When choice is demotivating: Can one desire too much of a good thing?

Current psychological theory and research affirm the positive affective and motivational consequences of having personal choice. These findings have led to the popular notion that the more choice, the better—that the human ability to manage, and the human desire for, choice is unlimited. Findings from 3 experimental studies starkly challenge this implicit assumption that having more choices is necessarily more intrinsically motivating than having fewer. These experiments, which were conducted in both field and laboratory settings, show that people are more likely to purchase gourmet jams or chocolates or to undertake optional class essay assignments when offered a limited array of 6 choices rather than a more extensive array of 24 or 30 choices. Moreover, participants actually reported greater subsequent satisfaction with their selections and wrote better essays when their original set of options had been limited. Implications for future research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Novel antitumor 2-cyanoaziridine-1-carboxamides

A set of 20 2-cyanoaziridine-1-carboxamides was synthesized from 2-cyanoaziridine and appropriate isocyanates. These compounds were active against a variety of solid and hematological tumor cells in culture, including strains resistant to doxorubicin and mitoxantrone. Their potencies in these assays correlated with the lipophilicity of substituents. The N-phenyl derivative was more potent and equally effective to imexon, a cyclized 2-cyanoaziridine-1-carboxamide of clinical interest, against cloned fresh human tumors.     

On throughput stabilization of network transport

A number of network applications require stable transport throughput for tasks such as control and coordination operations over wide-area networks. We present a window-based method that achieves stable throughput at a target level by utilizing a variation of the classical Robbins-Monro stochastic approximation algorithm. We analytically show the stability of this method under very mild conditions on the network, which are justified by Internet measurements. Our User Datagram Protocol (UDP)-based implementation provides stable throughput over the Internet under various traffic conditions.     

Parametric sensitivity of fracture behaviour of concrete

The fictitious crack method (FCM) is applied to determine the load-deflection diagrams of notched plain concrete beams under three-point bending using various forms of strain softening in the stress-deformation relationship. The results indicate that there is a need to determine a more realistic relationship.     

Optimization of wing structures to satisfy strength and frequency requirements

In this investigation minimum weight design of wing structures with restrictions on strength, stability and frequency characteristics is attempted. The multiweb delta wing structure is idealized with three different kinds of finite elements. The constant stress triangular plate elements, the rectangular shear panels and pin jointed bar elements are used to represent, respectively, the cover skins, webs and the stringers of wing structures. A parametric study is made to reduce the number of design variables which in turn reduces the required computational effort. The feasibility of employing linearly approximated redesigns is investigated. Numerical results are presented to illustrate the feasibility. Off-design charts have been obtained by performing sensitivity analysis about the final optimum design point.     

Testing the consistency of the Maxwell-Stefan formulation when predicting self-diffusion in zeolites with strong adsorption sites

The Maxwell-Stefan (MS) formulation, as applied to zeolites that contain both weak and strong adsorption sites, such as ZSM-5, is compared to dynamic Monte Carlo simulations, for the limiting case of single-component self-diffusion. This study is intended as a consistency check, and as a step towards an analytical or semi-analytical theory for self-diffusion in zeolites with multiple types of sites. In its original form, when it is assumed that ζ, the ratio of the self-exchange coefficient to the corrected diffusivity, is equal to 1, the MS formulation performs well for silicalite, the all-Si version of ZSM-5. However, when there are lattice heterogeneities or the topology of the pore network differs from that of silicalite, it is necessary to assume [Formula: see text]. Because ζ is generally occupancy dependent, the theory is unsuited as a fully predictive theory for self-diffusion in heterogeneous microporous solids, unless a theory for ζ is derived. However, since several studies have demonstrated that the MS formulation is able to predict multi-component diffusivities from single-component diffusivities for zeolites with one type of site, an extension to zeolites with multiple types of sites would be very valuable.