1,394 research outputs found

    Entwicklung eines neuen diamantbasierten Detektors fĂŒr Messungen von maschineninduziertem Hintergrund und LuminositĂ€t

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    The LHC is the largest particle accelerator and storage ring in the world, used to investigate fundamentals of particle physics and to develop at the same time the technology of accelerators and detectors. Four main experiments (ATLAS, ALICE, CMS and LHCb) , located around the LHC ring, provide insight into the nature of particles and search for answers to as yet unexplained phenomena in the universe. Two proton or heavy ion beams circulate in the LHC and are brought into collision in the four experiments. The physics potential of each experiment is determined by the luminosity, which is a ratio of the number of the events during a certain time period to the cross section of a physics process. A measurement of the luminosity is therefore essential to determine the cross section of interesting physics processes. In addition, safe and high-quality data-taking requires stable beam conditions with almost no beam losses. Each experiment has its own detectors to measure beam losses, hereafter called machine induced background. One such detector is installed in CMS, BCM1F. Based on diamond sensors it was designed and built to measure both, the luminosity and the machine induced background. BCM1F ran smoothly during the first LHC running period from 2009-2012 and delivered valuable beam loss and luminosity information to the control rooms of CMS and LHC. At the end of 2012 the LHC was shut down to improve the performance by increasing the proton energy to 7TeV and decreasing the proton bunch spacing to 25ns. Due to the success of BCM1F an upgrade of its sensors and readout components was planned in order to fulfil the new requirements. The upgrade of the sensors comprises a two pad instead of one pad metallization. 24 instead of the previous 8 single crystal diamond sensors were foreseen for the new BCM1F to enhance the robustness and redundancy. To instrument BCM1F, 59 sensors were electrically characterized by measuring the leakage current, signal stability and charge collection efficiency. Quality criteria were defined to select sensors for the final installation. An overview of these measurements including a summary of the results is given in this thesis. In addition, an upgraded amplifier was developed within the collaboration in 130nm CMOS technology. It has a peaking time of 7ns instead of the 22ns of the one previously installed. A BCM1F prototype comprising a two pad sensor and the upgraded amplifier was tested at the DESY-II accelerator in a 5GeV electron beam. Results of these test-beam measurements are presented in this thesis as well as simulations to interpret the measurements. The installation of the upgraded BCM1F was completed in 2014. In 2015 BCM1F was commissioned and started to measure luminosity and machine induced background. At the end, the thesis will describe both types of measurements with the focus on machine induced background demonstrating the functionality of BCM1F.Der LHC ist der grĂ¶ĂŸten Teilchenbeschleuniger und -speicherring der Welt. Er wurde gebaut, um Teilchenphysik bei höheren Energien zu erforschen bei gleichzeitiger Entwicklung der Beschleuniger- und Detektorphysik. Vier große Experimente (ATLAS, ALICE, CMS, LHCb) befinden sich am LHC, welche einen Einblick in die grundlegenden Strukturen des Universums und der Teilchenphysik geben. Zwei Protonen- oder Schwerionenstrahlen kreisen im LHC und werden in den vier Experimenten zur Kollision gebracht. Das Physikpotential in den jeweiligen Experimenten wird durch die LuminositĂ€t bestimmt. Die LuminositĂ€t ist das VerhĂ€ltnis der Zahl der Ereignisse wĂ€hrend einer bestimmten Zeiteinheit zum Wirkungsquerschnitt eines physikalischen Prozesses. Die Messung der LuminositĂ€t ist daher notwendig, um die Wirkungsquerschnitte interessanter Prozesse zu messen. Eine sichere und hochwertige Datennahmen benötigt stabile Strahlbedingungen, möglichst ohne Strahlverluste. Jedes Experiment hat seine Strahlverlustmonitore. Einer dieser Detektoren im CMS ist der BCM1F, welcher Diamantsensoren verwendet. BCM1F ist in der ersten LHC Laufzeit von 2009-2012 problemlos gelaufen und lieferte wertvolle Strahlverlust- und LuminositĂ€tsinformationen zum CMS- und LHC-Kontrollraum. Ende 2012 beendete der LHC seinen Betrieb fĂŒr das Upgrade auf 7TeV und der Reduzierung des Abstandes der Protonenpakete 25ns. Um diese neuen Anforderungen zu erfĂŒllen, wurde ein Upgrade der BCM1F Sensoren und Ausleseelektronik durchgefĂŒhrt. Auf die OberflĂ€che der Sensoren wurden zwei Metallelektroden, genannt Pads, aufgebracht, um die ZĂ€hlrate zu halbieren. Die Robustheit und Redundanz von BCM1F wurde gesteigert, indem die Anzahl der Sensoren von 8 auf 24 erhöht wurde. Insgesamt wurden 59 Sensoren elektrisch charakterisiert, was Messungen von Leckstrom, SignalstabilitĂ€t und Ladungssammlungseffizienz beinhaltet. QualitĂ€tskriterien fĂŒr die Auswahl von Sensoren wurden definiert. Ein Überblick dieser Messungen wird mit einer Zusammenfassung der Resultate in dieser Arbeit gegeben. ZusĂ€tzlich wird ein verbesserter VerstĂ€rker in 130nm CMOS Technologie und einer Anstiegszeit der Ausgangsspannung (proportional zur Eingangsspannung) von 7ns, statt der vorherigen 22ns, zur Signalauslese verwendet. Ein BCM1F Prototyp mit Zweikanalauslese und dem verbesserten VerstĂ€rker wurde am DESY-II Beschleuniger bei einem Elektronenstrahl von 5GeV Elektronen getestet. Resultate dieses Testes werden in dieser Arbeit gezeigt und mit Simulationen verglichen. Die Installation des neuen BCM1F Systems fand 2014 statt und 2015 startete BCM1F seine Messungen der LuminositĂ€t und der Rate von Teilchen des Strahlhintergrundes, der im Beschleuniger anfĂ€llt. Am Ende wird diese Arbeit Resultate der Messungen zeigen, sich dabei aber auf den maschinen-induzierten Hintergrund konzentrieren und dabei die sichere Funktionsweise von BCM1F demonstrieren

    Nicht-invasive Evaluation der hepatischen Manifestation bei Patienten mit Morbus Wilson mittels Transienter Elastographie, Acoustic Radiation Force Impulse (ARFI)-Elastographie und verschiedener laborbasierter Fibrose-Indices

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    Die vorliegende medizinische Dissertation beschĂ€ftigt sich mit der Evaluation nicht-invasiver Diagnostikverfahren zur Detektion einer Leberfibrose bei Patienten mit Morbus Wilson. Untersucht wurden die Transiente Elastographie (TE), die Acoustic Radiation Force Impulse (ARFI)-Elastographie sowie verschiedene laborbasierte Fibrose-Indices bezĂŒglich der Anwendbarkeit und ihres diagnostischen Nutzens. Der Morbus Wilson ist eine seltene hereditĂ€re Kupferspeicherkrankheit, die ĂŒber Kupferakkumulation im Leberparenchym zur Ausbildung einer Zirrhose fĂŒhren kann. Die Kenntnis des Leberfibrosegrades ist unabdingbar fĂŒr therapeutische Entscheidungen und prognostische EinschĂ€tzungen. DafĂŒr sind regelmĂ€ĂŸige Kontrollen der Leber im Krankheitsverlauf notwendig, wobei die Leberbiopsie den diagnostischen Goldstandard darstellt. Die InvasivitĂ€t sowie das Komplikationspotential limitieren jedoch deren wiederholte Anwendbarkeit. TE sowie ARFI bieten hierzu eine moderne Alternative, deren Nutzen anhand großer Studien bei Patienten mit verschiedenen chronischen Lebererkrankungen bereits aufgezeigt werden konnte. Die Verfahren beurteilen die Parenchymsteifigkeit als Surrogatparameter der Leberfibrose, wobei mit steigendem Fibrosegrad die Gewebesteifigkeit zunimmt. Die Grenzwerte zur Definition des Fibrosegrades sowie die Anwendbarkeit beider Verfahren variieren in AbhĂ€ngigkeit von der Grunderkrankung. Ziel dieser Studie war es, Grenzwerte und diagnostischen Nutzen der Elastographieverfahren bei M. Wilson zu definieren. Beide Verfahren können eine Leberbeteiligung des M. Wilson nachweisen und das Vorliegen einer Leberzirrhose detektieren. Die potentiell bessere diagnostische Treffsicherheit der TE wird durch EinschrĂ€nkungen in der Anwendbarkeit limitiert

    Confirmation of a galaxy cluster hidden behind the Galactic bulge using the VVV survey

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    Context. S uzaku and Chandra X-ray observations detected a new cluster of galaxies, Suzaku J1759−3450, at a redshift z = 0.13. It is located behind the Milky Way, and the high Galactic dust extinction renders it nearly invisible at optical wavelengths. Aims. We attempt here to confirm the galaxy cluster with near-infrared imaging observations and to characterize its central member galaxies. Methods. Images from the VVV survey were used to detect candidate member galaxies of Suzaku J1759−3450 within the central region of the cluster up to 350 kpc from the X-ray peak emission. Color–magnitude diagrams, color–color diagrams, and morphology criteria allowed us to select the galaxies among the numerous foreground sources. Results. Fifteen candidate cluster members were found very close to a modeled red-sequence at the redshift of the cluster. Five members are extremely bright, and one is possibly a cD galaxy. The asymmetry in the spatial distribution of the galaxies with respect to the X-ray peak emission is an indicator that this cluster is still suffering a virialization process. Conclusions. Our investigation of Suzaku J1759−3450 demonstrates the potential of the VVV survey to study the hidden population of galaxies in the zone of avoidance.Fil: Coldwell Lloveras, Georgina Vanesa. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, FĂ­sicas y Naturales. Departamento de GeofĂ­sica y AstronomĂ­a; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - San Juan; ArgentinaFil: Alonso Giraldes, Maria Sol. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, FĂ­sicas y Naturales. Departamento de GeofĂ­sica y AstronomĂ­a; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - San Juan; ArgentinaFil: Duplancic Videla, Maria Fernanda. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, FĂ­sicas y Naturales. Departamento de GeofĂ­sica y AstronomĂ­a; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - San Juan; ArgentinaFil: Hempel, Maren. Pontificia Universidad CatĂłlica de Chile; ChileFil: Ivanov, Valentin D.. Observatorio Europeo del Sur; ChileFil: Minniti, Dante. Observatorio Europeo del Sur; Chile. Specola Vaticana Osservatorio Astronomico Vaticano; Italia. Universidad AndrĂ©s Bello; Chil

    Complexity computation for compact 3-manifolds via crystallizations and Heegaard diagrams

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    The idea of computing Matveev complexity by using Heegaard decompositions has been recently developed by two different approaches: the first one for closed 3-manifolds via crystallization theory, yielding the notion of Gem-Matveev complexity; the other one for compact orientable 3-manifolds via generalized Heegaard diagrams, yielding the notion of modified Heegaard complexity. In this paper we extend to the non-orientable case the definition of modified Heegaard complexity and prove that for closed 3-manifolds Gem-Matveev complexity and modified Heegaard complexity coincide. Hence, they turn out to be useful different tools to compute the same upper bound for Matveev complexity.Comment: 12 pages; accepted for publication in Topology and Its Applications, volume containing Proceedings of Prague Toposym 201

    Computing Matveev's complexity via crystallization theory: the boundary case

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    The notion of Gem-Matveev complexity has been introduced within crystallization theory, as a combinatorial method to estimate Matveev's complexity of closed 3-manifolds; it yielded upper bounds for interesting classes of such manifolds. In this paper we extend the definition to the case of non-empty boundary and prove that for each compact irreducible and boundary-irreducible 3-manifold it coincides with the modified Heegaard complexity introduced by Cattabriga, Mulazzani and Vesnin. Moreover, via Gem-Matveev complexity, we obtain an estimation of Matveev's complexity for all Seifert 3-manifolds with base D2\mathbb D^2 and two exceptional fibers and, therefore, for all torus knot complements.Comment: 27 pages, 14 figure

    Risk factors and outcomes of unrecognised endobronchial intubation in major trauma patients

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    Background Emergency tracheal intubation during major trauma resuscitation may be associated with unrecognised endobronchial intubation. The risk factors and outcomes associated with this issue have not previously been fully defined. Methods We retrospectively analysed adult patients admitted directly from the scene to the ED of a single level 1 trauma centre, who received either prehospital or ED tracheal intubation prior to initial whole-body CT from January 2008 to December 2019. Our objectives were to describe tube-to- carina distances (TCDs) via CT and to assess the risk factors and outcomes (mortality, length of intensive care unit stay and mechanical ventilation) of patients with endobronchial intubation (TCD <0 cm) using a multivariable model. Results We included 616 patients and discovered 26 (4.2%) cases of endobronchial intubation identified on CT. Factors associated with an increased risk of endobronchial intubations were short body height (OR per 1 cm increase 0.89; 95% CI 0.84 to 0.94; p≀0.001), a high body mass index (OR 1.14; 95% CI 1.04 to 1.25; p=0.005) and ED intubation (OR 3.62; 95% CI 1.39 to 8.90; p=0.006). Eight of 26 cases underwent tube thoracostomy, four of whom had no evidence of underlying chest injury on CT. There was no statistically significant difference in mortality or length of stay although the absolute number of endobronchial intubations was small. Conclusions Short body height and high body mass index were associated with endobronchial intubation. Before considering tube thoracostomy in intubated major trauma patients suspected of pneumothorax, the possibility of unrecognised endobronchial intubation should be considered

    The Importance of the Microbiome in Critically Ill Patients: Role of Nutrition

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    Critically ill patients have an alteration in the microbiome in which it becomes a disease-promoting pathobiome. It is characterized by lower bacterial diversity, loss of commensal phyla, like Firmicutes and Bacteroidetes, and a domination of pathogens belonging to the Proteobacteria phylum. Although these alterations are multicausal, many of the treatments administered to these patients, like antibiotics, play a significant role. Critically ill patients also have a hyperpermeable gut barrier and dysregulation of the inflammatory response that favor the development of the pathobiome, translocation of pathogens, and facilitate the emergence of sepsis. In order to restore the homeostasis of the microbiome, several nutritional strategies have been evaluated with the aim to improve the management of critically ill patients. Importantly, enteral nutrition has proven to be more efficient in promoting the homeostasis of the gut microbiome compared to parenteral nutrition. Several nutritional therapies, including prebiotics, probiotics, synbiotics, and fecal microbiota transplantation, are currently being used, showing variable results, possibly due to the unevenness of clinical trial conditions and the fact that the beneficial effects of probiotics are specific to particular species or even strains. Thus, it is of great importance to better understand the mechanisms by which nutrition and supplement therapies can heal the microbiome in critically ill patients in order to finally implement them in clinical practice with optimal safety and efficacy.This work was supported by Junta de AndalucĂ­a (Spain) (research grants CTS 164 and PI-0206-2016) and cofinanced by the Fondo Europeo de Desarollo Regional (FEDER) from the European Union. RM has a RĂ­o Hortega contract (CM17/00237) and PA has a NicolĂĄs Monardes contract (C-0013-2018)

    Fast Beam Condition Monitor for CMS: performance and upgrade

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    The CMS beam and radiation monitoring subsystem BCM1F (Fast Beam Condition Monitor) consists of 8 individual diamond sensors situated around the beam pipe within the pixel detector volume, for the purpose of fast bunch-by-bunch monitoring of beam background and collision products. In addition, effort is ongoing to use BCM1F as an online luminosity monitor. BCM1F will be running whenever there is beam in LHC, and its data acquisition is independent from the data acquisition of the CMS detector, hence it delivers luminosity even when CMS is not taking data. A report is given on the performance of BCM1F during LHC run I, including results of the van der Meer scan and on-line luminosity monitoring done in 2012. In order to match the requirements due to higher luminosity and 25 ns bunch spacing, several changes to the system must be implemented during the upcoming shutdown, including upgraded electronics and precise gain monitoring. First results from Run II preparation are shown.Comment: 10 pages, 8 figures. To be published in NIM A as proceedings for the 9th Hiroshima Symposium on Semiconductor Tracking Detectors (2013

    Soluplus¼ as an effective absorption enhancer of poorly soluble drugs in vitro and in vivo

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    a b s t r a c t As many new active pharmaceutical ingredients are poorly water soluble, solubility enhancers are one possibility to overcome the hurdles of drug dissolution and absorption in oral drug delivery. In the present work a novel solubility enhancing excipient (Soluplus Ò ) was tested for its capability to improve intestinal drug absorption. BCS class II compounds danazol, fenofibrate and itraconazole were tested both in vivo in beagle dogs and in vitro in transport experiments across Caco-2 cell monolayers. Each drug was applied as pure crystalline substance, in a physical mixture with Soluplus Ò , and as solid solution of the drug in the excipient. In the animal studies a many fold increase in plasma AUC was observed for the solid solutions of drug in Soluplus Ò compared to the respective pure drug. An effect of Soluplus Ò in a physical mixture with the drug could be detected for fenofibrate. In vitro transport studies confirm the strong effect of Soluplus Ò on the absorption behavior of the three tested drugs. Furthermore, the increase of drug flux across Caco-2 monolayer is correlating to the increase in plasma AUC and C max in vivo. For these poorly soluble substances Soluplus Ò has a strong potential to improve oral bioavailability. The applicability of Caco-2 monolayers as tool for predicting the in vivo transport behavior of the model drugs in combination with a solubility enhancing excipient was shown. Also the improvement of a solid dispersion compared to physical mixtures of the drugs and the excipient was correctly reflected by Caco-2 experiments. In the case of fenofibrate the possible improvement by a physical mixture was demonstrated, underscoring the value of the used tool as alternative to animal studies
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