Anomalous Operating Performance During Economic Slowdowns

ABSTRACT Operating performance is an important and widely used measure for evaluating firms. This paper documents that, contrary to the common belief, firms experiencing sales declines during economic slowdowns exhibit higher operating margins than firms experiencing sales declines during normal periods. This anomalous behavior results from (1) a decrease in costs of goods sold overall during economic slowdowns and (2) an additional reduction in SG&A costs other than expenditures that could affect the competitiveness (i.e., R&D and advertising) of sales-down firms. The relatively higher operating performance reported by sales-down firms during economic slowdowns is associated with improvements in operational efficiency and cannot be explained as earnings management or simply as a response to financial distress or a large sales decline. Our findings provide important insights into how macroeconomic conditions affect firms' operating performance in a predictable way.

Impact of Hospital Operating Margin on Central Line–Associated Bloodstream Infections Following Medicare’s Hospital-Acquired Conditions Payment Policy

In October 2008, Medicare ceased additional payment for hospital-acquired conditions not present on admission. We evaluated the policy’s differential impact in hospitals with high vs low operating margins. Medicare’s payment policy may have had an impact on reducing central line–associated bloodstream infections in hospitals with low operating margins.Infect. Control Hosp. Epidemiol. 2015;37(1):100–103

Neutron Absorbers in CANDU Natural Uranium Fuel Bundles to Improve Operating Margins

Safety margins are particularly tight in natural uranium-fuelled CANDU reactors which are refueled on-power. During on-power refueling, the insertion of xenon-free fresh fuel bundles into the reactor core affects the reactor’s excess reactivity in such a way that this could lead to temporary power derating. It is desirable from a fuel management perspective, and to maintain safety margins to eliminate this xenon-free effect and any other power ripples such as the subsequent plutonium reactivity peak. A redesign of the CANDU NU fuel bundle with an appropriate combination of elements, with some including neutron-absorbers, could well address the issue of the xenon-free initial portion of the bundle’s irradiation and also lower the plutonium-peak that occurs shortly thereafter. This may improve the fuel utilization (by further optimizing the fuelling strategy) and provide improved safety margins (by lowering the maximum channel and bundle powers). The use of neutron-absorbers in fuel design and manufacturing has been a regular practice in Light Water Reactor fuels for more than three decades. In CANDU applications, neutron absorbers have also been considered for the conceptual Advanced CANDU Reactor and the Low Void Reactivity fuel designs, for which the fissile content is made of low enriched uranium (LEU) or MOX fuels. The application to CANDU natural uranium (NU) fuel, however, especially as burnable poisons, is a relative novel approach. The reason for this is that the neutron economy in natural uranium-fuelled CANDU reactors is a prime concern, thus the addition of extra neutron absorbers is generally shunned. In our proposed application of burnable poisons to existing CANDU NU fuel design, because of low excess reactivity for NU fuel, the amount of neutron-absorber is expected to be restricted to small quantities and in a manner whereby the poison effect is restricted to the initial period of excess reactivity of a newly inserted fuel bundle. This implies that the impact on neutron economy would be relatively minimal, but the fuel performance would be significantly improved. Small amounts and appropriate mixtures of neutron absorbers were selected (approximately 500 mg of absorbers in a CANDU fuel bundle having a nominal weight of 24 kg). Preliminary results indicate that the fuelling transient and the subsequent reactivity peak can be lowered to improve the reactor’s operating margins. A parametric study using the Los Alamos National Laboratories’ MCNP 5 and Atomic Energy of Canada Limited’s WIMS-AECL 3.1 codes is presented in this paper. Details of this project and future work are also to be discussed.