Now showing items 12506-12525 of 19159

    • The M.L.S. Degree: Time for a Two-Year Program?

      Rapple, Brendan A. (Association of Library and Information Science Education, 1996)
      The author began working by asking a question: how well are library schools preparing students for future participation in the library profession? She thought that one year is not long enough for students to gain what they need to become a library and information science professional. She suggested library schools to undertake a major restructuring of their programs and recommended a two-year M.L.S. program.
    • A Machine for Treating Cotton Seed with Sulphuric Acid

      Brown, J. G.; Gibson, Frederick (College of Agriculture, University of Arizona (Tucson, AZ), 1925-05-01)
    • A Machine Learning Approach to Inductive Query by Examples: An Experiment Using Relevance Feedback, ID3, Genetic Algorithms, and Simulated Annealing

      Chen, Hsinchun; Shankaranarayanan, Ganesan; She, Linlin; Iyer, Anand (Wiley Periodicals, Inc, 1998-06)
      Information retrieval using probabilistic techniques has attracted significant attention on the part of researchers in information and computer science over the past few decades. In the 1980s, knowledge-based techniques also made an impressive contribution to â â intelligentâ â information retrieval and indexing. More recently, information science researchers have turned to other newer inductive learning techniques including symbolic learning, genetic algorithms, and simulated annealing. These newer techniques, which are grounded in diverse paradigms, have provided great opportunities for researchers to enhance the information processing and retrieval capabilities of current information systems. In this article, we first provide an overview of these newer techniques and their use in information retrieval research. In order to familiarize readers with the techniques, we present three promising methods: The symbolic ID3 algorithm, evolution-based genetic algorithms, and simulated annealing. We discuss their knowledge representations and algorithms in the unique context of information retrieval. An experiment using a 8000-record COMPEN database was performed to examine the performances of these inductive query-by-example techniques in comparison with the performance of the conventional relevance feedback method. The machine learning techniques were shown to be able to help identify new documents which are similar to documents initially suggested by users, and documents which contain similar concepts to each other. Genetic algorithms, in particular, were found to out-perform relevance feedback in both document recall and precision. We believe these inductive machine learning techniques hold promise for the ability to analyze usersâ preferred documents (or records), identify usersâ underlying information needs, and also suggest alternatives for search for database management systems and Internet applications.
    • Machine Learning for Information Retrieval: Neural Networks, Symbolic Learning, and Genetic Algorithms

      Chen, Hsinchun (Wiley Periodicals, Inc, 1995-04)
      Information retrieval using probabilistic techniques has attracted significant attention on the part of researchers in information and computer science over the past few decades. In the 1980s, knowledge-based techniques also made an impressive contribution to “intelligent” information retrieval and indexing. More recently, information science researchers have turned to other newer artificial-intelligence- based inductive learning techniques including neural networks, symbolic learning, and genetic algorithms. These newer techniques, which are grounded on diverse paradigms, have provided great opportunities for researchers to enhance the information processing and retrieval capabilities of current information storage and retrieval systems. In this article, we first provide an overview of these newer techniques and their use in information science research. To familiarize readers with these techniques, we present three popular methods: the connectionist Hopfield network; the symbolic ID3/ID5R; and evolution- based genetic algorithms. We discuss their knowledge representations and algorithms in the context of information retrieval. Sample implementation and testing results from our own research are also provided for each technique. We believe these techniques are promising in their ability to analyze user queries, identify users’ information needs, and suggest alternatives for search. With proper user-system interactions, these methods can greatly complement the prevailing full-text, keywordbased, probabilistic, and knowledge-based techniques.
    • Machine Learning: Future Capabilities and their Implications

      Valacich, Joseph; Dehaven, Victoria Rose (The University of Arizona., 2014)
    • Machine Recognition of Rule-Based Phonological Patterns

      Ussishkin, Adam; Wainwright, Elizabeth Lorraine (The University of Arizona., 2017)
      This thesis is project-oriented, with the goal of the research being to create a computer program that will take a set of words in a language written in the International Phonetic Alphabet (IPA) and two sets of phonemes where one undergoes a phonological change to the other and return a phonological rule describing this data. The program was written in Python. It included several functions as well as a new class termed "Phoneme" to facilitate the storage of phonemic features. A reference was made of Phoneme objects for the program to refer to for feature information while analyzing a data set. The program's parameters were that it be able to return a rule given that the data that it was analyzing contained only phonemes found in the reference and that the change be caused by a phoneme directly adjacent to the phoneme undergoing the change. Five datasets were passed through the program and, with the exception of one, were found to return a passable phonological rule. The most notable improvement to be made is the elimination of feature redundancies within the rule.
    • Machine Vision and Autonomy Integration into a UAS Laark: Low-Altitude Aerial Reconnaissance Kit

      Gibson, Malcolm Thomas; Hony, Hans; Liggett, Elliott; Dianics, James; Palmer, Michael (The University of Arizona., 2011-08)
    • A Machine-Learning Approach to Measuring Tumor pH Using MRI

      Cárdenas-Rodríguez, Julio; DeGrandchamp, Joseph B.; Cárdenas-Rodríguez, Julio (The University of Arizona., 2017)
      Tumor pH can become an important consideration in diagnosis and choosing an effective therapy. Measuring pH currently requires invasive procedures or has problems with sensitivity. Previous methods for the measurement of pH by MRI are dependent on knowing the concentration of contrast agents or are useful at a limited pH range. Determining the concentration of a contrast agent in vivo is a very difficult task. We propose to use machine learning to decouple the estimation of pH from requiring knowledge of contrast agent concentration. This approach makes it possible to use new contrast agents and extends the ranges of pH than can be studied. In addition, this technique uses the entirety of the data instead of fitting parameters in order to make pH predictions. We evaluated the performance of this new method to measure pH by repurposing a clinically approved X-ray contrast agent, ioxilan, as an MRI agent. The pH was successfully measured in vitro with a small margin of error (RMSE = 0.0515), and the method was able to produce reliable parametric maps of pH for acquired image sets. We will extend this new method to measure pH in mouse models of cancer.
    • Machine-Made Cement Pipe for Irrigation Systems and Other Purposes

      Smith, G. E. P. (College of Agriculture, University of Arizona (Tucson, AZ), 1918-10-30)
    • Magellanic Cloud Investigations. IV. The LMC Blue Globular Cluster NGC 1850

      Tifft, W. G.; Connolly, L. P.; Univ Arizona, Steward Observ (Steward Observatory, The University of Arizona (Tucson, Arizona), 1972-11)
    • Magellanic Cloud Investigations. III. The LMC Bar

      Tifft, W. G.; Snell, C. M.; Univ Arizona, Steward Observ (Steward Observatory, The University of Arizona (Tucson, Arizona), 1970-08)
      Three -color photographic photometry has been carried out for three small regions at the west end of the LMC bar. Photoelectric calibration observations by Bok and Tifft for 26 stars were utilized. Program stars were selected so that the photographic photometry is uniformly representative to V = 16.6 magnitude in one region and to V = 18.0 magnitude in two smaller ones. The results include more than 600 stars with B and V and more than 160 of the brighter stars with U. Contamination by foreground stars is minimal since the regions are small. Color- magnitude diagrams show a narrow vertical blue sequence 0.25 magnitude wide extending from V = 14.5 to V = 18. The location of this sequence indicates about 0.13 magnitude of uniform reddening in the area. Red supergiants are seen between magnitude 14 and 16. A strong component of fainter red giants indicative of an older population is seen below magnitude 16. The red giants extend to B -V = 1.9. After reddening corrections the reddest normal giants have B -V = 1.8. A few very red stars, B -V = 2.2 to 2.8, are seen near V = 16. Two bright Harvard Variable Cepheids fall within the region under study. Light curves and color curves for both of these stars were obtained. The Cepheids lie to the red of the instability strip consistent with other local reddening effects. Fainter bright giants of intermediate color, including possible Cepheids, have been isolated using the color -color diagram. A period and light curve for one star has been derived. Matching the old giant star population a differential true modulus of 0.65 ±0.1 is derived between the SMC and LMC. For an SMC modulus of 19.1, the LMC modulus is 18.45. The three Cepheids in the field yield a modulus of 18.45 ±0.1 when the P -L -C relationship calibration of Sandage and Tammann (1969) is used. Outlying Cepheids as studied by Gascoigne (1969) are approximately 0.2 magnitudes fainter. Real intrinsic variation in Cepheid luminosities outside of the P -L -C relationship is possible but not large. An overall mean LMC true modulus of 18.5 ±0.1 is indicated.
    • MAGIC SPICES: Ayurvedic Medicine and the Heart

      Cohen, Zoe; Shroff, Erica (The University of Arizona., 2016)
      Ayurvedic medicine has been used in India for centuries as a dominant form of treatment and as a preventative measure for a number of chronic diseases. Not until recently have scientific studies identified the potential hypolipidemic, antiplatelet, and anti-tumor properties of various herbs/spices. The phytochemicals in these compounds may suppress the oxidation of bad LDL cholesterols, stimulate the performance of protective enzymes, and enhance immunestimulating properties that reduce an individual's risk of heart disease. As part of my honors senior thesis I conducted a literature review with my cardiovascular physiology professor, Dr. Cohen, which explores the impacts of Ayurveda on the heart. We wanted to investigate the scientific literature for turmeric and ginger specifically, in order to understand the exact physiology behind these spices. Overall, it seems as though Ayurvedic medicine can be health protective for a number of cardiovascular conditions such as high blood pressure and high cholesterol, but should be used in conjunction to modern medication. In addition, spices have considerable anti-inflammatory responses which have been shown to improve obesity-related inflammatory responses. After much research and analysis, these findings were presented at the Festival of Books in Tucson, AZ on March 12th as community outreach.
    • Magnesite

      Culin, F.L., Jr. (University of Arizona Bureau of Mines, 1916-11-01)
    • Magnesium and Calcium in Zeolitic Soils

      Breazeale, J. F. (College of Agriculture, University of Arizona (Tucson, AZ), 1929-05-10)
    • Magnet Ball Postmortem: An Experiment with End-to-End Rapid Prototyping for Game Development Projects

      Morrison, Clay T.; De La Cruz, Livio (The University of Arizona., 2014)
    • Magnetic Resonance Imaging as Non-Invasive Tool for Predicting Success of Islet Transplantation

      Asghar, Aeen Mostafa (The University of Arizona., 2012-05)
      The success of autologous islet transplantation greatly depends on the total islet yield. Using MRI as a non-invasive tool to determine the volume of the pancreas, the correlation between the calculated volume of the pancreas and the total islet yield has been determined. By using the volume of the pancreas as an indicator of total islet yield, MRI could be used as a predictive tool to determine the success of islet transplants. The data was gathered retrospectively from ten transplant patients, and the volume was determined by freehand contouring of the pancreas on MR images. With only ten patients, no significant correlation could be found between the volume vs. total islet yield, volume vs. IEQ (Islet Equivalent unit), mass vs. total islet yield, and mass vs. IEQ, with correlations of 0.238, 0.139, 0.343, and 0.219, respectively. The lack of correlation between the volume and total islet yield indicates other unaccounted variables such as fibrosis, inflammation, and fatty tissue infiltration that destroy islets but were not included in our volume calculations. Using a new protocol that takes the stated variables into account, we hope to find a better correlation between volume and total islet yield in future studies.
    • Magnitude and Strain Composition of Aspergillus flavus Soil Surface Populations in Yuma County Commerical Fields

      Nelson, M. R.; Bigelow, D. M.; Orum, T. V.; Howell, D. R.; Cotty, P. J.; Silvertooth, Jeff; Department of Plant Pathology, University of Arizona, Tucson; Cooperative Extension Service, University of Arizona; Southern Regional Research Center, USDA, ARS (College of Agriculture, University of Arizona (Tucson, AZ), 1996-03)
      Aflatoxin contamination of cottonseed occurs when cotton bolls are infected by certain strains of the fungus Aspergillus flavus. The risk of aflatoxin contamination in a field is partially dependent on both the quantity of A. flavus and the toxigenicity of A. flavus strains in that field. A. flavus can be easily divided into two major subdivisions known as strain S and strain L. Strain S isolates consistently produce large amounts of aflatoxin and, therefore, the percentage of strain S isolates in the population (percent S) is one indication of the aflatoxin producing potential of the population. Strain S isolates were found in every commercial field sampled at every sampling date in Yuma County, but percent S varied greatly among fields from 4% to 93 %. Significant differences among fields located near each other suggest that locally important, but not yet identified, variables such as crop rotation histories or soil type are affecting A. flavus population magnitude and composition.
    • Maidens dancing

      Flandrau Science Center & Planetarium, University of Arizona (1987)
    • Mail Order and Food Safety

      Meer, Ralph; Misner, Scottie; Nutritional Sciences (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 1999-05)
      Do you know how to identify if the homemade or mail order food packages you received are safe, especially those perishable foods? Perishable foods are typically foods that are high in protein and /or moisture (e.g., milk, eggs, meat, poultry, and seafood). Mishandling these foods can cause food-borne illness. This publication gives some food safety tips you need to keep in mind.
    • Maintaining Copper Homeostasis - Molecular Studies on Bacterial Copper Transporters

      McEvoy, Megan M.; Kim, Eun-Hae; Gerba, Charles; So, Magdalene; McEvoy, Megan M. (The University of Arizona., 2011)
      Bacteria have evolved sophisticated cellular transport mechanisms to maintain metal homeostasis to not only utilize metals as important cofactors but also to evade the toxicity of these ions. The delicate balance is maintained by several homeostatic mechanisms that range from active cytoplasmic export, modification, sequestration, and periplasmic detoxification of toxic metals to the extracellular milieu. One mechanism involves active periplasmic extrusion of toxic substrates via a transmembrane spanning tripartite protein complex. The mechanism of substrate binding and subsequent efflux has yet to be elucidated. However, genetic, comparative genomic, biochemical, and functional analyses of the components of the heavy-metal efflux family have allowed the development of proposed models for a substrate transport pathway. The goals of this research were to identify the roles these systems play and to further characterize these systems on a molecular level to ultimately understand the mechanism of substrate transport. Elucidating a transport pathway in metal transporters allows for the development of a revised working model, which ultimately can have implications for antimicrobial drug development.