Asymptotics of the quantum invariants for surgeries on the figure 8 knot

We investigate the Reshetikhin--Turaev invariants associated to SU(2) for the 3-manifolds M obtained by doing any rational surgery along the figure 8 knot. In particular, we express these invariants in terms of certain complex double contour integrals. These integral formulae allow us to propose a formula for the leading asymptotics of the invariants in the limit of large quantum level. We analyze this expression using the saddle point method. We construct a certain surjection from the set of stationary points for the relevant phase functions onto the space of conjugacy classes of nonabelian SL(2,C)-representations of the fundamental group of M and prove that the values of these phase functions at the relevant stationary points equal the classical Chern--Simons invariants of the corresponding flat SU(2)-connections. Our findings are in agreement with the asymptotic expansion conjecture. Moreover, we calculate the leading asymptotics of the colored Jones polynomial of the figure 8 knot following R. Kashaev. This leads to a slightly finer asymptotic description of the invariant than predicted by the volume conjecture of Kashaev and H. Murakami and J. Murakami.Comment: 70 pages, to appear in Journal of Knot Theory and Its Ramification

Is Embedding Entailed in Consumer Valuation of Food Safety Characteristics?

Consumers’ preferences for food safety characteristics are investigated with particular focus on existence of an embedding effect. Embedding exists if consumer valuation of food safety is insensitive to scope. Two choice experiments have been conducted valuing food safety in respectively minced pork and chicken breasts, exemplified by avoiding human risks of Salmonella infections and strengthening the restrictions of using antibiotics in the pork production and in terms of avoiding human risks of Salmonella and Campylobacter infections respectively. The results showed no indications of an embedding effect between the food safety characteristics, in neither of the cases.Valuation, Choice Experiment, Market Goods, Food Safety, Embedding., Agricultural and Food Policy, Food Consumption/Nutrition/Food Safety,

Multi-elemental speciation analysis of barley genotypes diering in tolerance to cadmium toxicity using SEC-ICP-MS and ESI-TOF-MS

Plants respond to Cd exposure by synthesizing heavy-metal-binding oligopeptides, called phytochelatins (PCs). These peptides reduce the activity of Cd2+ ions in the plant tissues by forming Cd chelates. The main objective of the present work was to develop an analytical technique, which allowed identication of the most prominent Cd species in plant tissue by SEC-ICP-MS and ESI-TOF-MS. An integrated part of the method development was to test the hypothesis that dierential Cd tolerance between two barley genotypes was linked to dierences in Cd speciation. Only one fraction of Cd species, ranging from 7001800 Da, was detected in the shoots of both genotypes. In the roots, two additional fractions ranging from 29004600 and 670015 000 Da were found. The Cd-rich SEC fractions were heart-cut, de-salted and demetallized using reversed-phase chromatography (RPC), followed by ESI-MS-TOF to identify the ligands. Three dierent families of PCs, viz. (gGlu-Cys)n-Gly (PCn), (gGlu-Cys)n-Ser (iso-PCn) and Cys-(gGlu-Cys)n-Gly (des-gGlu-PCn), the last lacking the N-terminal amino acid, were identied. The PCs induced by Cd toxicity also bound several essential trace elements in plants, including Zn, Cu, and Ni, whereas no Mn species were detected. Zn, Cu and Ni-species were distributed between the 7001800 Da and 670015 000 Da fractions, whereas only Cd species were found in the 29004600 Da fraction dominated by PC3 ligands. Although the total tissue concentration of Cd was similar for the two species, the tolerant barley genotype synthesized signicantly more CdPC3 species with a high Cd specicity than the intolerant genotype, clearly indicating a correlation between Cd tolerance and the CdPC speciation