The efficiency of financial markets and their potential to produce bubbles are central topics in academic and professional debates. Yet, little is known about the contribution of financial professionals to price efficiency. We run 116 experimental markets with 412 professionals and 502 students. We find that professional markets with bubble drivers – capital inflows or high initial capital supply – are susceptible to bubbles, although they are more efficient than student markets. In mixed markets with students, bubbles also occur, but professionals act as price stabilizers. We show that heterogeneous price beliefs drive overpricing, especially in bubble-prone market environments. Authors have furnished an Internet Appendix, which is available on the Oxford University Press Web site next to the link to the final published paper online.

(±)-Catechin is a flavan-3-ol that occurs in the organs of many plant species, especially fruits. Healthbeneficial effects have been studied extensively, and notable toxic effects have not been found. In contrast, (±)-catechin has been implicated as a 'chemical weapon' that is exuded by the roots of Centaurea stoebe, an invasive knapweed of northern America. Recently, this hypothesis has been rejected based on (±)-catechin's low phytotoxicity, instability at pH levels higher than 5, and poor recovery from soil. In the current study, (±)-catechin did not inhibit the development of white and black mustard to an extent that was comparable to the highly phytotoxic juglone, a naphthoquinone that is allegedly responsible for the allelopathy of the walnut tree. At high stress levels, caused by sub-lethal methanol concentrations in the medium, and a 12 h photoperiod, (±)-catechin even attenuated growth retardation. A similar effect was observed when (±)-catechin was assayed for brine shrimp mortality. Higher concentrations reduced the mortality caused by toxic concentrations of methanol. Further, when (±)-catechin was tested in variants of the deoxyribose degradation assay, it was an efficient scavenger of reactive oxygen species (ROS) when they were present in higher concentrations. This antioxidant effect was enhanced when iron was chelated directly by (±)-catechin. Conversely, if iron was chelated to EDTA, pro-oxidative effects were demonstrated at higher concentrations; in this case (±)-catechin reduced molecular oxygen and iron to reagents required by the Fenton reaction to produce hydroxyl radicals. A comparison of cyclic voltammograms of (±)-catechin with the phytotoxic naphthoquinone juglone indicated similar redoxcycling properties for both compounds although juglone required lower electrochemical potentials to enter redox reactions. In buffer solutions, (±)-catechin remained stable at pH 3.6 (vacuole) and decomposed at pH 7.4 (cytoplasm) after 24 h. The results support the recent rejection of the hypothesis that (±)-catechin may serve as a 'chemical weapon' for invasive plants. Instead, accumulation and exudation of (±)-catechin may help plants survive periods of stress.

Since the storage requirements of the BEM are proportional to 2 , only relative small problems can be solved on a PC or a workstation. In this paper we present an adaptive multilevel fast multipole method for the solution of electrostatic problems with the BEM. We will show, that in practice the storage requirements and the computational costs are approximately proportional to and therefore even large three dimensional problems can be solved on a relative small computer.Index Terms-Boundary element methods, fast multipole method, iterative methods, Laplace equations.

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The large intensities available with femtosecond (fs) laser pulses allow permanent structural modifications in transparent materials with high spatial resolution. Irradiation of self-standing transparent biopolymer films, such as collagen, pure and curcumin doped gelatine employing a 60-fs high-power 11 MHz Ti-Sapphire oscillator laser system linked to an optical microscope led to modifications and ablation. Swelling modifications consisting in the foaming of the irradiated area and formation of a single layer of bubbles arranged around the narrow ablation crater were investigated by optical, scanning force (SFM) and scanning electron (SEM) microscopy. These modifications occur at fluences below the respective ablation thresholds, i.e. ablation processes take place on modified swelled phases. The results are discussed in terms of local temperature increase, generation of thermoelastic stress, physico-chemical effects, and in terms of an incubation model, i.e. the accumulation of these phenomena upon successive pulse irradiation.