Local Thermal Equilibrium in Quantum Field Theory on Flat and Curved Spacetimes

The existence of local thermal equilibrium (LTE) states for quantum field theory in the sense of Buchholz, Ojima and Roos is discussed in a model-independent setting. It is shown that for spaces of finitely many independent thermal observables there always exist states which are in LTE in any compact region of Minkowski spacetime. Furthermore, LTE states in curved spacetime are discussed and it is observed that the original definition of LTE on curved backgrounds given by Buchholz and Schlemmer needs to be modified. Under an assumption related to certain unboundedness properties of the pointlike thermal observables, existence of states which are in LTE at a given point in curved spacetime is established. The assumption is discussed for the sets of thermal observables for the free scalar field considered by Schlemmer and Verch.Comment: 16 pages, some minor changes and clarifications; section 4 has been shortened as some unnecessary constructions have been remove

On a derivation of the Boltzmann equation in Quantum Field Theory

The Boltzmann equation (BE) is a commonly used tool for the study of non-equilibrium many particle systems. It has been introduced in 1872 by Ludwig Boltzmann and has been widely generalized throughout the years. Today it is commonly used in physical applications, from the study of ordinary fluids to problems in particle Cosmology where Quantum Field Theoretical techniques are essential. Despite its numerous experimental successes, the conceptual basis of the BE is not entirely clear. For instance, it is well known that it is not a fundamental equation of physics like, say, the Heisenberg equation (HE). A natural question then arises whether it is possible to derive the BE from physical first principles, i.e. the Heisenberg equation in Quantum Field Theory. In this work we attempted to answer this question and succeeded in deriving the BE from the HE, thus further clarifying its conceptual status. In particular, the results we have obtained are as follows. Firstly, we establish the non-perturbative validity of what we call the "pre-Boltzmann equation". The crucial point here is that this latter equation is equivalent to the Heisenberg equation. Secondly, we proceed to consider various limits of the pre-Boltzmann equation, namly the "low density" and the "weak coupling" limits, to obtain two equations that can be considered as generalizations of the BE. These limits are always taken together with the "long time" limit, which allows us to interpret the BE as an appropriate long time limit of the HE. The generalization we obtain consists in additional "correction" terms to the usual Boltzmann collision factor, and can be associated to multiple particle scattering. Unlike the pre-Boltzmann equation, these latter results are only valid pertubatively. Finally, we briefly consider the possibility to extend these results beyond said limits and outline some important aspects in this case

On the iterated Crank-Nicolson for hyperbolic and parabolic equations in numerical relativity

The iterated Crank-Nicolson is a predictor-corrector algorithm commonly used in numerical relativity for the solution of both hyperbolic and parabolic partial differential equations. We here extend the recent work on the stability of this scheme for hyperbolic equations by investigating the properties when the average between the predicted and corrected values is made with unequal weights and when the scheme is applied to a parabolic equation. We also propose a variant of the scheme in which the coefficients in the averages are swapped between two corrections leading to systematically larger amplification factors and to a smaller numerical dispersion.Comment: 7 pages, 3 figure

RENOVATION OF ACQUISITION PROCESS FOR ONE-TIME FINANCIAL HELP FOR NEWBORNS

Diplomsko delo obravnava postopek pridobitve enkratne denarne pomoči za novorojence, ki jo podeli Občina Kobarid. Problem, ki sem ga zaznala, je dolgotrajnost postopka. Vsa potrebna dokumentacija se ureja v papirnati obliki. To predstavlja veliko dela tako vlagatelju kot tudi referentu v sprejemni pisarni. Zato sem se odločila za reorganizacijo procesa. Uporabila sem Microsoftovo programsko orodje iGrafx , kjer sem predstavila obstoječ proces in prikazala usmeritve elektronskega poslovanja. Takšno poslovanje skrajša čas priprave vloge in zmanjša količino papirnih obrazcev. Predstavila bom prenovljen proces elektronskega poslovanja z digitalnim potrdilom in primerjavo med njima. Diplomsko delo sestavljata teoretični in praktični del. V teoretičnem delu bom predstavila definicije poslovnega procesa, prenovo poslovnih procesov, modeliranje in simuliranje poslovnih procesov. V praktičnem delu bom s pomočjo programskega orodja iGrafx predstavila oba modela, njihove simulacije in rezultate. Pri prenovi poslovnega procesa bom prikazala, da bi prenovljen proces pripomogel k zmanjšanju papirnatega poslovanja, krajši časovni izvedbi ter nižjim finančnim stroškom.The thesis analyses the procedure for getting a one-time financial aid for new-borns, given by the Municipality of Kobarid. The problem which I identified is the long duration of the process. All documentation is done in paper form. This means a lot of work for the applicant as well as the office. That is why I decided for a reorganisation of this process. I used a Microsoft software iGrafx to present the current process and show the directions for electronic processing. That would shorten the preparation time and cut the amount of paper forms. I will present the new electronic processing with digital certificate and compare the two. The thesis is divided into a theoretical and practical part. In the first part, I will present the definitions of a business process, the business processes, modelling and simulating of business processes. In the second part, I will present two models with the help of iGrafx software, where the simulations and results will be obtained. In the renovation of business process, I will demonstrate that the new process will help to reduce the paperwork, the time and other costs

Cytokine profile of regenerating T cells after transplantation of allogenic, CD34+ enriched PBSCT in pediatric patients

Das Ziel dieser Studie war die Charakterisierung der T-Zell-Regeneration von 22 Patienten nach verwandter und nichtverwandter CD34+ angereicherter PBSZT. In einem ersten Schritt wurde die T-Zell-Regeneration nach PBSZT mittels FACS-Analyse anhand des Phänotyps der Zellen charakterisiert. Hierbei zeigte sich ein Überwiegen der CD45RO+ Gedächtniszellen zu frühen Zeitpunkten der Regeneration, was die Thymus-unabhängige, periphere Expansion reifer T-Zellen des Transplantats widerspiegelte. Im weiteren Verlauf stiegen im Rahmen der Thymus-abhängigen Regeneration die naiven, CD45RA+ T-Zellen kontinuierlich an. In einem weiteren Schritt wurde die Funktion der regenerierenden T-Zellen dargestellt. Die Lymphozyten derselben Patienten wurden mit den Mitogenen PMA und Ionomycin stimuliert und die produzierten Zytokine mittels ELISA quantifiziert. Von den hier untersuchten THI/TCI-Zytokinen IL-2 und IFN-γ wurde früh nach Transplantation hauptsächlich IFN-γ synthetisiert. Später überwog die IL-2-Synthese, während gegen Ende des Beobachtungs-zeitraums IFN-γ das am meisten produzierte Zytokin war. Die TH-2-Zytokine IL-4 und IL-10 wurden nur zu geringem Ausmaß synthetisiert. Um eine Zuordnung der produzierten Zytokine zu erhalten, wurden die stimulierten, zytokinproduzierenden Zellen mit fluoreszenzmarkierten Antikörpern gegen charakteristische Oberflächenmoleküle und gegen intrazelluläre Zytokine angefärbt. Hier fiel im Vergleich zu den Lymphozyten der gesunden Kontrolle eine deutlich reduzierte Expression des Aktivierungsmarkers CD69 auf, die im weiteren Verlauf zunahm. Sowohl CD4+ als auch CD8+ T-Zellen produzierten alle untersuchten Zytokine, verglichen mit der gesunden Kontrolle jedoch in reduziertem Ausmaß. Die CD4+ Zellen waren in höherer Konzentration für IL-2 als für IFN-gamma positiv. Bei den CD8+ Zellen war das Verhältnis umgekehrt. Die defiziente Zytokinsynthese wurde mit dem Aktivierungsdefekt der T-Zellen in Zusammenhang gebracht, wofür, wie im Folgenden diskutiert, eine Vielzahl an Ursachen möglich sind.The aim of the present study was a characterization of immune reconstitution after CD34+ enriched PBSCT from related and unrelated donors. Regenerating T cells in 22 patients were analyzed during the first 18 months posttransplantation. In a first step T cell regeneration after PBSCT was phenotypically described and quantified by FACS-analysis. The result was a predominance of CD45RO+ memory cells in early phase of regeneration reflecting the thymus-independent peripheral expansion of mature T cells of the graft. During the follow-up naïve thymus-derived CD45RA+ T cells were increasing constantly. In a further step the function of the regenerating T cells was analyzed. Peripheral blood mononuclear cells (PBMCs) of the same patients were stimulated with PMA and Ionomycin. After isolating the supernatant the produced amount of cytokines was quantified by ELISA. Regarding the measured TH1/TC1-cytokines, mainly IFN- was synthesized in the early posttransplantation phase. 6 months after transplantation IL-2 synthesis predominated, whereas at the end of the observed intervall of time the mainly produced cytokine was IFN-. The TH2/TC2-cytokines IL-4 and IL-10 were secreted in a small amount. Compared with T cells of a healthy person the production of all cytokines was substantially reduced. Furthermore the secretion of cytokines in different T lymphocyte subpopulations was evaluated. Stimulated PBMCs were simultaneously incubated with monoclonal antibodies against surface marker epitopes and intracellular located cytokines. The amount of T cell activation was measured by expression of CD69. In comparison with PBMCs of a healthy control CD69 was distinctly reduced during the follow-up, although its expression was constantly increasing. Both, CD4+ and CD8+ T cells produced all measured cytokines, but compared with the healthy control this happened in a substantially reduced amount. CD4+CD45RA+ cells secreted more IL-2 than IFN-gamma. In the CD8+CD45RO+ cells this relation was vice versa. In summary a substantial functional deficiency of regenerating T cells could be demonstrated. This was manifested in a decreased T cell activation which resulted in a reduced synthesis of cytokines. The causes of this functional defect are discussed in the following