Plasmoids and the E-to-H transition in an inductively coupled plasma

An Inductively Coupled Plasma (ICP) exhibits two distinct modes of operation. A low input power capacitive E-mode, and a high input power inductive H-mode. The gas initially breaks down m the E-mode, switching to H-mode as input power is increased above a certain threshold. This transition between the E and H modes is observed by a dramatic increase in light output from the plasma, and a ‘glitch3 in the antenna current as the load characteristics of the plasma change from capacitive to inductive. The transition between the E and H modes exhibits hysteresis. The effect of introducing small amounts of molecular oxygen in an argon plasma on the E-to-H transition has been investigated. It has been observed that the addition of small amounts of molecular gas increases the size of the hysteresis instability window in the system, and also increases the ignition current required for the inductive mode. Withm the E-to-H instability window, gross spatial mhomogeneities (plasmoids) have been observed. We report the observation of plasmoids in a cylindrical inductively coupled rf plasma. Observations show plasmoid lobes as regions of higher plasma density and light emission distributed symmetrically around the antenna. They may also rotate and the number of lobes may change depending of plasma power, pressure, and gas mixture. In order to explain the behaviour of plasmoids we present the discharge as plasma transmission line with associated line capacitance and inductance as defined by the plasma. Plasmoids may be shown to be standing waves showing density and absorbed power modulation consistent with observed experimental results. A plasma simulation coupled to the theoretical model also shows results consistent with experimental observation

Scholarly Program Notes

This document is a compilation of biographical and musical information to aid in understanding the music and composers presented at the graduate recital of Mr. Keenan McCarter; including “Avant de quitter ces lieux” from Faust by Charles Gounod, “Questo amor vergogna mia” from Edgar by Giacomo Puccini, “Bess you is my woman now” and “Oh Bess” from Porgy and Bess by George Gershwin, and “Wheels of a dream” from Ragtime by Stephen Flaherty, Les cloches, Mandoline, and Romance by Claude Debussy, Und willst du deinen Liebsten, Fußreise, and Verborgenheit by Hugo Wolf, Calvary by Betty Jackson King, I want to be ready by Clarence Carter, and I want Jesus to walk with me by Lloyd Larson

Team-based Learning: Engaging learners and creating team accountability

YesTeam-based Learning (TBL) is a new teaching strategy that may take small group learning to a new level of effectiveness. TBL shifts the focus from content delivery by teachers to the application of course content by student teams. Teams work on authentic problems, make collaborative decisions, and develop problem-solving skills required in their future workplace. Prior to redesigning the MPharm programme according to TBL principles, several pilots were set up to research how students responded to this new way of teaching. One pilot focussed on the introduction of TBL as a phenomena and aimed to find out if and how TBL engaged students, how students were held accountable by their teams, and more importantly how that affected their lifeworld. Ashworth’s lifeworld contingencies provided the theoretical framework as it ranges from students’ selfhood, embodiment and social interactions to their ability to carry out tasks they are committed to and regard as essential (Ashworth, 2003)

On the Statistical Distribution of Epidermal Papillomata in Mice

IN a previous investigation reported from this laboratory (Ball and McCarter, 1960) it was noted that tumours produced in the skin of the CFW mouse by treatment with 7,12-dimethylbenz(a)anthracene (DMBA) and croton oil, were not distributed among the mice in accordance with the expected Poisson's distribution. Animals bearing no tumours and those bearing many were much more numerous than expected. A quantitative analysis of induced primary adenomatous pulmonary tumours in mice was reported by Polissar and Shimkin (1954). They showed that the occurrence of such tumours was subject to Poisson's distribution and that deviations from this distribution could be attributed to heterogeneity of susceptibility in the animals. We have now analyzed the data obtained in our laboratory in three populations of mice undergoing epidermal carcinogenesis. MATERIALS AND METHODS Strain CFW.-These mice were females, purchased from Carworth Farms Inc., New City, New York. They were housed in groups of 10 in acrylic plastic boxes with stainless steel tops. The bedding was sawdust. Water and Purina Fox Chow Cubes were freely available. Strain CFW/D.-This strain originated when, through error, a male was included among the female CFW mice purchased from the supplier in 1958. Since that time, brother-sister mating has been carried out with a view to obtaining a single inbred line. Litters selected for brother-sister mating were chosen on the basis of health, number in the litter and even distribution of the sexes and not for sensitivity to carcinogenesis. The mice were in the thirteenth and fourteenth inbred generations when used. They were cared for as described above. Strain I.-This strain was obtained several years ago through the kindness of Dr. H. B. Andervont. The mice had been mated brother-to-sister for 71 to 72 generations when the experiment was begun. Chemicals. 7,1 2-dimethylbenz(a)anthracene and benzo((a)pyrene were obtained from Eastman Organic Chemicals. Croton oil was obtained from Bush and Co., Canada. Paraffin oil viscosity 125/135 NF was a product of Fisher Scientific Co., Montreal, Canada. Meprobamate (Miltown) was kindly supplied by Dr. F. M

Investigating hookworm genomes by comparative analysis of two Ancylostoma species

Background Hookworms, infecting over one billion people, are the mostly closely related major human parasites to the model nematode Caenorhabditis elegans. Applying genomics techniques to these species, we analyzed 3,840 and 3,149 genes from Ancylostoma caninum and A. ceylanicum. Results Transcripts originated from libraries representing infective L3 larva, stimulated L3, arrested L3, and adults. Most genes are represented in single stages including abundant transcripts like hsp-20 in infective L3 and vit-3 in adults. Over 80% of the genes have homologs in C. elegans, and nearly 30% of these were with observable RNA interference phenotypes. Homologies were identified to nematode-specific and clade V specific gene families. To study the evolution of hookworm genes, 574 A. caninum / A. ceylanicum orthologs were identified, all of which were found to be under purifying selection with distribution ratios of nonsynonymous to synonymous amino acid substitutions similar to that reported for C. elegans / C. briggsae orthologs. The phylogenetic distance between A. caninum and A. ceylanicum is almost identical to that for C. elegans / C. briggsae. Conclusion The genes discovered should substantially accelerate research toward better understanding of the parasites' basic biology as well as new therapies including vaccines and novel anthelmintics