Three-point correlation function of galaxy clusters in cosmological models: a strong dependence on triangle shape

In this paper, we use large \pppm N-body simulations to study the three-point correlation function \zeta of clusters in two theoretical models. The first model (LCDM) is a low-density flat model of \Omega_0=0.3, \Lambda_0=0.7 and h=0.75, and the second model (PIM) is an Einstein-de-Sitter model with its linear power spectrum obtained from observations. We found that the scaled function Q(r,u,v), which is defined as the ratio of \zeta (r, ru, ru+rv) to the hierarchical sum \xi (r)\xi (ru)+ \xi (ru) \xi (ru+rv) +\xi (ru+rv)\xi (r) (where \xi is the two-point correlation function of clusters), depends weakly on r and u, but very strongly on v. Q(r,u,v) is about 0.2 at v=0.1 and 1.8 at v=0.9. A model of Q(r,u,v)=\Theta 10^{1.3v^2} can fit the data of \zeta very nicely with \Theta\approx 0.14. This model is found to be universal for the LCDM clusters and for the PIM clusters. Furthermore, Q(r,u,v) is found to be insensitive to the cluster richness. We have compared our N-body results with simple analytical theories of cluster formation, like the peak theories or the local maxima theories. We found that these theories do not provide an adequate description for the three-point function of clusters. We have also examined the observational data of \zeta presently available, and have not found any contradiction between the observations and our model predictions. The v-dependence of q in a projected catalogue of clusters is shown to be much weaker than the v-dependence of Q found in the three-dimensional case. It would be important to search for the v-dependence of Q in redshift samples of rich clusters

A cosmological model in Weyl-Cartan spacetime

We present a cosmological model for early stages of the universe on the basis of a Weyl-Cartan spacetime. In this model, torsion $T^{\alpha}$ and nonmetricity $Q_{\alpha \beta}$ are proportional to the vacuum polarization. Extending earlier work of one of us (RT), we discuss the behavior of the cosmic scale factor and the Weyl 1-form in detail. We show how our model fits into the more general framework of metric-affine gravity (MAG).Comment: 19 pages, 5 figures, typos corrected, uses IOP style fil

Social inertia in collaboration networks

This work is a study of the properties of collaboration networks employing the formalism of weighted graphs to represent their one-mode projection. The weight of the edges is directly the number of times that a partnership has been repeated. This representation allows us to define the concept of "social inertia" that measures the tendency of authors to keep on collaborating with previous partners. We use a collection of empirical datasets to analyze several aspects of the social inertia: 1) its probability distribution, 2) its correlation with other properties, and 3) the correlations of the inertia between neighbors in the network. We also contrast these empirical results with the predictions of a recently proposed theoretical model for the growth of collaboration networks.Comment: 7 pages, 5 figure

56-jährige Patientin mit pathologischer subkapitaler Humerusfraktur bei Morbus Gaucher

Zusammenfassung: Wir berichten über eine Patientin mit pathologischer Humerusfraktur bei Erstdiagnose eines Morbus Gaucher, der häufigsten autosomal-rezessiv vererbten Lipidspeicherkrankheit. Sie führt häufig zu schweren Knochenkomplikationen mit Schmerzen, Osteonekrosen, Frakturen oder Gelenkeinbrüchen. Bei begründetem Verdacht sollte in Hinblick auf die therapeutischen Konsequenzen zur Diagnosesicherung die β-Glucocerebrosidase in Leukozyten bestimmt werden. Durch eine Enzymersatztherapie ist die Krankheit effektvoll behandelba

Bioenergieträger - eine Chance für die “Dritte Welt”. Verfahren - Realisierung - Wirkungen

Die verstärkte Nutzung biogener Energieträger könnte eine Chance für Entwicklungsländer sein, wenn es gelingt, die damit verbundenen technischen und politisch-sozialen Probleme erfolgreich zu bearbeiten und die Gestaltungsoptionen in der Entwicklungs-, Klimaschutz-, Forschungs- und Technologiepolitik optimal auszuschöpfen. Die Autoren widmen sich in diesem Band beiden Fragekomplexen: den technischen wie den gesellschaftlichen. Sie dokumentieren den Stand und die Entwicklungsmöglichkeiten der Nutzung von Biofestbrennstoffen, Pflanzenölen und Biogas und zeigen, daß Bioenergieträgern im Feld der regenerativen Energien zunehmende Bedeutung zukommt, weil bei der Bereitstellung und bei den Konversionstechniken noch erhebliche Verbesserungspotentiale aktivierbar sind. Freilich hängt deren Aktivierung nicht zuletzt von der Überwindung nicht-technischer Hemmnisse in den Ländern der "Dritten Welt" ab. Der Band setzt sich daher auch mit den komplexen Zusammenhängen ökonomischer, ökologischer, soziokultureller sowie politischer und institutioneller Faktoren auseinander. Spezielles Augenmerk wird auf die im Kyoto-Protokoll vorgesehenen Instrumente für den internationalen Klimaschutz, vor allem den Clean Development Mechanism, gelegt

Conformally invariant wave-equations and massless fields in de Sitter spacetime

Conformally invariant wave equations in de Sitter space, for scalar and vector fields, are introduced in the present paper. Solutions of their wave equations and the related two-point functions, in the ambient space notation, have been calculated. The ``Hilbert'' space structure and the field operator, in terms of coordinate independent de Sitter plane waves, have been defined. The construction of the paper is based on the analyticity in the complexified pseudo-Riemanian manifold, presented first by Bros et al.. Minkowskian limits of these functions are analyzed. The relation between the ambient space notation and the intrinsic coordinates is then studied in the final stage.Comment: 21 pages, LaTeX, some details adde

Precision Measurement of the 29Si, 33S, and 36Cl Binding Energies

The binding energies of 29Si, 33S, and 36Cl have been measured with a relative uncertainty $< 0.59 \times 10^{-6}$ using a flat-crystal spectrometer. The unique features of these measurements are 1) nearly perfect crystals whose lattice spacing is known in meters, 2) a highly precise angle scale that is derived from first principles, and 3) a gamma-ray measurement facility that is coupled to a high flux reactor with near-core source capability. The binding energy is obtained by measuring all gamma-rays in a cascade scheme connecting the capture and ground states. The measurements require the extension of precision flat-crystal diffraction techniques to the 5 to 6 MeV energy region, a significant precision measurement challenge. The binding energies determined from these gamma-ray measurements are consistent with recent highly accurate atomic mass measurements within a relative uncertainty of $4.3 \times 10^{-7}$. The gamma-ray measurement uncertainties are the dominant contributors to the uncertainty of this consistency test. The measured gamma-ray energies are in agreement with earlier precision gamma-ray measurements.Comment: 13 pages, 4 figure

Interfaces for science: Conceptualizing an interactive graphical interface

6,849.32 new research journal articles are published every day. The exponential growth of Scientific Knowledge Objects (SKOs) on the Web, makes searches time-consuming. Access to the right and relevant SKOs is vital for research, which calls for several topics, including the visualization of science dynamics. We present an interface model aimed to represent of the relations that emerge in the science social space dynamics, namely through the visualization and navigation of the relational structures between researchers, SKOs, knowledge domains, subdomains, and topics. This interface considers the relationship between the researcher who reads and shares the relevant articles and the researcher who wants to find the most relevant SKOs within a subject matter. This article presents the first iteration of the conceptualization process of the interface layout, its interactivity and visualization structures. It is essential to consider the hierarchical and relational structures/algorithms to represent the science social space dynamics. These structures are not being used as analysis tools, because it is not objective to show the linkage properties of these relationships. Instead, they are used as a means of representing, navigating and exploring these relationships. To sum up, this article provides a framework and fundamental guidelines for an interface layout that explores the social science space dynamics between the researcher who seeks relevant SKOs and the researchers who read and share them.This work has been supported by COMPETE: POCI-01-0145-FEDER- 007043 and FCT - Fundação para a Ciência e Tecnologia within the Project Scope: (UID/CEC/00319/2013) and the Project IViSSEM: ref: POCI-010145-FEDER-28284