Expanded horizons for generating and exploring optical angular momentum in vortex structures

Spin provides for a well-known extension to the information capacity of nanometer-scale electronic devices. Spin transfer can be effected with high fidelity between quantum dots, this type of emission being primarily associated with emission dipoles. However, in seeking to extend the more common spectroscopic connection of dipole transitions with orbital angular momentum, it has been shown impossible to securely transmit information on any other multipolar basis – partly because point detectors are confined to polarization measurement. Standard polarization methods in optics provide for only two independent degrees of freedom, such as the circular states of opposing handedness associated with photon spin. Complex light beams with structured wave-fronts or vector polarization do, however, offer a basis for additional degrees of freedom, enabling individual photons to convey far more information content. A familiar example is afforded by Laguerre-Gaussian modes, whose helically twisted wave-front and vortex fields are associated with orbital angular momentum. Each individual photon in such a beam has been shown to carry the entire spatial helical-mode information, supporting an experimental basis for sorting beams of different angular momentum content. One very recent development is a scheme for such optical vortices to be directly generated through electronic relaxation processes in structured molecular chromophore arrays. © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE)

Optical vortex mode generation by nanoarrays with a tailored geometry

Light generated with orbital angular momentum, commonly known as an optical vortex, is widely achieved by modifying the phase structure of a conventional laser beam through the utilization of a suitable optical element. In recent research, a process has been introduced that can produce electromagnetic radiation with a helical wave-front directly from a source. The chirally driven optical emission originates from a hierarchy of tailored nanoscale chromophore arrays arranged with a specific propeller-like geometry and symmetry. In particular, a nanoarray composed of n particles requires each component to be held in a configuration with a rotation and associated phase shift of 2 π/n radians with respect to its neighbor. Following initial electronic excitation, each such array is capable of supporting delocalized doubly degenerate excitons, whose azimuthal phase progression is responsible for the helical wave-front. Under identified conditions, the relaxation of the electronically-excited nanoarray produces structured light in a spontaneous manner. Nanoarrays of escalating order, i.e. those containing an increasing number of components, enable access to a set of topological charges of higher order. Practical considerations for the development of this technique are discussed, and potential new applications are identified. © (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE)

Elf: computer automation and error correction for a microwave network analyzer

A microwave measurement system has been developed that combines a personal computer (PC) and an conventional vector network analyzer to yield a full complex-error-corrected automatic network analyzer. The system consists of a Hewlett-Packard HP 8410C network analyzer, an HP 8350B sweep oscillator, and an IBM PC. A program called Elf runs on the PC, performing calibration and measurement algorithms and providing a flexible, menu-oriented user interface. The system, when calibrated, achieves a worst-case measurement error vector of magnitude ≤ 0.02 for transmission and reflection coefficient measurements over the 2-12.4-GHz frequency range and has a measurement speed of three frequency points/s. Elf provides an inexpensive method for upgrading the HP 8410 to achieve the high accuracy of an automatic network analyzer

Puff, an Interactive Microwave Computer Aided Design Program for Personal Computers

We will demonstrate a CAD program designed for the lay out and analysis of microstrip circuits. The program runs on the IBM PC or AT. Circuit elements are selected from a parts list and drawn on the screen using the cursor keys. The analysis may then be performed, directly from the screen drawing. Puff has been used by microwave students in classes at the California Institute of Technology and the University of California at Los Angeles

The Arduous Pursuit of Ratification: A Community Effort and Benefit Towards Adoption of Countywide Zoning for Anson County, North Carolina to Aid in Economic Development

This consultancy project was designed to assist Anson County, North Carolina with understanding the impacts of enacting countywide zoning and how to develop a zoning ordinance. While a vast majority of cities and counties in North Carolina have zoning throughout their jurisdiction, Anson County does not. This project revealed the economic impacts of countywide zoning by assessing both qualitative and quantitative data, including a review of the literature. The literature review concluded counties that enact zoning increase economic or job opportunities. As evidence, a Georgia study concluded the average employment for counties with a zoning ordinance was more than double that of counties without a zoning policy or around 123.3% greater in 1999 (Wilkins et al., 2006). In addition, “counties with zoning tended to post lower unemployment rates and higher labor force participation rates” (Wilkins et al., 2006, p. 26). More specifically, this project revealed how adopting zoning countywide can help increase economic development opportunities, including job inducement, protecting property values, helping plan for future growth, and increasing community safety. The successful implementation of this project was directly related to community input and open house meetings held throughout the county. However, the primary deliverable was to draft a countywide zoning ordinance for Anson County to consider adopting. The research methodology employed focused on how Anson County leadership was in concert with community input. The success of this project was demonstrated through the final draft zoning ordinance and summary presentation to the Anson County Board of Commissioners

The geochemical evolution of saline groundwater within a fresh water aquifer south of Oakes, North Dakota

An area of saline/brackish groundwater south of Oakes, North Dakota has been reported by the North Dakota State Water Commission. The concentrated water (over 12,000 mg/L of total dissolved solids) is in direct hydraulic connection with relatively fresh water and shows an abrupt change in concentration and water chemistry between these two end members. The saline/brackish water is beneath a shallow trough or depression which has an approximate area of 6 square miles (15.5 square kilometres). The trough is within the northern part of the Glacial Lake Dakota plain. Sediments in the lake plain, which is an unconfined aquifer, are sands that grade downward to gravels. Within the trough sands are overlain by Holocene lacustrine silts and clays. A discontinuous unit of lacustrine silt lies beneath the upper sand and gravel aquifer. Below both these units is glacial till. Locally, a second sand and gravel aquifer underlies the till. The second aquifer is under confined conditions and is underlain by a second till unit. In May 1983 observation wells were installed to determine the horizontal extent of the saline/brackish water. In order to determine the vertical extent of that water, and to determine groundwater movement, two detailed traverses of nested piezometers were installed. Interpretation of hydraulic head data for the two traverses shows a general northerly flow along the N-S traverse and lateral flow along an E-W traverse, toward a central sink. Here, water is assumed to move along the axis of the trough toward the James River. During major recharge events, reversals of hydraulic gradients occur, indicating outward flow from the center of the depression and downward flow into the lower sand and gravel aquifer. Alternating recharge and stable flow results in relatively stagnant water. The major constituents of the saline groundwater are Na+ and SO42-; lesser amounts of HCo3-, Ca2+, Mg2+; and trace amounts of Fe, Mn, B, F, SiO2, and Cl-. Due to the large percentage of carbonates in the aquifer and tills, CaCO3 and (Ca,Mg)CO3 dissolved in the presence of acidified water yield Ca2+, Mg2+, and HCO3- ions. Gypsum (CaSO4 .2H2O) yields Ca2+ and SO42- ions. Pyrite oxidation yields Fe and SO42- ions. The tills and surficial clays contain montmorillonite, presumably sodium montmorillonite, which in the presence of Ca2+, exchanges Na+ for Ca2+. If the system is saturated with gypsum, loss of Ca2+ would create an undersaturated condition causing further dissolution of gypsum. Continued Ca2+ exchange for Na+ leads to a dominance of Na+ and SO42- ions. Evaporation is suggested as the concentrating mechanism within the center of the depression. Mineral precipitation occurs at the water table in surficial clays just below land surface. Major recharge events dissolve the precipitated minerals, move the saline water down to the water table, and-then by miscible displacement, transport the denser, saline water to the base of the aquifer. Repeated mineral precipitation and dissolution cycles have led to the concentrated saline/brackish water

Overview of (1→3)-β-D-glucan immunobiology

Glucans are (1→3)-β-D-glucose polymers that are found in the cell wall of fungi, bacteria and plants. Glucans are known to stim ulate humoral and cell-mediated immunity in humans and animals. In addition to the potent immune stimulatory effects of (1→3)-β-D-glucans, there are a number of toxicological effects associated with exposure to the water-insoluble, microparticulate form of the polymer. Recent investigations have suggested a potential role for (1→3)-β-D-glucans in inhalational toxicity. Specifically, (1→3)-β-D-glucans have been implicated in the symptomatology associated with ‘sick building’ syndrome. The mechanisms by which (1→3)-β-D-glucans mediate immune stimulation and, perhaps, toxicity are currently under investigation. It is now established that (1→3)-β-D-glucans are recognized by macrophages and, perhaps, neutrophils and natural killer cells via a (1→3)-β-glucan specific receptor. Following receptor binding, glucan modulates macrophage cytokine expression. Here we review the chemistry, immunobiology and toxicity of (1→3)-β-D-glucans and how it may relate to effects caused by inhalation

Wills

Covers cases on joint and mutual wills—lapse of the interest of the third party devisee