8,348 research outputs found
Noninvasive Measurement of Dissipation in Colloidal Systems
According to Harada and Sasa [Phys. Rev. Lett. 95, 130602 (2005)], heat
production generated in a non-equilibrium steady state can be inferred from
measuring response and correlation functions. In many colloidal systems,
however, it is a nontrivial task to determine response functions, whereas
details about spatial steady state trajectories are easily accessible. Using a
simple conditional averaging procedure, we show how this fact can be exploited
to reliably evaluate average heat production. We test this method using
Brownian dynamics simulations, and apply it to experimental data of an
interacting driven colloidal system
Nature of non-magnetic strongly-correlated state in delta-plutonium
Ab-initio relativistic dynamical mean-field theory is applied to resolve the
long-standing controversy between theory and experiment in the "simple"
face-centered cubic phase of plutonium called delta-Pu. In agreement with
experiment, neither static nor dynamical magnetic moments are predicted. In
addition, the quasiparticle density of states reproduces not only the peak
close to the Fermi level, which explains the large coefficient of electronic
specific heat, but also main 5f features observed in photoelectron
spectroscopy.Comment: 9 pages, 3 figure
Robust formation of morphogen gradients
We discuss the formation of graded morphogen profiles in a cell layer by
nonlinear transport phenomena, important for patterning developing organisms.
We focus on a process termed transcytosis, where morphogen transport results
from binding of ligands to receptors on the cell surface, incorporation into
the cell and subsequent externalization. Starting from a microscopic model, we
derive effective transport equations. We show that, in contrast to morphogen
transport by extracellular diffusion, transcytosis leads to robust ligand
profiles which are insensitive to the rate of ligand production
Structure and deformations of strongly magnetized neutron stars with twisted torus configurations
We construct general relativistic models of stationary, strongly magnetized
neutron stars. The magnetic field configuration, obtained by solving the
relativistic Grad-Shafranov equation, is a generalization of the twisted torus
model recently proposed in the literature; the stellar deformations induced by
the magnetic field are computed by solving the perturbed Einstein's equations;
stellar matter is modeled using realistic equations of state. We find that in
these configurations the poloidal field dominates over the toroidal field and
that, if the magnetic field is sufficiently strong during the first phases of
the stellar life, it can produce large deformations.Comment: 10 pages, 5 figures. Minor changes to match the version published on
MNRA
Structure, Deformations and Gravitational Wave Emission of Magnetars
Neutron stars can have, in some phases of their life, extremely strong
magnetic fields, up to 10^15-10^16 G. These objects, named magnetars, could be
powerful sources of gravitational waves, since their magnetic field could
determine large deformations. We discuss the structure of the magnetic field of
magnetars, and the deformation induced by this field. Finally, we discuss the
perspective of detection of the gravitational waves emitted by these stars.Comment: 11 pages, 2 figures, prepared for 19th International Conference on
General Relativity and Gravitation (GR19), Mexico City, Mexico, July 5-9,
201
Fostering creativity across countries: The moderating effect of cultural bundles on creativity
Research has traditionally focused on the moderating role of single cultural dimensions to capture differences in how individual creativity is fostered across cultures. Culture, however, is a multidimensional construct, with cultural dimensions operating interdependently. Building on this reasoning, we propose that the moderating effect of culture is better understood by focusing on the configuration of cultural bundles. We define a cultural bundle as set including the cultural value dimensions that characterize a given country, and the strength of the norms enforcing these values. We find support for this view in a mixed-methods study that combines a meta-analysis of 584 effect sizes from 205 studies set in 38 different countries with fuzzy-set qualitative comparative analysis (fs/QCA). We discuss the theoretical and practical implications of these findings, arguing for the importance of focusing on cultural bundles, rather than cultural dimensions in isolation, to understand the moderating effect of culture on creativity
Self-similarity and long-time behavior of solutions of the diffusion equation with nonlinear absorption and a boundary source
This paper deals with the long-time behavior of solutions of nonlinear
reaction-diffusion equations describing formation of morphogen gradients, the
concentration fields of molecules acting as spatial regulators of cell
differentiation in developing tissues. For the considered class of models, we
establish existence of a new type of ultra-singular self-similar solutions.
These solutions arise as limits of the solutions of the initial value problem
with zero initial data and infinitely strong source at the boundary. We prove
existence and uniqueness of such solutions in the suitable weighted energy
spaces. Moreover, we prove that the obtained self-similar solutions are the
long-time limits of the solutions of the initial value problem with zero
initial data and a time-independent boundary source
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