Hypercube sandwich approach to conferencing

This paper presents a novel cascaded conference network that provides distributed processing and signal transmission among members of disjoint sets of generic send/receive devices called conferees. It assumes an online request model in which idle groups of conferees may request the formation of a conference interconnection. Once a conference is established, all conferees remain connected until the entire conference is dissolved. The Hypercube Sandwich Network (HSN) consists of two components. A bidirectional permutation network is used for routing purposes to and from a hypercube of special processing elements for the purpose of conference formation. The HSN achieves strictly nonblocking performance for N conferees using O(Nlog N) processing elements, and this is shown to be tight to within a log ^1/4 N factor. Previous constructions required a quadratic number of processing elements for strictly nonblocking performance or could only provide wide-sense nonblocking conferencing. If the stronger requirement is made that the communication delay is logarithmic in the conference size, a simple algorithm is presented for wide-sense nonblocking conferencing in an HSN with O(N log N) processing elements.An earlier version of this paper was presented at the 1995 International Conference on Parallel Processing Techniques and Applications.     

Simple Penning ion source for laboratory research and development applications

A simple Penning ion generator (PIG) that can be easily fabricated with simple machining skills and standard laboratory accessories is described. The PIG source uses an iron cathode body, samarium cobalt permanent magnet, stainless steel anode, and iron cathode faceplate to generate a plasma discharge that yields a continuous 1 mA beam of positively charged hydrogen ions at 1 mTorr of pressure. This operating condition requires 5.4 kV and 32.4 W of power. Operation with helium is similar to hydrogen. The ion source is being designed and investigated for use in a sealed-tube neutron generator; however, this ion source is thoroughly described so that it can be easily implemented by other researchers for other laboratory research and development applications.     

Estimated genetic parameters for all genetically evaluated traits in Canadian Holsteins

Genetic improvement is a crucial tool to deal with the increasing demand for high quality, sustainably produced dairy. Breeding programs are based on genetic parameters, such as heritability and genetic correlations, for economically important traits in a population. In this study, we estimated population genetic parameters and genetic trends for 67 traits evaluated on heifers and first-lactation Canadian Holstein cows. The data consisted of approximately 500,000 records with pedigree information collected from 1980 to 2019. Genetic parameters were estimated using bivariate linear animal models under a Bayesian approach. Analyses for the 67 traits resulted in 2,211 bivariate combinations, from which the estimated genetic parameters are reported here. The most highly heritable traits were fat percent (0.66) and protein percent (0.69), followed by stature (0.47). Lowest heritabilities (0.01) were observed for disease-related traits, such as lameness and toe ulcer, and calf survival. The genetic correlations between gestation length, calf size, and calving ease measured on both heifer and cows were close to unity. On the other hand, traits such as body condition score and pin width, cystic ovaries and sole ulcer, rear teat placement, and toe ulcer were genetically unrelated. This study reports genetic parameters that have not been previously published for Canadian Holstein cows, and provides updates of those previously estimated. These estimates are useful for building new indexes, updating existing selection indexes, and for predicting correlated responses due to inclusion of novel traits in the breeding programs.     

Negative Consequences of Using α = 0.05 for Environmental Monitoring Decisions: A Case Study from a Decade of Canada's Environmental Effects Monitoring Program

Using the traditional α = 0.05 significance level for null hypothesis significance tests makes assumptions about relative costs of Type I vs relevant Type II errors and inflates their combined probabilities. We have examined the results of 1254 monitoring tests conducted under the Canadian Environmental Effects Monitoring (EEM) program from 1992 to 2003, focusing on how the choice of α affected the relative probabilities and implied costs of Type I and Type II errors. Using α = 0.05 resulted in implied relative costs of Type I vs Type II errors that were both inconsistent among monitoring end points and also inconsistent with the philosophy of the monitoring program. Using α = 0.05 also resulted in combinations of Type I and II error that were 15-17% larger than those for "optimal" α levels set to minimize Type I and II errors for each study, and 12% of all monitoring tests would have reached opposite conclusions had they used these optimal α levels for decision-making. Thus, if the Canadian EEM program used study-specific optimal α levels, they would reduce the incidence of relevant errors and eliminate inconsistent implied relative costs of these errors. Environmental research and monitoring programs using α = 0.05 as a decision-making threshold should re-evaluate the usefulness of this "one-size-fits-all" approach.     

Microcavity-enhanced electron emission from lead zirconate-titanate cathodes

Enhanced electron emission has been observed from lead zirconatetitanate (PZT) surfaces into which arrays of microcavities have been fabricated by nanopowder blasting. Arrays of microcavities, each having an elliptical cross-sectional geometry with major and minor axis lengths of 800 and 600 μm, respectively, and depths adjustable from 40 to 300 μm, exhibit a pronounced dependence of the emitter electron current on microcavity depth. For electric field strengths at the emitter surface of ∼5-12 V/μm, the RMS current density generated by an array of 250 μm-deep microcavities with a packing density of 214±2 cm^-2 ranges from ∼3 mA cm^-2 to beyond 8 mA cm^-2, or more than a factor of five larger than that produced from a planar PZT surface.