NASTRAN as a resource in code development

A case history is presented in which the NASTRAN system provided both guidelines and working software for use in the development of a discrete element program, PATCHES-111. To avoid duplication and to take advantage of the wide spread user familiarity with NASTRAN, the PATCHES-111 system uses NASTRAN bulk data syntax, NASTRAN matrix utilities, and the NASTRAN linkage editor. Problems in developing the program are discussed along with details on the architecture of the PATCHES-111 parametric cubic modeling system. The system includes model construction procedures, checkpoint/restart strategies, and other features

Immunizations in children with chronic kidney disease

Children with chronic kidney disease (CKD) are at increased risk for vaccine-preventable diseases. These patients may have a reduced response to and/or reduced duration of antibody after immunization and therefore monitoring of antibody levels or titers is indicated for some vaccines. In addition, pediatric CKD patients require immunizations not routinely provided to healthy children. Unfortunately, studies in pediatric CKD patients, including those on dialysis and awaiting kidney transplantation, have demonstrated sub-optimal immunization rates. In order to minimize the risk for vaccine-preventable disease in pediatric CKD patients, it is imperative that all who care for these patients remain abreast of the recommended childhood immunization schedule, as well as alterations to this schedule required for children with CKD, including end-stage kidney disease. This article reviews recent changes to the recommended childhood immunization schedule and alterations and additions to this schedule recommended for children with CKD. Where available, data on antibody response to immunizations in children with CKD are presented

A Tightly-Coupled INS/GPS Integration Using a MEMS IMU

Micro-Electro-Mechanical Systems (MEMS) technology holds great promise for future navigation systems because of the reduced size and cost of MEMS inertial sensors relative to conventional devices. Current MEMS devices are much less accurate than standard inertial sensors, but they can still be useful. In this thesis, data was recorded from an inexpensive MEMS inertial measurement unit and integrated with GPS measurements using a tightly-coupled Kalman filter. The overall goal of this research is to investigate the usefulness of MEMS sensors for a small, real-time, low-cost INS/GPS integration. A golf cart was used to collect dynamic data, along with a commercial INS/GPS system to provide reference data. This data was then post-processed, and the filter\u27s performance in the position, velocity, and attitude outputs were evaluated by comparing them to the reference system. The important system features of system alignment, bias feedback, and INS resets are described, and the filter\u27s performance is analyzed using its estimate and covariance outputs and comparing them to the true error. Filter residuals are also shown and discussed. The final results show that, with adequate processing available, the INS/GPS filter using the MEMS instruments provides good position, velocity, and attitude results over a period of up to 15 minutes, as long as the data is at least somewhat dynamic. Without vehicle motion, the vehicle yaw state tends to wander excessively, due to the bias and noise of the MEMS gyroscopes. Over a long static period, the filter\u27s position outputs would most likely diverge and become unstable. Recommendations are made to combat this problem, among them to conduct more characterization of the MEMS sensors, and to add GPS velocity measurements as an input to the filter

Random matrix theory for CPA: Generalization of Wegner's nn--orbital model

We introduce a generalization of Wegner's $n$-orbital model for the description of randomly disordered systems by replacing his ensemble of Gaussian random matrices by an ensemble of randomly rotated matrices. We calculate the one- and two-particle Green's functions and the conductivity exactly in the limit $n\to\infty$. Our solution solves the CPA-equation of the $(n=1)$-Anderson model for arbitrarily distributed disorder. We show how the Lloyd model is included in our model.Comment: 3 pages, Rev-Te

Metamaterial near-field sensor for deep-subwavelength thickness measurements and sensitive refractometry in the terahertz frequency range

We present a metamaterial-based terahertz (THz) sensor for thickness measurements of subwavelength-thin materials and refractometry of liquids and liquid mixtures. The sensor operates in reflection geometry and exploits the frequency shift of a sharp Fano resonance minimum in the presence of dielectric materials. We obtained a minimum thickness resolution of 12.5 nm (1/16000 times the wavelength of the THz radiation) and a refractive index sensitivity of 0.43 THz per refractive index unit. We support the experimental results by an analytical model that describes the dependence of the resonance frequency on the sample material thickness and the refractive index.Comment: 10 pages, 5 figure

A low-loss, broadband antenna for efficient photon collection from a coherent spin in diamond

We report the creation of a low-loss, broadband optical antenna giving highly directed output from a coherent single spin in the solid-state. The device, the first solid-state realization of a dielectric antenna, is engineered for individual nitrogen vacancy (NV) electronic spins in diamond. We demonstrate a directionality close to 10. The photonic structure preserves the high spin coherence of single crystal diamond (T2>100us). The single photon count rate approaches a MHz facilitating efficient spin readout. We thus demonstrate a key enabling technology for quantum applications such as high-sensitivity magnetometry and long-distance spin entanglement.Comment: 5 pages, 4 figures and supplementary information (5 pages, 8 figures). Comments welcome. Further information under http://www.quantum-sensing.physik.unibas.c

Rigorous mean field model for CPA: Anderson model with free random variables

A model of a randomly disordered system with site-diagonal random energy fluctuations is introduced. It is an extension of Wegner's $n$-orbital model to arbitrary eigenvalue distribution in the electronic level space. The new feature is that the random energy values are not assumed to be independent at different sites but free. Freeness of random variables is an analogue of the concept of independence for non-commuting random operators. A possible realization is the ensemble of at different lattice-sites randomly rotated matrices. The one- and two-particle Green functions of the proposed hamiltonian are calculated exactly. The eigenstates are extended and the conductivity is nonvanishing everywhere inside the band. The long-range behaviour and the zero-frequency limit of the two-particle Green function are universal with respect to the eigenvalue distribution in the electronic level space. The solutions solve the CPA-equation for the one- and two-particle Green function of the corresponding Anderson model. Thus our (multi-site) model is a rigorous mean field model for the (single-site) CPA. We show how the Llyod model is included in our model and treat various kinds of noises.Comment: 24 pages, 2 diagrams, Rev-Tex. Diagrams are available from the authors upon reques

Direct observation of superconducting vortex clusters pinned by a periodic array of magnetic dots in ferromagnetic/superconducting hybrid structures

Strong pinning of superconducting flux quanta by a square array of 1 $\mu$m-sized ferromagnetic dots in a magnetic-vortex state was visualized by low-temperature magnetic force microscopy (LT-MFM). A direct correlation of the superconducting flux lines with the positions of the dots was derived. The force that the MFM tip exerts on the individual vortex in the depinning process was used to estimate the spatial modulation of the pinning potential. It was found, that the superconducting vortices which are preferably located on top of the Py dots experience about 15 times stronger pinning forces as compared to the pinning force in the pure Nb film. The strong pinning exceeds the repulsive interaction between the superconducting vortices and allows the vortex clusters to be located at each dot. Our microscopic studies are consistent with global magnetoresistace measurements on these hybrid structures.Comment: 4 pages, 4 figure

Practical Approaches to Treating Patients with Bipolar Disorder

Many patients present to a primary care setting with symptoms of a mood disorder. These symptoms may be indicative of an anxiety disorder or a depressive disorder, but they may also represent bipolar disorder, which is more common than many practitioners think. Correctly diagnosing bipolar disorder can be complex, because patients tend to seek treatment when they are experiencing the symptoms of depression or anxiety rather than mania or hypomania. Comorbid disorders such as substance abuse and anxiety disorders may complicate the clinical presentation. Failing to correctly diagnose bipolar disorder can have serious consequences in terms of patients\u27 morbidity and mortality, quality of life, and financial costs