180 research outputs found
Simulating anthropogenic impacts to bird communities in tropical rain forests
We used an aggregated modelling approach to simulate the impacts ofanthropogenic disturbances on the long-term dynamics of faunal diversityin tropical rain forests. We restricted our study to bird communities eventhough the approach is more general. We developed a model calledBIODIV which simulated the establishment of hypothetical bird speciesin a forest. Our model was based on the results of a simple matrix modelwhich calculated the spatio-temporal dynamics of a tropical rain forest inMalaysia. We analysed the establishment of bird species in a secondaryforest succession and the impacts of 60 different logging scenarios on thediversity of the bird community. Of the three logging parameters(cycle length, method, intensity), logging intensity had the most servereimpact on the bird community. In the worst case the number of bird specieswas reduced to 23% of the species richness found in a primary forest
Patterns in syntactic dependency networks
Many languages are spoken on Earth. Despite their diversity, many robust language universals are known to exist. All languages share syntax, i.e., the ability of combining words for forming sentences. The origin of such traits is an issue of open debate. By using recent developments from the statistical physics of complex networks, we show that different syntactic dependency networks (from Czech, German, and Romanian) share many nontrivial statistical patterns such as the small world phenomenon, scaling in the distribution of degrees, and disassortative mixing. Such previously unreported features of syntax organization are not a trivial consequence of the structure of sentences, but an emergent trait at the global scale.Peer ReviewedPostprint (published version
AktionsrÀume in Dresden
In vorliegender Studie werden die AktionsrĂ€ume von Befragten in Dresden ĂŒber eine standardisierte Befragung (n=360) untersucht. Die den AktionsrĂ€umen zugrundeliegenden AktivitĂ€ten werden unterschieden in Einkaufen fĂŒr den tĂ€glichen Bedarf, Ausgehen (z.B. in CafĂ©, Kneipe, GaststĂ€tte), Erholung im Freien (z.B. spazieren gehen, Nutzung von GrĂŒnanlagen) und private Geselligkeit (z.B. Feiern, Besuch von Verwandten/Freunden). Der Aktionsradius wird unterschieden in Wohnviertel, Nachbarviertel und sonstiges weiteres Stadtgebiet. Um aus den vier betrachteten AktivitĂ€ten einen umfassenden Kennwert fĂŒr den durchschnittlichen Aktionsradius eines Befragten zu bilden, wird ein Modell fĂŒr den Kennwert eines Aktionsradius entwickelt. Die Studie kommt zu dem Ergebnis, dass das Alter der Befragten einen signifikanten â wenn auch geringen â Einfluss auf den Aktionsradius hat. Das Haushaltsnettoeinkommen hat einen mit EinschrĂ€nkung signifikanten, ebenfalls geringen Einfluss auf alltĂ€gliche AktivitĂ€ten der Befragten
Towards a nonequilibrium Green's function description of nuclear reactions: one-dimensional mean-field dynamics
Nonequilibrium Green's function methods allow for an intrinsically consistent
description of the evolution of quantal many-body body systems, with inclusion
of different types of correlations. In this paper, we focus on the practical
developments needed to build a Green's function methodology for nuclear
reactions. We start out by considering symmetric collisions of slabs in one
dimension within the mean-field approximation. We concentrate on two issues of
importance for actual reaction simulations. First, the preparation of the
initial state within the same methodology as for the reaction dynamics is
demonstrated by an adiabatic switching on of the mean-field interaction, which
leads to the mean-field ground state. Second, the importance of the Green's
function matrix-elements far away from the spatial diagonal is analyzed by a
suitable suppression process that does not significantly affect the evolution
of the elements close to the diagonal. The relative lack of importance of the
far-away elements is tied to system expansion. We also examine the evolution of
the Wigner function and verify quantitatively that erasing of the off-diagonal
elements corresponds to averaging out of the momentum-space details in the
Wigner function.Comment: 78 pages, 30 figure
Extensive Hartree-Fock + BCS calculation with Skyrme SIII force
We have performed deformed Hartree-Fock+BCS calculations with the Skyrme SIII
force for the ground states of even-even nuclei with 2 <= Z <= 114 and N
ranging from outside the proton drip line to beyond the experimental frontier
in the neutron-rich side. We obtained spatially localized solutions for 1029
nuclei, together with the second minima for 758 nuclei. The single-particle
wavefunctions are expressed in a three-dimensional Cartesian-mesh
representation, which is suitable to describe nucleon skins, halos, and exotic
shapes as well as properties of ordinary stable nuclei. After explaining some
of the practical procedures of the calculations, we compare the resulting
nuclear masses with experimental data and the predictions of other models. We
also discuss the quadrupole (m=0, 2) and hexadecapole (m=0, 2, 4) deformations,
the skin thicknesses, the halo radii, and the energy difference between the
oblate and the prolate solutions. Our results can be obtained via computer
network.Comment: 20 pages in Latex, 11 Postscript figures, uuencode-gzip-tar file, to
appear in Nuclear Physics A. Data tables available at
ftp://nt1.c.u-tokyo.ac.jp/hfs3
Notch1 signaling is mediated by importins alpha 3, 4, and 7
The Notch signaling pathway is an important regulation system for the development and self-renewal of different tissues. A specific feature of this signaling cascade is the function of Notch as a surface receptor and regulator of gene expression. Hence, Notch activation and signal transduction requires the proteolytic release of the Notch intracellular domain (NICD), which activates the transcription of cell-specific genes after its transport into the nucleus. To date, little is known about the mechanisms that mediate NICD nuclear import. We here show that transport of NICD into the nucleus is mediated by the canonical importin α/ÎČ1 pathway. GST pull-down experiments revealed that NICD binds via one of its four potential nuclear localization signals to importins α3, α4, and α7, but not to α1 and α5. siRNA-mediated knockdown experiments showed that importins α3, α4 (and to a lesser extent, α7) mediate nuclear import of NICD and thus are directly involved in Notch signaling
Modelization of the EOS
This article summarizes theoretical predictions for the density and isospin
dependence of the nuclear mean field and the corresponding nuclear equation of
state. We compare predictions from microscopic and phenomenological approaches.
An application to heavy ion reactions requires to incorporate these forces into
the framework of dynamical transport models. Constraints on the nuclear
equation of state derived from finite nuclei and from heavy ion reactions are
discussed.Comment: 17 pages, 13 figures, contributed paper to the World Consensus
Initiative (WCI) book "Dynamics and Thermodynamics with Nucleonic Degrees of
Freedom
The Elite and Popular Foundations of German Catholicism in the Age of Confessionalism: The Reichskirche.
The political, institutional, and religious particularism of the German church reinforced the loyalty of the population, to local religious traditions. This gave German Catholicism a local emphasis and hindered the imposition of reformed Catholicism, which sought to homogenize, centralize, and internationalize the church. While early modern German Catholicism was certainly conservative, it was not rigidly traditional. Religious change occurred in these centuries and it came out of the interaction between the local population, local institutions like the chapters and monasteries, the parish clergy, and reforming churchmen.[70] The role of chapters and monasteries was not insignificant in this process. Canons and monks, whose daily lives were taken up with religious practices that owed much more to medieval Christian traditions than to the reforms of the Council of Trent, undoubtedly sympathized with and participated in the religion of the people. In the context of the Holy Roman Empire, manyGerman church institutions fought to preserve their own particular privileges and traditions, which gave them little inclination to destroy the local religion of their subjects. Localism and particularism thus became a valued hallmark of German Catholicism, as much among the Catholic elite as among the people. [ABSTRACT FROM AUTHOR
Ground state properties of the stable nuclei in various mean field theories
The separation energies of neutrons and protons, binding energies, mean
square charge radii, electric quadrupole moments and deformation parameters of
the proton and neutron distributions are evaluated for stable even-even
nuclei with . We compare the theoretical estimates obtained
within the Hartree-Fock plus BCS model with a few sets of Skyrme forces,
relativistic mean-field theory and frequently used Saxon-Woods and Nilsson
potentials with experimental data.Comment: 15 pages, latex, 3 tables, 14 figures in thr eps format include
Medium effects in high energy heavy-ion collisions
The change of hadron properties in dense matter based on various theoretical
approaches are reviewed. Incorporating these medium effects in the relativistic
transport model, which treats consistently the change of hadron masses and
energies in dense matter via the scalar and vector fields, heavy-ion collisions
at energies available from SIS/GSI, AGS/BNL, and SPS/CERN are studied. This
model is seen to provide satisfactory explanations for the observed enhancement
of kaon, antikaon, and antiproton yields as well as soft pions in the
transverse direction from the SIS experiments. In the AGS heavy-ion
experiments, it can account for the enhanced ratio, the difference
in the slope parameters of the and transverse kinetic energy
spectra, and the lower apparent temperature of antiprotons than that of
protons. This model also provides possible explanations for the observed
enhancement of low-mass dileptons, phi mesons, and antilambdas in heavy-ion
collisions at SPS energies. Furthermore, the change of hadron properties in hot
dense matter leads to new signatures of the quark-gluon plasma to hadronic
matter transition in future ultrarelativistic heavy-ion collisions at RHIC/BNL.Comment: RevTeX, 65 pages, including 25 postscript figures, invited topical
review for Journal of Physics G: Nuclear and Particle Physic
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