Photon - Jet Correlations and Constraints on Fragmentation Functions

We study the production of a large-pT photon in association with a jet in proton-proton collisions. We examine the sensitivity of the jet rapidity distribution to the gluon distribution function in the proton. We then assess the sensitivity of various photon + jet correlation observables to the photon fragmentation functions. We argue that RHIC data on photon-jet correlations can be used to constrain the photon fragmentation functions in a region which was barely accessible in LEP experiments.Comment: 23 pages, 9 figure

Radiologische Diagnose des femoroazetabulären Impingements

Zusammenfassung: Beim femoroazetabulären Impingement (FAI) bewirkt ein anatomisches Missverhältnis zwischen proximalem Femur und Azetabulum eine frühzeitige Abnützung der Gelenkflächen. Um Symptome wie eingeschränkte Beweglichkeit und Schmerzen zu beheben, aber auch um dem degenerativen Prozess vorzubeugen oder ihn zu verlangsamen, ist häufig eine Operation notwendig. Dabei hängt das Resultat vom präoperativen Gelenkstatus ab - mit schlechten Ergebnissen bei bereits fortgeschrittener Hüftgelenkarthrose. Dies erklärt die Notwendigkeit einer akkuraten Diagnostik, um Frühstadien der Gelenkschädigung erkennen zu können. Die Diagnostik des FAI beinhaltet klinische Untersuchung, Röntgendiagnostik und Magnetresonanztomographie (MRT). Die Standardröntgen-radiologische Untersuchung beim FAI wird anhand von 2 Röntgenaufnahmen durchgeführt, der a.p.-Beckenaufnahme sowie einer seitlichen Aufnahme des proximalen Femurs wie z.B. der"lateralen cross-table”- oder der Lauenstein-Aufnahme. Hierbei müssen Positionskriterien eingehalten werden, um Verzerrungsartefakte auszuschließen. Die MRT-Bildgebung ermöglicht eine Untersuchung der Hüfte in 3 Ebenen und sollte zudem radial geplante Sequenzen für eine verbesserte Darstellung der randnahen Strukturen wie Labrum und peripherem Knorpel beinhalten. Die Verwendung von Kontrastmittel für ein direktes MR-Arthrogramm (MRA) hat sich insbesondere für die Darstellung von Labrumschäden als vorteilhaft erwiesen. Die Datenlage in Hinblick auf die Knorpelbildgebung ist noch unklar. Weiterentwicklungen der Techniken werden in naher Zukunft die Diagnostik der Hüfte verbessern können. Hierzu zählen u.a. biochemisch sensitive MRT-Anwendunge

Delayed gadolinium-enhanced magnetic resonance imaging of hip joint cartilage: pearls and pitfalls

With the increasing advances in hip joint preservation surgery, accurate diagnosis and assessment of femoral head and acetabular cartilage status is becoming increasingly important. Magnetic resonance imaging (MRI) of the hip does present technical difficulties. The fairly thin cartilage lining necessitates high image resolution and high contrast-to-noise ratio (CNR). With MR arthrography (MRA) using intraarticular injected gadolinium, labral tears and cartilage clefts may be better identified through the contrast medium filling into the clefts. However, the ability of MRA to detect varying grades of cartilage damage is fairly limited and early histological and biochemical changes in the beginning of osteoarthritis (OA) cannot be accurately delineated. Traditional MRI thus lacks the ability to analyze the biological status of cartilage degeneration. The technique of delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) is sensitive to the charge density of cartilage contributed by glycosaminoglycans (GAGs), which are lost early in the process of OA. Therefore, the dGEMRIC technique has a potential to detect early cartilage damage that is obviously critical for decision-making regarding time and extent of intervention for joint-preservation. In the last decade, cartilage imaging with dGEMRIC has been established as an accurate and reliable tool for assessment of cartilage status in the knee and hip joint

An examination of business occupier relocation decision making : distinguishing small and large firm behaviour

This paper explores how business occupiers decide whether and where to relocate. It captures the experience and behaviour of a range of sizes and types of business occupier and subjects their decision-making processes to detailed scrutiny. A linear three-stage decision model is used to sequence and structure interviews with individuals who have intimate involvement with the relocation of 28 firms and organizations in Tyne and Wear, in the north-east of England. The 'constant comparative' method is used to analyse the interview data, from which emerges 18 key concepts, comprising 51 characteristic components. Using an axial approach, these are organized into 10 cross-cutting themes that represent the main areas of consideration or influence on the thinking of the people involved in determining whether a firm or organization should relocate and, if so, where to. The resulting analysis finds that organizations adopt varying degrees of sophistication when making relocation decisions; small firms are more inclined to make decisions based on constrained information; larger organizations adopt a more complex approach. Regardless of firm size, key individuals exert considerable influence over the decision-making process and its outcome

El efecto preventivo de la sanción pecuniaria disuasiva

La concepción moderna que limitaba la función de la responsabilidad civil a la resarcitoria reinó en los ordenamientos jurídicos inspirados en el Código Francés de 1804, que acotaba la intervención del Derecho Privado a la etapa posterior al daño antijurídicamente causado. No obstante, ya en el siglo pasado se abrió un debate en la dogmática jurídica sobre la posibilidad de que aquel sistema cumpliera funciones distintas a las resarcitorias. En este camino, lentamente fueron ganando terreno aquellas concepciones doctrinarias que ampliaban las objetivos del denominado Derecho de Daños y ello se convirtió en una cuestión de intenso debate. Se comenzó así a hablar de la polifuncionalidad de esta rama del Derecho para hacer referencia a la idea del reconocimiento, a la par de la clásica función de reparación del daño, de otras finalidades, como la preventiva y la punitiva.Facultad de Ciencias Jurídicas y Sociale

Torn between two targets: German police officers talk about the use of force

Considering earlier research into police use of force as well as the judicial and practical frame of police work in Germany, the article presents the results of an empirical study on the individual and collective legitimization of the use of force by German police officers. There are numerous justifications for the use of force expressed by focus group participants in eight German Federal States who were responding to a hypothesized scenario. In the discussions observed within the groups, reference is first made to the state’s duty to prosecute alleged offences and the measures or formal actions to do this—hence, the legal authority to use force. In the course of the discussions, however, it became obvious that illegal violence may occur, although it was not perceived as such by the officers. Overall, and after an intensive analysis of the focus group discussions, it can be stated that use of force (whether legal or not) depends on the police officer’s perception of the resistance of the person being engaged with. In this regard, different social–cultural or physical–material factors can be identified. They have different influences on the individual legitimization of police actions, intertwined with the perception of the situation as constructed by the officer. Three ways of perceiving the situation can be deduced, resulting in different patterns of justification for the use of force

QCD

We discuss issues of QCD at the LHC including parton distributions, Monte Carlo event generators, the available next-to-leading order calculations, resummation, photon production, small x physics, double parton scattering, and backgrounds to Higgs production.Comment: 115 pages, Latex, 47 figures, to appear in the Report of the ``1999 CERN Workshop on SM Physics (and more) at the LHC'', S. Catani, M. Dittmar, D. Soper, W.J. Stirling, S. Tapprogge (convenors

Photon-pair jet production via gluon fusion at the LHC

Photon-pair direct or jet-associated productions are important for relevant standard model measurement, Higgs and new physics searches at the LHC. The loop-induced gluon-fusion process gg -> \gamma\gamma g, which although formally contributes only at the next-to-next-to-leading order to \gamma\gamma j productions, may get enhanced by the large gluon flux at the LHC. We have checked and confirmed previous results on gg -> \gamma\gamma, \gamma\gamma g at one loop, using now the traditional Feynman diagram based approach and taking into account the quark mass effects, and further updated them for the 7 and 14 TeV LHC with new inputs and settings. We provide the details and results of the calculations, which involves manipulation of rank-5 pentagon integrals. Our results show that the gluon-fusion process can contribute about 10% of the Born result, especially at small M_{\gamma\gamma} and PT_{\gamma\gamma}, and increase further the overall scale uncertainty. Top quark loop effects are examined in detail, which shows importance near or above the threshold M_{\gamma\gamma} \gsim 2m_t.Comment: 10 pages, 5 figure

Direct photon cross sections in proton-proton and antiproton-proton interactions at s=24.3\sqrt{s} = 24.3 GeV

We report results on inclusive direct photon $(\gamma), \pi_0$, and $\eta$ production in both pp and \={p}p interactions at $\sqrt{s} = 24.3$ GeV in the transverse momentum range {$4.1 \le p_T \le 7 .7$ GeV/$c$} and rapidity range \mbox{$-0.1 \le y \le 0.9$}. The data were collected between 1988 and 1990 by the UA6 experiment at CERN, which employed an internal $\mathrm{H_2}$ gas jet target in the S\={p}pS collider. The inclusive direct photon cross sections and the cross section difference \mbox{$\sigma(\overline{p}p) - \sigma(pp)$} expressed as functions of $p_T(\gamma)$ are compared w ith next-to-leading order QCD predictions