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Search Results: 1 - 10 of 1888 matches for " Wojciech Bartz "
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Metamorphic evolution of the amphibolites from the polish part of Stare M sto Zone (Sudetes, SW Poland)
Wojciech Bartz
Mineralogia Polonica , 2004,
Abstract: The Stare Mìsto Zone is the lowermost part of Lugicum, marking out the main boundarybetween the East and West Sudetes. Small part of the unit is exposed in Poland, in the vicinity of Bielicevillage. This area consists mainly of banded amphibolites, intruded by syntectonic granitoids. The bandedamphibolites are medium — to coarse grained. Main constituents are segregated into alternating, light —plagioclase rich, and dark—amphibole rich layers. Quartz and K-feldpars are subordinates. Accessories are:zircon, apatite, titanite, and locally garnet, biotite; secondary minerals are: chlorite and prehnite. Bandedamphibolites underwent progressive M1 amphibolite facies metamorphism, with PT peak conditions at650–720C and 8.0–9.5 kbar. This was followed by M2 and M3 regressive metamorphism, accompanied byrapid uplift, regional mylonitization and metamorphism under the greenschists and sub-greenschsits faciesconditions.
Induced and Complete Multinets
Jeremiah Bartz
Mathematics , 2015,
Abstract: Multinets are certain configurations of lines and points with multiplicities in the complex projective plane $\mathbb{P}^2$. They appear in the study of resonance and characteristic varieties of complex hyperplane arrangement complements and cohomology of Milnor fibers. In this paper, two properties of multinets, inducibility and completeness, and the relationship between them are explored with several examples presented. Specializations of multinets plays an integral role in our findings. The main result is the classification of complete 3-nets.
International Council of Nurses and person-centered care
Claudia C. Bartz
International Journal of Integrated Care , 2010,
Abstract:
Important configurations for NN processes in a Goldstone boson exchange model
D. Bartz,Fl. Stancu
Physics , 1998, DOI: 10.1103/PhysRevC.59.1756
Abstract: We study the short-range nucleon-nucleon interaction in a nonrelativistic chiral constituent quark model by diagonalizing a Hamiltonian containing a linear confinement and a Goldstone boson exchange interaction between quarks. A finite six-quark basis obtained from single particle cluster model states was previously used. Here we show that the configurations which appear naturally through the use of molecular orbitals, instead of cluster model states, are more efficient in lowering the six-quark energy.
NN Scattering Phase Shifts in a Chiral Constituent Quark Model
D. Bartz,Fl. Stancu
Physics , 2000, DOI: 10.1016/S0375-9474(00)00599-6
Abstract: We study the nucleon-nucleon interaction within a chiral constituent quark model which reproduces succesfully the baryon spectra. We calculate the 3S1 and 1S0 phase shifts by using the resonating group method. They clearly indicate the presence of a strong repulsive interaction at short distance, due to the spin-flavor symmetry of the quark-quark interaction and of the quark interchange between the two interacting nucleons. A sigma-exchange quark-quark interaction, providing a medium-range attraction, helps to get closer to the experimental phase shifts.
Nucleon-Nucleon interaction in a chiral constituent quark model
D. Bartz,Fl. Stancu
Physics , 1999, DOI: 10.1063/1.1303013
Abstract: We study the nucleon-nucleon (NN) problem as a six-quark system in a nonrelativistic chiral constituent quark model where the Hamiltonian contains a linear confinement and a pseudoscalar meson (Goldstone boson) exchange interaction between the quarks. This interaction has a long range Yukawa-type part, depending on the mass of the exchanged meson and a short range part, mainly responsible for the good description of the baryon spectra. We calculate the NN potential in the adiabatic approximation as a function of Z, the separation distance between the centres of the two three-quark clusters. The orbital part of the six-quark states is constructed either from the usual cluster model states or from molecular orbital single particle states. The latter are more realistic, having proper axially and reflectionally symmetries. In both cases the potential presents an important hard core at short distances, explained through the dominance of the [51]{FS} configuration. However in the molecular orbital basis the core is less repulsive, as a consequence of the fact that this basis gives a better upper bound for the energy of the six-quark system. We calculate the potential for the 3S1 and 3S0 channels with two different parametrizations. We find a small (few MeV) attractive pocket for one of these parametrizations. A middle range attraction is simulated by the addition of a sigma-meson exchange interaction between quarks, of a form similar to that of the pseudoscalar meson exchange. The present study is an intermediate, useful step towards dynamical calculations based on the resonating group method.
Nucleon-nucleon scattering in a chiral constituent quark model
D. Bartz,Fl. Stancu
Physics , 2000, DOI: 10.1103/PhysRevC.63.034001
Abstract: We study the nucleon-nucleon interaction in a chiral constituent quark model by using the resonating group method, convenient for treating the interaction between composite particles. The calculated phase shifts for the 3S1 and 1S0 channels show the presence of a strong repulsive core due to the combined effect of the quark interchange and the spin-flavour structure of the effective quark-quark interaction. Such a symmetry structure stems from the pseudoscalar meson exchange between the quarks and is a consequence of the spontaneous breaking of the chiral symmetry. We perform single and coupled channel calculations and show the role of coupling of the $\Delta\Delta$ and hidden color CC channels on the behaviour of the phase shifts.
NN interaction in a Goldstone boson exchange model
D. Bartz,Fl. Stancu
Physics , 1999, DOI: 10.1103/PhysRevC.60.055207
Abstract: Adiabatic nucleon-nucleon potentials are calculated in a six-quark nonrelativistic chiral constituent quark model where the Hamiltonian contains a linear confinement and a pseudoscalar meson (Goldstone boson) exchange interaction between quarks. Calculations are performed both in a cluster model and a molecular orbital basis, through coupled channels. In both cases the potentials present an important hard core at short distances, explained through the dominance of the [51]_{FS} configuration, but do not exhibit an attractive pocket. We add a scalar meson exchange interaction and show how it can account for some middle-range attraction.
SPOT: An R Package For Automatic and Interactive Tuning of Optimization Algorithms by Sequential Parameter Optimization
Thomas Bartz-Beielstein
Mathematics , 2010,
Abstract: The sequential parameter optimization (SPOT) package for R is a toolbox for tuning and understanding simulation and optimization algorithms. Model-based investigations are common approaches in simulation and optimization. Sequential parameter optimization has been developed, because there is a strong need for sound statistical analysis of simulation and optimization algorithms. SPOT includes methods for tuning based on classical regression and analysis of variance techniques; tree-based models such as CART and random forest; Gaussian process models (Kriging), and combinations of different meta-modeling approaches. This article exemplifies how SPOT can be used for automatic and interactive tuning.
Multinets in $\mathbb P^2$
Jeremiah Bartz,Sergey Yuzvinsky
Mathematics , 2013,
Abstract: Multinets are certain configurations of lines and points with multiplicities in the complex projective plane P2. They are used in the studies of resonance and characteristic varieties of complex hyperplane arrangement complements and cohomology of Milnor fibers. From combinatorics viewpoint they can be considered as generalizations of Latin squares. Very few exam- ples of multinets with non-trivial multiplicities are known. In this paper, we present new examples of multinets. These are obtained by using an analogue of nets in P3 and intersecting them by planes.
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