NEW THEORETICAL APPROACHES TO MEASURING INDUSTRY PERFORMANCE

Agribusiness,

RETAIL OLIGOPOLY POWER AND FLUID MILK PRICES IN BOSTON

This paper assesses the independent and joint impacts of oligopoly power of market intermediaries and the Northeast Dairy Compact (NEDC) on fluid milk prices in Boston. Empirical results reveal that price increases due to oligopoly power far outweighed those caused by the NEDC by more than 10 times. In fact, markups are estimated at approximately 33% of the retail milk price, translating into approximately $1/gallon overcharge at 2002 milk prices averaging around$3/gallon.Demand and Price Analysis,

RETAIL OLIGOPOLY POWER, DAIRY COMPACT, AND BOSTON MILK PRICES

This paper assesses the impacts of the Northeast Dairy Compact (NEDC) and retail oligopoly power on fluid milk prices in Boston. Empirical results reveal that price increases due to oligopoly power outweighed those caused by the NEDC by nearly seven times. In fact, markups are estimated at approximately 25% of the retail milk price, translating into approximately a little less than $0.75/gallon. We also estimated that only around two-thirds of the raw milk price changes were passed forward to consumers. This helps explain why consumer prices have come down only little after elimination of the NEDC. In fact, the new milk income loss contract program, which basically provides partial price subsidies to farmers, has contributed to low raw milk prices that have generated substantial benefits to milk processors and retailers, modest benefits to farmers and consumers, all at the expense of taxpayers.Industrial Organization, Livestock Production/Industries,

A Supermarket-Level Analysis of Demand for Breakfast Cereals: A Random Coefficients Approach

This paper applies the BLP approach to the demand for ready-to-eat cereals (RTECs) at the supermarket-chain level in Boston using IRI monthly data. The Random Coefficient Model is used to estimate the demand for 37 brands of RTECs at the leading supermarkets in the Boston area. The empirical results provide a wealth of consumer behavior information, including own- and cross-price elasticites for 37 brands of RTECs at four leading supermarkets in Boston. The demand for RTECs is generally price elastic (ranging between -3 and -8). Consumers respond positively and strongly to promotion, negatively and strongly to price, calories and fiber, and weakly to sugar content. Income has a strong interactive effect with product characteristics and thus is a useful variable for market segmentation. In comparison, the results with the more commonly used Logit model indicate significantly lower price elasticities, provide a limited window on consumer behavior, and yield predicted brand and supermarket market shares that are quite divergent from observed values.Demand and Price Analysis,

Annealing of defects in Fe after MeV Heavy ion irradiation

We report study of recovery dynamics, followed by in-situ resistivity measurement after 100 MeV oxygen ion irradiation, in cold rolled Fe at 300K. Scaling behavior with microstructural density and temperature of sample have been used to establish stress induced defects formed during irradiation as a new type of sink. The dynamics after irradiation has been shown to be due to migration of defects to two types of sinks i.e. stress induced defect as variable sinks and internal surfaces as fixed sinks. Experimental data obtained under various experimental conditions have been fitted to theoretical curves. Parameters thus obtained from fitting are employed to establish effect of electronic energy loss and temperature on recovery dynamics and stress associated with variable sinks.Comment: 12 pages, 7 figures. Europhysics Letter (in press

Towards the development of the psychosocial impact of assistive devices scale for continence (C-PIADS)

BACKGROUND: Current outcome measures for continence management devices do not adequately address psychosocial impact. The PIADS is an assessment tool that has been shown to reliably predict the adoption and use of assistive technology devices, but it is not widely used for continence devices. OBJECTIVE: To explore whether the PIADS requires modification to address the particular needs of continence device users and to inform any subsequent item development. METHODS: The study used interpretive methods in which qualitative information from semi-structured interviews was combined with the findings from cognitive interviews for questionnaire pre-testing. A total of 40 participants in UK and Canada were interviewed. RESULTS: Few participants had difficulty in understanding or relating to the majority of PIADS items. Several items were not considered relevant to continence and some areas for potential new items were uncovered. Embarrassment and concealment of urinary incontinence from others were common topics. CONCLUSIONS: The PIADS appears to fundamentally address many, but not all, of the important psychosocial concerns of adults who have continence difficulties. A version for continence, the C-PIADS, will require modification of the PIADS and is likely to contain some new items

Pinching instabilities in superconducting strings

Superconducting cosmic strings can exhibit longitudinal, pinching instabilities in some regions of the parameter space. We make predictions about the onset of this instability using the thin string approximation (TSA) and develop an improved analysis that remains applicable for small wavelength perturbations, where the TSA breaks down. We use simulations of perturbed strings to assess the accuracy of the TSA, test the predictions of our new analysis and demonstrate an improvement over previous methods in the literature. Notably, it appears that the instabilities are typically present for a larger range of magnetic strings than previously expected, and we show examples of pinching instabilities also occurring in electric strings. However, both our simulations and predictions agree that strings near the chiral limit are free from pinching instabilities and in particular our results support our previously published claim that vortons can be stable to all classical perturbations if they are sufficiently large.Comment: 14 pages, 7 figure

Global monopoles in the two-Higgs-doublet-model

We discuss monopoles formed due to the spontaneous breakdown of a global $SO(3)_{\rm HF}$ symmetry within the global two-Higgs doublet model. We explain that the Higgs sector dynamics can be described in terms of two vectors one of which is null, $R^A=(R^0,R^a,R^4,R^5)$ for $a=1,2,3$, with 5 independent components describing the Higgs family symmetry and another, $n^a$, with 3 independent components related to the ``would-be'' Goldstone bosons. When formed from random initial conditions we find that monopoles are formed with a charged vacuum in the centre which couples the two fields together. We find a spherical symmetric solution which is an approximately uniform, unit winding of the sphere in both the $R^a$ and $n^a$ vectors. These global monopoles are closely related to the Nambu monopole. The additional complexity and structure contained in these monopoles does not appear to prevent the scaling of their density.Comment: 12 pages, 4 figure

Diagnostic accuracy of PAT-POPS and ManChEWS for admissions of children from the emergency department

Background The Pennine Acute Trust (PAT) Paediatric Observation Priority Score (PAT-POPS) is a specific emergency department (ED) physiological and observational aggregate scoring system, with scores of 0–18. A higher score indicates greater likelihood of admission. The Manchester Children’s Early Warning System (ManChEWS) assesses six physiological observations to create a trigger score, classified as Green, Amber or Red. Methods Prospectively collected data were used to calculate PAT-POPS and ManChEWS on 2068 patients aged under 16 years (mean 5.6 years, SD 4.6) presenting over 1 month to a UK District General Hospital Paediatric ED. Receiver operating characteristics (ROC) comparison, using STATA V.13, was used to investigate the ability of ManChEWS and PAT-POPS to predict admission to hospital within 72 h of presentation to the ED. Results Comparison of the area under the ROC curve indicates that the ManChEWS ROC is 0.67 (95% CI 0.64 to 0.70) and the PAT-POPS ROC is 0.72 (95% CI 0.68 to 0.75). The difference is statistically significant. At a PAT-POPS cut-off of ≥2, 80% of patients had their admission risk correctly classified ( positive likelihood ratio 3.40, 95% CI 2.90 to 3.98) whereas for ManChEWS with a cut off of ≥Amber only 71% of patients were correctly classified ( positive likelihood ratio 2.18, 95% CI 1.94 to 2.45). Conclusions PAT-POPS is a more accurate predictor of admission risk than ManChEWS. Replacing ManChEWS with PAT-POPS would appear to be clinically appropriate in a paediatric ED. This needs validation in a multicentre study