Analysis of the Stieltjes imaging method for the calculation of resonance widths

Název práce: Analýza metody Stieltjes imaging pro výpočet rezonančních šířek Autor: Petra Votavová Ústav: Ústav teoretické fyziky Vedoucí bakalářské práce: RNDr. Přemysl Kolorenč, Ph.D., Ústav teoretické fyziky, Matematicko-fyzikální fakulta Univerzity Karlovy v Praze Abstrakt: Tato práce se zabývá řešením momentového problému metodou Stieltjes imaging a navrženou alternativní metodou, která je založena na přímém rozkladu do báze ortogonálních funkcí. Byly zvoleny celkem tři různé báze, které byly odvozeny z Legendreových polynomů. Vlastnosti těchto metod byly studovány na příkladu analytické funkce. Nakonec byly obě metody aplikovány na výpočet rezonanční šířky metastabilního iontu CH3F(2s-2 )2+ . Klíčová slova: momentový problém, Gaussova kvadratura, ortogonální polynomy, rezonanční šířka, rozpad metastabilního iontuTitle: Analysis of the Stieltjes imaging method for the calculation of resonance widths Author: Petra Votavová Department: Institute of Theoretical Physics Supervisor: RNDr. Přemysl Kolorenč, Ph.D., Institute of Theoretical Physics, Faculty of Mathematics and Physics, Charles University in Prague Abstract: This thesis deals with the moment problem in the context of the resonance widths. The moment problem was solved by the Stieltjes imaging method and proposed alternative method based on the direct decomposition into the orthogonal basis. Three different basis derived from the Legendre polynomials were chosen. The properties of these methods were studied by analytical function. Eventually, both methods were applied to the calculation of resonance width of the metastable ion CH3F(2s-2 )2+ . Keywords: moment problem, Gaussian quadrature, orthogonal polynomials, resonance widths, decay of metastable ionsInstitute of Theoretical PhysicsÚstav teoretické fyzikyMatematicko-fyzikální fakultaFaculty of Mathematics and Physic

The effect of IL-15/IL-15Rα complex on NK and T cells

Department of Cell BiologyKatedra buněčné biologieFaculty of SciencePřírodovědecká fakult

The virtual photon approximation for three-body interatomic Coulombic decay

Interatomic Coulombic decay (ICD) is a mechanism which allows microscopic objects to rapidly exchange energy. When the two objects are distant, the energy transfer between the donor and acceptor species takes place via the exchange of a virtual photon. On the contrary, recent ab initio calculations have revealed that the presence of a third passive species can significantly enhance the ICD rate at short distances due to the effects of electronic wave function overlap and charge transfer states [Phys. Rev. Lett. 119, 083403 (2017)]. Here, we develop a virtual photon description of three-body ICD, showing that a mediator atom can have a significant influence at much larger distances. In this regime, this impact is due to the scattering of virtual photons off the mediator, allowing for simple analytical results and being manifest in a distinct geometry-dependence which includes interference effects. As a striking example, we show that in the retarded regime ICD can be substantially enhanced or suppressed depending on the position of the ICD-inactive object, even if the latter is far from both donor and acceptor species

The issue of family business in Czech Republic

Předkládaná bakalářská práce se zaměřuje na problematiku rodinného podnikání. V teoretické části definuji rodinné podniky, jejich rozšíření ve světě a v České republice, uvádím možné členění těchto podniků. Dále se zabývám výhody a nevýhody, které s sebou toto podnikání nese a otázkou následovnictví. V části praktické porovnávám zjištěné poznatky s názory manažerů rodinných podniků různého zaměření pomocí řízených rozhovorů.This bachelor's thesis concentrates on family business problems and issues. In theoretical part, it defines family businesses in their substance and how family businesses expand in Czech Republic or in the world. Furthermore it introduces how these businesses can be separated and the next topics are the advantages and disadvantages of this kind of business and issue of discipleship. In practical part I discuss findings from part one with opinions of managers working in family businesses with different specializations by the medium of interviews

Potentiation of the biological activity of IL-2 and IL-15 in vivo

5 Abstract Interleukin-2 possesses strong stimulatory activity for activated T and NK cells and thus it is an attractive molecule for immunotherapy. However, its unfavourable pharmacological properties, extremely short half-life and severe toxicities associated with high-dose IL-2 are the most serious and limiting drawbacks. Moreover, IL-2 has been also implicated in the homeostasis of T regulatory cells where it plays a decisive role as an essential growth factor of these cells. Several different approaches to improve the therapeutic potential of IL-2 have been studied. Recently described IL-2/anti-IL-2 mAb immunocomplexes which show much higher and selective biological activity in contrast with free IL-2 in vivo are probably the most promising of them. In this study, we compared the biological activity of free IL-2 with IL-2/anti-IL-2 mAb immunocomplexes in order to demonstrate their benefits over free IL-2. We also demonstrated that IL-2/anti-IL-2 mAb immunocomplexes possess noticeable antitumor activity in two syngeneic mouse tumor models, namely EL4 T lymphoma and B16F10 melanoma, if administered early in tumor progression. Therefore, we justified potential use of IL-2/anti-IL-2 mAb immunocomplexes in tumor immunotherapy. We covalently conjugated IL-2 to synthetic semitelechelic polymeric carrier based..

Computing resonance widths using square integrable basis

Four different non-orthogonal basis sets are studied and compared in order to obtain the resonance properties of a model scattering problem. In particular, two types of Gaussian basis sets, one B-spline basis set and one hybrid Gaussian - B-spline basis set. Their ability to represent the scattering continuum is investigated along with their numerical properties. Particular attention is paid to the energy range within which each basis set gives reasonably accurate values of the phase shift and the decay width. The radial Schrödinger equation is solved by the Löwdin's symmetric orthogonalization method and the decay width is extracted by the Stieltjes imaging procedure. The R-matrix method within the framework of Feshbach-Fano projection operator formalism with polynomial basis set is utilized as a numerically exact reference method

Výpočet rezonančních šířek v kvadraticky integrabilních bázích

Tato práce se zabývá numerickým výpočtem fázových posuvů, rezonančních energií a rozpadových šířek. Za tímto účelem byly sestrojeny a porovnány čtyři různé neortogonální báze. Konkrétně se jedná o dva typy Gaussovských bází, jednu B-splinovou bázi a jednu hybridní Gaussovskou - B-splinovou bázi. Důraz je kladen především na jejich numerické vlastnosti a schopnost representovat kontinuum. Zvláštní pozornost je také věnována rozsahu energií, ve kterém daná báze dává hodnoty fázových posuvů a rozpadových šířek s dostatečně dobrou přesností. Radiální Schrödingerova rovnice je vyřešena Löwdinovou symetrickou ortogonalizací a rozpadová šířka je následně určena metodou Stieltjes imaging. R-maticová metoda v rámci Feshbachova-Fanova projekčního formalismu v polynomiální bázi je použita jako numericky přesná referenční metoda.Four different non-orthogonal basis sets are studied and compared in order to obtain the resonance properties of a model scattering problem. In particular, two types of Gaussian basis sets, one B-spline basis set and one hybrid Gaussian - B-spline basis set. Their ability to represent the scattering continuum is investigated along with their numerical properties. Particular attention is paid to the energy range within which each basis set gives reasonably accurate values of the phase shift and the decay width. The radial Schrödinger equation is solved by the Löwdin's symmetric orthogonalization method and the decay width is extracted by the Stieltjes imaging procedure. The R-matrix method within the framework of Feshbach-Fano projection operator formalism with polynomial basis set is utilized as a numerically exact reference method.Institute of Theoretical PhysicsÚstav teoretické fyzikyMatematicko-fyzikální fakultaFaculty of Mathematics and Physic

Mechanism of superexchange Interatomic Coulombic decay in rare gas clusters

International audienceInteratomic Coulombic Decay (ICD) is an ultrafast energy transfer process. Via ICD, an excited atom can transfer its excess energy to a neighboring atom which is thus ionized. On the example of NeHeNe cluster, we recently reported [Phys. Rev. Lett. 119, 083403 (2017)] that the total ICD widths are substantially enhanced in the presence of an ICD inactive atom. The enhancement occurs due to the coupling of the resonance state to intermediate virtual states of the bridge atom-a mechanism named superexchange ICD. In this follow-up work, we analyze the partial ICD widths in NeHeNe cluster and show that only some channels are affected by the superexchange ICD process. Furthermore, we consider superexchange ICD in NeHeAr. We show that in this system the enhancement is still present but the energy transfer mediated by the superexchange mechanism is less efficient than in NeHeNe owing to the different ionization potentials of Ar and Ne. The behavior of the computed ICD widths is explained with a simple model based on first-order perturbation theory and a Hartree-Fock-like description of the states