160 research outputs found

    Entwicklung eines Screening-Fragebogens fĂĽr die Erfassung des affektiv- behavioralen Status bei Patient:innen mit Morbus Parkinson

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    Die Tiefe Hirnstimulation (THS) ist ein anerkanntes Verfahren für die Therapie des fortgeschrittenen idiopathischen Parkinson-Syndroms. Klinisch relevante psychiatrische Komorbiditäten, wie Depression, Angst, Apathie, Manie und Impulskontrollstörungen haben einen großen Einfluss auf das Outcome der THS und stellen relative Kontraindikationen dar. Die THS kann sich jedoch auch positiv auf psychiatrische Symptome, insbesondere auf Angst und Impulskontrollstörungen auswirken. Eine sorgfältige präoperative Evaluation psychiatrischer Komorbiditäten ist sowohl für die Überprüfung der Kontraindikationen als auch der Indikationen essenziell. Das Ziel dieser Dissertation war die Entwicklung einer reduzierten Itembatterie als Grundlage für einen Screening-Fragebogen zur Optimierung der Erfassung des affektiv-behavioralen Status bei Parkinsonpatient:innen im Rahmen der Indikationsprüfung für eine THS. Als Basis für diese Itembatterie dienten die Daten von fünf etablierten Selbstbeurteilungsfragebögen (Beck-Depressions-Inventar-II, Hospital Anxiety and Depression Scale, Apathie- Evaluationsskala, Manie Selbstbeurteilungsskala, Questionnaire for Impulsive-Compulsive Disorders in Parkinson’s Disease-Rating Scale), die im Rahmen des Klinikstandards an der Uniklinik Köln in der Diagnostik psychischer Komorbiditäten bei Parkinsonpatient:innen seit einigen Jahren verwendet werden. Für die Entwicklung des reduzierten Itempools wurden die im Rahmen der Indikationsprüfung erhobenen Daten von 297 Parkinsonpatient:innen retrospektiv analysiert. In einem zweistufigen Prozess, bestehend aus einer statistischen Itemreduktion und einem Expertenrating wurden aus den fünf bestehenden Fragebögen die für Parkinsonpatient:innen relevanten Items herausgearbeitet. Die finale Auswahl aus den initial 129 Items ergab 38 Items, wobei acht Items Depression erfassen, fünf Items Angst, acht Items Apathie, zehn Items Manie, sechs Items Impulskontrollstörungen und ein Item Halluzinationen. Cutoff-Werte mit der jeweiligen Area under the curve, Sensitivität und Spezifität wurden für die einzelnen Subskalen ermittelt. Die Itemauswahl wurde anhand mehrerer statistischer Methoden (exploratorische und konfirmatorische Faktorenanalyse, Cronbach’s alpha, Korrelationen zwischen der Kurz- und Langversion und zwischen den Subskalen) analysiert. Die Ergebnisse zeigen, dass die reduzierte Itembatterie eine reliable, valide und effiziente Alternative zu den originalen Fragebögen für die Erfassung des affektiv-behavioralen Status bei Parkinsonpatient:innen darstellt

    Archäologie am Fuße des Pamirgebirges – Mit Magnetometer und Kappameter im Süden Tadschikistans

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    Ergebnisse geophysikalischer Prospektion in Tadschikista

    Free energy and molecular dynamics calculations for the cubic-tetragonal phase transition in zirconia

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    The high-temperature cubic-tetragonal phase transition of pure stoichiometric zirconia is studied by molecular dynamics (MD) simulations and within the framework of the Landau theory of phase transformations. The interatomic forces are calculated using an empirical, self-consistent, orthogonal tight-binding (SC-TB) model, which includes atomic polarizabilities up to the quadrupolar level. A first set of standard MD calculations shows that, on increasing temperature, one particular vibrational frequency softens. The temperature evolution of the free energy surfaces around the phase transition is then studied with a second set of calculations. These combine the thermodynamic integration technique with constrained MD simulations. The results seem to support the thesis of a second-order phase transition but with unusual, very anharmonic behaviour above the transition temperature

    Relative energetics and structural properties of zirconia using a self-consistent tight-binding model

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    We describe an empirical, self-consistent, orthogonal tight-binding model for zirconia, which allows for the polarizability of the anions at dipole and quadrupole levels and for crystal field splitting of the cation d orbitals. This is achieved by mixing the orbitals of different symmetry on a site with coupling coefficients driven by the Coulomb potentials up to octapole level. The additional forces on atoms due to the self-consistency and polarizabilities are exactly obtained by straightforward electrostatics, by analogy with the Hellmann-Feynman theorem as applied in first-principles calculations. The model correctly orders the zero temperature energies of all zirconia polymorphs. The Zr-O matrix elements of the Hamiltonian, which measure covalency, make a greater contribution than the polarizability to the energy differences between phases. Results for elastic constants of the cubic and tetragonal phases and phonon frequencies of the cubic phase are also presented and compared with some experimental data and first-principles calculations. We suggest that the model will be useful for studying finite temperature effects by means of molecular dynamics.Comment: to be published in Physical Review B (1 march 2000

    The measurement of stress and phase fraction distributions in pre and post-transition Zircaloy oxides using nano-beam synchrotron X-ray diffraction

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    Zircaloy-4 oxide stress profiles and tetragonal:monoclinic oxide phase fraction distributions were studied using nano-beam transmission X-ray diffraction. Continuous stress relief and phase transformation during the first cycle of oxide growth was observed. The in-plane monoclinic stress was shown to relax strongly up to each transition, whereas in-plane tetragonal stress-relief (near the metal-oxide interface) was only observed post transition. The research demonstrates that plasticity in the metal and the development of a band of in-plane cracking both relax the monoclinic in-plane stress.The observations are consistent with a model of transition in which in-plane cracking becomes interlinked prior to transition. These cracks, combined with the development of cracks with a through-thickness component (driven primarily by plasticity in the metal) and/or a porous network of fine cracks (associated with phase transformation), form a percolation path through the oxide layer. The oxidising species can then percolate from the oxide surface to the metal/oxide interface, at which stage transition then ensues

    Shackles for Bees? The ECJ's Judgment on GMO-Contaminated Honey

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    Jach-Su-Tal, Tadschikistan

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    The field campaigns in the Jach-Su valley (South Tajikistan) in 2012 and 2013 shed new light on the settlement history of the end of the 3rd and 2nd millennium BC, on the beginning of the Bronze Age occupation and especially on the transition to the Iron Age. The excavation in the necropoles of Gelot made it possible to reveal a burial complex contemporary with or earlier than the Bactria-Margiana Archaeological Complex. During a survey of the northern Jach-Su valley in 2010, a Bronze Age settlement was discovered on a loess terrace in Saridjar, 20 km to the north-east of Gelot. Excavations in 2012 and in 2013 prove that we are dealing with a 200 Ă— 200 m large settlement with at least three building phases. Excavations on the site of Karimberdy were reopened in 2012 and 2013. Here, pits and pit houses were found which belong to the Early Iron Age

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