http://repub.eur.nl/res/aut/3502/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/37933/ 2012-07-31T00:00:00Z Does the cue of money lead to selfish, greedy, exploitative behaviors or to fairness, exchange, and reciprocity? We found evidence for both, suggesting that people have both sets of meaningful associations, which can be differentially activated by exposure to clean versus dirty money. In a field experiment at a farmers’ market, vendors who handled dirty money subsequently cheated customers, whereas those who handled clean money gave fair value (Experiment 1). In laboratory studies with economic games, participants who had previously handled and counted dirty money tended toward selfish, unfair practices— unlike those who had counted clean money or dirty paper, both of which led to fairness and reciprocity. These patterns were found with the trust game (Experiment 2), the prisoner’s dilemma (Experiment 4), the ultimatum game (Experiment 5), and the dictator game (Experiment 6). Cognitive measures indicated that exposure to dirty money lowered moral standards (Experiment 3) and reduced positive attitudes toward fairness and reciprocity (Experiments 6–7), whereas exposure to clean money had the opposite effects. Thus, people apparently have 2 contradictory sets of associations (including behavioral tendencies) to money, which is a complex, powerful, and ubiquitous aspect of human social life and cultural organization. http://repub.eur.nl/res/pub/1590/ 1999-05-26T00:00:00Z We study stochastic linear--quadratic (LQ) optimal control problems over an infinite horizon, allowing the cost matrices to be indefinite. We develop a systematic approach based on semidefinite programming (SDP). A central issue is the stability of the feedback control; and we show this can be effectively examined through the complementary duality of the SDP. Furthermore, we establish several implication relations among the SDP complementary duality, the (generalized) Riccati equation, and the optimality of the LQ control problem. Based on these relations, we propose a numerical procedure that provides a thorough treatment of the LQ control problem via SDP: it identifies a stabilizing feedback control that is optimal or determines that the problem possesses no optimal solution. For the latter case, we develop an ε-approximation scheme that is asymptotically optimal. http://repub.eur.nl/res/pub/1566/ 1999-03-31T00:00:00Z We study a deterministic linear-quadratic (LQ) control problem over an infinite horizon, and develop a general apprach to the problem based on semi-definite programming (SDP)and related duality analysis. This approach allows the control cost matrix R to be non-negative (semi-definite), a case that is beyond the scope of the classical approach based on Riccati equations. We show that the complementary duality condition of the SDP is necessary and sufficient for the existence of an optimal LQ control. Moreover, when the complementary duality does hold, an optimal state feedback control is constructed explicitly in terms of the solution to the semidefinite program. On the other hand, when the complementary duality fails, the LQ problem has no attainable optimal solution, and we develop an E-approximation scheme that achieves asymptotic optimality. http://repub.eur.nl/res/pub/2514/ 1995-01-01T00:00:00Z The lysosomal storage disorder galactosialidosis results from a primary deficiency of the protective protein/cathepsin A (PPCA), which in turn affects the activities of beta-galactosidase and neuraminidase. Mice homozygous for a null mutation at the PPCA locus present with signs of the disease shortly after birth and develop a phenotype closely resembling human patients with galactosialidosis. Most of their tissues show characteristic vacuolation of specific cells, attributable to lysosomal storage. Excessive excretion of sialyloligosaccharides in urine is diagnostic of the disease. Affected mice progressively deteriorate as a consequence of severe organ dysfunction, especially of the kidney. The deficient phenotype can be corrected by transplanting null mutants with bone marrow from a transgenic line overexpressing human PPCA in erythroid precursor cells. The transgenic bone marrow gives a more efficient and complete correction of the visceral organs than normal bone marrow. Our data demonstrate the usefulness of this animal model, very similar to the human disease, for experimenting therapeutic strategies aimed to deliver the functional protein or gene to affected organs. Furthermore, they suggest the feasibility of gene therapy for galactosialidosis and other disorders, using bone marrow cells engineered to overexpress and secrete the correcting lysosomal protein.