Further results related to the turbulent boundary layer with slot injection of helium

Data from an experiment involving the slot injection of helium into a turbulent boundary layer in air are analyzed in terms of unconditioned and conditioned Favre-averages. The conditioning is based on two levels of helium concentration so that the contributions to the unconditioned statistics from air, helium, and mixture of these two gases can be determined. The distributions of intermittency associated with the two helium levels establish the domains of influence of air, helium, and mixture

Progress toward cascade cells made by OM-VPE

Organometallic Vapor Phase Epitaxy (COM-VPE) was used to make a sophisticated monolithic cascade cell, with a peak AMO efficiency of 16.6%, not corrected for 14% grid coverage. The cell has 9 epitaxial layers. The top cell is 1.35 microns thick with a 0.1 micron thich emitter. Both cells are heteroface n-p structures. The cascade cell uses metal interconnects. Details of growth and processing are described

GaAs VLSI for aerospace electronics

Advanced aerospace electronics systems require high-speed, low-power, radiation-hard, digital components for signal processing, control, and communication applications. GaAs VLSI devices provide a number of advantages over silicon devices including higher carrier velocities, ability to integrate with high performance optical devices, and high-resistivity substrates that provide very short gate delays, good isolation, and tolerance to many forms of radiation. However, III-V technologies also have disadvantages, such as lower yield compared to silicon MOS technology. Achieving very large scale integration (VLSI) is particularly important for fast complex systems. At very short gate delays (less than 100 ps), chip-to-chip interconnects severely degrade circuit clock rates. Complex systems, therefore, benefit greatly when as many gates as possible are placed on a single chip. To fully exploit the advantages of GaAs circuits, attention must be focused on achieving high integration levels by reducing power dissipation, reducing the number of devices per logic function, and providing circuit designs that are more tolerant to process and environmental variations. In addition, adequate noise margin must be maintained to ensure a practical yield

A Two-Layer Model of the North Atlantic Thermocline

A two-layer model of mid-oceanic thermocline is developed, and a comparison of the depth and temperature of the thermocline in this model is made with a root-mean-square description of the hydrographic structure of the North Atlantic. It is shown that the Sverdrup balance is maintained within the rms errors, and the entire estimated heat flux from the atmosphere is used to produce the observed density changes along the path of persistent flow

The effect of addition of sucrose and aeration to grape must on growth and metabolic activity of Saccharomyces cerevisiae

Supplementation of grape must with sucrose has an inhibitory effect on yeast growth, but increases the catabolic activity of yeast populations. It is best done after the initial phase of yeast growth (between days 2 and 4), simultaneously to a short period of aeration which stimulates yeast growth and rate of sugar utilisation

On the Early History of Current Algebra

The history of Current Algebra is reviewed up to the appearance of the Adler-Weisberger sum rule. Particular emphasis is given to the role current algebra played for the historical struggle in strong interaction physics of elementary particles between the S-matrix approach based on dispersion relations and field theory. The question whether there are fundamental particles or all hadrons are bound or resonant states of one another played an important role in this struggle and is thus also regarded.Comment: 17 page

Using geographic information systems to identify prospective marketing areas for a special library

BACKGROUND: The Center for Disability Resources (CDR) Library is the largest collection of its kind in the Southeastern United States, consisting of over 5,200 books, videos/DVDs, brochures, and audiotapes covering a variety of disability-related topics, from autism to transition resources. The purpose of the library is to support the information needs of families, faculty, students, staff, and other professionals in South Carolina working with individuals with disabilities. The CDR Library is funded on a yearly basis; therefore, maintaining high usage is crucial. A variety of promotional efforts have been used to attract new patrons to the library. Anyone in South Carolina can check out materials from the library, and most of the patrons use the library remotely by requesting materials, which are then mailed to them. The goal of this project was to identify areas of low geographic usage as a means of identifying locations for future library marketing efforts. METHODS: Nearly four years worth of library statistics were compiled in a spreadsheet that provided information per county on the number of checkouts, the number of renewals, and the population. Five maps were created using ArcView GIS software to create visual representations of patron checkout and renewal behavior per county. RESULTS: Out of the 46 counties in South Carolina, eight counties never checked out materials from the library. As expected urban areas and counties near the library's physical location have high usage totals. CONCLUSION: The visual representation of the data made identification of low usage regions easier than using a standalone database with no visual-spatial component. The low usage counties will be the focus of future Center for Disability Resources Library marketing efforts. Due to the impressive visual-spatial representations created with Geographic Information Systems, which more efficiently communicate information than stand-alone database information can, librarians may benefit from the software's use as a supplemental tool for tracking library usage and planning promotional efforts

Actions of the braid group, and new algebraic proofs of results of Dehornoy and Larue

This article surveys many standard results about the braid group with emphasis on simplifying the usual algebraic proofs. We use van der Waerden's trick to illuminate the Artin-Magnus proof of the classic presentation of the algebraic mapping-class group of a punctured disc. We give a simple, new proof of the Dehornoy-Larue braid-group trichotomy, and, hence, recover the Dehornoy right-ordering of the braid group. We then turn to the Birman-Hilden theorem concerning braid-group actions on free products of cyclic groups, and the consequences derived by Perron-Vannier, and the connections with the Wada representations. We recall the very simple Crisp-Paris proof of the Birman-Hilden theorem that uses the Larue-Shpilrain technique. Studying ends of free groups permits a deeper understanding of the braid group; this gives us a generalization of the Birman-Hilden theorem. Studying Jordan curves in the punctured disc permits a still deeper understanding of the braid group; this gave Larue, in his PhD thesis, correspondingly deeper results, and, in an appendix, we recall the essence of Larue's thesis, giving simpler combinatorial proofs.Comment: 51`pages, 13 figure

Calmodulin’s Interaction with α- Synuclein, a Protein Implicated in Parkinson’s Disease

60,000 people in one year diagnosed, 1 million in the United States, and over 10 million worldwide have Parkinson’s disease (PD), which is the 2nd most common neurodegenerative disease. PD is prevalent in males and is typically seen in patients in their 60s. The most notable symptom of PD is the degeneration of neuronal control, especially in the hands. Over $156 million is spent on researching this disease and about$25 billion is spent for diagnosed patients each year. Aside from managing the financial burdens of PD, patients also have physical burdens. Most patients develop tremors and have difficulties writing, eating, and can degenerate quickly. The PD has previously been attributed to the lack of the neurotransmitter, dopamine, in the patient’s brain; however recent biochemical studies have surfaced other biomolecular mechanisms that attribute to PD, such as the interaction between Calmodulin and α-Synuclein. Calmodulin (CaM) is a protein found in the brain of healthy patients and is an intermediate calcium (Ca2+) binding messenger with over 100 different targets in eukaryotic cells. α- Synuclein (α-Syn) is a protein found at the ends of neurons in the presynaptic terminals in healthy patients, suggesting involvement with neurotransmitter signaling, however the exact function of α- Syn is still under investigation. Recent studies show that α- Syn and CaM interact resulting in protein aggregation. The α- Syn aggregation is the main structural component of Lewy bodies which is enhanced in the presence of Ca2+. Lewy bodies are known to develop in cranial nerve cells of PD patients and interrupts neuronal function. Little is known about how Lewy bodies attribute to abnormalities in PD patients, but there are connections to low levels of acetylcholine and dopamine, in addition to an interruption of signals between nerve cells. By using fluorescence spectroscopy, we studied the interaction between α- Syn and CaM and explore Ca2+’s role in the interaction that promotes the degenerateness of PD patients

Can vesicle size distributions assess eruption intensity during volcanic activity?

Abstract. We studied three-dimensional (3-D) vesicle size distributions by X-ray microtomography in scoria collected during the relatively quiescent Phase II of the April–May 2010 eruption at Eyjafjallajökull volcano, Iceland. Our goal was to compare cumulative vesicle size distributions (VSDs) measured in these samples with those found in Stromboli volcano, Italy. Stromboli was chosen because its VSDs are well-characterized and show a correlation with eruption intensity: typical Strombolian activity produces VSDs with power-law exponents near 1, whereas larger and more energetic vulcanian-type explosions and Plinian eruptions produce VSDs with power-law exponents near 1.5. The first hypothesis to be tested was whether or not the samples studied in this work would contain VSDs similar to normal Strombolian products, display higher power-law exponents, or be described by exponential functions. Before making this comparison, we tested a second hypothesis, which was that the magma–water interactions in the Eyjafjallajökull eruption might have a significant effect on the VSDs. We performed 1 bar bubble-growth experiments in which the samples were inundated with water and compared them to similar control experiments without water inundation. No significant differences between the VSDs of the two sets of experiments were found, and the second hypothesis is not supported by the experimental evidence. The Phase II Eyjafjallajökull VSDs are described by power-law exponents of ~0.8, typical of normal Strombolian eruptions, and support the first hypothesis. The comparable VSDs and behavior of Phase II of the Eyjafjallajökull 2010 eruption to Stromboli are interpreted to be a reflection of similar conduit systems in both volcanoes that are being constantly fed by the ascent of mingled/mixed magma from depth. Such behavior implies that continued activity during Phase II of the Eyjafjallajökull eruption could be expected and would have been predicted, had our VSDs been measured in real time during the eruption. However, the products studied show no peculiar feature that could herald the renewed eruption intensity observed in the following Phase III of the eruption