TY - JOUR A1 - Zolotov, O. V. A1 - Prokhorov, Boris E. A1 - Namgaladze, Alexander A. A1 - Martynenko, O. V. T1 - Variations in the total electron content of the ionosphere during preparation of earthquakes JF - Russian journal of physical chemistry : B, Focus on physics N2 - The morphological features in the deviations of the total electron content (TEC) of the ionosphere from the background undisturbed state as possible precursors of the earthquake of January 12, 2010 (21:53 UT (16:53 LT), 18.46A degrees N, 72.5A degrees W, 7.0 M) in Haiti are analyzed. To identify these features, global and regional differential TEC maps based on global 2-h TEC maps provided by NASA in the IONEX format were plotted. For the considered earthquake, long-lived disturbances, presumably of seismic origin, were localized in the near-epicenter area and were accompanied by similar effects in the magnetoconjugate region. Both decreases and increases in the local TEC over the period from 22 UT of January 10 to 08 UT of January 12, 2010 were observed. The horizontal dimensions of the anomalies were similar to 40A degrees in longitude and similar to 20A degrees in latitude, with the magnitude of TEC disturbances reaching similar to 40% relative to the background near the epicenter and more than 50% in the magnetoconjugate area. No significant geomagnetic disturbances within January 1-12, 2010 were observed, i.e., the detected TEC anomalies were manifestations of interplay between processes in the lithosphere-atmosphere-ionosphere system. KW - TEC KW - ionospheric precursors of earthquakes KW - GPS Y1 - 2011 U6 - https://doi.org/10.1134/S1990793111030146 SN - 1990-7931 VL - 5 IS - 3 SP - 435 EP - 438 PB - Pleiades Publ. CY - New York ER - TY - THES A1 - Hanisch, Florian T1 - Variational problems on supermanifolds T1 - Variationsprobleme auf Supermannigfaltigkeiten N2 - In this thesis, we discuss the formulation of variational problems on supermanifolds. Supermanifolds incorporate bosonic as well as fermionic degrees of freedom. Fermionic fields take values in the odd part of an appropriate Grassmann algebra and are thus showing an anticommutative behaviour. However, a systematic treatment of these Grassmann parameters requires a description of spaces as functors, e.g. from the category of Grassmann algberas into the category of sets (or topological spaces, manifolds). After an introduction to the general ideas of this approach, we use it to give a description of the resulting supermanifolds of fields/maps. We show that each map is uniquely characterized by a family of differential operators of appropriate order. Moreover, we demonstrate that each of this maps is uniquely characterized by its component fields, i.e. by the coefficients in a Taylor expansion w.r.t. the odd coordinates. In general, the component fields are only locally defined. We present a way how to circumvent this limitation. In fact, by enlarging the supermanifold in question, we show that it is possible to work with globally defined components. We eventually use this formalism to study variational problems. More precisely, we study a super version of the geodesic and a generalization of harmonic maps to supermanifolds. Equations of motion are derived from an energy functional and we show how to decompose them into components. Finally, in special cases, we can prove the existence of critical points by reducing the problem to equations from ordinary geometric analysis. After solving these component equations, it is possible to show that their solutions give rise to critical points in the functor spaces of fields. N2 - In dieser Dissertation wird die Formulierung von Variationsproblemen auf Supermannigfaltigkeiten diskutiert. Supermannigfaltigkeiten enthalten sowohl bosonische als auch fermionische Freiheitsgrade. Fermionische Felder nehmen Werte im ungeraden Teil einer Grassmannalgebra an, sie antikommutieren deshalb untereinander. Eine systematische Behandlung dieser Grassmann-Parameter erfordert jedoch die Beschreibung von Räumen durch Funktoren, z.B. von der Kategorie der Grassmannalgebren in diejenige der Mengen (der topologischen Räume, Mannigfaltigkeiten, ...). Nach einer Einführung in das allgemeine Konzept dieses Zugangs verwenden wir es um eine Beschreibung der resultierenden Supermannigfaltigkeit der Felder bzw. Abbildungen anzugeben. Wir zeigen, dass jede Abbildung eindeutig durch eine Familie von Differentialoperatoren geeigneter Ordnung charakterisiert wird. Darüber hinaus beweisen wir, dass jede solche Abbildung eineindeutig durch ihre Komponentenfelder, d.h. durch die Koeffizienten einer Taylorentwickelung bzgl. von ungeraden Koordinaten bestimmt ist. Im Allgemeinen sind Komponentenfelder nur lokal definiert. Wir stellen einen Weg vor, der diese Einschränkung umgeht: Durch das Vergrößern der betreffenden Supermannigfaltigkeit ist es immer möglich, mit globalen Koordinaten zu arbeiten. Schließlich wenden wir diesen Formalismus an, um Variationsprobleme zu untersuchen, genauer betrachten wir eine super-Version der Geodäte und eine Verallgemeinerung von harmonischen Abbildungen auf Supermannigfaltigkeiten. Bewegungsgleichungen werden von Energiefunktionalen abgeleitet und wir zeigen, wie sie sich in Komponenten zerlegen lassen. Schließlich kann in Spezialfällen die Existenz von kritischen Punkten gezeigt werden, indem das Problem auf Gleichungen der gewöhnlichen geometrischen Analysis reduziert wird. Es kann dann gezeigt werden, dass die Lösungen dieser Gleichungen sich zu kritischen Punkten im betreffenden Funktor-Raum der Felder zusammensetzt. KW - Supergeometrie KW - Variationsrechnung KW - Differentialoperatoren KW - Funktorgeometrie KW - supergeometry KW - variational calculus KW - differential operators KW - functor geometry Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-59757 ER - TY - JOUR A1 - Nehring, Benjamin A1 - Zessin, Hans T1 - The Papangelou process a concept for gibbs, fermi and bose processes JF - Journal of contemporary mathematical analysis N2 - This note is a revised and enlarged version of the german article [16] in a slightly different framework. We here correct a serious mistake in the first version and generalize the class of Polya sum processes considered there. (A corrected version of the same results can be found already in the thesis of Mathias Rafler [12].) Moreover, the class of Polya difference processes is constructed here for the first time. In analogy to classical statistical mechanics we propose a theory of interacting Bosons and Fermions. We consider Papangelou processes. These are point processes specified by some kernel which represents the conditional intensity of the process. The main result is a general construction of a large class of such processes which contains Cox, Gibbs processes of classical statistical mechanics, but also interacting Bose and Fermi processes. KW - Papangelou process KW - Polya sum KW - Polya difference process Y1 - 2011 U6 - https://doi.org/10.3103/S1068362311060069 SN - 1068-3623 VL - 46 IS - 6 SP - 326 EP - 337 PB - Allerton CY - New York ER - TY - JOUR A1 - Pfäffle, Frank A1 - Stephan, Christoph A. T1 - The holst action by the spectral action principle JF - Communications in mathematical physics N2 - We investigate the Holst action for closed Riemannian 4-manifolds with orthogonal connections. For connections whose torsion has zero Cartan type component we show that the Holst action can be recovered from the heat asymptotics for the natural Dirac operator acting on left-handed spinor fields. Y1 - 2011 U6 - https://doi.org/10.1007/s00220-011-1303-0 SN - 0010-3616 VL - 307 IS - 1 SP - 261 EP - 273 PB - Springer CY - New York ER - TY - JOUR A1 - Tarkhanov, Nikolai Nikolaevich T1 - The dirichlet to Neumann operator for elliptic complexes JF - Transactions of the American Mathematical Society N2 - We define the Dirichlet to Neumann operator for an elliptic complex of first order differential operators on a compact Riemannian manifold with boundary. Under reasonable conditions the Betti numbers of the complex prove to be completely determined by the Dirichlet to Neumann operator on the boundary. KW - Elliptic complexes KW - Dirichlet to Neumann operator KW - inverse problems Y1 - 2011 SN - 0002-9947 VL - 363 IS - 12 SP - 6421 EP - 6437 PB - American Mathematical Soc. CY - Providence ER - TY - BOOK ED - Blath, Jochen ED - Imkeller, Peter ED - Roelly, Sylvie T1 - Surveys in stochastic processes Y1 - 2011 SN - 978-3-03719-072-2 PB - European Mathematical Society CY - Zürich ER - TY - JOUR A1 - Roul, Pradip A1 - Schinner, Alexander A1 - Kassner, Klaus T1 - Simulation of the strain distribution under a two-dimensional sand pile JF - Powder technology : an international journal on the science and technology of wet and dry particulate systems N2 - We study the averaged macroscopic strain tensor for a sand pile consisting of soft convex polygonal particles numerically, using the discrete-element method (DEM). First, we construct two types of "sand piles" by two different pouring protocols. Afterwards, we deform the sand piles, relaxing them under a 10% reduction of gravity. Four different types of methods, three best-fit strains and a derivative strain, are adopted for determining the strain distribution under a sand pile. The results of four different versions of strains obtained from DEM simulation are compared with each other. Moreover, we compare the vertical normal strain tensor between two types of sand piles qualitatively and show how the construction history of the piles affects their strain distribution. KW - Numerical simulation KW - Sand pile KW - Stress KW - Strain KW - Granular matter KW - Discrete-element method Y1 - 2011 U6 - https://doi.org/10.1016/j.powtec.2011.08.039 SN - 0032-5910 VL - 214 IS - 3 SP - 406 EP - 414 PB - Elsevier CY - Lausanne ER - TY - JOUR A1 - Elin, Mark A1 - Shoikhet, David A1 - Tarkhanov, Nikolai Nikolaevich T1 - Separation of boundary singularities for holomorphic generators JF - Annali di matematica pura ed applicata N2 - We prove a theorem on separation of boundary null points for generators of continuous semigroups of holomorphic self-mappings of the unit disk in the complex plane. Our construction demonstrates rather strikingly the particular role of the binary operation au broken vertical bar given by 1/ f au broken vertical bar g = 1/f + 1/g on generators. KW - Semigroup KW - Holomorphic map KW - Unit disk KW - Angular derivatives Y1 - 2011 U6 - https://doi.org/10.1007/s10231-010-0165-y SN - 0373-3114 VL - 190 IS - 4 SP - 595 EP - 618 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Gaci, Said A1 - Zaourar, Naima A1 - Briqueu, Louis A1 - Holschneider, Matthias T1 - Regularity analysis applied to sonic logs data a case study from KTB borehole site JF - Arabian journal of geosciences N2 - Borehole logs provide in situ information about the fluctuations of petrophysical properties with depth and thus allow the characterization of the crustal heterogeneities. A detailed investigation of these measurements may lead to extract features of the geological media. In this study, we suggest a regularity analysis based on the continuous wavelet transform to examine sonic logs data. The description of the local behavior of the logs at each depth is carried out using the local Hurst exponent estimated by two (02) approaches: the local wavelet approach and the average-local wavelet approach. Firstly, a synthetic log, generated using the random midpoints displacement algorithm, is processed by the regularity analysis. The obtained Hurst curves allowed the discernment of the different layers composing the simulated geological model. Next, this analysis is extended to real sonic logs data recorded at the Kontinentales Tiefbohrprogramm (KTB) pilot borehole (Continental Deep Drilling Program, Germany). The results show a significant correlation between the estimated Hurst exponents and the lithological discontinuities crossed by the well. Hence, the Hurst exponent can be used as a tool to characterize underground heterogeneities. KW - Regularity analysis KW - Wavelet transform KW - Well log KW - Fractal KW - Lithology Y1 - 2011 U6 - https://doi.org/10.1007/s12517-010-0129-y SN - 1866-7511 VL - 4 IS - 1-2 SP - 221 EP - 227 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Ramadan, Ayad M. T1 - Range of lower bounds JF - Applied mathematics and computation N2 - Each of n jobs is to be processed without interruption on a single machine. Each job becomes available for processing at time zero. The objective is to find a processing order of the jobs which minimizes the sum of weighted completion times added with maximum weighted tardiness. In this paper we give a general case of the theorem that given in [6]. This theorem shows a relation between the number of efficient solutions, lower bound LB and optimal solution. It restricts the range of the lower bound, which is the main factor to find the optimal solution. Also, the theorem opens algebraic operations and concepts to find new lower bounds. KW - Lower bound KW - Multi objective function KW - Efficient solutions Y1 - 2011 U6 - https://doi.org/10.1016/j.amc.2011.03.066 SN - 0096-3003 VL - 218 IS - 3 SP - 1008 EP - 1011 PB - Elsevier CY - New York ER - TY - JOUR A1 - Schmidt, Hans-Jürgen T1 - Perihelion advance for orbits with large eccentricities in the Schwarzschild black hole N2 - We deduce a new formula for the perihelion advance $Theta$ of a test particle in the Schwarzschild black hole by applying a newly developed non-linear transformation within the Schwarzschild space-time. By this transformation we are able to apply the well-known formula valid in the weak-field approximation near infinity also to trajectories in the strong-field regime near the horizon of the black hole. The resulting formula has the structure $Theta = c_1 - c_2 ln(c^2_3 - e^2) $ with positive constants $c_{1,2,3}$ depending on the angular momentum of the test particle. It is especially useful for orbits with large eccentricities $e < c_3 < 1$ showing that $Theta o infty$ as $e o c_3$. Y1 - 2011 UR - http://link.aps.org/doi/10.1103/PhysRevD.83.124010 SN - 1550-7998 ER - TY - JOUR A1 - Enders, Jörg A1 - Müller, Reto A1 - Topping, Peter M. T1 - On Type-I singularities in Ricci flow JF - Communications in analysis and geometry N2 - We define several notions of singular set for Type-I Ricci flows and show that they all coincide. In order to do this, we prove that blow-ups around singular points converge to nontrivial gradient shrinking solitons, thus extending work of Naber [15]. As a by-product we conclude that the volume of a finite-volume singular set vanishes at the singular time. We also define a notion of density for Type-I Ricci flows and use it to prove a regularity theorem reminiscent of White's partial regularity result for mean curvature flow [22]. Y1 - 2011 SN - 1019-8385 VL - 19 IS - 5 SP - 905 EP - 922 PB - International Press of Boston CY - Somerville ER - TY - BOOK A1 - Keller, Peter A1 - Roelly, Sylvie A1 - Valleriana, Angelo T1 - On Time Duality for Markov Chains with Asborbing Boundardies T3 - Preprint / Universität Potsdam, Institut für Mathematik, Mathematische Statistik un Y1 - 2011 SN - 1613-3307 PB - Univ. CY - Potsdam ER - TY - JOUR A1 - Dimitrova, Ilinka A1 - Koppitz, Jörg T1 - On the maximal regular subsemigroups of ideals of order-preserving or order-reversing transformations JF - Semigroup forum N2 - We characterize the maximal regular subsemigroups of the ideals of the semigroup of all order-preserving transformations as well as of the semigroup of all order-preserving or order-reversing transformations on a finite ordered set. KW - Transformation semigroups KW - Regular semigroups KW - Order-preserving transformations KW - Order-reversing transformations KW - Maximal subsemigroups Y1 - 2011 U6 - https://doi.org/10.1007/s00233-010-9272-8 SN - 0037-1912 VL - 82 IS - 1 SP - 172 EP - 180 PB - Springer CY - New York ER - TY - JOUR A1 - Roul, Pradip T1 - Numerical solutions of time fractional degenerate parabolic equations by variational iteration method with Jumarie-modified Riemann-Liouville derivative JF - Mathematical methods in the applied sciences N2 - In this article, the fractional variational iteration method is employed for computing the approximate analytical solutions of degenerate parabolic equations with fractional time derivative. The time-fractional derivatives are described by the use of a new approach, the so-called Jumarie modified Riemann-Liouville derivative, instead in the sense of Caputo. The approximate solutions of our model problem are calculated in the form of convergent series with easily computable components. Moreover, the numerical solution is compared with the exact solution and the quantitative estimate of accuracy is obtained. The results of the study reveal that the proposed method with modified fractional Riemann-Liouville derivatives is efficient, accurate, and convenient for solving the fractional partial differential equations in multi-dimensional spaces without using any linearization, perturbation or restrictive assumptions. KW - variational iteration method KW - biological population equations KW - fractional calculus KW - exact solution KW - Mittag-Leffler function Y1 - 2011 U6 - https://doi.org/10.1002/mma.1418 SN - 0170-4214 VL - 34 IS - 9 SP - 1025 EP - 1035 PB - Wiley-Blackwell CY - Malden ER - TY - JOUR A1 - Böckmann, Christine A1 - Kammanee, Athassawat A1 - Braunss, Andreas T1 - Logarithmic convergence rate of Levenberg-Marquardt method with application to an inverse potential problem JF - Journal of inverse and ill-posed problems N2 - We prove logarithmic convergence rate of the Levenberg-Marquardt method in a Hilbert space if a logarithmic source condition is satisfied. This method is applied to an inverse potential problem. Numerical implementations demonstrate the convergence rate. KW - Levenberg-Marquardt method KW - inverse potential problems KW - logarithmic convergence rate KW - discrepancy principle KW - logarithmic source condition Y1 - 2011 U6 - https://doi.org/10.1515/JIIP.2011.034 SN - 0928-0219 VL - 19 IS - 3 SP - 345 EP - 367 PB - De Gruyter CY - Berlin ER - TY - JOUR A1 - von Kleist, Max A1 - Menz, Stephan A1 - Stocker, Hartmut A1 - Arasteh, Keikawus A1 - Schuette, Christof A1 - Huisinga, Wilhelm T1 - HIV quasispecies dynamics during pro-active treatment switching impact on multi-drug resistance and resistance archiving in latent reservoirs JF - PLoS one N2 - The human immunodeficiency virus (HIV) can be suppressed by highly active anti-retroviral therapy (HAART) in the majority of infected patients. Nevertheless, treatment interruptions inevitably result in viral rebounds from persistent, latently infected cells, necessitating lifelong treatment. Virological failure due to resistance development is a frequent event and the major threat to treatment success. Currently, it is recommended to change treatment after the confirmation of virological failure. However, at the moment virological failure is detected, drug resistant mutants already replicate in great numbers. They infect numerous cells, many of which will turn into latently infected cells. This pool of cells represents an archive of resistance, which has the potential of limiting future treatment options. The objective of this study was to design a treatment strategy for treatment-naive patients that decreases the likelihood of early treatment failure and preserves future treatment options. We propose to apply a single, pro-active treatment switch, following a period of treatment with an induction regimen. The main goal of the induction regimen is to decrease the abundance of randomly generated mutants that confer resistance to the maintenance regimen, thereby increasing subsequent treatment success. Treatment is switched before the overgrowth and archiving of mutant strains that carry resistance against the induction regimen and would limit its future re-use. In silico modelling shows that an optimal trade-off is achieved by switching treatment at & 80 days after the initiation of antiviral therapy. Evaluation of the proposed treatment strategy demonstrated significant improvements in terms of resistance archiving and virological response, as compared to conventional HAART. While continuous pro-active treatment alternation improved the clinical outcome in a randomized trial, our results indicate that a similar improvement might also be reached after a single pro-active treatment switch. The clinical validity of this finding, however, remains to be shown by a corresponding trial. Y1 - 2011 U6 - https://doi.org/10.1371/journal.pone.0018204 SN - 1932-6203 VL - 6 IS - 3 PB - PLoS CY - San Fransisco ER - TY - JOUR A1 - Förster, M. A1 - Namgaladze, Alexander A. A1 - Doronina, E. N. A1 - Prokhorov, Boris E. T1 - High-latitude thermospheric winds: Satellite data and model calculations JF - Russian journal of physical chemistry : B, Focus on physics N2 - The thermospheric crosswind velocities at an altitude of 400 km measured by an accelerometer on board of the CHAMP satellite are compared with the results of model calculations performed using the Upper Atmosphere Model (UAM). The results of measurements averaged over the year in 2003 reveal a two-vortex structure of high-latitude winds corresponding to magnetospheric-ionospheric convection of ions in the F2 ionosphere region. A similar picture with similar speed values was obtained in model calculations. A comparison of the crosswind speed obtained in individual measurements on October 28, 2003 with the corresponding model values revealed close agreement between them in some flights and differences in others. Taking into account the dependence of convection electric field on the B (y) component of interplanetary magnetic field sometimes improved agreement between thermospheric crosswind speeds obtained in model calculations and measured using the satellite. KW - CHAMP satellite KW - upper atmosphere model KW - thermospheric wind KW - ionospheric convection Y1 - 2011 U6 - https://doi.org/10.1134/S1990793111030043 SN - 1990-7931 VL - 5 IS - 3 SP - 439 EP - 446 PB - Pleiades Publ. CY - New York ER - TY - JOUR A1 - Pilari, Sabine A1 - Preusse, Cornelia A1 - Huisinga, Wilhelm T1 - Gestational influences on the pharmacokinetics of gestagenic drugs a combined in silico, in vitro and in vivo analysis JF - European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences, EUFEPS N2 - During preclinical development of a gestagenic drug, a significant increase of the total plasma concentration was observed after multiple dosing in pregnant rabbits, but not in (non-pregnant) rats or monkeys. We used a PBPK modeling approach in combination with in vitro and in vivo data to address the question to what extent the pharmacologically active free drug concentration is affected by pregnancy induced processes. In human, a significant increase in sex hormone binding globulin (SHBG), and an induction of hepatic CYP3A4 as well as plasma esterases is observed during pregnancy. We find that the observed increase in total plasma trough levels in rabbits can be explained as a combined result of (i) drug accumulation due to multiple dosing, (ii) increase of the binding protein SHBG, and (iii) clearance induction. For human, we predict that free drug concentrations in plasma would not increase during pregnancy above the steady state trough level for non-pregnant women. KW - PBPK KW - Pregnancy KW - Gestagenic drug KW - Protein binding KW - SHBG KW - Clearance induction Y1 - 2011 U6 - https://doi.org/10.1016/j.ejps.2010.12.003 SN - 0928-0987 VL - 42 IS - 4 SP - 318 EP - 331 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Schmidt, Hans-Jürgen T1 - Gauss-Bonnet Lagrangian G ln G and cosmological exact solutions N2 - For the Lagrangian L = G ln G where G is the Gauss-Bonnet curvature scalar we deduce the field equation and solve it in closed form for 3-flat Friedman models using a statefinder parametrization. Further we show, that among all lagrangians F(G) this L is the only one not having the form G^r with a real constant r but possessing a scale-invariant field equation. This turns out to be one of its analogies to f(R)-theories in 2-dimensional space-time. In the appendix, we systematically list several formulas for the decomposition of the Riemann tensor in arbitrary dimensions n, which are applied in the main deduction for n=4. Y1 - 2011 UR - http://arxiv.org/pdf/1102.0241v2 SN - 1550-7998 ER -