Original and Cumulative Prospect Theory: A Discussion of Empirical Differences

This paper discusses di€erences between prospect theory and cumulative prospect theory. It shows that cumulative prospect theory is not merely a formal correction of some theoretical problems in prospect theory, but it also gives di€erent predictions. Some experiments by Lola Lopes are re-analyzed, and are demonstrated to favor cumulative prospect theory over prospect theory. It turns out that the mathematical form of cumulative prospect theory is well suited for modeling the psychological phenomenon of diminishing sensitivity. *c 1997 by John Wiley & Sons, Ltd. KEY WORD

A Test of Rank-Dependent Utility in the Context of Ambiguity

Experimental investigations of non-expected utility have primarily concentrated on decision under risk (probability triangles). The literature suggests, however, that ambiguity is one of the main causes for deviations from expected utility (EU). This article investigates the descriptive performance of rank-dependent utility (RDU) in the context of choice under ambiguity. We use the axiomatic difference between RDU and EU to critically test RDU against EU. Surprisingly, the RDU model does not provide any descriptive improvement over EU. Our data suggest other framing factors that do provide descriptive improvements over EU

A Multi-Objective Decision Framework for Lifecycle Investment

In this paper we propose a multi-objective decision framework for lifecycle investment choice. Instead of optimizing individual strategies with respect to a single-valued objective, we suggest evaluation of classes of strategies in terms of the quality of the tradeoffs that they provide. The proposed framework takes inspiration from psychological theories which, on the one hand, assert that humans analyze risky choice situations in terms of several competing factors, and, on the other hand, recognize that attribute overload is detrimental to decision making. In particular, we use SP/A (security-potential/aspiration) theory as developed by Lopes and co-authors. The proposed approach is illustrated in a simple lifecycle model. As decision factors, we consider (a) the contribution paid, (b) the ambition level (targeted level of retirement income), and (c) the guarantee level (a level of retirement income that will be achieved with high probability). In terms of the tradeoffs generated between these indices, we compare a class of traditional lifecycle strategies, defined in terms of a glide path, with a class of so called collar strategies

Recombinant factor VIIa reverses the anticoagulant effect of the long-acting pentasaccharide idraparinux in healthy volunteers

We investigated whether the anticoagulant effect of idraparinux, a selective long-acting factor Xa inhibitor, could be neutralized by recombinant factor VIIa (rFVIIa) in healthy male volunteers. We performed a randomized, placebo-controlled trial, comparing idraparinux [7.5 mg subcutaneous (s.c.)] followed at 3 h by rFVIIa [90 mug/kg intravenous (i.v.)] (n=6), or idraparinux (7.5 mg s.c) followed after 1 week by rFVIIa (90 mug/kg i.v.)(n=6). rFVIIa, given 3 h after idraparinux, significantly reversed the increased thrombin generation time (TGT), the increased activated partial thromboplastin time (aPTT) and prothrombin time (PT), and the reduced prothrombin fragment 1+2 (F1+2) levels caused by idraparinux, although no clear effect of rFVIIa on the endogenous thrombin potential (ETP) was observed. One week after idraparinux, injection of rFVIIa resulted in a similar relative reduction of the remaining increased aPTT, PT and TGT, with correction to pre-idraparinux values. A clear increase of F1+2 was observed, together with a small increase in ETP. We conclude that rFVIIa has significant effects on the idraparinux-inhibited thrombin generation and clotting parameters. These results suggest that rFVIIa may be useful in serious bleeding complications in idraparinux treated patient

Deep Neuromuscular Blockade Improves Laparoscopic Surgical Conditions: A Randomized, Controlled Study

INTRODUCTION: Sustained deep neuromuscular blockade (NMB) during laparoscopic surgery may facilitate optimal surgical conditions. This exploratory study assessed whether deep NMB improves surgical conditions and, in doing so, allows use of lower insufflation pressures during laparoscopic cholecystectomy. We further assessed whether use of low insufflation pressure improves patient pain scores after surgery. METHODS: This randomized, controlled, blinded study (NCT01728584) compared use of deep (1-2 post-tetanic-counts) or moderate (train-of-four ratio 10%) NMB, and lower (8 mmHg) or higher (12 mmHg; 'standard') insufflation pressure in a 2 × 2 factorial design. Primary endpoint was surgeon's overall satisfaction with surgical conditions, rated at end of surgery using an 11-point numerical scale. Post-operative pain scores were also evaluated. Data were analyzed using analysis of covariance. RESULTS: Of 127 randomized patients, 120 had evaluable data for the primary endpoint. Surgeon's score of overall satisfaction with surgical conditions was significantly higher with deep versus moderate NMB indicated by a least-square mean difference of 1.1 points (95% confidence interval 0.1-2.0; P = 0.026). Furthermore, strong evidence of an effect was observed for standard versus low pressure: least-square mean difference of 3.0 points (95% confidence interval 2.1-4.0; P < 0.001). No significant difference was observed in average pain scores within 24 h post-surgery for low versus standard pressure [0.17 (95% confidence interval -0.67 to +0.33); P = 0.494]. CONCLUSIONS: Although associated with significantly improved surgical conditions, deep NMB alone was insufficient to promote use of low insufflation pressure during laparoscopic cholecystectomy. Furthermore, low insufflation pressure did not result in reduced pain, compared with standard pressure. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov identifier, NCT01728584.status: publishe