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Discriminative Stimulus Properties of Cocaine: Tolerance and Cross-Tolerance Characteristics

Description: Rats were trained to discriminate an injection of cocaine, 5.0 mg/kg, from an injection of saline, using a two-lever choice paradigm: one lever was correct after cocaine injection, the other lever was correct after a saline injection. After training, cocaine and methamphetamine were generalized to the cocaine lever, but phenethylamine (PEA) was only partially generalized. Cocaine was injected every 8 hrs, 20.0 mg/kg, and the discriminability of 5.0 mg/kg was tested every other day. Redetermination of the cocaine generalization curve after 6 days of chronic administration showed a shift to the right, from an ED50 of 4.1 mg/kg in the pre-chronic condition to 10.0 mg/kg. Tolerance did not develop to the behavioral effects of cocaine, measured by time to the first reinforcement and response rate. There was cross-tolerance to methamphetamine; however, no evidence for cross-tolerance to PEA was obtained. Following the acquisition of tolerance, chronic administration of cocaine was terminated, and the discriminability of 5.0 mg/kg was tested every other day for loss of tolerance. After 8 days the ED50 returned to 5.0 mg/kg.
Date: May 1985
Creator: Wood, Douglas M. (Douglas Michael)
Partner: UNT Libraries

Multithreading for Synchronization Tolerance in MatrixFactorization

Description: Physical constraints such as power, leakage and pin bandwidth are currently driving the HPC industry to produce systems with unprecedented levels of concurrency. In these parallel systems, synchronization and memory operations are becoming considerably more expensive than before. In this work we study parallel matrix factorization codes and conclude that they need to be re-engineered to avoid unnecessary (and expensive) synchronization. We propose the use of multithreading combined with intelligent schedulers and implement representative algorithms in this style. Our results indicate that this strategy can significantly outperform traditional codes.
Date: July 16, 2007
Creator: Buttari, Alfredo; Dongarra, Jack; Husbands, Parry; Kurzak, Jakub & Yelick, Katherine
Partner: UNT Libraries Government Documents Department

Positional Tolerancing at Sandia Corporation

Description: Abstract: "This report presents a brief introduction to the Positional Tolerance Method of DImensioning as employed by Sandia Corporation. The emphasis is placed on the elimination of ambiguities and increase in tolerances provided by this method as compared to the older, bilateral method" (p. 2).
Date: September 1961
Creator: Sandia Corporation. Design Definition Department.
Partner: UNT Libraries Government Documents Department

Positional Tolerancing at Sandia Corporation

Description: Abstract: "This brochure presents a brief introduction to the Positional Tolerance Method of DImensioning as employed by Sandia Corporation. The emphasis is placed on the elimination of ambiguities and increase in tolerances provided by this method as compared to the older, bilateral method."
Date: May 1959
Creator: Sandia Corporation. Design Definition Department.
Partner: UNT Libraries Government Documents Department

Anatomical and Morphological Responses of Cardiospermum Halicacabum L. (Balloon Vine), to Four Levels of Water Availability

Description: C. halicacabum (Sapindaceae) is an invasive plant that is considered a nuisance species in Texas riparian environments. Little is known of the tolerance of C. halicacabum to flooding and drought; however, this information may provide insight into the characteristics that contribute to C. halicacabum purported invasiveness. C. halicacabum seedlings (n = 92) were exposed to one of four levels of water availability (flooded, saturated, intermediate and dry) over six weeks under greenhouse conditions. Plant performance was affected by water availability; however, there was no effect on survivorship. Flooded and saturated plants exhibited morphological adaptations; producing adventitious roots, hypertrophy, and aerenchyma tissue. Morphological measures, anatomical responses, and patterns of biomass allocation all indicate that C. halicacabum is able to survive periodic inundation, perform in saturation, and establish and thrive on the drier end of a moisture gradient.
Date: May 2011
Creator: Dempsey, Matthew Anthony
Partner: UNT Libraries

Neuropharmacological Characteristics of Tolerance for Cocaine Used as a Discriminative Stimulus

Description: The main purpose of this research was to investigate the phenomenon of tolerance to cocaine. Tolerance is operationally defined as a decreased drug effect due to prior history of drug administration. The animal model that was chosen to investigate tolerance to cocaine was the drug discrimination model, which is an animal analogue of human subjective drug effects. In the drug discrimination procedure, animals are trained to emit one behavior when injected with saline. In the present experiments, rats were trained to press one lever when injected with cocaine, 10 mg/kg, and a different lever when injected with saline for food reinforcement. Once rats are trained, they can accurately detect the cocaine stimulus greater than 95% of the time.
Date: August 1987
Creator: Wood, Douglas M. (Douglas Michael)
Partner: UNT Libraries

Characterization of Tolerance and Cross-tolerance between Noncompetitive N-methyl-D-aspartate (NMDA) Antagonists in Rats Trained to Self-administer Ketamine

Description: Ketamine and phencyclidine (PCP) are noncompetitive antagonists of the N-methyl-D-aspartate (NMDA) type of ligand-gated glutamate receptors. Both agents have high abuse liability, and may produce dependence. Tolerance to the reinforcing effects of drugs of abuse is widely regarded as a key component of the dependence process. Therefore, the present study was conducted to examine whether tolerance develops to the reinforcing effects of ketamine, and whether PCP and dizocilpine, a noncompetitive NMDA antagonist with negligible abuse liability, produce cross-tolerance to the reinforcing effects of ketamine. Further, identification of the neural mechanisms that underlie tolerance to the reinforcing effects of drugs may yield information regarding drug dependence.
Date: December 1995
Creator: Ward, Amie S. (Amie Sue)
Partner: UNT Libraries


Description: In this paper we discuss the effect on the emittance of the residual dispersion in the insertion devices. The dispersion in the straights could be generated by the lattice error, trim dipole, and insertion device. The effect on the emittance is examined, and the dispersion tolerances are given for the NSLS-11.
Date: June 25, 2007
Creator: LIN,F. & GUO, W.
Partner: UNT Libraries Government Documents Department

Adaptive Mesh Refinement Algorithms for Parallel Unstructured Finite Element Codes

Description: This project produced algorithms for and software implementations of adaptive mesh refinement (AMR) methods for solving practical solid and thermal mechanics problems on multiprocessor parallel computers using unstructured finite element meshes. The overall goal is to provide computational solutions that are accurate to some prescribed tolerance, and adaptivity is the correct path toward this goal. These new tools will enable analysts to conduct more reliable simulations at reduced cost, both in terms of analyst and computer time. Previous academic research in the field of adaptive mesh refinement has produced a voluminous literature focused on error estimators and demonstration problems; relatively little progress has been made on producing efficient implementations suitable for large-scale problem solving on state-of-the-art computer systems. Research issues that were considered include: effective error estimators for nonlinear structural mechanics; local meshing at irregular geometric boundaries; and constructing efficient software for parallel computing environments.
Date: February 3, 2006
Creator: Parsons, I D & Solberg, J M
Partner: UNT Libraries Government Documents Department

Direction-preserving and Schur-monotonic Semi-separable Approximations of Symmetric Positive Definite Matrices

Description: For a given symmetric positive definite matrix A {element_of} R{sup nxn}, we develop a fast and backward stable algorithm to approximate A by a symmetric positive-definite semi-separable matrix, accurate to any prescribed tolerance. In addition, this algorithm preserves the product, AZ, for a given matrix Z {element_of} R{sup nxd}, where d << n. Our algorithm guarantees the positive-definiteness of the semi-separable matrix by embedding an approximation strategy inside a Cholesky factorization procedure to ensure that the Schur complements during the Cholesky factorization all remain positive definite after approximation. It uses a robust direction-preserving approximation scheme to ensure the preservation of AZ. We present numerical experiments and discuss potential implications of our work.
Date: October 20, 2009
Creator: Gu, Ming; Li, Xiaoye Sherry & Vassilevski, Panayot S.
Partner: UNT Libraries Government Documents Department

Cognitive Strategies for the Control of Experimentally Induced Pain: The Role of Pleasantness and Relevance of Content in Imagery

Description: This study compared the relative efficacy of four imagery techniques in increasing tolerance to cold pressor pain. Relevant pleasant, relevant unpleasant, irrelevant pleasant, and irrelevant unpleasant imagery strategies were compared in a two-way factorial design. Prior research suggested that pleasantness and relevance both affect imagery potency. This study attempted to assess the relative contribution of these two variables to increases in pain tolerance. Also investigated were the roles of several hypothesized mediating variables; namely, contextual valence, self-efficacy, treatment credibility, and involvement in imagery. The subjects were 60 female undergraduates who were randomly assigned to the four imagery groups. Two-way analysis of covariance were performed on all dependent variables, using pain threshold as the covariate. Pearons r.'s were used to test correlational hypotheses.
Date: August 1982
Creator: Geary, Thomas Dennis
Partner: UNT Libraries


Description: The LLNL inspection shop is chartered to make dimensional measurements of components for critical programmatic experiments. These measurements ensure that components are within tolerance and provide geometric details that can be used to further refine simulations. For these measurements to be useful, they must be significantly more accurate than the tolerances that are being checked. For example, if a part has a specified dimension of 100 millimeters and a tolerance of 1 millimeter, then the precision and/or accuracy of the measurement should be less than 1 millimeter. Using the ''10-to-1 gaugemaker's rule of thumb'', the desired precision of the measurement should be less than 100 micrometers. Currently, the process for associating measurement uncertainty with data is not standardized, nor is the uncertainty based on a thorough uncertainty analysis. The goal of this project is to begin providing measurement uncertainty statements with critical measurements performed in the inspection shop. To accomplish this task, comprehensive knowledge about the underlying sources of uncertainty for measurement instruments need to be understood and quantified. Moreover, measurements of elemental uncertainties for each physical source need to be combined in a meaningful way to obtain an overall measurement uncertainty.
Date: December 20, 2006
Creator: Nederbragt, W. W.
Partner: UNT Libraries Government Documents Department

Genome-wide analysis of the omega-3 fatty acid desaturase gene family in Gossypium

Description: This article identifies and characterizes the omega-3 fatty acid desaturase gene family in Gossypium hirsutum, with an emphasis on identifying omega-3 fatty acid desaturase involved in cold temperature adaption.
Date: November 18, 2014
Creator: Yurchenko, Olga P.; Park, Sunjung; Ilut, Daniel C.; Inmon, Jay J.; Millhollon, Jon C.; Liechty, Zach et al.
Partner: UNT College of Arts and Sciences

Soft Error Vulnerability of Iterative Linear Algebra Methods

Description: Devices are increasingly vulnerable to soft errors as their feature sizes shrink. Previously, soft error rates were significant primarily in space and high-atmospheric computing. Modern architectures now use features so small at sufficiently low voltages that soft errors are becoming important even at terrestrial altitudes. Due to their large number of components, supercomputers are particularly susceptible to soft errors. Since many large scale parallel scientific applications use iterative linear algebra methods, the soft error vulnerability of these methods constitutes a large fraction of the applications overall vulnerability. Many users consider these methods invulnerable to most soft errors since they converge from an imprecise solution to a precise one. However, we show in this paper that iterative methods are vulnerable to soft errors, exhibiting both silent data corruptions and poor ability to detect errors. Further, we evaluate a variety of soft error detection and tolerance techniques, including checkpointing, linear matrix encodings, and residual tracking techniques.
Date: January 19, 2008
Creator: Bronevetsky, G & de Supinski, B
Partner: UNT Libraries Government Documents Department


Description: The LHC aperture imposes a tight tolerance of 20% on the maximum acceptable beta-beat in the machine. An accurate knowledge of the transfer functions for the individually powered insertion quadrupoles and techniques to compensate beta-beat are key prerequisites for successful operation with high intensity beams. They perform realistic simulations to identify quadrupole errors in LHC and explore possible ways of correction to minimize beta-beat below the 20% level.
Date: June 26, 2006
Partner: UNT Libraries Government Documents Department

Potential for Accelerated Bioremediation and Restoration of Oil-Impacted Marshes through the Selection of Superior Oil-Tolerant Vegetation

Description: Report describing a study of the genotypes two plants (Spartina Patens and Spartina Alterniflora) that are tolerant to oil spills that have occurred in the coastal marshes of Louisiana. The research was to determine if these two plants could utilized for restoration and bioremediation of areas effected by oil spills. A plants tolerance to oil is determined by three factors: growth response and plant production, superior vegetative regrowth in soil effected by oil, and superior oil degradation potential.
Date: May 2000
Creator: Hester, Mark W.; Lin, Quixan; Mendellsohn, Irving A. & DesRoches, Dennis, J.
Partner: UNT Libraries Government Documents Department