Clustering and melting in a wet granular monolayer

We investigate experimentally the collective behavior of a wet granular monolayer under vertical vibrations. The spherical particles are partially wet such that there are short-ranged attractive interactions between adjacent particles. As the vibration strength increases, clustering, reorganizing and melting regimes are identified subsequently through a characterization with the bond-orientational order parameters and the mean kinetic energy of the particles. The melting transition is found to be a continuous process starting from the defects inside the crystal.Comment: 4 pages, 3 figures, accepted by Powders and Grains 201

„Heimatregion im Koffer“ – Raumnarrationen in den Ergebnissen eines SchülerInnenwettbewerbs

Zu Beginn des Jahres 2005 forderte das Fränkische Freilandmuseum Fladungen alle Schülerinnen und Schüler an den Schulen der Landkreise Bad Kissingen und Rhön-Grabfeld zur Teilnahme an einem SchülerInnenwettbewerb auf. Rund 30 Schulklassen verschiedenster Altersstufen und Schultypen bekundeten ihr Interesse an der Teilnahme und erhielten Anfang April vom Museum einen historischen Koffer. „Was macht unsere Heimatregion aus? Packe sie in einen Koffer!“ lautete die Aufgabe für die Schülerinnen und Schüler. Zum Abgabetermin am 31. Mai erreichten 22 gefüllte Koffer das Freilandmuseum. Nach ihrer Auswertung und Begutachtung kam es am 14. Juni zur feierlichen Preisverleihung. Die von den Schülerinnen und Schülern bearbeiteten Koffer wurden dann vom 15. September bis zum Saisonende am 1. November 2005 im Rahmen einer „Werkschau“ im Sonderausstellungsraum des Freilandmuseums der Öffentlichkeit präsentiert (Abb. 1)

Spherically symmetric equilibria for self-gravitating kinetic or fluid models in the non-relativistic and relativistic case - A simple proof for finite extension

We consider a self-gravitating collisionless gas as described by the Vlasov-Poisson or Einstein-Vlasov system or a self-gravitating fluid ball as described by the Euler-Poisson or Einstein-Euler system. We give a simple proof for the finite extension of spherically symmetric equilibria, which covers all these models simultaneously. In the Vlasov case the equilibria are characterized by a local growth condition on the microscopic equation of state, i.e., on the dependence of the particle distribution on the particle energy, at the cut-off energy E_0, and in the Euler case by the corresponding growth condition on the equation of state p=P(\rho) at \rho=0. These purely local conditions are slight generalizations to known such conditions.Comment: 20 page

Impact of droughts on the carbon cycle in European vegetation : a probabilistic risk analysis using six vegetation models

Peer reviewedPublisher PD

Genome-wide analysis of PAPS1-dependent polyadenylation identifies novel roles for functionally specialized poly(A) polymerases in Arabidopsis thaliana

The poly(A) tail at 3’ ends of eukaryotic mRNAs promotes their nuclear export, stability and translational efficiency, and changes in its length can strongly impact gene expression. The Arabidopsis thaliana genome encodes three canonical nuclear poly(A) polymerases,PAPS1, PAPS2 and PAPS4. As shown by their different mutant phenotypes, these three isoforms are functionally specialized, with PAPS1 modifying organ growth and suppressing a constitutive immune response. However, the molecular basis of this specialization is largely unknown. Here, we have estimated poly(A)-tail lengths on a transcriptome-wide scale in wild-type and paps1 mutants. This identified categories of genes as particularly strongly affected in paps1 mutants, including genes encoding ribosomal proteins, cell-division factors and major carbohydrate-metabolic proteins. We experimentally verified two novel functions of PAPS1 in ribosome biogenesis and redox homoeostasis that were predicted based on the analysis of poly(A)-tail length changes in paps1 mutants. When overlaying the PAPS1-dependent effects observed here with coexpression analysis based on independent microarray data, the two clusters of transcripts that are most closely coexpressed with PAPS1 show the strongest change in poly(A)-tail length and transcript abundance in paps1 mutants in our analysis. This suggests that their coexpression reflects at least partly the preferential polyadenylation of these transcripts by PAPS1 versus the other two poly(A)-polymerase isoforms. Thus, transcriptome-wide analysis of poly(A)-tail lengths identifies novel biological functions and likely target transcripts for polyadenylation by PAPS1. Data integration with large-scale co-expression data suggests that changes in the relative activities of the isoforms are used as an endogenous mechanism to co-ordinately modulate plant gene expression

President of the United States, Destroyer of Worlds: Considering Congress\u27s Authority to Enact a Nuclear No-First-Use Law

This article argues that Congress can exercise its constitutional war powers to enact a law restricting the President from using nuclear weapons first. The article contends that using a nuclear weapon is qualitatively different from conventional warfare and that the first use of nuclear weapons marks a decision to enter into war. Therefore, nuclear first use is not a battlefield decision within the President’s commander in chief power but rather a choice to enter the United States into a new type of conflict that could pose a direct, immediate, and existential threat to the U.S. homeland. Regulating that decision falls under Congress’s exclusive war powers. Congress can limit its authorizations of war and prohibit military actions beyond its authorization. Therefore, Congress could stipulate that its war authorizations extend only to conventional hostilities unless Congress expressly authorizes the first use of nuclear weapons. Using its authority to limit authorizations of for the use of military force, Congress can enact a no-first-use law