Evaluating a supermarket relocation strategy using spatial competition analysis

The purpose of this paper is to show, in the context of a specific labor relations case, that spatial competition analysis can help regulatory authorities evaluate a firm's location strategy. The case involves the relocation of a supermarket franchisee, and two alternative explanations for the move are advanced. In the first explanation, it is argued that the supermarket relocation can be a form of strategic behavior that provides the least costly way of circumventing an institutional constraint that would otherwise make it difficult to convert a store from union to nonunion status. The second explanation is that the move is motivated by competitive considerations, particularly the desire of the franchisor to save a failing franchisee by moving it, and so that a new franchise could be opened in the vacated store and compete more aggressively with a recent entrant. A locational investigation, in conjunction with a regression analysis of sales data, support the rejection of the second explanation.The author would like to thank Brad Reid, Stuart Landon, Noxy Dastoor, Balder Von Hohenbalken, Dave Ryan, Greg Dow, Arnold Berry, David Batten, seminar participants at the University of British Columbia, and two anonymous referees for their many helpful suggestions. Financial support from the University of Alberta's Endowment Fund for the Future is gratefully acknowledged     

Transfer of analog temporal data vita standard dual-channel digital fiberoptic links

Two standard fiberoptic links designed for digital application have been used to transfer analog spatial information using a time-to-amplitude converter. The inferred 50–60 ps relative jitter between the two links results in about 10% degradation of spatial resolution.     

Design and Experimental Verification of a Linear Permanent Magnet Generator for a Free-Piston Energy Converter

This paper discusses issues that are pertinent to the design of a linear permanent magnet generator for application in a free-piston energy converter. To achieve the required high power density, high efficiency, and low moving mass, a tubular machine equipped with a modular stator winding and a quasi-Halbach magnetized armature is employed. It is shown that the machine design can be optimized with respect to three key dimensional ratios while satisfying other performance requirements. It is also shown that, when the generator is interfaced to an electrical system via a power electronic converter, both the converter volt-amps rating and the converter loss should be taken into account when optimizing the machine design. The performance of such a tubular generator is demonstrated by measurements on a 10-pole/9-slot prototype machine.     

Effects of bovine somatotropin on dry matter intake, milk yield and body temperature in Holstein and Jersey cows during heat stress

Thirty-one lactating Holstein and Jersey cows were used to determine the effect of daily injections of 0 or 20 mg of recombinant bST in hot, humid weather. The comparison period lasted 80 d, from mid-June through August. The maximum and minimum ambient temperature and relative humidity averaged 34.6 and 22.2 degrees C and 100 and 59.8%, respectively. Body temperatures of somatotropin-treated Holsteins were elevated over controls by .2 and .3 degrees C at the a.m. and p.m. milkings, respectively, whereas corresponding treatment effects for Jerseys were .5 and .6 degrees C, thus demonstrating a breed by treatment interaction. The response of milk and FCM yields and apparent efficiency of production to somatotropin administration depended on the level of production prior to treatment. Cows at low pretreatment production increased milk and FCM yields to a greater degree than did cows at higher production. A breed by treatment interaction showed that Holsteins increased milk and FCM yields more than Jerseys upon administration of somatotropin. Intake of DM was not affected by treatment. Cows administered bST lost BW and condition score. Greater heat stress was associated with the higher milk production of cows administered bST.     

马尔克海的眼睛

West 8是一个国际性的城市设计和景观设计事务所,由Adriaan Geuze于1987年成立。在过去20年West 8已经成长为一个由景观建筑师和工程师组成的国际领先的实践性公司。     

Toxicity of individual naphthenic acids to Vibrio fischeri

Numerous studies have suggested that the toxicity of organic compounds containing at least one carboxylic acid group and broadly classified as "naphthenic acids", is of environmental concern. For example, the acute toxicity of the more than 1 billion m(3) of oil sands process-affected water and the hormonal activity of some offshore produced waters has been attributed to the acids. However, experimental evidence for the toxicity of the individual acids causing these effects has not been very forthcoming. Instead, most data have been gathered from assays of incompletely characterized extracts of the water, which may contain other toxic constituents. An alternative approach is to assay the individual identified toxicants. Since numerous petroleum-derived naphthenic acids and some in oil sands process water, have recently been identified, we were able to measure the toxicity of some individual acids to the bioluminescent bacterium, Vibrio fischeri. Thirty-five pure individual acids were either synthesized or purchased for this purpose. We also used the US EPA ECOSAR computer model to predict the toxicity of each acid to the water flea, Daphnia magna. Both are well-accepted toxicological screening end points. The results show how toxic some of the naphthenic acids really are (e.g., V. fischeri Effective Concentrations for 50% response (EC(50)) 0.004 to 0.7 mM) and reveal the influence of hydrophobicity and aqueous solubility on the toxicities. Comparison with measured toxicities of other known, but more minor, constituents of oil sands process water, such as polycyclic aromatic hydrocarbons and alkylphenols, helps place these toxicities into a wider context. Given the reported toxicological effects of naphthenic acids to other organisms (e.g., fish, plants), the toxicities of the acids to further end points should now be determined.     

Identification and quantification of mineral precipitation in Fe0 filings from a column study

Thermogravimetric analysis (TGA) combined with X-ray diffraction (XRD) was used to identify mineral phases and determine corrosion rates of granular iron samples from a 2-yr field column study. Similar to other studies, goethite, magnetite, aragonite, and calcite were found to be the major precipitated minerals, with Fe2(OH)2CO3 and green rust as minor phases. Based on TGA-mass spectrometry (MS) analysis, Fe0 corrodes at rates of 0.5-6.1 mmol kg(-1) d(-1) in the high NO3- (up to 13.5 mM) groundwater; this rate is significantly higher than previously reported. Porosity reduction was 40.6%-45.1% for the inlet sand/Fe0 interface and 7.4%-25.6% for effluent samples of two test columns. Normalized for treatment volumes, porosity loss values are consistent with studies that use high levels of SO4(2-) but are higher than those using low levels of corrosive species. Aqueous mass balance calculations yield corrosion rates similar to the TGA-MS method, providing an alternative to coring and mineralogical analysis. A severely corroded iron sample from the column simulating a 17-yr treatment throughput showed >75% porosity loss. Extensive porosity loss due to high levels of corrosive species in groundwater will have significant impact on long-term performance of permeable reactive barriers.     

A Detailed Model for the Sintering of Polydispersed Nanoparticle Agglomerates

In this study the coagulation, condensation, and sintering of nanoparticles is investigated using a stochastic particle model. Each stochastic particle consists of interacting polydisperse primary particles that are connected to each other. In the model sintering occurs between each individual pair of neighboring primary particles. This is important for particles in which the range of the size of the primary particles varies significantly. The sintering time is obtained from the viscous flow model. The model is solved using a stochastic particle algorithm. The particles are represented in a binary tree that contains the connectivity as well as the degree of sintering information. Particles are forme, coagulate, sinter, and experience condensation according to known rate laws. The particle binary tree, along with it the degree of sintering, is updated after each time step according to the rates of the different processes. The stochastic particle method uses the technique of fictitious jumps and linear process deferment. The theoretical results are fitted against experimental values for the formation of SiO ₂ nanoparticles and computer generated TEM pictures are presented and compared to experiments.     

Signal-detection analysis of group decision making.

How effectively can groups of people make yes-or-no decisions? To answer this question, we used signal-detection theory to model the behavior of groups of human participants in a visual detection task. The detection model specifies how performance depends on the group's size, the competence of the members, the correlation among members' judgments, the constraints on member interaction, and the group's decision rule. The model also allows specification of performance efficiency, which is a measure of how closely a group's performance matches the statistically optimal group. The performance of our groups was consistent with the theoretical predictions, but efficiency decreased as group size increased. This result was attributable to a decrease in the effort that members gave to their individual tasks rather than an inefficiency in combining the information in the members' judgments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)