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Search Results: 1 - 10 of 10100 matches for " Stefan Wolter "
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Complications, Mineral and Vitamin Deficiencies: Comparison between Roux-en-Y Gastric Bypass and Sleeve Gastrectomy  [PDF]
Nina Sauer, Jan Wienecke, Clarissa Schulze zur Wiesfch, Stefan Wolter, Oliver Mann, Jens Aberle
Surgical Science (SS) , 2013, DOI: 10.4236/ss.2013.412106
Abstract:

Objective: Nutritional deficiencies are known side-effects of bariatric surgeries, specifically in those that bypass the proximal intestine. Therefore, in clinical practice, vitamin and mineral supplementations are often necessary after such operations. It was our intention to evaluate, whether alimentary deficiencies occur with the same frequency in patients following Sleeve-Gastrectomy (SG) compared to Roux-en-Y Gastric Bypass (RYGB) surgeries. Methods: We conducted a retrospective data analysis of 171 patients (121 RYGB, 50 SG). Vitamin levels were compared between SG and RYGB patients over the first post-operative year. Furthermore, regression analysis was performed with regard to vitamin and iron supplementations and their recommended dosages. Complications occurring within the first post-surgical year were documented as well. Results: Other than vitamin B6 deficiency, which was found to be more frequent in SG patients, there was no other significant difference regarding the type of operation and the number of patients who had these deficiencies. There was no significant difference in average vitamin and iron levels between RYGB and SG. A minimum dose of 1000 IU vitamin D per day was necessary to affect vitamin D levels. The intramuscular administration of vitamin B12 was the only route found to be effective. Complications within the first year were rare. Conclusions: Against common assumptions, vitamin and iron deficiencies in SG patients are not less frequent in the first post-surgical year in comparison to RYGB patients. Standard supplementations should include iron in premenopausal women: Vitamin D at least 1000 IU per day and vitamin B12 i.m. administration in case of a deficiency.

Electromagnetic Dissociation as a Tool for Nuclear Structure and Astrophysics
Gerhard Baur,Kai Hencken,Dirk Trautmann,Stefan Typel,Hermann H. Wolter
Physics , 2000, DOI: 10.1016/S0146-6410(01)00113-2
Abstract: Coulomb dissociation is an especially simple and important reaction mechanism. Since the perturbation due to the electric field of the nucleus is exactly known, firm conclusions can be drawn from such measurements. Electromagnetic matrix elements and astrophysical S-factors for radiative capture processes can be extracted from experiments. We describe the basic theory, new results concerning higher order effects in the dissociation of neutron halo nuclei, and briefly review the experimental results obtained up to now. Some new applications of Coulomb dissociation for nuclear astrophysics and nuclear structure physics are discussed.
Size dependent exciton dynamics in one-dimensional perylene bisimide aggregates
Steffen Wolter,Janis Aizezers,Franziska Fennel,Marcus Seidel,Frank Würthner,Oliver Kühn,Stefan Lochbrunner
Physics , 2012, DOI: 10.1088/1367-2630/14/10/105027
Abstract: The size dependent exciton dynamics of one-dimensional aggregates of substituted perylene bisimides are studied by ultrafast transient absorption spectroscopy and kinetic Monte-Carlo simulations in dependence on the temperature and the excitation density. For low temperatures the aggregates can be treated as infinite chains and the dynamics is dominated by diffusion driven exciton-exciton annihilation. With increasing temperature the aggregates decompose into small fragments consisting of very few monomers. This scenario is also supported by the time dependent anisotropy deduced from polarization dependent experiments.
Quantum Analogs of Tensor Product Representations of su(1,1)
Wolter Groenevelt
Symmetry, Integrability and Geometry : Methods and Applications , 2011,
Abstract: We study representations of U_q(su(1,1)) that can be considered as quantum analogs of tensor products of irreducible *-representations of the Lie algebra su(1,1). We determine the decomposition of these representations into irreducible *-representations of U_q(su(1,1)) by diagonalizing the action of the Casimir operator on suitable subspaces of the representation spaces. This leads to an interpretation of the big q-Jacobi polynomials and big q-Jacobi functions as quantum analogs of Clebsch-Gordan coefficients.
Eskatologie in die Evangelie van Lukas
Michael Wolter
Nederduitse Gereformeerde Teologiese Tydskrif , 2012, DOI: 10.5952/51-3-95
Abstract: Eschatology in the Gospel of Luke In unfolding his eschatology the author of the Gospel of Luke acknowledges that the final fate of mankind and of the world has not come about and that the Christians are still waiting for the parousia of the Son of man. The eschatology of Luke is primarily determined by quality and not so much by time. Eschatological life means to live as if Jesus could come at any time. This means that in terms of time eschatology is absorbed in ethics. Apart from that the eschatological thinking is developed as part of Luke’s Christological thinking.
The Nuclear Symmetry Energy in Heavy Ion Collisions
Hermann Wolter
Physics , 2015,
Abstract: In this contribution I discuss the nuclear symmetry energy in the regime of hadronic degrees of freedom. The density dependence of the symmetry energy is important from very low densities in supernova explosions, to the structure of neutron-rich nuclei around saturation density, and to several times saturation density in neutron stars. Heavy ion collisions are the only means to study this density dependence in the laboratory. Numerical simulations of transport theories are used to extract the equation-of-state, and thus also the symmetry energy. I discuss some examples, which relate particularly to the high density symmetry energy, which is of particular interest today. I review the status and point out some open problems in the determination of the symmetry energy in heavy ion collisions.
Wilson function transforms related to Racah coefficients
Wolter Groenevelt
Mathematics , 2005,
Abstract: The irreducible $*$-representations of the Lie algebra $su(1,1)$ consist of discrete series representations, principal unitary series and complementary series. We calculate Racah coefficients for tensor product representations that consist of at least two discrete series representations. We use the explicit expressions for the Clebsch-Gordan coefficients as hypergeometric functions to find explicit expressions for the Racah coefficients. The Racah coefficients are Wilson polynomials and Wilson functions. This leads to natural interpretations of the Wilson function transforms. As an application several sum and integral identities are obtained involving Wilson polynomials and Wilson functions. We also compute Racah coefficients for $U_q(\su(1,1))$, which turn out to be Askey-Wilson functions and Askey-Wilson polynomials.
Fourier transforms related to a root system of rank 1
Wolter Groenevelt
Mathematics , 2005,
Abstract: We introduce an algebra $\mathcal H$ consisting of difference-reflection operators and multiplication operators that can be considered as a $q=1$ analogue of Sahi's double affine Hecke algebra related to the affine root system of type $(C^\vee_1, C_1)$. We study eigenfunctions of a Dunkl-Cherednik-type operator in the algebra $\mathcal H$, and the corresponding Fourier transforms. These eigenfunctions are non-symmetric versions of the Wilson polynomials and the Wilson functions.
Multivariable Wilson polynomials and degenerate Hecke algebras
Wolter Groenevelt
Mathematics , 2007,
Abstract: We study a rational version of the double affine Hecke algebra associated to the nonreduced affine root system of type $(C^\vee_n,C_n)$. A certain representation in terms of difference-reflection operators naturally leads to the definition of nonsymmetric versions of the multivariable Wilson polynomials. Using the degenerate Hecke algebra we derive several properties, such as orthogonality relations and quadratic norms, for the nonsymmetric and symmetric multivariable Wilson polynomials.
Orthogonality relations for Al-Salam--Carlitz polynomials of type II
Wolter Groenevelt
Mathematics , 2013,
Abstract: Using a special case of Askey's $q$-beta integral evaluation formula, we determine orthogonality relations for the Al-Salam--Carlitz polynomials of type II with respect to a family of measures supported on a discrete subset of $\mathbb R$. From spectral analysis of the corresponding second-order $q$-difference operator we obtain an infinite set of functions that complement the Al-Salam--Carlitz II polynomials to an orthogonal basis of the associated $L^2$-space.
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