Programmatic efficiency comparisons between unequally sized groups of DMUs in DEA

Data envelopment analysis (DEA) is a popular non-parametric technique for determining the efficiency of a homogeneous set of decision-making units (DMUs). In many practical cases, there is some doubt if the all the DMUs form a single group with a common efficiency distribution. The Mann-Whitney rank statistic has been used in DEA both to test if two groups of DMUs come from a common efficiency distribution and also to test if the two groups have a common frontier, each of which are likely to have important but different policy implications for the management of the groups. In this paper it is demonstrated that where the Mann-Whitney rank statistic is used for the second of these it is likely to overestimate programmatic inefficiency, particularly of the smaller group. A new non-parametric statistic is proposed for the case of comparing the efficient frontiers of two groups, which overcomes the problems we identify in the use of the Mann-Whitney rank statistic for this purpose. © 2005 Operational Research Society Ltd. All rights reserved

Specific Appetite for Carotenoids in a Colorful Bird

Background: Since carotenoids have physiological functions necessary for maintaining health, individuals should be selected to actively seek and develop a specific appetite for these compounds. Methodology/Principal Findings: Great tits Parus major in a diet choice experiment, both in captivity and the field, preferred carotenoid-enriched diets to control diets. The food items did not differ in any other aspects measured besides carotenoid content. Conclusions/Significance: Specific appetite for carotenoids is here demonstrated for the first time, placing these compounds on a par with essential nutrients as sodium or calcium

A phase I and II study of 2-weekly irinotecan with capecitabine in advanced gastroesophageal adenocarcinoma

We investigated 2-weekly intravenous irinotecan combined with oral capecitabine in patients with advanced gastroesophageal adenocarcinoma. In phase I, doses were escalated in chemotherapy naïve or pretreated patients to establish maximum tolerated doses (MTD). In phase II, patients were treated at MTD as first-line therapy with the primary end point of RECIST response. Dose levels in phase I were as follows: Level 1: irinotecan 150 mg m−2 on day 1; capecitabine 850 mg m−2 12-hourly on days 1–9. Level 2: as level 1 but capecitabine 1000 mg m−2. Level 3: as level 2 but irinotecan 180 mg m−2. Level 4: as level 3 but capecitabine 1250 mg m−2. In phase I, 21 patients were entered. Maximum tolerated dose was level 3. Dose-limiting toxicities were lethargy, diarrhoea, vomiting and mucositis. In phase II, 31 patients were entered at level 3. During the first six cycles, 13 of these patients underwent dose reduction and three patients stopped treatment for toxicity. A further six patients stopped for progressive disease. The commonest grade 3–4 toxicities were lethargy (20%), diarrhoea (17%), nausea (10%) and anorexia (10%). There were no treatment-related deaths. The response rate was 32% (95% CI 16–52%). Median overall survival was 10 months. This regimen is active in gastroesophageal adenocarcinoma. However, using the MTD defined in phase I, fewer than 50% patients tolerated six cycles without modification in phase II; therefore, modification of these doses is recommended for further study