COX inhibitors and breast cancer

There is considerable evidence to suggest that prostaglandins play an important role in the development and growth of cancer. The enzyme cyclo-oxygenase (COX) catalyses the conversion of arachidonic acid to prostaglandins. In recent years, there has been interest in a possible role for COX inhibitors in the prevention and treatment of malignancy. Cyclo-oxygenase-2 (COX-2) is overexpressed in several epithelial tumours, including breast cancer. Preclinical evidence favours an antitumour role for COX inhibitors in breast cancer. However, the epidemiological evidence for an association is conflicting. Trials are being conducted to study the use of COX inhibitors alone and in combination with other agents in the chemoprevention of breast cancer, and in the neo-adjuvant, adjuvant, and metastatic treatment settings. In evaluating the potential use of these agents particularly in cancer chemoprophylaxis, the safety profile is as important as their efficacy. Concern over the cardiovascular safety of both selective and nonselective COX-inhibitors has recently been highlighted

Incentives and service quality in the restaurant industry: the tipping-service puzzle

Tipping is a significant economic activity (tips in the US food industry alone amount to about $42 billion annually) that was claimed to improve service quality and increase economic efficiency, because it gives incentives to provide excellent service, and therefore allows to avoid costly monitoring of workers. The article suggests that this common wisdom might be wrong. A simple model shows formally that tips can improve service only if they are sensitive enough to service quality. Empirical evidence suggests that tips are hardly affected by service quality. Nevertheless, rankings of service quality by customers are very high; the co-existence of these two findings is denoted 'the tipping-service puzzle,' and several possible explanations for it are offered.