Adhesion of microcapsules

The adhesion of microcapsules to an attractive contact potential is studied theoretically. The axisymmetric shape equations are solved numerically. Beyond a universal threshold strength of the potential, the contact radius increases like a square root of the strength. Scaling functions for the corresponding amplitudes are derived as a function of the elastic parameters.Comment: 4 pages, 4 figure

Enhancing the resolution of cohesin dynamics in meiosis

Meiosis is a specialized form of cell division in which one diploid mother cell is converted into four haploid daughter cells. Cohesin is a multi-protein complex, providing cohesion to replicated chromosomes. During meiosis, cohesin is removed from chromosomes in two steps. First, it is proteolytically cleaved from chromosome arms in anaphase I, whereas cohesin in the vicinity of the centromere is protected from cleavage. This pericentromeric cohesin is then removed in anaphase II. This stepwise loss of cohesin is part of the current model of meiotic chromosome segregation. Evidence for this kind of cohesin dynamics came originally from immunofluorescence experiments with very limited spatial resolution. A new workflow was established by combining a novel synchronization system for budding yeast meiosis with a calibrated and optimized ChIP-Seq protocol. This workflow allows resolving the cohesin dynamics in the course of the two meiotic divisions with unprecedented temporal and spatial resolution. With this new experimental system, we confirmed the existence of two cohesin fractions on chromosomes, a protected and an unprotected fraction. Contrary to the current model, we detected both fractions in the region around the centromere. This indicates that the distinction between arm cohesin and pericentromeric cohesin is not identical to the classification into unprotected cohesin and protected cohesin. These results suggest that the mechanism of protection is not only determined by the localization of the cohesin protein complex. Additionally, we discovered significant differences in the cohesin protection activity among individual chromosomes. The protein Sgo1 is required for the centromeric protection of cohesin. Sgo1 was analyzed directly with the new workflow, and we generated novel insights into the loading of the protection machinery onto chromosomes and the establishment of centromeric protection in meiosis. The protection machinery is loaded onto chromosomes in a cohesin-dependent mechanism, and a novel model of a dynamic three-step loading mechanism of the protection machinery is presented. This model explains how the cells are able to provide a robust and reliable protection to cohesin located in very diverse patterns on different chromosomes. Moreover, the model suggests a new function of the protein Sgo1 in centromeric protection. A last result is that the polo-like kinase of budding yeast, Cdc5, is involved in regulating the levels of the protection machinery, which are loaded onto chromosomes

The Resonance Peak in Sr2_2RuO4_4: Signature of Spin Triplet Pairing

We study the dynamical spin susceptibility, $\chi({\bf q}, \omega)$, in the normal and superconducting state of Sr$_2$RuO$_4$. In the normal state, we find a peak in the vicinity of ${\bf Q}_i\simeq (0.72\pi,0.72\pi)$ in agreement with recent inelastic neutron scattering (INS) experiments. We predict that for spin triplet pairing in the superconducting state a {\it resonance peak} appears in the out-of-plane component of $\chi$, but is absent in the in-plane component. In contrast, no resonance peak is expected for spin singlet pairing.Comment: 4 pages, 4 figures, final versio

The Making of Transnational Contract Law

The definition and creation of contract law is entrenched in a common understanding of the strong role of the modern state in the administration of justice. This article argues that this understanding is currently subject to a fundamental transformation as a result of the increasing demand for legal certainty in cross-border transactions. Traditional concepts of private international law, mainly the law of conflicts and multilateral treaty harmonization, have proven unable to keep pace with globalization, allowing private actors to step in and gain a dominant position in providing legal services to international commerce. The resulting privatization of lawmaking leads to concerns regarding the legitimacy of transnational contract law. This paper suggests using the concepts of rough consensus and running code to reconceptualize the ideas of democratic lawmaking under the rule of law in order to adapt them to the reality of transnational lawmaking. Governing Contracts – Public and Private Perspectives, Symposium. Osgoode Hall Law School, Toronto, November 9-10, 200