Techn. Universiẗat, Diss., 2006--Darmstadt.

Introdução: A adoção de um Sistema de Arquivamento e Distribuição de Imagens (PACS, do inglês Picture Archiving and Communication System) é condição fundamental para a estruturação de um ambiente radiológico sem filme. Um PACS é composto basicamente por equipamentos e sistemas informatizados interconectados em rede, direcionados à aquisição, armazenamento (ou arquivamento), recuperação e apresentação de imagens médicas aos especialistas responsáveis por avaliá-las e laudá-las. A computação em nuvem vem ao encontro dos PACS e surge como uma maneira de simplificar o compartilhamento de imagens entre organizações de saúde e promover a virtualização de espaços físicos e para garantir o seu funcionamento ininterrupto.Objetivo: Este estudo teve como objetivo implementar um PACS simplificado em ambiente cloud computing privado, com foco nas funcionalidades de arquivamento e disponibilização de imagens médicas e avaliar questões de segurança e performance. Metodologia: As imagens que compuseram o PACS do ambiente cloud foram obtidas através do PACS físico atualmente em uso no Centro de Ciência das Imagens e Física Médica do Hospital das Clinicas da Faculdade de Medicina de Ribeirão Preto - CCIFM/HCFMRP. Para os procedimentos da avaliação de segurança foram construídos cenários que possibilitavam a: 1) anominização de dados de identificação dos pacientes através de criptografia computacional em base de dados utilizando o algoritmo de criptografia Advanced Encryption Standard - AES, 2) transferência de imagens médicas seguras através de conexão com a Internet utilizando Virtual Network Private - VPN sobre o protocolo Internet Protocol Security - IPSec (VPN/IPSec) e 3) envio seguro através de tunelamento baseado em Secure Shell - SSH. Resultados: Foi identificada uma queda de performance no envio de informações para a nuvem quando submetidos aos níveis de segurança propostos, sugerindo a relação entre aumento de segurança e perda de performance, apontando para a necessidade de estudos de desempenho quando da condução de projetos envolvam a adoção em ambientes clínicos de solução PACS baseada em cloud computing. / Introduction: the adoption of a PCAS (Picture Archiving and Communication System) is fundamental for the structuring of a radiological environment without film. A PACS comprises, essentially, hardware and information systems interconnected in a network, oriented towards acquisition, storage (or archiving), retrieving and presentation of medical images to specialists entrusted with analyzing and assessing them. Cloud computing comes to support of PCAS, simplifying medical imaging sharing between health care organizations and promoting the virtualization of physical infrastructure to assure uninterrupted availability of the PCAS. Goal: This study aimed to implement a simplified PCAS in a private cloud computing environment, and subsequently to evaluate its security and performance. Methodology: The images that formed the new PCAS were obtained from the exiting PCAS of Centro de Ciência das Imagens e Física Médica of Hospital das Clinicas da Faculdade de Medicina de Ribeirão Preto - CCIFM/HCFMRP. To evaluate its security, scenarios were built within the following framework: 1) patient identification data anonymization through computational database cryptography, using the AES (Advanced Encription Standards) algorithm ; 2) transfer of encrypted medical images on the Internet using VPN (Virtual Private Network) over IPSec (Internet Protocol Security); and 3) safe traffic through Secure Shell (SSH) tunneling. Results: There was a performance drop on traffic of information to the cloud under the proposed security levels that suggests a relationship between increase in security and loss of performance, pointing to the need for performance studies when the project involving driving adoption in clinical environments PACS solution based on cloud computing.

Monte-Carlo estimates of the subthreshold Phi meson production are performed for the reaction 12C + 12C at 2 AGeV assuming the Phi's to be emitted isotropically and distributed thermally in the center-of-mass system of the colliding nuclei. Different scenarios involving the detector installations FOPI and HADES at SIS/GSI are considered to determine the expected yields of Phi(1020) mesons identified via the K+K- and e+e- decay channels.

Introdução: A adoção de um Sistema de Arquivamento e Distribuição de Imagens (PACS, do inglês Picture Archiving and Communication System) é condição fundamental para a estruturação de um ambiente radiológico sem filme. Um PACS é composto basicamente por equipamentos e sistemas informatizados interconectados em rede, direcionados à aquisição, armazenamento (ou arquivamento), recuperação e apresentação de imagens médicas aos especialistas responsáveis por avaliá-las e laudá-las. A computação em nuvem vem ao encontro dos PACS e surge como uma maneira de simplificar o compartilhamento de imagens entre organizações de saúde e promover a virtualização de espaços físicos e para garantir o seu funcionamento ininterrupto.Objetivo: Este estudo teve como objetivo implementar um PACS simplificado em ambiente cloud computing privado, com foco nas funcionalidades de arquivamento e disponibilização de imagens médicas e avaliar questões de segurança e performance. Metodologia: As imagens que compuseram o PACS do ambiente cloud foram obtidas através do PACS físico atualmente em uso no Centro de Ciência das Imagens e Física Médica do Hospital das Clinicas da Faculdade de Medicina de Ribeirão Preto - CCIFM/HCFMRP. Para os procedimentos da avaliação de segurança foram construídos cenários que possibilitavam a: 1) anominização de dados de identificação dos pacientes através de criptografia computacional em base de dados utilizando o algoritmo de criptografia Advanced Encryption Standard - AES, 2) transferência de imagens médicas seguras através de conexão com a Internet utilizando Virtual Network Private - VPN sobre o protocolo Internet Protocol Security - IPSec (VPN/IPSec) e 3) envio seguro através de tunelamento baseado em Secure Shell - SSH. Resultados: Foi identificada uma queda de performance no envio de informações para a nuvem quando submetidos aos níveis de segurança propostos, sugerindo a relação entre aumento de segurança e perda de performance, apontando para a necessidade de estudos de desempenho quando da condução de projetos envolvam a adoção em ambientes clínicos de solução PACS baseada em cloud computing. / Introduction: the adoption of a PCAS (Picture Archiving and Communication System) is fundamental for the structuring of a radiological environment without film. A PACS comprises, essentially, hardware and information systems interconnected in a network, oriented towards acquisition, storage (or archiving), retrieving and presentation of medical images to specialists entrusted with analyzing and assessing them. Cloud computing comes to support of PCAS, simplifying medical imaging sharing between health care organizations and promoting the virtualization of physical infrastructure to assure uninterrupted availability of the PCAS. Goal: This study aimed to implement a simplified PCAS in a private cloud computing environment, and subsequently to evaluate its security and performance. Methodology: The images that formed the new PCAS were obtained from the exiting PCAS of Centro de Ciência das Imagens e Física Médica of Hospital das Clinicas da Faculdade de Medicina de Ribeirão Preto - CCIFM/HCFMRP. To evaluate its security, scenarios were built within the following framework: 1) patient identification data anonymization through computational database cryptography, using the AES (Advanced Encription Standards) algorithm ; 2) transfer of encrypted medical images on the Internet using VPN (Virtual Private Network) over IPSec (Internet Protocol Security); and 3) safe traffic through Secure Shell (SSH) tunneling. Results: There was a performance drop on traffic of information to the cloud under the proposed security levels that suggests a relationship between increase in security and loss of performance, pointing to the need for performance studies when the project involving driving adoption in clinical environments PACS solution based on cloud computing.

Monte-Carlo estimates of the subthreshold Phi meson production are performed for the reaction 12C + 12C at 2 AGeV assuming the Phi's to be emitted isotropically and distributed thermally in the center-of-mass system of the colliding nuclei. Different scenarios involving the detector installations FOPI and HADES at SIS/GSI are considered to determine the expected yields of Phi(1020) mesons identified via the K+K- and e+e- decay channels.

Rare-earth nickel borocarbids RNi2B2C are particularly suitable for investigations on one of the most interesting problems in modern solid-state physics: these compounds display competition and coexistence of superconductivity and magnetism. Depending on the R3+ ion, the transition temperatures are in an experimentally easy accessible range of 1 K to 25 K. This thesis presents experimental studies on the interplay of both ordering phenomena. Neutron diffraction is used to determine the magnetic order and the resulting changes of the crystal structure. Experiments are performed on polycrystalline and single crystal samples in dependence on temperature and external magnetic fields. The Ni-B stoichiometry of the tetragonal RNi2B2C compounds is systematically varied and the magnetic R3+ ions are partially substituted by other magnetic or nonmagnetic R?3+ ions. The experimental results are compared with macroscopic magnetic and electrical properties. For HoNi2B2C three different magnetic structures are found in a narrow temperature range. While for two magnetic structures the Ho3+ moments are modulated along the c axis, a third magnetic structure with a modulation in a direction is observed. Both, partial substitution of Ho3+ ions and variation of the Ni-B stoichiometry, strongly modify the formation of these different types of magnetic order. The comparison with the concomitant changes of the superconducting properties yields the following scenario for HoNi2B2C-based compounds: superconductivity coexists with both magnetic structures with modulations in c direction. However, the onset of magnetic order weakens the superconductivity. For the magnetic structure with modulation along the a axis, components of the magnetic moments arise in c direction. The resulting local magnetic fields on Ni sites yield a strong suppression of the superconductivity. The observed competition between superconductivity and the magnetic structure with modulation along the a axis strongly suggests that the modification of the electronic structure due to the superconducting state influences the magnetic ordering. As a further impact of the magnetism in RNi2B2C compounds with R = Ho, Dy, Tb and Er changes of the crystal structure are investigated. Using high-resolution neutron diffraction, tetragonal-to-orthorhombic lattice distortions are found. They are induced by those magnetic structures with either parallel or anti-parallel alignement of R3+ magnetic moments. The direction of the lattice distortions, the dependence of their size on the square of the effective ordered magnetic moment and on the type of the R3+ ions indicate that the magneto-elastic interactions are determined by crystal-field effects. This fact also facilitates the elucidation of the magnetic phase diagrams by neutron diffraction experiments in external magnetic fields. For a given phase, absence or presence of magneto-elastic lattice distortions restrict the set of possible magnetic structures. For HoNi2B2C the magnetic phases reported in literature are confirmed. The experimental results for DyNi2B2C are interpreted using a simple model to determine the magnetic structures. Based on mean field calculations, the differences in the magnetic structures for increasing and decreasing magnetic fields can be understood as very strong hysteresis effects in connection with first-order phase transitions. / Seltenerd-Nickel-Borkarbid-Verbindungen RNi2B2C sind bestens zur Untersuchung eines der interessantesten Probleme der modernen Festkörperphysik geeignet: Diese Substanzen weisen Konkurrenz und Koexistenz von Supraleitung und Magnetismus auf, wobei die vom R3+-Ion abhängigen Übergangstemperaturen in einem experimentell gut zugänglichen Bereich von 1 K bis 25 K liegen. Die vorliegende Dissertation stellt experimentelle Arbeiten zum Wechselspiel der beiden Ordnungsphänomene vor. Für poly- und einkristalline Proben werden die magnetischen Ordnungen und resultierende Veränderungen der Kristallstruktur mittels Neutronendiffraktion in Abhängigkeit von der Temperatur und vom äußeren Magnetfeld bestimmt und mit den makroskopischen magnetischen und elektrischen Eigenschaften verglichen. Hierbei werden die tetragonalen RNi2B2C-Verbindungen gezielt in ihrer Ni-B-Stöchiometrie variiert sowie die magnetischen R3+-Ionen partiell durch andere magnetische als auch unmagnetische R?3+-Ionen substituiert. Für HoNi2B2C werden in einem engen Temperaturbereich drei verschiedene magnetische Strukturen nachgewiesen. Während in zwei magnetischen Ordnungen die Ho3+-Momente entlang der c-Achse moduliert sind, wird für die dritte magnetische Ordnung eine Modulation in a-Richtung beobachtet. Sowohl durch die partielle Substitution der Ho3+-Ionen als auch durch die Ni-B-Stöchiometrievariation wird die Ausprägung der magnetischen Strukturen stark modifiziert. Der Vergleich mit den ebenfalls veränderten supraleitenden Eigenschaften ergibt das folgende Bild für die HoNi2B2C-Verbindungen: Die Supraleitung koexistiert mit den beiden c-Achsen-modulierten magnetischen Strukturen, das Einsetzen der magnetischen Ordnung führt jedoch zu einer Schwächung der Supraleitung. Die a-Achsen-modulierte magnetische Struktur weist Momentkomponenten in c-Richtung auf, die auf Grund der resultierenden lokalen Magnetfelder an den Ni-Plätzen eine starke Unterdrückung der Supraleitung bewirken. Die beobachtete Konkurrenz zwischen der Supraleitung und der a-Achsen-modulierten magnetischen Struktur gibt andererseits einen starken Hinweis darauf, daß die Modifizierung der elektronischen Struktur im supraleitenden Zustand auf das magnetische System rückwirkt. Als weitere Auswirkung des Magnetismus kommt es in RNi2B2C-Verbindungen mit R = Ho, Dy, Tb und Er zu Veränderungen der Kristallstruktur. Mittels hochauflösender Neutronendiffraktion werden magnetisch induzierte, tetragonal-zu-orthorhombische Gitterverzerrungen für diejenigen magnetischen Ordnungen nachgewiesen, bei denen die magnetischen Momente der R3+-Ionen parallel bzw. antiparallel ausgerichtet sind. Die Richtung der Gitterverzerrung, die Abhängigkeit ihrer Größe vom Quadrat des geordneten magnetischen Momentes als auch von der Art der R3+-Ionen deuten darauf hin, daß die magneto-elastischen Wechselwirkungen durch Kristallfeldeffekte bestimmt werden. Diese Einsicht unterstützt auch die Aufklärung der magnetischen Phasendiagramme mittels magnetfeldabhängiger Neutronenbeugungsexperimente. Für eine magnetische Phase schränkt das Auftreten bzw. Fehlen der magneto-elastischen Effekte die Vielfalt der möglichen magnetischen Strukturen ein. Die aus der Literatur bekannten magnetischen Phasen von HoNi2B2C werden bestätigt. Für DyNi2B2C werden die experimentellen Ergebnisse unter Nutzung eines einfachen Modelles interpretiert und die magnetischen Strukturen bestimmt. Anhand von Molekularfeldrechnungen können die Unterschiede in den magnetischen Strukturen für ansteigendes und für abnehmendes Magnetfeld als sehr starke Hystereseeffekte in Zusammenhang mit Phasenübergängen erster Ordnung gedeutet werden.

Objectives: This study identifies modern information technologies that can improve the clinical practice of Picture Archiving and Communication Systems (PACS) and determines the approaches that are needed to improve the functionality of current PACS to provide better next generation PACS and to improve the future of radiology practices and workflow with future PACS generations. Method: A parallel mixed method approach was adopted including qualitative method (semi-structured interviews), quantitative method (questionnaire survey) and observation of online discussion groups on PACS. Five databases were searched to find salient literature, including Science Direct, Springer Link, Scopus, CINAHL Plus and Google Scholar. Six radiologists were interviewed and questionnaires were collected from 120 radiologists. Four online discussion groups related to PACS were monitored via LinkedIn. The data were analysed thematically using the thematic analysis method. Finally, a focus group was held with a separate group of radiologists to validate the findings. Results: Eight themes emerged from the thematic analysis of the data: (1) limitations of traditional PACS; (2) user needs and requirements that can increase PACS functionality; (3) Web based solutions of PACS; (4) PACS on mobile phones; (5) Vendor Neutral Archive (VNA); (6) full integration of voice recognition in PACS; (7) backup solutions for the system and (8) continuous training for PACS users. Discussion: With the development of healthcare information and communication technology (ICT) and with the increased demands of the radiologists to expand PACS usability, traditional PACS must be updated to follow the changes. Modern technologies can provide better solutions to enhance the functionality of current PACS. The next generation of PACS can fulfil the future requirements of users. This study considers the issues between the needs and requirements of the users of a PACS system in the future and the developing solutions in ICT and the PACS industry. Moreover, highly developed PACS systems with advanced features will have a direct impact in changing and improving radiology workflow. Accordingly, a model has been developed that proposes new features for the next generation PACS system, which may be applied to the next generation radiology practice. The model was validated with the focus group and, by using a separate group of radiologists in another country, was determined to be generalisable. Conclusion: It is widely recognised that traditional PACS must be updated to adopt recent advances in ICT. This research has identified themes that, when incorporated, will enhance the functionality of PACS and radiology workflow and provide better quality clinical practice. The findings from this empirical research can be used: as recommendations to vendors; for technology development; and by medical institutes to consider aspects when undertaking implementation of PACS and training future radiologists. Keywords: 'Picture archiving and communication system’, PACS, Future trends, next generation, Organisational efficiency, Productivity, Clinical practice, Ubiquitous.

Rare-earth nickel borocarbids RNi2B2C are particularly suitable for investigations on one of the most interesting problems in modern solid-state physics: these compounds display competition and coexistence of superconductivity and magnetism. Depending on the R3+ ion, the transition temperatures are in an experimentally easy accessible range of 1 K to 25 K. This thesis presents experimental studies on the interplay of both ordering phenomena. Neutron diffraction is used to determine the magnetic order and the resulting changes of the crystal structure. Experiments are performed on polycrystalline and single crystal samples in dependence on temperature and external magnetic fields. The Ni-B stoichiometry of the tetragonal RNi2B2C compounds is systematically varied and the magnetic R3+ ions are partially substituted by other magnetic or nonmagnetic R?3+ ions. The experimental results are compared with macroscopic magnetic and electrical properties. For HoNi2B2C three different magnetic structures are found in a narrow temperature range. While for two magnetic structures the Ho3+ moments are modulated along the c axis, a third magnetic structure with a modulation in a direction is observed. Both, partial substitution of Ho3+ ions and variation of the Ni-B stoichiometry, strongly modify the formation of these different types of magnetic order. The comparison with the concomitant changes of the superconducting properties yields the following scenario for HoNi2B2C-based compounds: superconductivity coexists with both magnetic structures with modulations in c direction. However, the onset of magnetic order weakens the superconductivity. For the magnetic structure with modulation along the a axis, components of the magnetic moments arise in c direction. The resulting local magnetic fields on Ni sites yield a strong suppression of the superconductivity. The observed competition between superconductivity and the magnetic structure with modulation along the a axis strongly suggests that the modification of the electronic structure due to the superconducting state influences the magnetic ordering. As a further impact of the magnetism in RNi2B2C compounds with R = Ho, Dy, Tb and Er changes of the crystal structure are investigated. Using high-resolution neutron diffraction, tetragonal-to-orthorhombic lattice distortions are found. They are induced by those magnetic structures with either parallel or anti-parallel alignement of R3+ magnetic moments. The direction of the lattice distortions, the dependence of their size on the square of the effective ordered magnetic moment and on the type of the R3+ ions indicate that the magneto-elastic interactions are determined by crystal-field effects. This fact also facilitates the elucidation of the magnetic phase diagrams by neutron diffraction experiments in external magnetic fields. For a given phase, absence or presence of magneto-elastic lattice distortions restrict the set of possible magnetic structures. For HoNi2B2C the magnetic phases reported in literature are confirmed. The experimental results for DyNi2B2C are interpreted using a simple model to determine the magnetic structures. Based on mean field calculations, the differences in the magnetic structures for increasing and decreasing magnetic fields can be understood as very strong hysteresis effects in connection with first-order phase transitions. / Seltenerd-Nickel-Borkarbid-Verbindungen RNi2B2C sind bestens zur Untersuchung eines der interessantesten Probleme der modernen Festkörperphysik geeignet: Diese Substanzen weisen Konkurrenz und Koexistenz von Supraleitung und Magnetismus auf, wobei die vom R3+-Ion abhängigen Übergangstemperaturen in einem experimentell gut zugänglichen Bereich von 1 K bis 25 K liegen. Die vorliegende Dissertation stellt experimentelle Arbeiten zum Wechselspiel der beiden Ordnungsphänomene vor. Für poly- und einkristalline Proben werden die magnetischen Ordnungen und resultierende Veränderungen der Kristallstruktur mittels Neutronendiffraktion in Abhängigkeit von der Temperatur und vom äußeren Magnetfeld bestimmt und mit den makroskopischen magnetischen und elektrischen Eigenschaften verglichen. Hierbei werden die tetragonalen RNi2B2C-Verbindungen gezielt in ihrer Ni-B-Stöchiometrie variiert sowie die magnetischen R3+-Ionen partiell durch andere magnetische als auch unmagnetische R?3+-Ionen substituiert. Für HoNi2B2C werden in einem engen Temperaturbereich drei verschiedene magnetische Strukturen nachgewiesen. Während in zwei magnetischen Ordnungen die Ho3+-Momente entlang der c-Achse moduliert sind, wird für die dritte magnetische Ordnung eine Modulation in a-Richtung beobachtet. Sowohl durch die partielle Substitution der Ho3+-Ionen als auch durch die Ni-B-Stöchiometrievariation wird die Ausprägung der magnetischen Strukturen stark modifiziert. Der Vergleich mit den ebenfalls veränderten supraleitenden Eigenschaften ergibt das folgende Bild für die HoNi2B2C-Verbindungen: Die Supraleitung koexistiert mit den beiden c-Achsen-modulierten magnetischen Strukturen, das Einsetzen der magnetischen Ordnung führt jedoch zu einer Schwächung der Supraleitung. Die a-Achsen-modulierte magnetische Struktur weist Momentkomponenten in c-Richtung auf, die auf Grund der resultierenden lokalen Magnetfelder an den Ni-Plätzen eine starke Unterdrückung der Supraleitung bewirken. Die beobachtete Konkurrenz zwischen der Supraleitung und der a-Achsen-modulierten magnetischen Struktur gibt andererseits einen starken Hinweis darauf, daß die Modifizierung der elektronischen Struktur im supraleitenden Zustand auf das magnetische System rückwirkt. Als weitere Auswirkung des Magnetismus kommt es in RNi2B2C-Verbindungen mit R = Ho, Dy, Tb und Er zu Veränderungen der Kristallstruktur. Mittels hochauflösender Neutronendiffraktion werden magnetisch induzierte, tetragonal-zu-orthorhombische Gitterverzerrungen für diejenigen magnetischen Ordnungen nachgewiesen, bei denen die magnetischen Momente der R3+-Ionen parallel bzw. antiparallel ausgerichtet sind. Die Richtung der Gitterverzerrung, die Abhängigkeit ihrer Größe vom Quadrat des geordneten magnetischen Momentes als auch von der Art der R3+-Ionen deuten darauf hin, daß die magneto-elastischen Wechselwirkungen durch Kristallfeldeffekte bestimmt werden. Diese Einsicht unterstützt auch die Aufklärung der magnetischen Phasendiagramme mittels magnetfeldabhängiger Neutronenbeugungsexperimente. Für eine magnetische Phase schränkt das Auftreten bzw. Fehlen der magneto-elastischen Effekte die Vielfalt der möglichen magnetischen Strukturen ein. Die aus der Literatur bekannten magnetischen Phasen von HoNi2B2C werden bestätigt. Für DyNi2B2C werden die experimentellen Ergebnisse unter Nutzung eines einfachen Modelles interpretiert und die magnetischen Strukturen bestimmt. Anhand von Molekularfeldrechnungen können die Unterschiede in den magnetischen Strukturen für ansteigendes und für abnehmendes Magnetfeld als sehr starke Hystereseeffekte in Zusammenhang mit Phasenübergängen erster Ordnung gedeutet werden.

The explosion of super PAC activity in presidential primaries since the 2012 election cycle prompts an examination of these organizations’ behavior and its effects on other types of committees. Specifically, this study investigates how fundraising and spending efforts by candidate-specific super PACs, or single-candidate super PACs, benefit their supported candidate’s principal campaign committee. Integrating data from the Federal Election Commission (FEC), Federal Communications Commission (FCC), and various qualitative sources, this study explores how candidate-specific super PACs are progressively exploiting their unique legal structure to fundraise for themselves and their candidate’s authorized committee. The probing reveals that candidate-specific super PACs steer contributions toward campaign committees through a process where soft money is transformed into hard dollars for the campaign to spend. Ordinary least squares and probit regression analysis are also used to determine whether the financial strength of candidate-specific super PACs relative to their candidate’s authorized committee influences the number and types of basic campaign activities the super PAC undertakes. The results indicate that the more a super PAC spends compared to its linked campaign, the more it will engage in more traditional campaign activities and have a greater probability of shouldering particular persuasion and get-out-the-vote (GOTV) efforts. The study’s synthesized findings suggest that the financial activities of candidate-specific super PACs in a presidential nomination contest significantly and increasingly facilitate the operations of presidential hopefuls’ campaigns.

Provést ekonomickou analýzu způsobu získávání a uchování pacientských dat ?moderními? metodami (IS +PACS) v porovnání se ?staršími? (fotografie, rentgeny, papír). Zhodnotit přínos zavedení moderních metod.