High-frequency analysis of the Ellipticus antenna

Efficient numerical solution techniques have been developed and used to examine the electromagnetic fields that can be developed in the working volume of the CW Ellipticus antenna operated at frequencies from 100 kHz to 1 GHz. An exponentially tapered transition section is designed to obtain the desired illumination pattern in the working volume. The input transition section is needed for impedance matching and to drive efficiently the Ellipticus antenna. A parametric study is performed to ascertain the performance of the Ellipticus antenna for frequencies up to 1 GHz     

The Execution of Legal Documents by Sexual Minority Individuals.

Sexual minority individuals (specifically bisexual, gay, lesbian and transgendered [BGLT]) have identities and relationships that are socially stigmatized and legally unrecognized. An online survey of 398 BGLT individuals was conducted concerning their execution of 5 legal planning documents: a will, powers of attorney for finances and health care, a living will, and hospital visitation authorization. We found support for the hypothesis that BGLT individuals who are in committed relationships, have disclosed their sexual orientation to immediate family, and have more income are more likely to have executed some or all of these documents. The authors discuss implications for BGLT individuals and same-sex couples, the need for policy changes and therapeutic intervention, and future directions for research in this area. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mass spectrometry of atmospheric aerosols--recent developments and applications. Part I: Off-line mass spectrometry techniques

Many of the significant advances in our understanding of atmospheric particles can be attributed to the application of mass spectrometry. Mass spectrometry provides high sensitivity with a fast response time to probe chemically complex particles. This review focuses on recent developments and applications in the field of mass spectrometry of atmospheric aerosols. In Part I of this two-part review, we concentrate on off-line mass spectrometry techniques, which require sample collection on filters but can provide detailed molecular speciation. In particular, off-line mass spectrometry techniques utilizing tandem mass spectrometry experiments and high resolution mass analyzers provide improved insight into secondary organic aerosol formation and heterogeneous reaction pathways through detailed structural elucidation at the molecular level.     

Interpretation of mass spectra from organic compounds in aerosol time-of-flight mass spectrometry

Organic compounds containing a variety of functional groups have been analyzed using aerosol time-of-flight mass spectrometry. Both positive and negative laser desorption/ionization mass spectra have been acquired for compounds of relevance to ambient air particulate matter, including polycyclic aromatic hydrocarbons, heterocyclic analogues, aromatic oxygenated compounds such as phenols and acids, aliphatic dicarboxylic acids, and reduced nitrogen species such as amines. In many cases, positive ion mass spectra are similar to those found in libraries for 70-eV electron impact mass spectrometry. However, formation of even-electron molecular ions due to adduct formation also plays a major role in ion formation. Negative ion mass spectra suggest that organic compounds largely disintegrate into carbon cluster fragments (C(n)- and C(n)H-). However, information about the heteroatoms present in organic molecules, especially nitrogen and oxygen, is carried dominantly by negative ion spectra, emphasizing the importance of simultaneous analysis of positive and negative ions in atmospheric samples.     

Investigations of the diurnal cycle and mixing state of oxalic acid in individual particles in Asian aerosol outflow

The mixing state of oxalic acid was measured in Asian outflow during ACE-Asia by direct shipboard measurements using an ATOFMS single-particle mass spectrometer. Oxalic and malonic acids were found to be predominantly internally mixed with mineral dust and aged sea salt particles. A persistent diurnal cycle of oxalic acid in mineral dust occurred for over 25 days in marine, polluted marine, and dust storm air masses. The preferential enrichment of diacids in mineral dust over carbonaceous particles and their diurnal behavior indicate a photochemical source of the diacids. Oxalate was only detected simultaneously with elevated aged dust particle counts. This suggests that the diurnal production of diacids most likely results from episodic atmospheric processing of the polluted dust aerosol. We propose a mechanism to explain these observations in which the photochemical oxidation of volatile organic compounds is followed by partitioning of the diacids and precursors to the alkaline Asian dust, with subsequent heterogeneous and aqueous oxidation. Our data indicate that the particulate diacids were produced over just a few hours close to the source; no significant production or destruction appears to have occurred during long-range transport to the ship. No evidence of extensive cloud processing of the sampled aerosol was found. This mixing state of diacids has important implications for the solubility and cloud nucleation properties of the dominant fraction of water-soluble organics and the bioavailability of iron in dust.     

Heterostructure photonic crystals: theory and applications

A hybrid structure combining square and hexagonal photonic crystal lattices is presented. This structure, which we refer to as heterostructure, offers the ability to tailor, optimize, and match the band structure of different lattices. The availability of heterostructures in photonic crystals opens abroad range of possibilities for optical device development. In particular, heterostructure photonic crystals are well suited for the application of optical beam splitting (Y coupler) and combining. Numerical experiments performed by use of the finite-difference time-domain method are shown to illustrate the device implemented in both unistructure and heterostructure lattices.     

Electromagnetic analysis of axially symmetric diffractive lenses with the method of moments

We present the electromagnetic analysis of axially symmetric diffractive lenses. Analysis is performed by numerically solving the electric and magnetic field integral equations using the method of moments, and it exploits axial symmetry to reduce computational cost. Formulations for the analysis of loss less dielectric and perfectly conducting lenses are presented. The analysis of binary and eight-level lenses are performed to illustrate the utility of the technique.     

Three-dimensional analysis of subwavelength diffractive optical elements with the finite-difference time-domain method

We present a three-dimensional (3D) analysis of subwavelength diffractive optical elements (DOE's), using the finite-difference time-domain (FDTD) method. To this end we develop and apply efficient 3D FDTD methods that exploit DOE properties, such as symmetry. An axisymmetric method is validated experimentally and is used to validate the more general 3D method. Analyses of subwavelength gratings and lenses, both with and without rotational symmetry, are presented in addition to a 2 x 2 subwavelength focusing array generator.     

Videoendoscopic diagnosis of esophageal motility disorders

PURPOSE: Looking for a valid, reliable, and feasible method to collect data on the performances of practicing family physicians, the authors compare the measurement characteristics of a multiple-station examination (MSE) using standardized patients with those of a video assessment of regular consultations in daily practice (practice video assessment, PVA). METHOD: In a cross-sectional study, consultations of 90 family physicians were videotaped both in an MSE and in their daily practices. Peer-observers used a validated instrument (MAAS-Global) to assess the physicians' communication with patients and their medical performances. The physicians were randomly divided into two groups, comparable for demographic characteristics, and half underwent the assessments in reverse order to test for time-order effects. Content validity, criterion validity, reliability, and feasibility of the two methods were compared. RESULTS: Content validity of the PVA was superior to that of the MSE, since the domain of general family practice care was better covered. Observed participants judged the videotaped practice consultations to be "natural," whereas hardly any family physician, after reviewing the videotaped consultations of the MSE, recognized his or her usual working style. Specific criteria made it possible to standardize real practice. Concerning criterion validity, only the medical-performance components of the two methods correlated. No correlation was found for the communication components. Real-practice performance proved to be less influenced by observation than was performance during the MSE. The reliabilities of the two methods, expected to be better in the controlled MSE, were comparable. The administration of the PVA was more flexible, less costly, and better accepted by the family physicians than was that of the MSE. CONCLUSION: Assessment for quality improvement of family physicians' practices by video observation in daily practice is superior to video assessment in a simulated setting using standardized patients.