1,726 research outputs found
Computations involving differential operators and their actions on functions
The algorithms derived by Grossmann and Larson (1989) are further developed for rewriting expressions involving differential operators. The differential operators involved arise in the local analysis of nonlinear dynamical systems. These algorithms are extended in two different directions: the algorithms are generalized so that they apply to differential operators on groups and the data structures and algorithms are developed to compute symbolically the action of differential operators on functions. Both of these generalizations are needed for applications
CDM analysis
The C Data Manager (CDM) is an advanced tool for creating an object-oriented database and for processing queries related to objects stored in that database. The CDM source code was purchased and will be modified over the course of the Arachnid project. In this report, the modified CDM is referred to as MCDM. Using MCDM, a detailed series of experiments was designed and conducted on a Sun Sparcstation. The primary results and analysis of the CDM experiment are provided in this report. The experiments involved creating the Long-form Faint Source Catalog (LFSC) database and then analyzing it with respect to following: (1) the relationships between the volume of data and the time required to create a database; (2) the storage requirements of the database files; and (3) the properties of query algorithms. The effort focused on defining, implementing, and analyzing seven experimental scenarios: (1) find all sources by right ascension--RA; (2) find all sources by declination--DEC; (3) find all sources in the right ascension interval--RA1, RA2; (4) find all sources in the declination interval--DEC1, DEC2; (5) find all sources in the rectangle defined by--RA1, RA2, DEC1, DEC2; (6) find all sources that meet certain compound conditions; and (7) analyze a variety of query algorithms. Throughout this document, the numerical results obtained from these scenarios are reported; conclusions are presented at the end of the document
Insulating Materials Comprising Polysilazane, Methods of Forming Such Insulating Materials, and Precursor Formulations Comprising Polysilazane
Methods of forming an insulating material comprising combining a polysilazane, a cross-linking compound, and a gas-generating compound to form a reaction mixture, and curing the reaction mixture to form a modified polysilazane. The gas-generating compound may be water, an alcohol, an amine, or combinations thereof. The cross-linking compound may be an isocyanate, an epoxy resin, or combinations thereof. The insulating material may include a matrix comprising one of a reaction product of a polysilazane and an isocyanate and a reaction product of a polysilazane and an epoxy resin. The matrix also comprises a plurality of interconnected pores produced from one of reaction of the polysilazane and the isocyanate and from reaction of the polysilazane and the epoxy resin. A precursor formulation that comprises a polysilazane, a cross-linking compound, and a gas-generating compound is also disclosed
The Changing Face of Veterinary Practice: A Special Focus on Rural America
Rural and food animal veterinary practice is evolving in response to changes in society, veterinary student demographics, and business opportunities available in the 21st century. The gravitation of veterinarians toward metropolitan areas has created a perception of under-serviced animal health needs in rural communities. Many rural communities are heavily reliant on agriculture; therefore, this perceived need for veterinarians influences the food animal industry as a whole. Veterinary colleges have changed in response to the increased number of students who are interested in companion animal medicine. These changes have resulted in diminished large animal content in the professional curricula, attrition of the number of faculty teaching food animal medicine, increases in the number of faculty dedicated to small animal curriculum, and an overwhelming sense that the veterinary program is centered around training in preparation for a career in companion animal practice. A multitude of factors likely contribute to the continued gravitation of veterinary students toward small animal practice. Veterinary colleges must strive to maintain a balanced, open-minded view of the profession so that students have an equal opportunity to choose a path that best suits their desires and interests
Comparison of classification algorithms to predict outcomes of feedlot cattle identified and treated for Bovine Respiratory Disease
Bovine respiratory disease (BRD) continues to be the primary cause of morbidity and mortality in feedyard cattle. Accurate identification of those animals that will not finish the production cycle normally following initial treatment for BRD would provide feedyard managers with opportunities to more effectively manage those animals. Our objectives were to assess the ability of different classification algorithms to accurately predict an individual calf’s outcome based on data available at first identification of and treatment for BRD and also to identify characteristics of calves where predictive models performed well as gauged by accuracy.
Data from 23 feedyards in multiple geographic locations within the U.S. from 2000 to 2009 representing over one million animals were analyzed to identify animals clinically diagnosed with BRD and treated with an antimicrobial. These data were analyzed both as a single dataset and as multiple datasets based on individual feedyards and partitioned into training, testing, and validation datasets. Classifiers were trained and optimized to identify calves that did not finish the production cycle with their cohort. Following classifier training, accuracy was evaluated using validation data. Analysis was also done to identify sub-groups of calves within populations where classifiers performed better compared to other sub-groups.
Accuracy of individual classifiers varied by dataset. The accuracy of the best performing classifier by dataset ranged from a low of 63% in one dataset up to 95% in a different dataset. Sub-groups of calves were identified within some datasets where accuracy of a classifiers were greater than 98%; however these accuracies must be interpreted in relation to the prevalence of the class of interest within those populations. We found that by pairing the correct classifier with the data available, accurate predictions could be made that would provide feedlot managers with valuable information
Interpreting statistics from published research to answer clinical and management questions
Citation: White, B. J., Larson, R. L., & Theurer, M. E. (2016). Interpreting statistics from published research to answer clinical and management questions. Journal of Animal Science, 94(11), 4959-4971. doi:10.2527/jas2016-0706Appropriate statistical analysis is critical in interpreting results from published literature to answer clinical and management questions. Internal validity is an assessment of whether the study design and statistical analysis are appropriate for the hypotheses and study variables while controlling for bias and confounding. External validity is an assessment of the appropriateness of extrapolation of the study results to other populations. Knowledge about whether treatment or observation groups are truly different is unknown, but studies can be broadly categorized as exploratory or discovery, based on knowledge about previous research, biology, and study design, and this categorization affects interpretation. Confidence intervals, P-values, prediction intervals, credible intervals, and other decision aids are used singly or in combination to provide evidence for the likelihood of a given model but can be interpreted only if the study is internally valid. These decision aids do not test for bias, study design, or the appropriateness of applying study results to other populations dissimilar to the population tested. The biologic and economic importance of the magnitude of difference between treatment groups or observation groups as estimated by the study data and statistical interpretation is important to consider in clinical and management decisions. Statistical results should be interpreted in light of the specific question and production system addressed, the study design, and knowledge about pertinent aspects of biology to appropriately aid decisions
AN UPDATE ON THE REVISION OF THE HANDBOOK, PREVENTION AND CONTROL OF WILDLIFE DAMAGE
Wildlife species have an important role in our environment and they provide many recreational, economic, and aesthetic benefits. Management of these species is necessary, however, when they cause damage to agricultural, industrial, and natural resources, and threaten personal property, public health, and safety. Published estimates indicate that commensal rodents, field rodents, and predators combined, cause \u3e$2 billion in damage in North America annually. Because of the social and economic impacts of wildlife damage, there is a need for up-to-date information on the prevention and control of wildlife damage for producers, resource managers, administrators, and the public. The book, Prevention and Control of Wildlife Damage, edited by Robert M. Timm (1983) (Handbook) has served as the principal reference in this field. The Handbook currently contains 65 chapters (650 pages) by 45 authors who are recognized as authorities in wildlife damage management. Over 8,500 copies have been sold and are being used by personnel from the U.S. Department of Agriculture -Extension Service (ES) and Division of Animal Damage Control (ADC), natural resources agencies, municipalities, private pest control operations and others throughout the United States, as well as other countries. The Handbook has been reprinted four times and was recognized by the Natural Resources Council of America as Outstanding Book for 1983. Previous Handbook sponsors include the University of Nebraska-Cooperative Extension (UNCE), ES, U.S. Environmental Protection Agency (EPA) and the Great Plains Agricultural Council
- …