162,350 research outputs found
Collective effects in cellular structure formation mediated by compliant environments: a Monte Carlo study
Compliant environments can mediate interactions between mechanically active
cells like fibroblasts. Starting with a phenomenological model for the
behaviour of single cells, we use extensive Monte Carlo simulations to predict
non-trivial structure formation for cell communities on soft elastic substrates
as a function of elastic moduli, cell density, noise and cell position
geometry. In general, we find a disordered structure as well as ordered
string-like and ring-like structures. The transition between ordered and
disordered structures is controlled both by cell density and noise level, while
the transition between string- and ring-like ordered structures is controlled
by the Poisson ratio. Similar effects are observed in three dimensions. Our
results suggest that in regard to elastic effects, healthy connective tissue
usually is in a macroscopically disordered state, but can be switched to a
macroscopically ordered state by appropriate parameter variations, in a way
that is reminiscent of wound contraction or diseased states like contracture.Comment: 45 pages, 7 postscript figures included, revised version accepted for
publication in Acta Biomateriali
Successfull Blossom Thinning and Crop Load Regulation for Organic Apple Growing with Potassium-bi-carbonate (Armicarb(R)): Results of Field Experiments over 3 Years and with 11 Cultivars
With field trials over 3 years in a commercial organic orchard in Switzerland we have tested the efficacy of ArmicarbÂź (potassium-bi-carbonate) for flower thinning in organic apple production. Over time, Armicarb was tested on 11 cultivars, at different application periods, in different concentrations, and always in comparison to other agents that are already allowed for thinning in organic fruit production in the European Union as e.g. lime sulphur, molasses, mechanical rope-thinner or combinations of methods. Armicarb proved to be an efficient and reliable thinning agent with an efficacy similar to the now recommended methods with rope device, molasses or lime sulphur but has the advantage to be an environmentally very friendly product. On the other hand, the risk for fruit russeting is comparably elevated especially with cultivars âElstarâ, âGolden Del.â âand âGalaâ. Finally, we have elaborated cultivar-specific recommendations for the use of Armicarb for thinning purposes, which were the basis for the Swiss Federal approval to use Armicarb for thinning in conventional and organic apple production in 2011/2012
Influence of Thyme and Juniper on the Microbiological Properties of Pork Brisket
The aim of the work is to determine an influence of non-traditional mixtures of spicy-aromatic plants of thyme and juniper, their essential oils and alcohol extracts on the course of microbiological processes in pork brisket. Pork brisket was an experimental sample. It was added with black pepper, thyme and juniper, in the dry condition, as essential oils and alcohol extracts. Pork brisket, added with dry plants, essential oils, extracts of black and fragrant pepper, was taken as a control. According to the microbiological studies, it was established, that an exceed of the standard index of the content of mesophilic-aerobic and facultative anaerobic microorganisms (more than 1,0Ă103 g/CCU) takes place in brisket samples with dry black pepper. And also in samples with thyme and juniper in ratios 0,9:0,7:0,2 and 0,9:0,6:0,3. An exceed of nMAFAM index is also fixed in experiments using essential oils of these spices. It was established, that after 80 min of the experiment, these mixtures remain resistant to spoilage by 20 min longer comparing with using dry black and fragrant pepper. Most intense antibacterial properties relative to the development of microorganisms were observed in experimental samples. It is noticeable in a sample with using dry comminuted spices thyme and juniper in ratios 0,9:0,8:0,1. The use of spicy-aromatic plants of thyme and juniper allow to increase the storage term of ready products
The Pierre Auger Project and Enhancements
The current status of the scientific results of the Auger Observatory will be
discussed which include spectrum, anisotropy in arrival directions, chemical
composition analyses, and limits on neutrino and photon fluxes. A review of the
Observatory detection systems will be presented. Auger has started the
construction of its second phase which encompasses antennae for radio detection
of cosmic rays, high-elevation telescopes, and surface plus muon detectors.
Details will be presented on the latter, AMIGA (Auger Muons and Infill for the
Ground Array), an Auger project consisting of 85 detector pairs each one
composed of a surface water-Cherenkov detector and a buried muon counter. The
detector pairs are arranged in an array with spacings of 433 and 750 m in order
to perform a detailed study of the 10^17 eV to 10^19 eV spectrum region.
Preliminary results on the performance of the 750 m array of surface detectors
and the first muon counter prototype will be presented.Comment: 10 pages, 8 figures, VIII Latin American Symposium on Nuclear Physics
and Applications December 15-19, 2009, Santiago, Chil
Cyclic and ruled Lagrangian surfaces in complex Euclidean space
We study those Lagrangian surfaces in complex Euclidean space which are
foliated by circles or by straight lines. The former, which we call cyclic,
come in three types, each one being described by means of, respectively, a
planar curve, a Legendrian curve of the 3-sphere or a Legendrian curve of the
anti de Sitter 3-space. We also describe ruled Lagrangian surfaces. Finally we
characterize those cyclic and ruled Lagrangian surfaces which are solutions to
the self-similar equation of the Mean Curvature Flow. Finally, we give a
partial result in the case of Hamiltonian stationary cyclic surfaces
Effective interactions for light nuclei: an effective (field theory) approach
One of the central open problems in nuclear physics is the construction of
effective interactions suitable for many-body calculations. We discuss a
recently developed approach to this problem, where one starts with an effective
field theory containing only fermion fields and formulated directly in a
no-core shell-model space. We present applications to light nuclei and to
systems of a few atoms in a harmonic-oscillator trap. Future applications and
extensions, as well as challenges, are also considered
Effective Theory for Trapped Few-Fermion Systems
We apply the general principles of effective field theories to the
construction of effective interactions suitable for few- and many-body
calculations in a no-core shell model framework. We calculate the spectrum of
systems with three and four two-component fermions in a harmonic trap. In the
unitary limit, we find that three-particle results are within 10% of known
semi-analytical values even in small model spaces. The method is very general,
and can be readily extended to other regimes, more particles, different species
(e.g., protons and neutrons in nuclear physics), or more-component fermions (as
well as bosons). As an illustration, we present calculations of the
lowest-energy three-fermion states away from the unitary limit and find a
possible inversion of parity in the ground state in the limit of trap size
large compared to the scattering length. Furthermore, we investigate the lowest
positive-parity states for four fermions, although we are limited by the
dimensions we can currently handle in this case.Comment: 8 pages, 5 figure
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