Abstract:
Bacterial spores are protected by a coat consisting of about 60 different proteins assembled as a biochemically complex structure with intriguing morphological and mechanical properties. Historically, the coat has been considered a static structure providing rigidity and mainly acting as a sieve to exclude exogenous large toxic molecules, such as lytic enzymes. Over recent years, however, new information about the coat's architecture and function have emerged from experiments using innovative tools such as automated scanning microscopy, and high resolution atomic force microscopy.

Abstract:
the objective of this article is to outline some of the main aspects of an urban cultural phenomenon: the urban handicrafts from fairs in buenos aires city. the issues this paper addresses are handicraft production, the circulation of these goods with emphasis on fairs as privileged places of exchange, sociability and handicraft consumption. i consider this type of production a complex phenomena that shapes an heterodox cultural practice, recreating through its own codes the hybrid sociability that contemporary cities induce.

Abstract:
lantana lundiana and l. velutina, (verbenaceae, lantana sect. callioreas) are recorded for the first time for argentina and paraguay. descriptions and illustrations of each taxon are included.

Abstract:
Este artículo tiene por objeto rese ar algunos de los principales aspectos de un fenómeno cultural citadino: las artesanías urbanas feriales de la Ciudad de Buenos Aires. La problemática abordada contempla las instancias de la producción artesanal, la circulación de estos bienes con énfasis en las Ferias como sitios privilegiados del intercambio y ámbitos relevantes de sociabilidad y el consumo de artesanías. Consideramos que este tipo de producción, que constituye un fenómeno complejo, conforma una práctica cultural heterodoxa, recreando con códigos propios la sociabilidad híbrida que inducen las ciudades contemporáneas. The objective of this article is to outline some of the main aspects of an urban cultural phenomenon: the urban handicrafts from fairs in Buenos Aires city. The issues this paper addresses are handicraft production, the circulation of these goods with emphasis on fairs as privileged places of exchange, sociability and handicraft consumption. I consider this type of production a complex phenomena that shapes an heterodox cultural practice, recreating through its own codes the hybrid sociability that contemporary cities induce.

Abstract:
Das Spektrum der diagnostischen M glichkeiten zur Detektion von Arrhythmien hat sich durch st ndige technische Neuerungen wie den implantierbaren Loop-Rekorder und 3dimensionales Mapping stark erweitert. Auch das Verst ndnis von Mechanismus und Ursachen von Arrhythmien konnte durch die rasche Weiterentwicklung der genetischen Forschung verbessert werden. Die Kenntnis der Ionenkanaldefekte als Ursache von Arrhythmien gibt uns in naher Zukunft die M glichkeit, eine kausale Therapie einzuleiten.

Abstract:
We present a simple lattice model showing a glassy behavior. $R$ matrix analysis predicts critical termination of the super-cooled fluid branch at density $\rho_g=0.1717$. This prediction is confirmed by dynamical numerical simulations, showing power-law divergences of relaxation time $\tau_{1/2}$, as well as the 4-susceptibility $\chi_4$ peak's location and height exactly at the predicted density. The power-law divergence of $\chi_4$ continues up to $\chi_4$ as high as $10^4$. Finite-size scaling study reveals divergence of correlation length accompanying the transition.

Abstract:
For a large class of repulsive interaction models, the Mayer cluster integrals can be transformed into a tridiagonal real symmetric matrix $R_{mn}$, whose elements converge to two constants. This allows for an effective extrapolation of the equation of state for these models. Due to a nearby (nonphysical) singularity on the negative real z axis, standard methods (e.g. Pad\`e approximants based on the cluster integrals expansion) fail to capture the behavior of these models near the ordering transition, and, in particular, do not detect the critical point. A recent work (Eisenberg and Baram, PNAS {\bf 104}, 5755 (2007)) has shown that the critical exponents $\sigma$ and $\sigma'$, characterizing the singularity of the density as a function of the activity, can be exactly calculated if the decay of the $R$ matrix elements to their asymptotic constant follows a $1/n^2$ law. Here we employ renormalization arguments to extend this result and analyze cases for which the asymptotic approach of the $R$ matrix elements towards their limiting value is of a more general form. The relevant asymptotic correction terms (in RG sense) are identified and we then provide a corrected exact formula for the critical exponents. We identify the limits of usage of the formula, and demonstrate one physical model which is beyond its range of validity. The new formula is validated numerically and then applied to analyze a number of concrete physical models.

Abstract:
The super-cooled $N3$ model exhibits an increasingly slow dynamics as density approaches the model's random closest packing density. Here, we present a direct measurement of the dynamical correlation function $G_4(r,t)$, showing the emergence of a growing length scale $\xi_4$ across which the dynamics is correlated. The correlation length measured, up to 120 lattice sites, power-law diverges as the density approaches $\rho_t$, the density at which the fluid phase of the model is predicted to terminate. It is shown that the four-point susceptibility, often used as an agent to estimate $\xi_4$, does not depend simply on the latter. Rather, it depends strongly on the short-range behavior of $G_4(r,t)$. Consequently, $\chi_4$ peaks before $\xi_4$ reaches its maximal value. The two quantities should therefore be studied independently.

Abstract:
We consider a tiling model of the two-dimensional square-lattice, where each site is tiled with one of the sixteen Wang tiles. The ground states of this model are all quasi-periodic. The systems undergoes a disorder to quasi-periodicity phase transition at finite temperature. Introducing a proper order-parameter, we study the system at criticality, and extract the critical exponents characterizing the transition. The exponents obtained are consistent with hyper-scaling.

Abstract:
Let x and y be two (not necessarily distinct) points on a closed Riemannian manifold M of dimension n. According to a celebrated theorem by J.P. Serre there exist infinitely many geodesics between x and y. The length of the shortest of these geodesics is obviously less than the diameter of M. But what can be said about the length of the other geodesics? We conjecture that for every k there are k geodesics between x and y of length not exceeding kd, where d denotes the diameter of M.This conjecture is obviously true for round spheres and it is not difficult to prove it for all closed Riemannian manifolds with non-trivial torsion-free fundamental groups. In this paper we announce two further results in the direction of this conjecture. Our first result is that the length of the second shortest geodesic between x and y does not exceed 2nd. Our second result is that if n=2 and M is diffeomorphic to the two-dimensional sphere, then for every k every two points on M can be connected by k geodesics of length not exceeding $(k^2/2 + 3k/2 +2)d$.