lichen group are highly specific in their relationships. The mycorrhizal fungus group have a potential for being introduced as mycorrhiza already established with the roots of particular …

More Than A Century Of Change In The Ames, Iowa Flora (1859-2000), William R. Norris, Mark P. Widrlechner, Deborah Q. Lewis, Jimmie D. Thompson, Richard O. Pope

Journal of the Iowa Academy of Science: JIAS

We compared two floras compiled in Ames, Iowa: (1) an "historic" flora based on two published floras (1871, 1890) and on 1450 herbarium voucher specimens of plants collected in Ames between 1859 and 1899, and (2) a "current" flora compiled by us during recent fieldwork (1990-2000). Our goals were to determine 1) long-term changes in composition (i.e., the proportion of native species) over time, 2) long-term changes in the abundance of individual plant species over time, and 3) the extent of gains and losses of native and non-native plant species. We found that the proportion of native species declined over …

Exotic And Invasive Woody Plant Species In Iowa, Donald R. Farrar

Journal of the Iowa Academy of Science: JIAS

Seventy species and hybrids of exotic woody trees, shrubs, and vines have naturalized in Iowa. Nearly half of these species (31) have become invasive pests in parts of the state or have potential do so. Most of the seriously invasive species are spread by bird ingestion of whole fruits. Widespread dispersal by birds hinders eradication efforts and should be considered a trait indicative of potential invasiveness. The economic and ecological values of Iowa forests are seriously compromised by exotic invasive woody species, especially where forests recovering from cropland and pasture are dominated by exotic species. Thus, a simple measure of …

Forest Invasives In Iowa: Current Problems And Future Issues, John Walkowiak, John Haanstad

Journal of the Iowa Academy of Science: JIAS

Iowa's forest resources of primarily deciduous trees covers over 0.8 million hectares (2 million acres) of upland and floodplain sites too steep or too wet for traditional row crop agriculture. These limited natural forests along with urban trees and shelterbelts plantings of trees are critical for environmental and economic enhancement in the state. Although not yet established in the state, exotic insects, such as gypsy moth, Asian longhorned beetle, and pine shoot beetle, threaten native tree vitality. Established exotic diseases such as oak wilt and Dutch elm disease continue to plague the survival of Iowa's oak and elm resources, respectively. …

Back Cover

Journal of the Iowa Academy of Science: JIAS

No abstract provided.

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Journal of the Iowa Academy of Science: JIAS

No abstract provided.

Purple Loosestrife: History, Management, And Biological Control In Iowa, Amy P. Wiebe, John J. Obrycki

Journal of the Iowa Academy of Science: JIAS

Purple loosestrife (Lythrum salicaria) is an invasive plant species infesting wetlands in North America. Biodiversity and wetland habitat quality are reduced following purple loosestrife establishment. Several management tactics, including cultural, mechanical, and chemical controls, have had limited success in reducing the spread of purple loosestrife. Beginning in the 1990s, a biological control program has introduced several species of natural enemies from Europe that feed on purple loosestrife. Since 1994, Iowa State University has reared and released two species of beetles that feed on purple loosestrife, Galerucella calmariensis and G. pusilla. Biological control is one component of an integrated purple loosestrife …

Ecological Problems With Iowa's Invasive And Introduced Fishes, Neil P. Bernstein, John R. Olson

Journal of the Iowa Academy of Science: JIAS

Since the time of European settlement, at least 59 non-indigenous fish species have been introduced, reached, or moved within Iowa waters. At least 28 nonnative fish species have been introduced into, or reported from Iowa waters since settlement. Of that number, 10 are established at this time through natural reproduction. In addition, many species of native fishes have been translocated within the state, and we provide documentation for 31 of these species. Two translocated species, gizzard shad (Dorosoma cepedianum) and yellow bass (Marone mississippiensis), have had adverse impacts on Iowa's aquatic ecosystems. While many introductions are thought to be benign, …

Invasive Birds In Iowa: Status, Problems, And Threats, James J. Dinsmore

Journal of the Iowa Academy of Science: JIAS

A total of 18 invasive bird species has been introduced into or have expanded their range to include Iowa. These include ten non-North American species, one North American species that has been displaced and now is established in Iowa, and seven native species that have been released to reestablish Iowa populations. Twelve of those are regularly occurring species in Iowa, and they comprise 3.0% (12 of 404) of the species known from Iowa and 5% (10 of 199) of Iowa's nesting avifauna. These percentages are similar to those found in neighboring states. Several more species are likely to become established …

Reaction Rate Of 17f(P,Γ)18ne And Its Implications For Nova Nucleosynthesis, Suzanne Parete-Koon

Masters Theses

The rate of the 17F(p,γ)18Ne reaction has a profound effect on the abundances of several isotopes produced during a nova outburst. In 1999 a new rate for 17F(p,γ)18Ne was determined from a measurement of the excitation function for the 1H(17F,p)17F reaction at Oak Ridge National Laboratory's (hereafter ORNL) Holifield Radioactive Ion Beam Facility[1]. This experiment yielded the first definite evidence of a Jπ =3+ state in 18Ne. This state provided a new resonance in the 17F +p capture, which could, depending on its properties, dominate the rate of 17F(p,γ)18Ne at stellar explosive temperatures. The new rate for 17F(p,γ) 18Ne was …

Image Compression By Wavelet Transform., Panrong Xiao

Electronic Theses and Dissertations

Digital images are widely used in computer applications. Uncompressed digital images require considerable storage capacity and transmission bandwidth. Efficient image compression solutions are becoming more critical with the recent growth of data intensive, multimedia-based web applications.

This thesis studies image compression with wavelet transforms. As a necessary background, the basic concepts of graphical image storage and currently used compression algorithms are discussed. The mathematical properties of several types of wavelets, including Haar, Daubechies, and biorthogonal spline wavelets are covered and the Enbedded Zerotree Wavelet (EZW) coding algorithm is introduced. The last part of the thesis analyzes the compression results to …

A Meta-Analysis And Risk Assessment Of Heavy Metal Uptake In Common Garden Vegetables., Trent David Lecoultre

Electronic Theses and Dissertations

Peer reviewed literature was searched to identify research pertaining to the uptake of heavy metals (As, Cd, Pb and Zn) by vegetables (cabbage, carrot, lettuce, and radish). The objectives of this research were to 1) determine the relationship between heavy metal concentrations in the soil and heavy metal concentrations in vegetables, and 2) determine the level of risk associated with exposure to heavy metals through ingestion of contaminated vegetables. Highly variable estimates and biologically implausible regression equations resulted from this meta-analysis. Exposure to arsenic through the ingestion of lettuce grown on contaminated soil significantly increases cancer risk, especially in children. …

Deploying Integrated Web-Based Spatial Applications Within An Oracle Database Environment, James Carswell

Conference papers

In this paper, we describe the architectural and functional characteristics of e-Spatial™ technology, comprising an innovative software package that represents a timely alternative to traditional and complex proprietary GIS application packages. The two main components of the package, developed by e- Spatial Solutions, are the iSMART™ database development technology and the i-Spatial™ Information Server (iSIS), both implemented within an Oracle 9i Spatial database environment. This technology allows users to build and deploy spatially enabled or standard Internet applications without requiring any application-specific source code. It can be deployed on any Oracle supported hardware platform and on any device that supports …

History And Development Of The Eurasian Watermilfoil Program In Iowa, Gary S. Phillips

Journal of the Iowa Academy of Science: JIAS

Following a concerted effort by citizens of the Iowa Great Lakes area to address the threat posed by Eurasian watermilfoil (Myriophyllum spicatum L.) to waterbodies in Iowa, the Iowa Eurasian Watermilfoil Law was passed in 1996 by the Iowa legislature. Passage of this law led to the establishment of the Eurasian Watermilfoil Program in July 1996 to address the requirements specified by this legislation. Since establishment of the Eurasian Watermilfoil Program, numerous activities have been carried out to address the threat posed to aquatic ecosystems by Eurasian watermilfoil. These include public awareness and education, boat access monitoring, aquatic vegetation monitoring, …

Groundwater Study Of The Koorda Townsite, Louise Hopgood

Resource management technical reports

A groundwater study was carried out in the townsite of Koorda. It aimed to accelerate the implementation of effective salinity risk management. The study consisted of a drilling investigation and expansion of a piezometer network, a pumping test, groundwater flow modelling and a flood risk analysis.

Lort And Young Rivers Catchment : Catchment Appraisal 2001, Jamie Bowyer, Esperance Catchment Support Team (Wa)

Resource management technical reports

Using the Rapid Catchment Appraisal process, this report summarises current information for the Lort and Young Rivers Catchment, 75 kilometres west of Esperance in Western Australia. The Rapid Catchment Appraisal (RCA) process is one of the processes included in the strategy to tackle salinity and its management in Western Australia. The RCA process provides a 'snap shot' of information on the risk and impact to agricultural production and natural resources within regional geographic catchments.

Field-Dependent Tilt And Birefringence Of Electroclinic Liquid Crystals: Theory And Experiment, J. V. Selinger, Peter J. Collings, R. Shashidhar

Physics & Astronomy Faculty Works

An unresolved issue in the theory of liquid crystals is the molecular basis of the electroclinic effect in the smectic-A phase. Recent x-ray scattering experiments suggest that, in a class of siloxane-containing liquid crystals, an electric field changes a state of disordered molecular tilt in random directions into a state of ordered tilt in one direction. To investigate this issue, we measure the optical tilt and birefringence of these liquid crystals as functions of field and temperature, and we develop a theory for the distribution of molecular orientations under a field. A comparison of theory and experiment confirms that these …

Modeling Intersections Of Geospatial Lifelines, Ramaswam Hariharan

Electronic Theses and Dissertations

Modeling moving objects involves spatio-temporal reasoning. The continuous movements of objects in space-time captured as discrete samples form geospatial lifelines. Existing lifeline models can represent the movement of objects between samples from most likely location to all possible locations. This thesis builds on a model called lifeline bead and necklace that captures all the possible locations of moving objects. Beads are 3-dimensional representations of an object's movements and a series of beads form a necklace. The extent of finding the possible locations is constrained by the speed of movement of the objects. Intersections of lifelines occur when two or more …

Magmatic Enclaves And Evidence For Magma Mixing In The Oak Point Granite, Deer Isle, Maine, Usa, Ben Johnston

Electronic Theses and Dissertations

The Coastal Maine Magmatic Province (CMMP) consists of over 100 post tectonic plutons with ages varying from Silurian to Carboniferous. Predominately, plutons are either felsic or mafic with little intermediate material. Several plutons within the CMMP show evidence for direct interaction of contemporaneous mafic and felsic magmas. These are classified as Mafic and Silicic Layered Intrusions (MASLI), a specific group of plutons with characteristics indicative of mafic magma replenishment into silicic magma chambers. While the Maine coast contains several MASLI type plutons, other plutons in the CMMP contain less definitive, more cryptic evidence that suggests interaction of mafic and silicic …

Effects Of An Increasing Harbor Seal Population On Changes In Sites Used For Pupping, Nikolina Guldager

Electronic Theses and Dissertations

Aerial survey data from 198 1 to 1997 of an increasing harbor seal (Phoca vitulina concolor) population in Penobscot and Blue Hill bays, Maine, were used to evaluate spatial and temporal patterns of use of pupping sites by mother-pup pairs. Pupping sites refer to haul-out sites where pups were observed during surveys, and are assumed to be used consistently from birth to weaning. Sites with pups were spatially clustered to remove spatial auto-correlation, reduce temporal variability and provide biologically cohesive and independent sample units. Spatial, temporal and habitat analyses were completed for 2 spatial scales: individual sites and …

Variables Influencing Nest Success Of Eastern Wild Turkeys In Connecticut: Nesting Habitat, Home Range-Scale Fragmentation, And Nest Attentiveness, Shelley M. Spohr

Electronic Theses and Dissertations

Nest success is the most important demographic parameter influencing rates of population change of eastern wild turkeys (Meleagris gallopavo si1vestris) and many variables operating at multiple spatial and temporal scales may influence whether a nest is successful. Most studies of nest success and survival of turkeys have occurred in forested or agricultural landscapes; variables influencing nest success have not been studied in suburban landscapes. My objectives were to: 1 ) quantify survival and reproductive parameters of eastern wild turkey hens in the suburban environment of southeastern Connecticut and compare results to studies conducted in other northeastern states; 2) …

Large Nondipole Effects In The Angular Distributions Of K-Shell Photoelectrons From Molecular Nitrogen, Oliver Hemmers, H. Wang, P. Focke, I. A. Sellin, Dennis W. Lindle, J. C. Arce, J. A. Sheehy, P. W. Langhoff

Environmental Studies Faculty Publications

Measurements of angular distributions of K-shell electrons photoejected from molecular nitrogen are reported which reveal large deviations at relatively low photon energies ( ħω≤500eV) from emission patterns anticipated from the dipole approximation to interactions between radiation and matter. A concomitant theoretical analysis incorporating the effects of electromagnetic retardation attributes the observed large nondipole behaviors in N₂ to bond-length-dependent terms in the E1⊗(E2,M1) photoelectron emission amplitudes which are indicative of a potentially universal nondipole behavior in molecular photoionization.

Inside Unlv, Diane Russell, Jennifer Vaughan, Richard Jensen, Mae Worthey-Flennoy

Inside UNLV

No abstract provided.

Groundwater Study Of The Woodanilling Townsite, Ben Whitfield

Resource management technical reports

A groundwater study was carried out in the townsite of Woodanilling, Western Australia. It aimed to accelerate the implementation of effective salinity management options. The study consisted of a drilling investigation, installation of a piezometer network, groundwater flow modelling and a flood risk analysis.

Effects Of A Large Mesospheric Temperature Enhancement On The Hydroxyl Rotational Temperature As Observedfrom The Ground, S. M.L. Melo, R. P. Lowe, W. R. Pendleton Jr., Michael J. Taylor, B. Williams, C. Y. She

All Physics Faculty Publications

The rotational temperature obtained from the rotational population distribution in the bands of the hydroxyl airglow has been shown to be a suitable proxy for the temperature at a height of 87 km [She and Lowe, 1998]. In this paper we examine in detail simultaneous observations on November 2–3, 1997, at Fort Collins, Colorado (41°N, 105°W), with both a sodium temperature lidar and the Coupling, Energetics, and Dynamics of Atmospheric Regions (CEDAR) OH mesospheric temperature mapper during which significant differences between the hydroxyl and lidar temperatures occur. The large differences are associated with a major temperature enhancement in the region …

Risk Mapping For Northern Kenya And Southern Ethiopia, D. Layne Coppock

Environment and Society Faculty Publications

We used results from 120 group interviews collected in 1998 to quantify how inhabitants across northern Kenya and southern Ethiopia perceive and rank various risks to their livelihoods. We also mapped risk patterns using Global Positioning System (GPS) coordinates. Respondents recognized 15 sources of risk overall, with the most common being reliable access to food and water. Other risks were not mentioned by a majority of respondents and reflected diversity in local situations. Country of residence, wealth class, gender, and predominant means of food production (pastoralism, agro-pastoralism, and farming) influenced risk ranking. For example, wealthy males were most concerned about …

Techniques For The Regeneration Of Wideband Speech From Narrowband Speech, Jason A. Fuemmeler, Russell C. Hardie, William R. Gardner

Electrical and Computer Engineering Faculty Publications

This paper addresses the problem of reconstructing wideband speech signals from observed narrowband speech signals. The goal of this work is to improve the perceived quality of speech signals which have been transmitted through narrowband channels or degraded during acquisition. We describe a system, based on linear predictive coding, for estimating wideband speech from narrowband. This system employs both previously identified and novel techniques. Experimental results are provided in order to illustrate the system’s ability to improve speech quality. Both objective and subjective criteria are used to evaluate the quality of the processed speech signals.

Metaxpath, Curtis Dyreson, Michael H. Böhen, Christian S. Jensen

Curtis Dyreson

This paper presents the METAXPath data model and query language. METAXPath extends XPath with support for XML metadata. XPath is a specification language for locations in an XML document it serves as the basis for XML query languages like XSLT and the XML Query Algebra.

The METAXPath data model is a nested XPath tree. Each level of metadata induces a new level of nesting. The data model separates metadata and data into different data spaces, supports meta-metadata and enables sharing of metadata common to a group of nodes without duplication. The METAXPath query language has a level shift operator to …