University of Oklahoma

About: University of Oklahoma is a education organization based out in Norman, Oklahoma, United States. It is known for research contribution in the topics: Population & Radar. The organization has 25269 authors who have published 52609 publications receiving 1821706 citations. The organization is also known as: OU & Oklahoma University.

Lanczos Filtering in One and Two Dimensions

Abstract: A Fourier method of filtering digital data called Lanczos filtering is described Its principal feature is the use of “sigma factors” which significantly reduce the amplitude of the Gibbs oscillation A pair of graphs is developed that can be used to determine filter response quality given the number of weights and the value of the cutoff frequency, the only two inputs required by the method Examples of response functions in one and two dimensions are given and comparisons are made with response functions from other filters The simplicity of calculating the weights and the adequate response make Lanczos filtering an attractive filtering method

Safety and Efficacy of Gene Transfer for Leber's Congenital Amaurosis

Abstract: S um m a r y Leber's congenital amaurosis (LCA) is a group of inherited blinding diseases with onset during childhood. One form of the disease, LCA2, is caused by mutations in the retinal pigment epithelium-specific 65-kDa protein gene (RPE65). We investiga t ed the safety of subretinal delivery of a recombinant adeno-associated virus (AAV) carry- ing RPE65 complementary DNA (cDNA) (ClinicalTrials.gov number, NCT00516477). Three patients with LCA2 had an acceptable local and systemic adverse-event pro- file after delivery of AAV2.hRPE65v2. Each patient had a modest improvement in measures of retinal function on subjective tests of visual acuity. In one patient, an asymptomatic macular hole developed, and although the occurrence was considered to be an adverse event, the patient had some return of retinal function. Although the follow-up was very short and normal vision was not achieved, this study pro- vides the basis for further gene therapy studies in patients with LCA.

The Dartmouth Stellar Evolution Database

Abstract: The ever-expanding depth and quality of photometric and spectroscopic observations of stellar populations increase the need for theoretical models in regions of age-composition parameter space that are largely unexplored at present. Stellar evolution models that employ the most advanced physics and cover a wide range of compositions are needed to extract the most information from current observations of both resolved and unresolved stellar populations. The Dartmouth Stellar Evolution Database is a collection of stellar evolution tracks and isochrones that spans a range of [Fe/H] from –2.5 to +0.5, [α/Fe] from –0.2 to +0.8 (for [Fe/H] ≤ 0) or +0.2 (for [Fe/H] > 0), and initial He mass fractions from Y = 0.245 to 0.40. Stellar evolution tracks were computed for masses between 0.1 and 4 M☉, allowing isochrones to be generated for ages as young as 250 Myr. For the range in masses where the core He flash occurs, separate He-burning tracks were computed starting from the zero age horizontal branch. The tracks and isochrones have been transformed to the observational plane in a variety of photometric systems including standard UBV(RI)C, Stromgren uvby, SDSS ugriz, 2MASS JHKs, and HST ACS/WFC and WFPC2. The Dartmouth Stellar Evolution Database is accessible through a Web site at http://stellar.dartmouth.edu/~models/ where all tracks, isochrones, and additional files can be downloaded.

Analysis and Performance of Fiber Composites

Abstract: Preface. 1 Introduction. 1.1 Definition. 1.2 Characteristics. 1.3 Classification. 1.4 Particulate Composites. 1.5 Fiber-Reinforced Composites. 1.6 Applications of Fiber Composites. Exercise Problems. References. 2 Fibers, Matrices, and Fabrication of Composites. 2.1 Advanced Fibers. 2.1.1 Glass Fibers. 2.1.2 Carbon and Graphite Fibers. 2.1.3 Aramid Fibers. 2.1.4 Boron Fibers. 2.1.5 Other Fibers. 2.2 Matrix Materials. 2.2.1 Polymers. 2.2.2 Metals. 2.3 Fabrication of Composites. 2.3.1 Fabrication of Thermosetting Resin Matrix Composites. 2.3.2 Fabrication of Thermoplastic-Resin Matrix Composites (Short-Fiber Composites). 2.3.3 Fabrication of Metal Matrix Composites. 2.3.4 Fabrication of Ceramic Matrix Composites. Suggested Reading. 3 Behavior of Unidirectional Composites. 3.1 Introduction. 3.1.1 Nomenclature. 3.1.2 Volume and Weight Fractions. 3.2 Longitudinal Behavior of Unidirectional Composites. 3.2.1 Initial Stiffness. 3.2.2 Load Sharing. 3.2.3 Behavior beyond Initial Deformation. 3.2.4 Failure Mechanism and Strength. 3.2.5 Factors Influencing Longitudinal Strength and Stiffness. 3.3 Transverse Stiffness and Strength. 3.3.1 Constant-Stress Model. 3.3.2 Elasticity Methods of Stiffness Prediction. 3.3.3 Halpin-Tsai Equations for Transverse Modulus. 3.3.4 Transverse Strength. 3.4 Prediction of Shear Modulus. 3.5 Prediction of Poisson's Ratio. 3.6 Failure Modes. 3.6.1 Failure under Longitudinal Tensile Loads. 3.6.2 Failure under Longitudinal Compressive Loads. 3.6.3 Failure under Transverse Tensile Loads. 3.6.4 Failure under Transverse Compressive Loads. 3.6.5 Failure under In-Plane Shear Loads. 3.7 Expansion Coefficients and Transport Properties. 3.7.1 Thermal Expansion Coefficients. 3.7.2 Moisture Expansion Coefficients. 3.7.3 Transport Properties. 3.7.4 Mass Diffusion. 3.8 Typical Unidirectional Fiber Composite Properties. Exercise Problems. References. 4 Short-Fiber Composites. 4.1 Introduction. 4.2 Theories of Stress Transfer. 4.2.1 Approximate Analysis of Stress Transfer. 4.2.2 Stress Distributions from Finite-Element Analysis. 4.2.3 Average Fiber Stress. 4.3 Modulus and Strength of Short-Fiber Composites. 4.3.1 Prediction of Modulus. 4.3.2 Prediction of Strength. 4.3.3 Effect of Matrix Ductility. 4.4 Ribbon-Reinforced Composites. Exercise Problems. References. 5 Analysis of an Orthotropic Lamina. 5.1 Introduction. 5.1.1 Orthotropic Materials. 5.2 Stress-Strain Relations and Engineering Constants. 5.2.1 Stress-Strain Relations for Specially Orthotropic Lamina. 5.2.2 Stress-Strain Relations for Generally Orthotropic Lamina. 5.2.3 Transformation of Engineering Constants. 5.3 Hooke's Law and Stiffness and Compliance Matrices. 5.3.1 General Anisotropic Material. 5.3.2 Specially Orthotropic Material. 5.3.3 Transversely Isotropic Material. 5.3.4 Isotropic Material. 5.3.5 Specially Orthotropic Material under Plane Stress. 5.3.6 Compliance Tensor and Compliance Matrix. 5.3.7 Relations between Engineering Constants and Elements of Stiffness and Compliance Matrices. 5.3.8 Restrictions on Elastic Constants. 5.3.9 Transformation of Stiffness and Compliance Matrices. 5.3.10 Invariant Forms of Stiffness and Compliance Matrices. 5.4 Strengths of an Orthotropic Lamina. 5.4.1 Maximum-Stress Theory. 5.4.2 Maximum-Strain Theory. 5.4.3 Maximum-Work Theory. 5.4.4 Importance of Sign of Shear Stress on Strength of Composites. Exercise Problems. References. 6 Analysis of Laminated Composites. 6.1 Introduction. 6.2 Laminate Strains. 6.3 Variation of Stresses in a Laminate. 6.4 Resultant Forces and Moments: Synthesis of Stiffness Matrix. 6.5 Laminate Description System. 6.6 Construction and Properties of Special Laminates. 6.6.1 Symmetric Laminates. 6.6.2 Unidirectional, Cross-Ply, and Angle-Ply Laminates. 6.6.3 Quasi-isotropic Laminates. 6.7 Determination of Laminae Stresses and Strains. 6.8 Analysis of Laminates after Initial Failure. 6.9 Hygrothermal Stresses in Laminates. 6.9.1 Concepts of Thermal Stresses. 6.9.2 Hygrothermal Stress Calculations. 6.10 Laminate Analysis Through Computers. Exercise Problems. References. 7 Analysis of Laminated Plates and Beams. 7.1 Introduction. 7.2 Governing Equations for Plates. 7.2.1 Equilibrium Equations. 7.2.2 Equilibrium Equations in Terms of Displacements. 7.3 Application of Plate Theory. 7.3.1 Bending. 7.3.2 Buckling. 7.3.3 Free Vibrations. 7.4 Deformations Due to Transverse Shear. 7.4.1 First-Order Shear Deformation Theory. 7.4.2 Higher-Order Shear Deformation Theory. 7.5 Analysis of Laminated Beams. 7.5.1 Governing Equations for Laminated Beams. 7.5.2 Application of Beam Theory. Exercise Problems. References. 8 Advanced Topics in Fiber Composites. 8.1 Interlaminar Stresses and Free-Edge Effects. 8.1.1 Concepts of Interlaminar Stresses. 8.1.2 Determination of Interlaminar Stresses. 8.1.3 Effect of Stacking Sequence on Interlaminar Stresses. 8.1.4 Approximate Solutions for Interlaminar Stresses. 8.1.5 Summary. 8.2 Fracture Mechanics of Fiber Composites. 8.2.1 Introduction. 8.2.2 Fracture Mechanics Concepts and Measures of Fracture Toughness. 8.2.3 Fracture Toughness of Composite Laminates. 8.2.4 Whitney-Nuismer Failure Criteria for Notched Composites. 8.3 Joints for Composite Structures. 8.3.1 Adhesively Bonded Joints. 8.3.2 Mechanically Fastened Joints. 8.3.3 Bonded-Fastened Joints. Exercise Problems. References. 9 Performance of Fiber Composites: Fatigue, Impact, and Environmental Effects. 9.1 Fatigue. 9.1.1 Introduction. 9.1.2 Fatigue Damage. 9.1.3 Factors Influencing Fatigue Behavior of Composites. 9.1.4 Empirical Relations for Fatigue Damage and Fatigue Life. 9.1.5 Fatigue of High-Modulus Fiber-Reinforced Composites. 9.1.6 Fatigue of Short-Fiber Composites. 9.2 Impact. 9.2.1 Introduction and Fracture Process. 9.2.2 Energy-Absorbing Mechanisms and Failure Models. 9.2.3 Effect of Materials and Testing Variables on Impact Properties. 9.2.4 Hybrid Composites and Their Impact Strength. 9.2.5 Damage Due to Low-Velocity Impact. 9.3 Environmental-Interaction Effects. 9.3.1 Fiber Strength. 9.3.2 Matrix Effects. Exercise Problems. References. 10 Experimental Characterization of Composites. 10.1 Introduction. 10.2 Measurement of Physical Properties. 10.2.1 Density. 10.2.2 Constituent Weight and Volume Fractions. 10.2.3 Void Volume Fraction. 10.2.4 Thermal Expansion Coefficients. 10.2.5 Moisture Absorption and Diffusivity. 10.2.6 Moisture Expansion Coefficients. 10.3 Measurement of Mechanical Properties. 10.3.1 Properties in Tension. 10.3.2 Properties in Compression. 10.3.3 In-Place Shear Properties. 10.3.4 Flexural Properties. 10.3.5 Measures of In-Plane Fracture Toughness. 10.3.6 Interlaminar Shear Strength and Fracture Toughness. 10.3.7 Impact Properties. 10.4 Damage Identification Using Nondestructive Evaluation Techniques. 10.4.1 Ultrasonics. 10.4.2 Acoustic Emission. 10.4.3 x-Radiography. 10.4.4 Thermography. 10.4.5 Laser Shearography. 10.5 General Remarks on Characterization. Exercise Problems. References. 11 Emerging Composite Materials. 11.1 Nanocomposites. 11.2 Carbon-Carbon Composites. 11.3 Biocomposites. 11.3.1 Biofibers. 11.3.2 Wood-Plastic Composites (WPCs). 11.3.3 Biopolymers. 11.4 Composites in "Smart" Structures. Suggested Reading. Appendix 1: Matrices and Tensors. Appendix 2: Equations of Theory of Elasticity. Appendix 3: Laminate Orientation Code. Appendix 4: Properties of Fiber Composites. Appendix 5: Computer Programs for Laminate Analysis. Index.

A comprehensive 1000 Genomes–based genome-wide association meta-analysis of coronary artery disease

Abstract: Existing knowledge of genetic variants affecting risk of coronary artery disease (CAD) is largely based on genome-wide association study (GWAS) analysis of common SNPs. Leveraging phased haplotypes from the 1000 Genomes Project, we report a GWAS meta-analysis of ∼185,000 CAD cases and controls, interrogating 6.7 million common (minor allele frequency (MAF) > 0.05) and 2.7 million low-frequency (0.005 < MAF < 0.05) variants. In addition to confirming most known CAD-associated loci, we identified ten new loci (eight additive and two recessive) that contain candidate causal genes newly implicating biological processes in vessel walls. We observed intralocus allelic heterogeneity but little evidence of low-frequency variants with larger effects and no evidence of synthetic association. Our analysis provides a comprehensive survey of the fine genetic architecture of CAD, showing that genetic susceptibility to this common disease is largely determined by common SNPs of small effect size.