424 research outputs found
Ferromagnetic ordering of linearly coordinated Co ions in LiSr[CoN]
LiSr[CoN] single crystals were successfully grown out of Li-rich
flux. Temperature- and field-dependent measurements of the magnetization in the
range of K and up to T as well as
measurements of the heat capacity are presented. Ferromagnetic ordering emerges
below K and comparatively large coercivity fields of
T as well as pronounced anisotropy are observed upon cooling. Polycrystalline
samples of the Ca analog LiCa[CoN] were obtained and investigated in a
similar way. In both compounds Co manifests orbital contributions to the
magnetic moment and large single-ion anisotropy that is caused by second-order
Spin-orbit coupling. Quantum chemistry calculations reveal a magnetic
anisotropy energy of 7 meV, twice as large as the values reported for similar
Co systems.Comment: 21 pages, 6 figures, 5 table
From 'nothing' to inflation and back again
A procedure for solving Wheeler-DeWitt equation in Euclidean region,
following step by step the construction of tunneling wave function in
nonrelativistic quantum mechanics by Banks, Bender and Wu, is proposed.
Solutions for a universe satisfying no-boundary condition and a universe
created from 'nothing' are compared to the corresponding solutions for a
particle in a two-dimensional potential well, and effects of indefiniteness of
metric and zero energy in Wheeler-DeWitt equation are discussed.Comment: 8 pages, presented at the conference Relativity and Gravitation, 100
years after Einstein in Prague (Prague 2012
Effective relational dynamics
We provide a synopsis of an effective approach to the problem of time in the
semiclassical regime. The essential features of this new approach to evaluating
relational quantum dynamics in constrained systems are illustrated by means of
a simple toy model.Comment: 4 pages, based on a talk given at Loops '11 in Madrid, to appear in
Journal of Physics: Conference Series (JPCS
Spinning around or stagnation - what do osteoblasts and chondroblasts really like?
<p>Abstract</p> <p>Objective</p> <p>The influcence of cytomechanical forces in cellular migration, proliferation and differentation of mesenchymal stem cells (MSCs) is still poorly understood in detail.</p> <p>Methods</p> <p>Human MSCs were isolated and cultivated onto the surface of a 3 × 3 mm porcine collagen I/III carrier. After incubation, cell cultures were transfered to the different cutures systems: regular static tissue flasks (group I), spinner flasks (group II) and rotating wall vessels (group III). Following standard protocols cells were stimulated lineage specific towards the osteogenic and chondrogenic lines. To evaluate the effects of applied cytomechanical forces towards cellular differentiation distinct parameters were measured (morphology, antigen and antigen expression) after a total cultivation period of 21 days in vitro.</p> <p>Results</p> <p>Depending on the cultivation technique we found significant differences in both gen and protein expression.</p> <p>Conclusion</p> <p>Cytomechanical forces with rotational components strongly influence the osteogenic and chondrogenic differentiation.</p
Atomic scale analysis of the GaP Si 100 heterointerface by in situ reflection anisotropy spectroscopy and ab initio density functional theory
A microscopic understanding of the formation of polar on nonpolar interfaces is a prerequisite for well defined heteroepitaxial preparation of III V compounds on 100 silicon for next generation high performance devices. Energetically and kinetically driven Si 100 step formations result in majority domains of monohydride terminated Si dimers oriented either parallel or perpendicular to the step edges. Here, the intentional variation of the Si 100 surface reconstruction controls the sublattice orientation of the heteroepitaxial GaP film, as observed by in situ reflection anisotropy spectroscopy RAS in chemical vapor ambient and confirmed by benchmarking to surface science analytics in ultrahigh vacuum. Ab initio density functional calculations of both abrupt and compensated interfaces are carried out. For P rich chemical potentials at abrupt interfaces, Si P bonds are energetically favored over Si Ga bonds, in agreement with in situ RAS experiments. The energetically most favorable interface is compensated with an intermixed interfacial layer. In situ RAS reveals that the GaP sublattice orientation depends on the P chemical potential during nucleation, which agrees with a kinetically limited formation of abrupt interface
Conservation value of the native Hungarian wild grape (Vitis sylvestris Gmel.) evaluated by microsatellite markers
Wild grape (Vitis sylvestris GMEL.) has became a highly threatened species in Europe because of habitat loss, competition with alien grape species and intensive forest exploitation. Twenty-three Vitis spp. samples were analysed at 8 microsatellite loci to estimate the genetic diversity of the natural Vitis sylvestris specimens. In order to analyse the morphological traits and to perform molecular analysis, 11 native individuals were sampled from 6 remnant Hungarian habitats of the wild grape. To compare the genetic relationships among the wild specimens, samples from Turkish habitats, as well as cultivars of Vitis vinifera, Vitis labrusca and Vitis riparia were also included. Genetic diversity was higher within the Hungarian wild grape locations, with a mean of He = 0.74, which was higher that of samples originating from a larger area of Turkey, He = 0.69. Most of the Hungarian samples formed a well-defined, separate branch on the NJ tree. Based on the morphological traits and molecular analysis on the territory of Szentendre Island, formerly considered to be one of the largest native locations of wild grape, interspecific hybrids of Vitis sylvestris and Vitis riparia were identified. It can be concluded from the results that most of the Hungarian habitats studied could be valuable for the conservation. This paper reports on Hungarian Vitis sylvestris habitats, providing the first genetic study on diversity and on the relationship of Vitis sylvestris to other Vitis specimens, wild or cultivated, in the central part of the Carpathian Basin
- …