Field theoretic calculation of the surface tension for a model electrolyte system

We carry out the calculation of the surface tension for a model electrolyte to first order in a cumulant expansion about a free field theory equivalent to the Debye-H\"uckel approximation. In contrast with previous calculations, the surface tension is calculated directly without recourse to integrating thermodynamic relations. The system considered is a monovalent electrolyte with a region at the interface, of width h, from which the ionic species are excluded. In the case where the external dielectric constant epsilon_0 is smaller than the electrolyte solution's dielectric constant epsilon we show that the calculation at this order can be fully regularized. In the case where h is taken to be zero the Onsager-Samaras limiting law for the excess surface tension of dilute electrolyte solutions is recovered, with corrections coming from a non-zero value of epsilon_0/epsilon.Comment: LaTeX, 14 pages, 3 figures, 1 tabl

Curvature-Induced Defect Unbinding in Toroidal Geometries

Toroidal templates such as vesicles with hexatic bond orientational order are discussed. The total energy including disclination charges is explicitly computed for hexatic order embedded in a toroidal geometry. Related results apply for tilt or nematic order on the torus in the one Frank constant approximation. Although there is no topological necessity for defects in the ground state, we find that excess disclination defects are nevertheless energetically favored for fat torii or moderate vesicle sizes. Some experimental consequences are discussed.Comment: 12 pages, 15 eps figure

Design and Evaluation of an Integrated Safeguards System: Principles

An integrated safeguards system is defined as a collection of safeguards activities in which system components are coordinated to meet safeguards objectives efficiently within constraints imposed by safeguards resources, facility operations, potential adversaries, and regulatory requirements. This paper describes principles for designing and evaluating an integrated safeguards system that consists of four parts: (1) a problem definition phase that specifies resources and constraints composing the problem boundary values; (2) a system analysis/synthesis phase that describes how to select and integrate safeguards activities for efficient attainment of system objectives; (3) a system evaluation/optimization phase that defines measures of safeguards performance and develops methods for evaluating them; and (4) a decision-making phase that develops principles for selecting admissible designs and preference-ordering designs. 6 references, 4 figures, 5 tables

Molecular Diagnostics of Histoplasmosis

Histoplasmosis is a systemic fungal disease that occurs worldwide. The highest incidence of the disease is reported on the American continent. It also occurs in China, India, South-Eastern Asia, Africa, Australia and Europe. Clinical syndromes of histoplasmosis are not specific and in most cases immunocompetent individuals are asymptomatic or present mild influenza-like disease. Immunocompromised patients especially individuals with AIDS, can develop a severe and fatal disease due to fungal dissemination to many organs. Etiological agent of histoplasmosis is the dimorphic fungus Histoplasma capsulatum, which inhabits the soils contaminated with bird or bat droppings. Three biological varieties are considered for this fungus: H. capsulatum var. capsulatum, H. capsulatum var. duboissii and H. capsulatum var. farciminosum. Genetic differences are observed among H. capsulatum strains from diverse regions of the world. The main molecular methodologies for genetic typing of fungi are based on DNA fingerprinting. They have been an important instrument to identify possible sources of infection in outbreaks of histoplasmosis. Genetic profiles of H. capsulatum, isolated from bats and humans, helped to understand the distribution of the disease in certain endemic regions. The con-ventional diagnosis of histoplasmosis is performed by means of cultural and microscopic examination of samples from the respiratory tract and biologic fluids. However, these techniques yield positive results in only 50 % of cases. In the last two decades, approaches for the detecting of H. capsulatum in clinical samples, using different molecular targets, based on PCR assay have been developed. Their use can shorten the time span of analysis for diagnosis confirmation. Molecular methods have high specificity and sensitivity and reduce the risk of infection for the laboratory personnel. In this study we reviewed the recently published data on the use of main molecular methods for diagnosis of histoplasmosis

Fire Ant Alate Wing Motion Data and Numerical Reconstruction

The wing motions of a male and a female fire ant alate, which beat their wings at 108 and 96 Hz, respectively, were captured with a stereo imaging system at a high frame rate of 8,000 frames per second. By processing the high-speed image frames, the three-dimensional wingtip positions and the wing surface orientation angles were determined with a high phase resolution, i.e. 74 and 83 phases per period for the male and the female, respectively. A numerical reconstruction of the stereo wingbeat images demonstrated that the data collected described almost all the details of the wing surface motion, so that further computational fluid dynamic simulations are possible for fire ant alate flight

Synchronization modulation increases transepithelial potentials in MDCK monolayers through Na/K pumps

Peer reviewedPublisher PD

Behavior of Metallic Inclusions in Uranium Dioxide

The mobility of micron-size powders of refractory and noble metals in UO{sub 2} was investigated under isothermal and temperature gradient conditions, The metal particles were initially placed between two polished surfaces of UO{sub 2} and any movement which occurred during high temperature annealing was determined microscopically. Tungsten and molybdenum particles 1 to 10 {micro}m in diameter were immobile in UO{sub 2} at 2500°C in a temperature gradient of 1400°C/cm. Ruthenium, however, dissolved into and spread through hypostoichiometric, polycrystalline urania and was found after isothermal annealing as the U-Ru intermetallic compound in the grain boundaries of the oxide. The mechanism does not involve bodily motion of the metal particles. Rather, ruthenium dissolves in the grain bmmdaries of the oxide, migrates as atoms via the same pathway, and reacts while migrating to form URu{sub 3}, This product grows as layers in the grain boundaries. Isothermal ruthenium spreading followed simple diffusion theory, and apparent solubilities and effective diffusivities were obtained from the data for the temperature nmge 2000 to 2300°C. In a temperature gradient, ruthenium moves to the hot zones of UO{sub 2}; the mechanism appears to be the same as found for isothermal spreading, but the extent of movement up the temperature gradient cannot be explained by simple diffusion theory, even with an appreciable Soret effect

How to obtain division algebras used for fast-decodable space-time block codes

We present families of unital algebras obtained through a doubling process from a cyclic central simple algebra D, employing a K-automorphism tau and an invertible element d in D. These algebras appear in the construction of iterated space-time block codes. We give conditions when these iterated algebras are division which can be used to construct fully diverse iterated codes. We also briefly look at algebras (and codes) obtained from variations of this method

Continuous selections of multivalued mappings

This survey covers in our opinion the most important results in the theory of continuous selections of multivalued mappings (approximately) from 2002 through 2012. It extends and continues our previous such survey which appeared in Recent Progress in General Topology, II, which was published in 2002. In comparison, our present survey considers more restricted and specific areas of mathematics. Note that we do not consider the theory of selectors (i.e. continuous choices of elements from subsets of topological spaces) since this topics is covered by another survey in this volume