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The Apollonian tiling of the plane into circles is analyzed with respect to its group properties. The relevant group, which is noncompact and discrete, is found to be identical to the symmetry group of a particular geometric tree graph in hyperbolic three-space. A linear recursive method to compute the radii is obtained. Certain modifications of the problem are investigated, and relations to other

I höst kommer rymdobservatoriet Gaia att sändas upp. Ett av dess mål är att mätapositionen av stjärnor med väldigt hög noggrannhet, denna positionsbestämning kallas astrometri. Gaias noggrannhet är såpass bra att det kommer bli möjligt att även mäta hur planeter när de färdas i sina banor runt stjärnor påverkar positionen av stjärnan. Astrometri kan inte ge en fullständig bild av hur planeten rörContext: The Gaia satellite will be provide astrometry with micro-arcsecond accuracy. This will allow for the determination of the orbital elements of exoplanets with measurable astrometric signature. Astrometry alone is not be able to disentangle an ambiguity in the orientation of planetary orbits, just as radial velocity is only able to give the mass of orbiting planets combined with multiplicat

Denna rapport är en brandteknisk riskvärdering av neonatalintensivvårdsavdelningen på Skånes universitetssjukhus i Lund. Syftet med rapporten är att göra en brandteknisk riskvärdering för att undersöka om personsäkerheten på neo-IVA kan säkerställas vid brand på avdelningen. Patienterna på denna avdelning är för tidigt födda barn som inte överlever utan den livsuppehållande utrustning som finns i This report is a fire safety evaluation of the neonatal intensive care unit at the Skåne University Hospital in Lund. The purpose of the report is to make a fire safety evaluation to investigate whether the personal safety can be ensured in the event of a fire in the ward. The patients in this ward do not survive without their life-sustaining equipment and cannot evacuate their rooms on their own

The aim of this study is to look at the discourses of European identity from two different angles. The first angle is European identity from an EU perspective which EU seeks to create amongst the European citizens. This is studied in the book European Foreign Policy, consisting of legislations and treaties connected to the Common Foreign and Security Policy. The second angle is the images of Europ

We compare different procedures for combining fixed-order tree-level matrix-element generators with parton showers. We use the case of W-production at the Tevatron and the LHC to compare different implementations of the so-called CKKW and MLM schemes using different matrix-element generators and different parton cascades. We find that although similar results are obtained in all cases, there are i

Event generators play a crucial role in the exploration of LHC physics. This presentation summarizes news and plans for the three general-purpose pp generators HERWIG, PYTHIA and SHERPA, as well as briefer notes on a few other generators. Common themes, such as the matching and merging between matrix elements and parton showers, are highlighted. Other topics include a historical introduction, from

An overview is given of Chiral Perturbation Theory and various applications to eta decays. In particular. the main decay eta --> 3pi is discussed at the one-loop level, and estimates of the higher order corrections are given. The importance of p(6) and higher order effects in double Dalitz and eta --> pi(0)gammagamma decays is pointed out. In all these cases the need for new experimental results i

We discuss some of the effects of twisted boundary conditions in finite volume using continuum SU(3) Chiral Perturbation Theory. We point out how broken cubic symmetry affects the definitions of quantities such as form-factors. Using the π+ as an example, we give one loop results for the mass, decay constants and electromagnetic form-factor and illustrate how the relevant Ward identities are satis

We show that the geometry of the Wilson lines, entering the operator definition of the transverse-momentum dependent parton distributions and that of the soft factor, follows from the kinematics of the underlying physical process in conjunction with the gauge invariance of the QCD Lagrangian. We demonstrate our method in terms of concrete examples and determine the paths of the associated Wilson l

This review contains an overview of strong interaction effects in weak decays starting with a historical introduction. It contains a short overview of semileptonic decays and their relevance for measuring CKM matrix elements. The main part is devoted to the theoretical calculation on nonleptonic matrix elements relevant for K⁰-K⁰bar mixing and K to pi pi decays. It concludes

After a brief discussion of the statistics available to the four LEP experiments at the time of writing and an overview of B-event characteristics, the authors consider in particular the theory, practice and potential pitfalls of neural networks, a new approach to B tagging which attracted a great deal of interest. They then consider some of the QCD aspects of heavy flavour physics. Finally there

We present a method to combine the all-order treatment of the High Energy Jets exclusive partonic Monte Carlo (HEJ) with the parton shower of Pythia8, while retaining the logarithmic accuracy of both. This procedure enables the generation of fully realistic and hadronised events with HEJ. Furthermore, the combination of the two allorder treatments leads to improvements in the quality of the descri

A framework of operator product expansion (OPE) allows us to study high-energy behaviour of Green functions. A calculation of such Green functions within chiral perturbation theory (PT) or resonance chiral theory (RT) and subsequent matching of the result to the OPE enables us to determine constraints for unknown parameters of the effective theories. We present such procedure for Green functions i

The present status of Chiral Perturbation Theory (ChPT) in the strong mesonic sector is discussed. A very short introduction to ChPT is followed by an overview of existing two-loop calculations and the determination of the Low-Energy-Constants (LECs). I discuss the case of $\eta\to\pi\pi\pi$ decays in somewhat more detail and finish by mentioning some recent work on partially quenched ChPT and on

This talk describes the reasons why $\eta$ and $\eta^\prime$ decays are an interesting topic of study for both theory and experiment. The main part discusses the results of the recent calculation of $\eta\to3\pi$ at two-loop order in ChPT. Some puzzling aspects of the results compared to earlier dispersive calculations are highlighted. I also like to remind the reader of the use of $\eta$ and $\et

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