1,804 research outputs found
The randomly driven Ising ferromagnet, Part I: General formalism and mean field theory
We consider the behavior of an Ising ferromagnet obeying the Glauber dynamics
under the influence of a fast switching, random external field. After
introducing a general formalism for describing such systems, we consider here
the mean-field theory. A novel type of first order phase transition related to
spontaneous symmetry breaking and dynamic freezing is found. The
non-equilibrium stationary state has a complex structure, which changes as a
function of parameters from a singular-continuous distribution with Euclidean
or fractal support to an absolutely continuous one.Comment: 12 pages REVTeX/LaTeX format, 12 eps/ps figures. Submitted to Journal
of Physics
Aligning vocational training to the electromobile transformation by establishing the “training factory stator production” - A methodical deficit analysis with derivation of measures
In addition to the current challenges in production technology due to the shift from conventional powertrains towards electrified drive technologies, the disruptive transformation of mobility confronts OEMs and suppliers with major personnel challenges, which include new requirement profiles for prospective skilled workers. In order to meet the personnel requirements of industry and ensure the high quality of vocational training in Germany nonetheless, the current training concepts must be strengthened by the targeted integration of specific contents and be geared holistically to the needs of new occupational profiles. This paper presents a methodological approach for deriving current deficits in vocational education and training through the systematic analysis of framework curricula and the targeted survey of teachers working at German vocational schools as well as the derived training program to support the qualification of trainees. In order to obtain a training concept of high didactic quality, the approach is based on pedagogical methods to provide the best possible support and to convey the learning objectives related to professional, social, methodical, and personal skills. With the newly conceived “Training Factory Stator Production” at the wbk Institute of Production Science of the Karlsruhe Institute of Technology, a program for the training and further education of trainees, skilled employees and engineers will be introduced using the example of producing stators with hairpin technology, to support especially small and medium-sized companies in the personnel transformation process
Increased levels of anti-glycan antibodies in patients with cystic fibrosis
<p>Abstract</p> <p>Background</p> <p>The prevalence of Crohn's disease (CD) is increased in patients with cystic fibrosis (CF). Anti-Saccharomyces cerevisiae antibodies (ASCA) have been suggested as a screening tool to detect CD in CF. Recently, several new anti-glycan antibodies have been reported in CD.</p> <p>Materials and methods</p> <p>The sera of 119 CF patients of various age groups were prospectively screened for ASCA type IgG (gASCA), anti-laminaribioside carbohydrate IgG antibodies (ALCA), anti-chitobioside carbohydrate IgA antibodies (ACCA), and anti-mannobioside carbohydrate IgG antibodies (AMCA). The frequency of these anti-glycan antibodies was then compared in patients with CD, ulcerative colitis, rheumatoid arthritis and healthy volunteers.</p> <p>Results</p> <p>A significant number of CF patients were positive for gASCA (51.3% [41.6-60.6]) and up to three other anti-glycan antibodies concurrently. Serum levels of anti-glycan antibodies in CF and CD were not related to parameters of inflammation. Despite the well-documented difference in clinical course between male and female CF patients no gender difference of anti-glycan antibodies was found. In contrast, there was a significant positive correlation between anti-glycan markers and age in CF patients.</p> <p>Conclusions</p> <p>Our findings demonstrate for the first time the increased frequency of a panel of anti-glycan antibodies in CF and provide a link between the presence of these serological biomarkers and patient's age. Anti-glycan antibody profiling may therefore become a valuable tool in the care of patients with CF.</p
The Dynamics of Nestedness Predicts the Evolution of Industrial Ecosystems
In economic systems, the mix of products that countries make or export has
been shown to be a strong leading indicator of economic growth. Hence, methods
to characterize and predict the structure of the network connecting countries
to the products that they export are relevant for understanding the dynamics of
economic development. Here we study the presence and absence of industries at
the global and national levels and show that these networks are significantly
nested. This means that the less filled rows and columns of these networks'
adjacency matrices tend to be subsets of the fuller rows and columns. Moreover,
we show that nestedness remains relatively stable as the matrices become more
filled over time and that this occurs because of a bias for industries that
deviate from the networks' nestedness to disappear, and a bias for the missing
industries that reduce nestedness to appear. This makes the appearance and
disappearance of individual industries in each location predictable. We
interpret the high level of nestedness observed in these networks in the
context of the neutral model of development introduced by Hidalgo and Hausmann
(2009). We show that, for the observed fills, the model can reproduce the high
level of nestedness observed in these networks only when we assume a high level
of heterogeneity in the distribution of capabilities available in countries and
required by products. In the context of the neutral model, this implies that
the high level of nestedness observed in these economic networks emerges as a
combination of both, the complementarity of inputs and heterogeneity in the
number of capabilities available in countries and required by products. The
stability of nestedness in industrial ecosystems, and the predictability
implied by it, demonstrates the importance of the study of network properties
in the evolution of economic networks.Comment: 26 page
Liquid 4He near the superfluid transition in the presence of a heat current and gravity
The effects of a heat current and gravity in liquid 4He near the superfluid
transition are investigated for temperatures above and below T_lambda. We
present a renormalization-group calculation based on model F for the Green's
function in a self-consistent approximation which in quantum many-particle
theory is known as the Hartree approximation. The approach can handle a zero
average order parameter above and below T_lambda and includes effects of
vortices. We calculate the thermal conductivity and the specific heat for all
temperatures T and heat currents Q in the critical regime. Furthermore, we
calculate the temperature profile. Below T_lambda we find a second correlation
length which describes the dephasing of the order parameter field due to
vortices. We find dissipation and mutual friction of the superfluid-normal
fluid counterflow and calculate the Gorter-Mellink coefficient A. We compare
our theoretical results with recent experiments.Comment: 26 pages, 9 figure
Evidence for a change in the nuclear mass surface with the discovery of the most neutron-rich nuclei with 17<Z <25
The results of measurements of the production of neutron-rich nuclei by the
fragmentation of a 76-Ge beam are presented. The cross sections were measured
for a large range of nuclei including fifteen new isotopes that are the most
neutron-rich nuclides of the elements chlorine to manganese (50-Cl, 53-Ar,
55,56-K, 57,58-Ca, 59,60,61-Sc, 62,63-Ti, 65,66-V, 68-Cr, 70-Mn). The enhanced
cross sections of several new nuclei relative to a simple thermal evaporation
framework, previously shown to describe similar production cross sections,
indicates that nuclei in the region around 62-Ti might be more stable than
predicted by current mass models and could be an indication of a new island of
inversion similar to that centered on 31-Na.Comment: 4 pages, 3 figures, to be published in Physical Review Letters, 200
Stationary Properties of a Randomly Driven Ising Ferromagnet
We consider the behavior of an Ising ferromagnet obeying the Glauber dynamics
under the influence of a fast switching, random external field. Analytic
results for the stationary state are presented in mean-field approximation,
exhibiting a novel type of first order phase transition related to dynamic
freezing. Monte Carlo simulations performed on a quadratic lattice indicate
that many features of the mean field theory may survive the presence of
fluctuations.Comment: 5 pages in RevTex format, 7 eps/ps figures, send comments to
"mailto:[email protected]", submitted to PR
A robust, scanning quantum system for nanoscale sensing and imaging
Controllable atomic-scale quantum systems hold great potential as sensitive
tools for nanoscale imaging and metrology. Possible applications range from
nanoscale electric and magnetic field sensing to single photon microscopy,
quantum information processing, and bioimaging. At the heart of such schemes is
the ability to scan and accurately position a robust sensor within a few
nanometers of a sample of interest, while preserving the sensor's quantum
coherence and readout fidelity. These combined requirements remain a challenge
for all existing approaches that rely on direct grafting of individual solid
state quantum systems or single molecules onto scanning-probe tips. Here, we
demonstrate the fabrication and room temperature operation of a robust and
isolated atomic-scale quantum sensor for scanning probe microscopy.
Specifically, we employ a high-purity, single-crystalline diamond nanopillar
probe containing a single Nitrogen-Vacancy (NV) color center. We illustrate the
versatility and performance of our scanning NV sensor by conducting
quantitative nanoscale magnetic field imaging and near-field single-photon
fluorescence quenching microscopy. In both cases, we obtain imaging resolution
in the range of 20 nm and sensitivity unprecedented in scanning quantum probe
microscopy
Production cross sections of neutron rich isotopes from a 82Se beam
Production cross sections for neutron-rich nuclei from the fragmentation of a
82Se beam at 139 MeV/u were measured. The longitudinal momentum distributions
of 122 neutron-rich isotopes of elements were determined by
varying the target thickness. Production cross sections with beryllium and
tungsten targets were determined for a large number of nuclei including several
isotopes first observed in this work. These are the most neutron-rich nuclides
of the elements (64Ti, 67V, 69Cr, 72Mn). One event was
registered consistent with 70Cr, and another one with 75Fe. A one-body Qg
systematics is used to describe the production cross sections based on thermal
evaporation from excited prefragments. The current results confirm those of our
previous experiment with a 76Ge beam: enhanced production cross sections for
neutron-rich fragments near Z=20.Comment: Talk given at the 11th International Conference on Nucleus-Nucleus
Collisions (NN2012), San Antonio, Texas, USA, May 27-June 1, 2012. To appear
in the NN2012 Proceedings in Journal of Physics: Conference Series (JPCS
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