568 research outputs found
Parameter analysis of the Glottal Area Waveform based on high-speed recordings within a synthetic larynx model
Der Titel meiner Dissertation lautet: Parameteranalyse der Glottal Area Waveform basierend auf Hochgeschwindigkeitsaufnahmen von synthetischen Larynxmodellen.
Hintergrund und Ziele Die aktuellen diagnostischen Methoden im klinischen Alltag in Bezug auf Dysphonie beruhen fast ausschlieĂlich auf dem Erfahrungsschatz des jeweiligen Untersuchers. FĂźr eine detaillierte Diagnostik kann aktuell nicht auf verlässliche objektive Parameter zur UnterstĂźtzung des Untersuchers zurĂźckgegriffen werden, da diese im Moment noch nicht ausgereift sind. In dieser Arbeit finden die Analyse und Beurteilung des kĂźnstlichen Kehlkopfmodells hinsichtlich einer korrekten Abbildung der Physiologie der menschlichen Phonation statt Die Entwicklung von synthetischen Stimmlippenmodellen unterstĂźtzt den Versuch objektive Parameter valider zu machen, da diese im Gegensatz zu menschlichen Probanden einige Vorteile in der Forschung aufweisen: besserer Zugang (sowohl in Bezug auf das Zeitmanagement, als auch auf die Untersuchung), bessere Reproduzierbarkeit und keine ethischen Verpflichtungen gegenĂźber den Modellen.. Doch um diese Vorteile nutzen zu kĂśnnen, mĂźssen die synthetischen Modelle die menschlichen Stimmlippen so gut wie mĂśglichen imitieren, wobei nur eine vereinfachte Version der Realität wiedergegeben werden kann.
Methoden Diese Arbeit bezieht sich auf den Aufbau und die Modelle aus âFluid-Structure-Acoustic Interaction during Phonation in a Synthetic Larynx Modelâ von S. Kniesburges (2014). Wichtig fĂźr den Versuchsaufbau sind die Einschicht- und Mehrschichtmodelle, welche in verschiedenen Steifheitsgraden untersucht werden. Ebenfalls entscheidend ist der weitenverstellbare supraglottale Kanal und die einsetzbaren Taschenfalten. Diese einzelnen Komponenten beeinflussen die Phonation der Stimmlippen maĂgeblich. Um die objektiven Parameter (fundamental frequency, shimmer, mean-jitter, jitter, harmonics-to-noise ratio [HNR], cepstral peak prominence [CPP] und maximum area declination [MADR]) der synthetischen Modelle mit denen der Physiologie menschlicher Stimmlippen zu vergleichen, werden verschiedene physiologische Datensätze herangezogen. Zusätzlich werden die Modelle und deren unterschiedliche Konfigurationen untereinander verglichen, um den Effekt der einzelnen variablen Komponenten auf die synthetischen Stimmlippen zu erkennen.
Die unterschiedlichen Konstellationen der Modelle und deren daraus resultierenden Werte der objektiven Parameter sind im Anschluss mit denen der physiologischen Datensätze verglichen worden.
Ergebnisse Zusammengefasst bilden die beobachteten synthetischen Stimmlippenmodelle die Physiologie nicht in jeder Hinsicht nach, jedoch vor allem die Werte der fundamental frequency, shimmer in percent, HNR und MADR eine hohe Ăbereinstimmung zur den physiologischen Datensätzen zeigen. Auffällig ist, dass die Werte der männlichen Datensätze stark mit den Werten der Ein- und Mehrschichtmodelle Ăźbereinstimmen. Vor allem in Bezug auf die fundamental frequency.
Schlussfolgerungen Der Kontakt der Stimmlippen beim kompletten Glottisschluss weist in beiden synthetischen Modellen eine stabilere Stimmlippenschwingung auf. Sichtbar wird dies durch die Verringerung der Standardabweichung der fundamental frequency im Vergleich zu keinem Kontakt der Stimmlippen bei der Phonation. Ebenfalls wird bei der Betrachtung der HNR deutlich, dass der Einfluss des supraglottalen Kanaldurchmessers auf die Mehrschichtmodelle grĂśĂer ist als auf die Einschichtmodelle. Dazu kommt, dass die VergrĂśĂerung des supraglottalen Kanaldurchmessers zu einem schnelleren Schluss der Stimmritze in fast allen Modellen und Schwingungsmodi fĂźhrt. Des Weiteren weisen die Ein- und Mehrschichtmodellen beim Einsetzen der Taschenfalten eine erhĂśhte Tonalität und Periodizität auf. Die synthetischen Stimmlippenmodelle bilden die physiologische menschliche Phonation valide ab, was anhand der Ăbereinstimmungen der objektiven Parameter von Modellen und Probanden zu erkennen ist
A comprehensive analysis of the importance of translation initiation factors for Haloferax volcanii applying deletion and conditional depletion mutants
Translation is an important step in gene expression. The initiation of translation is phylogenetically diverse, since currently five different initiation mechanisms are known. For bacteria the three initiation factors IF1 â IF3 are described in contrast to archaea and eukaryotes, which contain a considerably higher number of initiation factor genes. As eukaryotes and archaea use a non-overlapping set of initiation mechanisms, orthologous proteins of both domains do not necessarily fulfill the same function. The genome of Haloferax volcanii contains 14 annotated genes that encode (subunits of) initiation factors. To gain a comprehensive overview of the importance of these genes, it was attempted to construct single gene deletion mutants of all genes. In 9 cases single deletion mutants were successfully constructed, showing that the respective genes are not essential. In contrast, the genes encoding initiation factors aIF1, aIF2Îł, aIF5A, aIF5B, and aIF6 were found to be essential. Factors aIF1A and aIF2β are encoded by two orthologous genes in H. volcanii. Attempts to generate double mutants failed in both cases, indicating that also these factors are essential. A translatome analysis of one of the single aIF2β deletion mutants revealed that the translational efficiency of the second ortholog was enhanced tenfold and thus the two proteins can replace one another. The phenotypes of the single deletion mutants also revealed that the two aIF1As and aIF2βs have redundant but not identical functions. Remarkably, the gene encoding aIF2Îą, a subunit of aIF2 involved in initiator tRNA binding, could be deleted. However, the mutant had a severe growth defect under all tested conditions. Conditional depletion mutants were generated for the five essential genes. The phenotypes of deletion mutants and conditional depletion mutants were compared to that of the wild-type under various conditions, and growth characteristics are discussed
Analysis of single crystalline microwires under torsion using a dislocation-based continuum formulation
A bottom-up continuum approach of crystal plasticity for the analysis of fcc microwires under torsion
The microstructural evolution of faceâcentered cubic microwires is studied using a physical motivated, homogenized continuum model of crystal plasticity. The dislocation configuration in the threeâdimensional space is thereby described via a Continuum Dislocation Dynamics (CDD) theory including a dislocation source term. The resulting spatial distribution of dislocation densities and strain components are shown for a relaxation problem with torsional loading
Analysis of interpenetrating metal ceramic composite structures using an enhanced random sequential absorption microstructure generation algorithm
A data-based derivation of the internal stress in the discrete-continuum transition regime of dislocation based plasticity
The causal mind:An affordance-based account of causal engagement
Causal cognition is a core aspect of how we deal with the world; however, existing psychological theories tend not to target intuitive causal engagement that is done in daily life. To fill this gap, we propose an Ecological-Enactive (E-E) affordance-based account of situated causal engagement, that is, causal judgments and perceptions. We develop this account to improve our understanding of this way of dealing with the world, which includes making progress on the causal selection problem, and to extend the scope of embodied cognitive science to causal cognition. We characterize identifying causes as selectively attending to the relevant ecological information to engage with relevant affordances, where these affordances are dependent on individual abilities. Based on this we construe causal engagement as based on a learned skill. Moreover, we argue that to understand judgments of causation as we make them in our daily lives, we need to see them as situated in sociocultural practices. Practices are about doing, and so this view helps us understand why people make these judgments so ubiquitously: to get things done, to provide an effective path to intervening in the world. Ultimately this view on causal engagement allows us to account for individual differences in causal perceptions, judgments, and selections by appealing to differences in learned skills and sociocultural practices.</p
Adapted teaching: a chance to reduce the effect of social origin? A comparison between Germany and Norway, using PIRLS 2011
Adapted teaching is associated with high hopes regarding its potential to meet heterogeneity in the classroom and has, as such, been anchored in nearly all federal school laws in Germany. As this is a fairly new, not yet fully implemented development that comes with a number of obstacles, an international comparison was conducted to estimate its capability of reducing social disparities in school, giving prospects of its potential development in Germany. For this, Norway was chosen since adapted teaching has a long tradition there. Using a multilevel structural equation model and data from PIRLS 2011, it is analysed whether adapted teaching reduces the effect that social origin has on reading achievement and self-concept in reading. (DIPF/Orig.)Dieser Beitrag greift die Frage des Herkunftseffekts und der kompensatorischen InterventionsmÜglichkeiten von Schulen auf. Der Beitrag umfasst einen Ländervergleich anhand von in Deutschland und Norwegen repräsentativ erhobenen Daten, in dem zum einen das Ausmaà der Unterschiedlichkeit zwischen den beiden Ländern thematisiert wird und zum anderen auch die Grenzen von Sekundäranalysen fßr Ländervergleiche thematisiert werden. (DIPF/Orig.
Development and validation of a measurement-driven inter crystal scatter recovery algorithm with in-system calibration
In PET a high percentage of gamma photons being detected undergo Compton
scattering in the scintillator. Scintillator blocks are often built from
optically isolated crystals. Depending on the angle of incidence and the
scintillator geometry this might lead to inter crystal scatter (ICS) events,
where energy is deposited in two or more crystals in the detector, which common
positioning and reconstruction algorithms cannot resolve. Therefore, ICS events
worsen the spatial resolution and the signal-to-noise ratio in the
reconstructed image. We want to address this challenge by recovering individual
crystals from ICS events with their corresponding energy deposits. This
information could ultimately be fed into an image reconstruction framework. In
this work, we established an algorithm based on a detector that couples a
readout channel to each crystal (one-to-one coupling), which combines a
measurement-driven calibration and a fitting routine to achieve the recovery of
crystal interactions from measured light patterns. Using Geant4 simulations, we
validated and optimized this approach by comparing the recovered events to the
simulation ground truth. We showed that, with the best performing algorithm
versions, all correct crystals could be identified for 95-97% of the simulated
events and the crystal energies as well as the event energy sum could be
recovered adequately. For the event energy sum a deviation of less than 5%
could be achieved for 96% of all events. Overall, the developed ICS recovery
algorithm was successfully validated for one-to-one coupled detector. Future
application for other detector configurations should be possible and will be
investigated. Additionally, using the new crystal interaction information to
determine the most likely first interaction crystal is being examined to
improve efficiency and signal-to-noise ratio in the PET reconstruction.Comment: 18 pages, 10 figure
Comparison of different strategies to measure medication adherence via claims data in patients with chronic heart failure
Medication adherence correlates with morbidity and mortality in patients with chronic heart failure (CHF), but is difficult to assess. We conducted a retrospective methodological cohort study in 3,808 CHF patients, calculating adherence as proportion of days covered (PDC) utilizing claims data from 2010 to 2015. We aimed to compare different parametersâ influence on the PDC of elderly CHF patients exemplifying a complex chronic disease. Investigated parameters were the assumed prescribed daily dose (PDD), stockpiling, and periods of hospital stay. Thereby, we investigated a new approach using the PDD assigned to different percentiles. The different dose assumptions had the biggest influence on the PDC, with variations from 41.9% to 83.7%. Stockpiling and hospital stays increased the values slightly. These results queries that a reliable PDC can be calculated with an assumed PDD. Hence, results based on an assumed PDD have to be interpreted carefully and should be presented with sensitivity analyses to show the PDC's possible range
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