Fragmentation versus Stability in Bimodal Coalitions

Competing bimodal coalitions among a group of actors are discussed. First, a model from political sciences is revisited. Most of the model statements are found not to be contained in the model. Second, a new coalition model is built. It accounts for local versus global alignment with respect to the joining of a coalition. The existence of two competing world coaltions is found to yield one unique stable distribution of actors. On the opposite a unique world leadership allows the emergence of unstable relationships. In parallel to regular actors which have a clear coalition choice, ``neutral" ``frustrated" and ``risky" actors are produced. The cold war organisation after world war II is shown to be rather stable. The emergence of a fragmentation process from eastern group disappearance is explained as well as continuing western group stability. Some hints are obtained about possible policies to stabilize world nation relationships. European construction is analyzed with respect to european stability. Chinese stability is also discussed.Comment: 14 pages, latex, no figures, to appear in Physica

Stochastic Renormalization Group in Percolation: I. Fluctuations and Crossover

A generalization of the Renormalization Group, which describes order-parameter fluctuations in finite systems, is developed in the specific context of percolation. This ``Stochastic Renormalization Group'' (SRG) expresses statistical self-similarity through a non-stationary branching process. The SRG provides a theoretical basis for analytical or numerical approximations, both at and away from criticality, whenever the correlation length is much larger than the lattice spacing (regardless of the system size). For example, the SRG predicts order-parameter distributions and finite-size scaling functions for the complete crossover between phases. For percolation, the simplest SRG describes structural quantities conditional on spanning, such as the total cluster mass or the minimum chemical distance between two boundaries. In these cases, the Central Limit Theorem (for independent random variables) holds at the stable, off-critical fixed points, while a ``Fractal Central Limit Theorem'' (describing long-range correlations) holds at the unstable, critical fixed point. This first part of a series of articles explains these basic concepts and a general theory of crossover. Subsequent parts will focus on limit theorems and comparisons of small-cell SRG approximations with simulation results.Comment: 33 pages, 6 figures, to appear in Physica A; v2: some typos corrected and Eqs. (26)-(27) cast in a simpler (but equivalent) for

Frustration - how it can be measured

A misfit parameter is used to characterize the degree of frustration of ordered and disordered systems. It measures the increase of the ground-state energy due to frustration in comparison with that of a relevant reference state. The misfit parameter is calculated for various spin-glass models. It allows one to compare these models with each other. The extension of this concept to other combinatorial optimization problems with frustration, e.g. p-state Potts glasses, graph-partitioning problems and coloring problems is given.Comment: 10 pages, 1 table, no figures, uses revtex.st

Dynamic structure factor of the Ising model with purely relaxational dynamics

We compute the dynamic structure factor for the Ising model with a purely relaxational dynamics (model A). We perform a perturbative calculation in the $\epsilon$ expansion, at two loops in the high-temperature phase and at one loop in the temperature magnetic-field plane, and a Monte Carlo simulation in the high-temperature phase. We find that the dynamic structure factor is very well approximated by its mean-field Gaussian form up to moderately large values of the frequency $\omega$ and momentum $k$. In the region we can investigate, $k\xi \lesssim 5$, $\omega \tau \lesssim 10$, where $\xi$ is the correlation length and $\tau$ the zero-momentum autocorrelation time, deviations are at most of a few percent.Comment: 21 pages, 3 figure

Nonequilibrium relaxation of the two-dimensional Ising model: Series-expansion and Monte Carlo studies

We study the critical relaxation of the two-dimensional Ising model from a fully ordered configuration by series expansion in time t and by Monte Carlo simulation. Both the magnetization (m) and energy series are obtained up to 12-th order. An accurate estimate from series analysis for the dynamical critical exponent z is difficult but compatible with 2.2. We also use Monte Carlo simulation to determine an effective exponent, z_eff(t) = - {1/8} d ln t /d ln m, directly from a ratio of three-spin correlation to m. Extrapolation to t = infinity leads to an estimate z = 2.169 +/- 0.003.Comment: 9 pages including 2 figure

El nuevo Código Procesal Penal de la Nación Argentina

El nuevo Código Procesal Penal de la Nación Argentin

Serine 25 phosphorylation inhibits RIPK1 kinase-dependent cell death in models of infection and inflammation

RIPK1 regulates cell death and inflammation through kinase-dependent and -independent mechanisms. As a scaffold, RIPK1 inhibits caspase-8-dependent apoptosis and RIPK3/MLKL-dependent necroptosis. As a kinase, RIPK1 paradoxically induces these cell death modalities. The molecular switch between RIPK1 pro-survival and pro-death functions remains poorly understood. We identify phosphorylation of RIPK1 on Ser25 by IKKs as a key mechanism directly inhibiting RIPK1 kinase activity and preventing TNF-mediated RIPK1-dependent cell death. Mimicking Ser25 phosphorylation (S > D mutation) protects cells and mice from the cytotoxic effect of TNF in conditions of IKK inhibition. In line with their roles in IKK activation, TNF-induced Ser25 phosphorylation of RIPK1 is defective in TAK1- or SHARPIN-deficient cells and restoring phosphorylation protects these cells from TNF-induced death. Importantly, mimicking Ser25 phosphorylation compromises the in vivo cell death-dependent immune control of Yersinia infection, a physiological model of TAK1/IKK inhibition, and rescues the cell death-induced multi-organ inflammatory phenotype of the SHARPIN-deficient mice

Students\u27 notions of microbes

Ein großer Teil der lebendigen Welt ist so klein, dass er unserer Wahrnehmung entgeht. Lebensweltlich ist die Welt des Kleinen einerseits nicht erfahrbar, andererseits ist privat und auch massenmedial die Rede von Keimen, Bazillen und Bakterien. Der Artikel beschäftigt sich mit Lernervorstellungen zur Gestalt, Größe, Ernährung, Beweglichkeit und zum Wachstum der Mikroben. Analysiert und theoriegeleitet reinterpretiert werden zum einen empirisch erhobene Lernervorstellungen aus der Literatur und zum anderen in Vermittlungsexperimenten erhobene eigene Befunde. Die erfassten Lernerkonzepte werden durch vier Denkfiguren strukturiert: Mikroben als kleine Behälter, Mikroben als Tiere, Mikroben als Pflanzen sowie Mikroben als unbelebter Schmuddel. (DIPF/Orig.)A large part of the living world is so small that it is imperceptible. On the one hand the microcosm is beyond everyday experience, on the other hand we talk about germs, bacteria or bacilli and even the mass media report on them. This paper deals with students conceptions related to the structure, size, nutrition, locomotion and growth of microbes. Both empirically identified learners’ conceptions in the literature as well as our own study conducted by means of teaching experiments were analysed and subsequently reinterpreted according to theoretical principles. Based on these results four figures of thought were reconstructed: microbes as small containers, microbes as animals or people, microbes as plants, microbes as inanimate muck. (DIPF/Orig.

Development of students\u27 conceptions of biological adaptation. Understanding students\u27 learning difficulties and addressing them with appropriate learning activities

Zahlreiche Studien belegen die Schwierigkeiten, die Schüler mit dem Erlernen von Evolution haben. Das wesentliche Ziel dieser Untersuchung besteht darin, die Schwierigkeiten der Schüler mit einem zentralen Aspekt von Evolution, der stammesgeschichtlichen Anpassung, zu untersuchen und die Wirkung von Lernangeboten auf deren Vorstellungen zu erheben. Auf Grundlage des Modells der Didaktischen Rekonstruktion besteht das Untersuchungsdesign aus den Schritten Fachliche Klärung, Erfassen der Lernerperspektiven und Didaktische Strukturierung. Die Lernangebote werden in fünf Vermittlungsexperimenten mit je drei Schülerinnen und Schülern der Oberstufe (16 - 18 Jahre) evaluiert. Die Vorstellungen der Schüler und deren Entwicklung in den Vermittlungsexperimenten werden in Form von "Denkpfaden" festgehalten. Den theoretischen Rahmen für die Interpretation der Denkpfade bildet die Theorie des erfahrungsbasierten Verstehens. Theoretischer Rahmen, Methoden und Ergebnisse können zu einem vertieften Verständnis der konzeptuellen Struktur der Lernervorstellungen zu stammesgeschichtlicher Anpassung beitragen und den Prozess der Vorstellungsentwicklung bei der Arbeit mit didaktisch rekonstruierten Lernangeboten aufdecken. (DIPF/Orig.)Students encounter various difficulties in understanding the theory of biological evolution. Therefore, our research project has focussed on the investigation of students’ difficulties in learning the important concept of biological adaptation and studying the impact of teaching and learning activities on students’ conceptions. Using the Model of Educational Reconstruction, a four-phase design was carried out. Firstly, a clarification of science matter was performed. Secondly, students’ conceptions were investigated, and thirdly, teaching and learning activities were designed. Finally the learning activities were evaluated using five teaching experiments, each with three students aged 16–18. Interpretation of students’ conceptions and their “learning pathways” during the teaching experiments were framed theoretically by experiential realism. The theoretical framework, methods as well as outcomes may contribute to a deeper understanding of students’ ways of thinking about biological adaptation and reveal the process of conceptual development while working with well-designed teaching and learning activities. (DIPF/Orig.

Towards Scalable Real-time Analytics:: An Architecture for Scale-out of OLxP Workloads

We present an overview of our work on the SAP HANA Scale-out Extension, a novel distributed database architecture designed to support large scale analytics over real-time data. This platform permits high performance OLAP with massive scale-out capabilities, while concurrently allowing OLTP workloads. This dual capability enables analytics over real-time changing data and allows fine grained user-specified service level agreements (SLAs) on data freshness. We advocate the decoupling of core database components such as query processing, concurrency control, and persistence, a design choice made possible by advances in high-throughput low-latency networks and storage devices. We provide full ACID guarantees and build on a logical timestamp mechanism to provide MVCC-based snapshot isolation, while not requiring synchronous updates of replicas. Instead, we use asynchronous update propagation guaranteeing consistency with timestamp validation. We provide a view into the design and development of a large scale data management platform for real-time analytics, driven by the needs of modern enterprise customers