A Majorization-Minimization Approach to Design of Power Transmission Networks

We propose an optimization approach to design cost-effective electrical power transmission networks. That is, we aim to select both the network structure and the line conductances (line sizes) so as to optimize the trade-off between network efficiency (low power dissipation within the transmission network) and the cost to build the network. We begin with a convex optimization method based on the paper ``Minimizing Effective Resistance of a Graph'' [Ghosh, Boyd \& Saberi]. We show that this (DC) resistive network method can be adapted to the context of AC power flow. However, that does not address the combinatorial aspect of selecting network structure. We approach this problem as selecting a subgraph within an over-complete network, posed as minimizing the (convex) network power dissipation plus a non-convex cost on line conductances that encourages sparse networks where many line conductances are set to zero. We develop a heuristic approach to solve this non-convex optimization problem using: (1) a continuation method to interpolate from the smooth, convex problem to the (non-smooth, non-convex) combinatorial problem, (2) the majorization-minimization algorithm to perform the necessary intermediate smooth but non-convex optimization steps. Ultimately, this involves solving a sequence of convex optimization problems in which we iteratively reweight a linear cost on line conductances to fit the actual non-convex cost. Several examples are presented which suggest that the overall method is a good heuristic for network design. We also consider how to obtain sparse networks that are still robust against failures of lines and/or generators.Comment: 8 pages, 3 figures. To appear in Proc. 49th IEEE Conference on Decision and Control (CDC '10

Two Case Examples of Reaching the Hard-to-Reach: Low Income Minority and LGBT Individuals

‘Hard-to-reach’ is a term primarily used by researchers to describe groups of people who have been historically difficult to find or contact. It is important for the public interest to include hard-to-reach groups in research because excluding certain sub-populations diminishes the ability to identify groups that potentially have the highest burden of illness and to develop an understanding of why group differences exist. Thus, the purposes of this paper are to: 1) describe the challenges in recruiting hard-to-reach population in two separate research studies; 2) discuss the strategies that were used to overcome those challenges; and 3) provide recommendations for researchers. This paper followed a case study research strategy, with the authors using two of their own research studies involving hard-to-reach populations as case studies. The research studies used in these case studies involved two different hard-to-reach groups—low-income ethnic minorities who were un- or under-insured and lesbian or bisexual women and transgender men. Two overarching themes were identified as barriers to reaching the population of interest: (1) gaining interest and (2) building trust. These themes add to the literature regarding the multi-prong approach that is needed to recruit members of hard-to-reach populations. Despite the authors having buy-in from stakeholders and a multi-prong recruiting approach, barriers to gaining the interest of potential participants included language in recruitment flyers, competing demands for time, and transportation to the data collection site. Building trust with interested study participants was also a large issue noted between both studies, especially concerning sensitive questions or cultural barriers regardless of the reliability and validity of the tools used in the study

Fishes of the Eleven Point River Within Arkansas

A survey of the fishes of the Eleven Point River and its tributaries was made between 31 January 1976 and 13 February 1977. Sixty-three collections, literature records and personal communications revealed 90 species distributed among 19 families. This study revealed 31 species previously not reported for this river system. The Eleven Point River is a clear, predominantly springfed Ozark stream which is located in western Randolph County. From the Arkansas-Missouri state line, the Eleven Point River flows south for approximately 64 km before joining the Spring River. Terrain in the Arkansas portion of this river is rugged as the river meanders through the Salem Plateau of the Ozark Mountains

Indigenizing \u3cem\u3eKing Lear\u3c/em\u3e

Staged with an all‑aboriginal cast, the 2012 production of William Shakespeare’s King Lear at Canada’s National Arts Centre creatively reimagined the play in a frontier New World setting. Directed by Peter Hinton, and starring August Schellenberg (Mohawk) as Lear, the production placed Shakespeare’s drama in seventeenth‑century Canada, amongst a group of Algonquin people on the outer edge of European colonialism and cultural contact. The idea for this resetting of the play originated with August Schellenberg—some 45 years ago—who thought that Lear would be particularly adaptable to an indigenous / First Nations setting. That it took nearly half a century to realize that vision says much about the difficulty of getting mainstream audiences and theater companies to consider the inclusion of indigenous peoples in cultural activities outside of often stereotyped and limited representational roles. By placing an all‑aboriginal cast on stage at the National Arts Centre in the capital city of Ottawa, this unique production of King Lear intervened in a cultural discourse that has marginalized and excluded indigenous voices from the national arts scene

What is the Value of Public Goods Generated by a National Football League Team: A CVM Approach

Using the Contingent Valuation Method, this paper estimates the value of public goods the National Football League’s Jaguars produce for Jacksonville, Florida, including the value of elevating Jacksonville to major league status. It also estimates the incremental value of public goods potentially produced by a National Basketball Association team in Jacksonville. The present value of public goods created by the Jaguars is $25 million or less, far below subsidies provided to attract the Jaguars. For a basketball team, the figure is less than$12.7 million. Sports public goods probably cannot justify the large public expenditures on stadiums and arenas.

Concanavalin A-Binding Enzymes of Crotalus scutulatus scutulatus Venom

Crotalus scutulatus scutulatus crude venom was separated into two fractions by Concanavalin A Sepharose 4B affinity chromatography. The proteins binding to Con A exhibited phosphomonoesterase (orthophosphoric monoester phosphohydrolase EC 3.1.3.2), phosphodiesterase, 5\u27-nucleotidase (5\u27-ribonucleotide phosphohydrolase EC 3.1.3.5), phospholipase A(phosphatidate 2-acylhydrolase EC 3.1.1 .4), hyaluronidase (hyaluronate glycanohydrolase EC 3.2.1 d), N-benzoyl-L-arginine ethyl esterase, p-toluenesulfonyl-L-arginine methyl esterase, L-amino acid oxidase (L-amino acid: 02 oxidoreductase [deaminating] EC 1.4.3.2), and caseinolytic activities. Thrombin-like and NAD nucleosidase (5\u27-ribonucleotide phosphohydrolase EC 3.1.3.5) activities were not observed. The crude venom and the fraction containing the glycoproteins which bound to Con A were fractionated by DEAE Sephadex A-50 ion exchange chromatography. Each of these samples yielded fractions having caseinolytic activities

ATR-FTIR Spectroscopic Analysis of Sorption of Aqueous Analytes into Polymer Coatings Used with Guided SH-SAW Sensors

Attenuated total internal reflectance Fourier transform infrared (ATR-FTIR) spectroscopy was used for the investigation of sorption of aqueous solutions of analytes into polymer coatings. A series of simple model polymers, such as poly(dimethylsiloxane), poly(epichlorhydrin), and poly(isobutylene), and films and analytes, such as aqueous solutions of ethylbenzene, xylenes, toluene, and nitrobenzene, were used to evaluate the use of ATR-FTIR spectroscopy as a screening tool for sensor development. The ratios of integrated infrared absorption bands provided a simple and efficient method for predicting trends in partition coefficients. Responses of polymer-coated guided shear horizontal surface acoustic wave (SH-SAW) sensor platforms to the series of analytes, using polymer coatings with similar viscoelastic properties, were consistent with ATR-FTIR predictions. Guided SH-SAW sensor responses were linear in all cases with respect to analyte concentration in the tested range. Comparison of ATR-FTIR data with guided SH-SAW sensor data identifies cases where mass loading is not the dominant contribution to the response of the acoustic wave sensor. ATR-FTIR spectra of nitrobenzene, coupled with computational chemistry, provided additional insight into analyte/polymer interactions

Concanavalin A-Nonbinding Enzymes of Crotalus scutulatus scutulatus Venom

Crotalus scutulatus scutulatus crude venom was separated into two fractions by Concanavalin A Sepharose 4B affinity chromatography. The Concanavalin A-nonbinding fraction (F-l) exhibited phosphomonoesterase (orthophosphoric monoester phosphohydrolase EC 3.1 .3.2), phosphodiesterase, 5 \u27-nucleotidase (5 \u27-ribonucleotide phosphohydrolase EC 3.1.3.5), phospholipase A (phosphatidate 2-acylhydrolase EC 3.1.1.4), hyaluronidase (hyaluronate glycanohydrolase EC 3.2.1.d), N-benzoyl-Larginine ethyl esterase, p-toluenesulfonyl-L-arginine methyl esterase, L-amino acid oxidase (L-amino acid: O2 oxidoreductase [deaminating] EC 1.4.3.2), and caseinolytic activities. Thrombin-like and NAD nucleosidase (5 \u27-ribonudeotide phosphohydrolase EC 3.1.3.5) activities were not observed. DEAE Sephadex A-50 ion exchange chromatography by two stage elution of F-l yielded several fractions having proteinase activities. Proteinase activity was observed in the latter fractions of the first elution and in the fractions of the second elution