Digital Commons Network^™

Spatially Varying Threshold Models For The Automated Segmentation Of Radiodense Tissue In Digitized Mammograms, Richard Edson Eckert Iii

Theses and Dissertations

The percentage of radiodense (bright) tissue in a mammogram has been correlated to an increased risk of breast cancer. This thesis presents an automated method to quantify the amount of radiodense tissue found in a digitized mammogram. The algorithm employs a radial basis function neural network in order to segment the breast tissue region from the remainder of the X-ray. A spatially varying Neyman-Pearson threshold is used to calculate the percentage of radiodense tissue and compensate for the effects of tissue compression that occurs during a mammography procedure. Results demonstrating the efficacy of the technique are demonstrated by exercising the …

Pion-Kaon Correlations In Central Au+Au Collisions At √SNn=130 Gev, Star Collaboration, T.D. Gutierrez

Physics

Pion-kaon correlation functions are constructed from central Au+Au STAR data taken at √s_NN=130  GeV by the STAR detector at the Relativistic Heavy Ion Collider (RHIC). The results suggest that pions and kaons are not emitted at the same average space-time point. Space-momentum correlations, i.e., transverse flow, lead to a space-time emission asymmetry of pions and kaons that is consistent with the data. This result provides new independent evidence that the system created at RHIC undergoes a collective transverse expansion.

Multi-Sensor Data Fusion Using Geometric Transformations For The Nondestructive Evaluation Of Gas Transmission Pipelines, Philip James Kulick

Theses and Dissertations

Nondestructive evaluation (NDE) plays a vital component in the operation and maintenance of large infrastructure such as gas transmission pipelines, nuclear power plants, aircraft, bridges and highways, etc. As this infrastructure continues to age it is essential that the inspection techniques reliably and accurately predict the integrity of these systems. No single NDE method is capable of inspecting all types of anomalies and extracting all required information – a combination of methods must be used and the resulting data fused. Moreover, newer systems that are developed are often made of composite materials that include metals and dielectrics. One interrogation modality …

Simulation Of The Communication Process In A Pin Mill, Ambrose J. M. Itika

Tanzania Journal of Engineering and Technology (TJET)

Prediction of the performance of comminution equipment by mathematical models and simulation poses a great challenge to the chemical engineer. This paper describes the simulation of grinding results obtained using an impact mill. Single particle results have been used to generate breakage and selection coefficients that were used for the evaluation of the model. Results have shown that simulation model is in good agreement with the experimental data obtained at a circumferential speed above 60 m/s. At lower speeds, the models shows only partial agreement in the middle particle size ranges. The application of the model is therefore limited for …

Petrology And Lithogeochemistry Of The Mineralized Tanzanite-Grossular Bearings Rocks In The Merelani-Lelatema Area, Northeastern Tanzania, Ep Malisa

Tanzania Journal of Science

The Merelani-Lelatema area, which is occupied by late Proterozoic metasedimentary rocks, lies along the Lelatema fault zone. The rocks are mainly pelitic and semi-pelitic gneisses, psammitic gneisses, hydrothermally altered rocks, crystalline dolostones, pegmatites and quartz veins. The occurrence of gem-quality tanzanite and grossular has been found to occur mainly in boudinaged pegmatitic veins and hydrothermal fracture fillings. These fracture fillings occur in brecciated and hydrothermally altered graphite-bearing gneiss in a mineral association containing glass-clear quartz, diopside, zoisite, graphite and calcite. The psammitic gneisses are more siliceous and enriched in feldspars. They are grouped into graphite-kyanite gneiss with thin interlayers of …

Performance Of Pleurotus Flabellatus On Water Hyacinth (Eichhornia Crassipes) Shoots At Two Different Temperature And Relative Humidity Regimes, Ak Kivaisi, Fss Magingo, B Mamiro

Tanzania Journal of Science

Efforts are being made in Tanzania to promote mushroom cultivation, and identification of abundantly available plant biomass residues appropriate for growing mushrooms is part of the efforts. This study investigated the suitability of water hyacinth as a bulk substrate for growing a newly domesticated local oyster mushroom, Pleurotus flabellatus. The performance of the mushroom was investigated under ambient temperature and relative humidity (RH) regimes of 18-25/27-29 oC and 55-85/78-93%, respectively. The growth cycle of the mushroom was completed in 40 days with three and four flushes respectively. At the higher temperature and RH regime, the mushroom grew faster and the …

Metal Concentrations In Sediment And Fish Of Lake Victoria Near And Away From Catchments With Gold Mining Acctivities, Jf Machiwa

Tanzania Journal of Science

Concentrations of metals in sediment and fish as well as organic matter contents of sediment from Lake Victoria were investigated. The objective of the study was to compare levels of metals in sediment and fish from areas of the lake that are within and outside catchments with gold mining activities.The results showed that the concentration of As was less than 6 mg g-1 dw and Cd was below 1.9 mg g-1 dw in sediment samples. Lead, zinc and copper concentrations were highest (58.1±17.6 mg g-1 dw, 101.9±20.6 mg g-1 dw and 32.6±2.8 mg g-1 dw respectively) in sediment samples that …

Ammonite Biostratigraphy Of The Jurassic Of Tanzania, S Kapilima

Tanzania Journal of Science

The present paper summarizes the previous biostratigraphical researches and incorporates the recent research findings on the Jurassic rocks in the coastal basin of Tanzania. The ammonites used for the biostratigraphical classification are from two sub-basins along the coastal belt of Tanzania: Mandawa (south) and Ruvu- Tanga (north). The oldest known ammonites from these basins are of Aalenian age. The biostratigraphical classification of the Jurassic sequence, on the basis of the vertical and horizontal distributions of the ammonite assemblages, permits the erection of eight sub stages of Jurassic: Upper Aalenian (Concavum-Zone), Bajocian (Humphrieasianum-Zone), Middle Callovian (Coronatum-Jason Zone), Upper Callovian (Lamberti-Athleta Zone), …

A Study On The Preparation For The Introduction Of The Dual Purpose Training System, Philip Mathews

World Maritime University Dissertations

No abstract provided.

Bajocian Ammonites From Msata Hill (Lugoba Formation) In The Hinterland Of Dar Es Salaam, Tanzania, S Kapilima

Tanzania Journal of Science

Ammonites from the Middle Jurassic exposures of the Lugoba Formation at Msata, are described for the first time in Tanzania. Out of a number of ammonite fragments recovered from the bluish-green silty limestone (M3), only three fragments were fairly well preserved to permit their specific identification. Two species were identified: Dorsetensia cf. D. romani (OPPEL) and Oecotraustes (Paroecotraustes?) cf. angustus DOUVILLE. This ammonite assemblage is biostratigraphically correlatable with the Lower Bajocian Posidonia shale of the Kambe Limestone series in Kenya, in which similar ammonites species and other related Bajocian species have been described. Pending new discovery of ammonoid fauna and …

Synthesis Of Some Cis-4,4-Dimethyl-2-Isopropenylcyclopentane Derivatives As Potential Intermediates Towards The Protoilludane Skeleton, Sjm Mdachi

Tanzania Journal of Science

The three gem-dimethyl-substituted cyclopentane derivatives 1-(2-propionyl)-4,4-dimethyl-2-isopropenylcyclopentane, 2-isopropenyl-4,4-dimethylcyclopentanecarboxyaldehyde and 1-hydroxy- methyl-2-isopropenyl-4,4-dimethylcyclopentane have been synthesized employing a thermally induced ene reaction as a key step. Each of the three compounds has been obtained predominantly as the cis isomer. The successful synthesis of these compounds affords opportunities for their further ellaboration towards sesquiterpenes of the protoilludane skeleton.

Anomaly In Conformal Quantum Mechanics: From Molecular Physics To Black Holes, Horacio E. Camblong

Physics and Astronomy

A number of physical systems exhibit a particular form of asymptotic conformal invariance: within a particular domain of distances, they are characterized by a long-range conformal interaction (inverse square potential), the apparent absence of dimensional scales, and an SO(2,1) symmetry algebra. Examples from molecular physics to black holes are provided and discussed within a unified treatment. When such systems are physically realized in the appropriate strong-coupling regime, the occurrence of quantum symmetry breaking is possible. This anomaly is revealed by the failure of the symmetry generators to close the algebra in a manner shown to be independent of the renormalization …

Solvent And Primary Deuterium Isotope Effects Show That Lactate Ch And Oh Bond Cleavages Are Concerted In Y254f Flavocytochrome B2, Consistent With A Hydride Transfer Mechanism, Pablo Sobrado, Paul F. Fitzpatrick

Chemistry Faculty Research & Creative Works

Yeast flavocytochrome b2 catalyzes the oxidation of lactate to pyruvate; because of the wealth of structural and mechanistic information available, this enzyme has served as the model for the family of flavoproteins catalyzing oxidation of α-hydroxy acids. Primary deuterium and solvent isotope effects have now been used to analyze the effects of mutating the active site residue Tyr254 to phenylalanine. Both the Vmax and the V/Klactate values decrease about 40-fold in the mutant enzyme. The primary deuterium isotope effects on the Vmax and the V/K lactate values increase to 5.0, equivalent to the intrinsic isotope effect for the wild-type enzyme. …

Final Report: An Assessment To Determine The Most Suitable Location And Design For The Development Of A City-Run, Boat Sewage Pumpout Facility To Service Commercial And Recreational Vessels That Utilize The Waters Within The Jurisdiction Of The City Of Boston, Urban Harbors Institute, University Of Massachusetts Boston

Urban Harbors Institute Publications

This report presents the findings of a site and equipment feasibility study, as well as, a permit overview for the installation of a vessel sewage pumpout system for servicing commercial and recreational vessels in the City of Boston. As part of the analysis, we reviewed a number of sites located within the City of Boston’s jurisdiction in Boston Harbor. We contacted facilities that have made recent investments in commercial grade pumpouts to learn more about the available technology. In analyzing the permit process, we reviewed local zoning requirements and had conversations with relevant City and state officials.

The project, as …

Live Capture Of Denning Mammals Using An Improved Box-Trap Enclosure: Kit Foxes As A Test Case, Adam J. Kozlowski, Tim J. Bennett, Eric M. Gese, Wendy M. Arjo

United States Department of Agriculture Wildlife Services: Staff Publications

The ability to capture and recapture animals efficiently is ,In integral part of many wildlife studies. For many species of small terrestrial carnivores, the baited box trap has been a staple of live-capture trapping efforts. Combined with an enclosure, the box trap is especially effective on species with a den or refuge that can be encircled. However, increased trapping success of these enclosure designs often is offset by increased cost, labor, and awkwardness of transporting and establishing the enclosure trap. We describe a new enclosure design, the tunnel trap, which improves on the mobility and effectiveness of previous enclosure designs. …

On Analytical Methods And Inferences For 2 X 2 Contingency Table Data Using Wildlife Examples, Richard M. Engeman, George D. Swanson

United States Department of Agriculture Wildlife Services: Staff Publications

The 2 X 2 contingency table is common analytical method for wildlife studies, but inappropriate analyses and inferences are not uncommon. Issues of concern are presented for selecting the appropriate test for analyzing these data sets. These include the choice of test relative to experimental or sampling design and breadth of intended inferences, the careful statement of hypotheses, and analyses with small sample sizes. Examples from the wildlife literature are used to reinforce the statistical concepts.

Coyote (Canis Latrans), Marc Bekoff, Eric M. Gese

United States Department of Agriculture Wildlife Services: Staff Publications

Coyotes

A Review Of Color Vision In White-Tailed Deer, Kurt C. Vercauteren, Michael J. Pipas

United States Department of Agriculture Wildlife Services: Staff Publications

A better understanding of the color vision abilities of white-tailed deer (Odocoileus virginianus) helps to determine how these animals interpret their environment. We review and summarize the literature related to the color vision abilities of white-tailed deer. Physiological measurements using advanced techniques such as molecular genetics, electroretinography, and electron microscopy have demonstrated conclusively that whitetailed deer possess the anatomical requisites for color vision. Operant conditioning techniques employed in pen studies using trained cervids confirm that deer see color. The eyes of white-tailed deer are characterized by 3 classes of photopigments: a short-wavelengthsensitive cone mechanism, a middle-wavelength-sensitive cone mechanism, …

Macrocyclic Antibiotics As Separation Agents, Daniel W. Armstrong

Chemistry Faculty Research & Creative Works

Macrocyclic antibiotics having ring structures with at least 10 members act as separation agents in crystallization, precipitation, filtration, electrophoresis, and chromatography. The macrocyclic antibiotics include ansamacrolides, macrolides, macrocyclic peptides, polyenes and derivatives thereof. The process has been found to be especially advantageous for separation of optical isomers by electrophoresis and chromatography.

An Exploration Of The Pay Levels Needed To Attract Students With Mathematics, Science And Technology Skills To A Career In K-12 Teaching, Anthony Milanowski

Education Policy Analysis Archives (EPAA)

In an exploratory study of the role of salary level and other factors in motivating undergraduate math, science, and technology majors to consider a career as a K-12 teacher, the salary level students said would motivate them to consider a career in teaching was related to the salary expected in their chosen non-teaching occupation, but not to three of the Big 5 personality dimensions of extroversion, agreeableness, and openness, nor concern for others or career risk aversion. ...

Education Policy Analysis Archives 11/50 , Arizona State University, University Of South Florida

College of Education Publications

Exploration of the pay levels needed to attract students with mathematics, science and technology skills to a career in K-12 teaching / Anthony Milanowski.

Lewis And Clark And The Geology Of Nebraska And Parts Of Adjacent States, Robert F. Diffendal Jr., Anne P. Diffendal

School of Natural Resources: Faculty Publications

Meriwether Lewis and William Clark undertook their journey with the Corps of Discovery in 1804–1806 in order to explore the area that the United States had purchased from France in 1803. Then known as Louisiana, this region included almost everything west of the Mississippi to the continental divide (illustrated below). In order to find the best route across the continent, President Thomas Jefferson charged Lewis to follow the Missouri River to its headwaters and then locate rivers flowing down the west side of the Rocky Mountains to the Columbia River and into the Pacific Ocean. Jefferson's written instructions further specified …

Robust Likelihood-Based Analysis Of Multivariate Data With Missing Values, Rod Little, An Hyonggin

The University of Michigan Department of Biostatistics Working Paper Series

The model-based approach to inference from multivariate data with missing values is reviewed. Regression prediction is most useful when the covariates are predictive of the missing values and the probability of being missing, and in these circumstances predictions are particularly sensitive to model misspecification. The use of penalized splines of the propensity score is proposed to yield robust model-based inference under the missing at random (MAR) assumption, assuming monotone missing data. Simulation comparisons with other methods suggest that the method works well in a wide range of populations, with little loss of efficiency relative to parametric models when the latter …

Three-Pion Hanbury Brown–Twiss Correlations In Relativistic Heavy-Ion Collisions From The Star Experiment, Star Collaboration, T.D. Gutierrez

Physics

Data from the first physics run at the Relativistic Heavy-Ion Collider at Brookhaven National Laboratory, Au+Au collisions at √s_NN=130   GeV, have been analyzed by the STAR Collaboration using three-pion correlations with charged pions to study whether pions are emitted independently at freeze-out. We have made a high-statistics measurement of the three-pion correlation function and calculated the normalized three-particle correlator to obtain a quantitative measurement of the degree of chaoticity of the pion source. It is found that the degree of chaoticity seems to increase with increasing particle multiplicity.

Former Mathematics Chair Gives $300,000 For Student Scholarships, Faculty Research, Nicklaus Simpson

University of Mississippi News

OXFORD, Miss. - Knowing firsthand the value of private funding in education, a former chair of the University of Mississippi's Department of Mathematics has given $300,000 for student scholarships and faculty research. Roy Sheffield and his wife, Reda, of Dorsey recently visited the Oxford campus to deliver the gift and attend a reception in their honor.

Resonant Emergence Of Global And Local Spatiotemporal Order In A Nonlinear Field Model, Marcelo Gleiser, Rafael C. Howell

Dartmouth Scholarship

We investigate the nonequilibrium evolution of a scalar field in (2+1) dimensions. The field is set in a double-well potential in contact (open) or not (closed) with a heat bath. For closed systems, we observe the synchronized emergence of coherent spatiotemporal configurations, identified with oscillons. This initial global ordering degenerates into localized order until all oscillons disappear. We show that the synchronization is driven by resonant parametric oscillations of the field’s zero mode and that local ordering is only possible outside equipartition. None of these orderings occur for open systems.

Uncertainty And The Value Of Diagnostic Information With Application To Axillary Lymph Node Dissection In Breast Cancer, Giovanni Parmigiani

Johns Hopkins University, Dept. of Biostatistics Working Papers

In clinical decision making, it is common to ask whether, and how much, a diagnostic procedure is contributing to subsequent treatment decisions. Statistically, quantification of the value of the information provided by a diagnostic procedure can be carried out using decision trees with multiple decision points, representing both the diagnostic test and the subsequent treatments that may depend on the test's results. This article investigates probabilistic sensitivity analysis approaches for exploring and communicating parameter uncertainty in such decision trees. Complexities arise because uncertainty about a model's inputs determines uncertainty about optimal decisions at all decision nodes of a tree. We …

Grand Valley Forum, Volume 028, Number 20, December 22, 2003, Grand Valley State University

2003-2004, Volume 28

Grand Valley Forum is Grand Valley State's faculty and staff newsletter, published from 1976 to the present.

Marginalized Transition Models For Longitudinal Binary Data With Ignorable And Nonignorable Dropout, Brenda F. Kurland, Patrick J. Heagerty

UW Biostatistics Working Paper Series

We extend the marginalized transition model of Heagerty (2002) to accommodate nonignorable monotone dropout. Using a selection model, weakly identified dropout parameters are held constant and their effects evaluated through sensitivity analysis. For data missing at random (MAR), efficiency of inverse probability of censoring weighted generalized estimating equations (IPCW-GEE) is as low as 40% compared to a likelihood-based marginalized transition model (MTM) with comparable modeling burden. MTM and IPCW-GEE regression parameters both display misspecification bias for MAR and nonignorable missing data, and both reduce bias noticeably by improving model fit

Establishing A Quantitative Foundation For Exactly Constrained Design, Alisha M. Hammond

Theses and Dissertations

Exactly constrained (EC) design is a robust design method which can be used for mechanical assemblies. It entails using the minimum number of constraints to eliminate all desired motion.

While found by some engineers in industry to have many benefits (including robust assembly, no binding or play, ease of assembly, and the ability to tolerate the wear of parts), EC designs remain somewhat unrecognized by academia. One reason for this minimal exposure may be the lack of a quantitative foundation for such designs. This thesis describes the history and current background for EC designs, and it also begins to develop …