Geodesic systems of tunnels in hyperbolic 3-manifolds

It is unknown whether an unknotting tunnel is always isotopic to a geodesic in a finite volume hyperbolic 3-manifold. In this paper, we address the generalization of this problem to hyperbolic 3-manifolds admitting tunnel systems. We show that there exist finite volume hyperbolic 3-manifolds with a single cusp, with a system of at least two tunnels, such that all but one of the tunnels come arbitrarily close to self-intersecting. This gives evidence that systems of unknotting tunnels may not be isotopic to geodesics in tunnel number n manifolds. In order to show this result, we prove there is a geometrically finite hyperbolic structure on a (1;n)-compression body with a system of core tunnels such that all but one of the core tunnels self-intersect.Comment: 19 pages, 4 figures. V2 contains minor updates to references and exposition. To appear in Algebr. Geom. Topo

A Coordinated Europeanization of the Comics Industry through Distribution: The Politics of the Global Journey of Astérix and Tintin through the Strategic Distribution of their Magazines and Contents in the 1960s

Researchers have usually focused on the Tintin and Astérix series’ global book diffusion through translation. However, little has been discussed about the distribution policies of the comics magazine format, a key factor in the development of European comics. This paper will consider the continentalization of western European national comics industries via the intra-EEC networking of distribution channels during the 1960s. By facilitating the exchange of comics features in the Franco-Belgian area, publishers such as Casterman, Le Lombard, and Dargaud ensured the rise of the industry and of the products they wanted to disseminate. Contemplating the motivations of publishers this article will delve deeper into the emergence of cooperative and competitive distribution channels among national publishers and between countries. Through the archives of Casterman and primary sources this article intends to contribute to a greater understanding of how the carefully planned distribution network of comics influenced the development of the European industry as a whole

Modification of the biological intercept model to account for ontogenetic effects in laboratory-reared delta smelt (Hypomesus transpacificus)*

We investigated age, growth, and ontogenetic effects on the proportionality of otolith size to fish size in laboratory-reared delta smelt (Hypomesus transpacificus) from the San Francisco Bay estuary. Delta smelt larvae were reared from hatching in laboratory mesocosms for 100 days. Otolith increments from known-age fish were enumerated to validate that growth increments were deposited daily and to validate the age of fish at first ring formation. Delta smelt were found to lay down daily ring increments; however, the first increment did not form until six days after hatching. The relationship between otolith size and fish size was not biased by age or growth-rate effects but did exhibit an interruption in linear growth owing to an ontogenetic shift at the postflexon stage. To back-calculate the size-at-age of individual fish, we modified the biological intercept (BI) model to account for ontogenetic changes in the otolith-size−fish-size relationship and compared the results to the time-varying growth model, as well as the modified Fry model. We found the modified BI model estimated more accurately the size-at-age from hatching to 100 days after hatching. Before back-calculating size-at-age with existing models, we recommend a critical evaluation of the effects that age, growth, and ontogeny can have on the otolith-size−fish-size relation

On the optimization of bipartite secret sharing schemes

Optimizing the ratio between the maximum length of the shares and the length of the secret value in secret sharing schemes for general access structures is an extremely difficult and long-standing open problem. In this paper, we study it for bipartite access structures, in which the set of participants is divided in two parts, and all participants in each part play an equivalent role. We focus on the search of lower bounds by using a special class of polymatroids that is introduced here, the tripartite ones. We present a method based on linear programming to compute, for every given bipartite access structure, the best lower bound that can be obtained by this combinatorial method. In addition, we obtain some general lower bounds that improve the previously known ones, and we construct optimal secret sharing schemes for a family of bipartite access structures.Peer ReviewedPostprint (author's final draft

The effect of benthic microalgal photosynthetic oxygen production on nitrogen fluxes across the sediment-water interface in a shallow, sub-tropical estuary

Benthic microalgae (BMA) are a highly productive component of benthic ecosystems. BMA production and nitrogen fluxes were examined in four sub-basins of Florida Bay, in both seagrass and seagrass-free patches, as well as seasonally in a persistent seagrass-free patch in eastern Florida Bay. BMA biomass and oxygen production was highest in seagrass-free sediments with little seasonal variability. Despite high porewater NH4+ concentrations there was little NH4+ efflux. As in temperate estuaries, sub-tropical BMA production and N-assimilation act as a filter to prevent the release of nutrients to the water column. Microelectrode measurements revealed that BMA production causes a doubling of the depth to which O2 penetrates, increasing suitable conditions for nitrification and coupled denitrification. However, the presence of H2S in surface sediments can inhibit nitrification, and there is little nitrogen removal from Florida Bay by denitrification. As a result, BMA N-assimilation is an important nutrient sink in this oligotrophic estuary

High-Precision Entropy Values for Spanning Trees in Lattices

Shrock and Wu have given numerical values for the exponential growth rate of the number of spanning trees in Euclidean lattices. We give a new technique for numerical evaluation that gives much more precise values, together with rigorous bounds on the accuracy. In particular, the new values resolve one of their questions.Comment: 7 pages. Revision mentions alternative approach. Title changed slightly. 2nd revision corrects first displayed equatio