824 research outputs found
Strategien zur Erzeugung von Qualitätsgetreide in viehlosen/-armen Marktfruchtbetrieben
In diesem Workshop sollen sowohl bereits bewährte als auch innovative Anbaustrategien auf ihre Eignung für nachhaltige Getreideerzeugung in ökologischen viehlosen Marktfruchtbetrieben untersucht werden
A systematic comparison of jet quenching in different fluid-dynamical models
Comparing four different (ideal and viscous) hydrodynamic models for the
evolution of the medium created in 200 AGeV Au-Au collisions, combined with two
different models for the path length dependence of parton energy loss, we study
the effects of jet quenching on the emission-angle dependence of the nuclear
suppression factor R_AA(phi) and the away-side per trigger yield I_AA(phi).
Each hydrodynamic model was tuned to provide a reasonable description of the
single-particle transverse momentum spectra for all collision centralities, and
the energy loss models were adjusted to yield the same pion nuclear suppression
factor in central Au-Au collisions. We find that the experimentally measured
in-plane vs. out-of-plane spread in R_AA(phi) is better reproduced by models
that shift the weight of the parton energy loss to later times along its path.
Among the models studied here, this is best achieved by energy loss models that
suppress energy loss at early times, combined with hydrodynamic models that
delay the dilution of the medium density due to hydrodynamic expansion by
viscous heating. We were unable to identify a clear tomographic benefit of a
measurement of I_AA(phi) over that of R_AA(phi).Comment: 17 pages, 11 figure
Ein physiologisch gehörgerechtes Verfahren zur automatisierten Melodietranskription
Abstract
The implementation of a method for automatic transcription of music is proposed
in this thesis. The human ability of musical perception, and espescially tasks
performed by skilled professional musicians, can by far not be duplicated by
recent technical systems. It can therefore be considered a plausible approach to
make use of perceptually motivated strategies as far as possible in order to
bridge this gap for systems for music analysis and understanding. In the
presented work the basic processing mechanisms used by the mammalian auditory
periphery, as well as high-level cognitive processes are applied to the analysis
of musical input.
A detailed summary describes state-of-the-art algorithms for detection of
fundamental frequencies as well as segmentation of musical phrases. Current
systems for monophonic and polyphonic melody transcription are introduced.
The fundamental physiological components of the auditory periphery and
principles based on Gestalt psychology are illustrated. Furthermore the models
used in this thesis, including active sound preprocessing of the inner ear, are
described. In order to take account of auditive
postprocessing, principles of pitch perception and a hierarchical
model based on assumptions from Gestalt psychology are utilized.
Besides the development of the hierarchical model the core of the presented
thesis consists of the implementation of the methods regarding monophonic and
polyphonic transcription strategies. Aurally justified pitch extraction,
psychoacoustically motivated segmentation and postprocessing based on music
theory constitute the basis for monophonic transcription. The polyphonic parts,
as partial interference, pitch hypothesis or octave detection, are thought of
setting up the fundamentals of subsequent implementations. The thesis concludes
with the evaluation of the proposed system. A variety of different test series
in the context of a metadata
search engine are described. The results show the potential of the method
regarding (commercial) applications.:
Das Thema dieser Dissertation ist die Implementierung eines Verfahrens zur automatisierten Transkription von Musik. Die Fähigkeit des Menschen, insbesondere die von musikalischen Experten, bezüglich der Wahrnehmung musikalischer Inhalte kann von aktuellen technischen Systemen bei weitem nicht
reproduziert werden. Einen plausiblen Ansatz, um diese Lücke für Anwendungen der automatisierten Musikanalyse zu schliessen, stellt die Verwendung perzeptuell motivierter Strategien dar. Die vorliegende Arbeit wendet daher konsequent grundlegende Verarbeitungsmechanismen der menschlichen auditorischen Peripherie sowie kognitiv höher angesiedelter Gehirnzentren an.
In einer ausfürlichen Darstellung des Standes der Technik werden die aktuellen Algorithmen zur Bestimmung der Grundfrequenzen und zur Segmentierung musikalischer Phrasen sowie deren Anwendung in monophonen und polyphonen Melodietranskriptionssystemen erläutert.
Nach der Beschreibung der fundamentalen physiologischen Komponenten der auditorischen Peripherie und Prinzipien der Gestaltpsychologie werden die in dieser Arbeit verwendeten Modelle der teilweise aktiven Schallvorverarbeitung
des Innenohres erläutert. Im Bereich der auditiven Weiterverarbeitung werden Prozesse der Frequenzwahrnehmung sowie ein auf gestaltbasierenden Annahmen aufgebautes eigenes Hierarchiemodell eingeführt.
Neben der Aufstellung dieses Hierarchiemodells besteht der Kernpunkt der Arbeit in der Implementierung der ausgewählten Modelle bezüglich monophoner und polyphoner Transkriptionsstrategien. Gehörgerechte Pitchextraktion, psychoakustisch motivierte Segmentierung und musiktheoretisch
untermauerte Nachbearbeitung bilden die Basis einstimmiger Analyse. Die Untersuchung von Partialtoninterferenzen, polyphonen Pitchhypothesen und Ansätzen zur Oktaverkennung sollen als Grundlage weiterführender Arbeiten im mehrstimmigen Anwendungsfall aufgefasst werden.
Die Arbeit schliesst mit der Evaluierung des Verfahrens anhand der Diskussion einer Anzahl verschiedener Testreihen im Umfeld eines Metadaten-Suchsystems. Die erhaltenen Ergebnisse verdeutlichen das (auch kommerzielle) Anwendungspotential der vorgestellten Methode
The Effect Of Knowledge Management Systems On Absorptive Capacity: Findings From International Law Firms
This case study is engaged in examining the effects of knowledge management systems (KMS) on absorptive capacity (ACAP). Often regarded as the major source of innovation and firm competitive advantage, ACAP raises questions of how to value, assimilate and apply new knowledge. Based on a multiple case study design we specifically investigate KMS as antecedent of ACAP. We interviewed six experts employed in knowledge management functions at two different international law firms operating in the Asian-Pacific, American, and European legal market. The findings from our case study analysis demonstrate that KMS have a positive effect on ACAP, especially on knowledge acquisition and assimilation
Inhibition of diacylglycerol–sensitive TRPC channels by synthetic and natural steroids
TRPC channels are a family of nonselective cation channels that regulate ion homeostasis and intracellular Ca2+ signaling in numerous cell types. Important physiological functions such as vasoregulation, neuronal growth, and pheromone recognition have been assigned to this class of ion channels. Despite their physiological relevance, few selective pharmacological tools are available to study TRPC channel function. We, therefore, screened a selection of pharmacologically active compounds for TRPC modulating activity. We found that the synthetic gestagen norgestimate inhibited diacylglycerol-sensitive TRPC3 and TRPC6 with IC50s of 3–5 µM, while half-maximal inhibition of TRPC5 required significantly higher compound concentrations (>10 µM). Norgestimate blocked TRPC-mediated vasopressin-induced cation currents in A7r5 smooth muscle cells and caused vasorelaxation of isolated rat aorta, indicating that norgestimate could be an interesting tool for the investigation of TRP channel function in native cells and tissues. The steroid hormone progesterone, which is structurally related to norgestimate, also inhibited TRPC channel activity with IC50s ranging from 6 to 18 µM but showed little subtype selectivity. Thus, TRPC channel inhibition by high gestational levels of progesterone may contribute to the physiological decrease of uterine contractility and immunosuppression during pregnancy
Pharmacometric Characterization of Dabigatran Hemodialysis
BACKGROUND: Hemodialysis has been shown to be a useful method of decreasing dabigatran plasma levels in situations that require rapid elimination of this thrombin inhibitor. However, there is currently no clinical recommendation for the accelerated/optimized elimination of dabigatran via hemodialysis (e.g., flow rates, filter type, duration of dialysis). OBJECTIVES: The primary objective of the present work was to characterize, via pharmacometric methods, the effects of different blood flow rates in hemodialysis on the pharmacokinetics of dabigatran, using data from a dedicated phase I dialysis study of end-stage renal disease (ESRD) patients. In addition, the effects of various clinically relevant hemodialysis settings were evaluated by simulation to assess their potential use in non-ESRD situations. METHODS: Seven patients with ESRD were investigated in an open-label, fixed-sequence, two-period comparison trial. A population pharmacokinetic model was developed to fit the data and then used for various simulations. Data analyses were performed using NONMEM(®), Berkeley Madonna, or SAS. RESULTS: The pharmacokinetics of dabigatran were best described by a two-compartment model with first-order absorption and a lag time. In addition to total body clearance in ESRD subjects, a first-order dialysis clearance was implemented which was greater than zero during hemodialysis and zero during the interdialytic periods. The relationship between the dialysis clearance and the blood flow rate was best described by the Michaels function. Simulations showed that varying clinically relevant dialysis settings such as filter properties or flow rates had only minor effects. Dialysis duration had the strongest impact on dabigatran plasma concentration. The observed geometric mean redistribution effect after hemodialysis was low (<16 %). The final model was successfully evaluated through the prediction of plasma concentrations from a case report undergoing dialysis. CONCLUSIONS: This analysis allowed the influences of various hemodialysis parameters on the dabigatran plasma concentration to be predicted in detail for the first time. Dialysis duration was identified as having the strongest impact on the reduction in dabigatran plasma concentration. The model developed here can potentially serve as a tool to provide guidance when considering the use of hemodialysis in patients who have received dabigatran
BF/M-Spiegel : Journal des Betriebswirtschaftlichen Forschungszentrums für Fragen der mittelständischen Wirtschaft e. V. an der Universität Bayreuth, 2016, Heft 1
CO2-Konzentration der Bodenluft und Phosphatase-Aktivität als Indikatoren der natürlichen Regeneration auf Rückegassen im Kalkbuchenwald
Durch das Fahren von Forstmaschinen im Wald kommt es auf den Rückegassen zu Bodenverdichtung. Dabei ist weitgehend unbekannt, ob und in welchem Zeitraum eine natürliche Regeneration auf den verdichteten Waldböden stattfindet. In dieser Untersuchung wurden CO2-Konzentration und Phosphatase-Aktivität auf unterschiedlich alten Rückegassen (5, 15, 24 und 38 nach der letzten Befahrung) untersucht, um den Regenerationsfortschritt festzustellen. Die CO2-Konzentration ist auf der fünf Jahre alten Rückegasse am höchsten, die Phosphatase-Aktivität hingegen ist auf der Fahrspur und im Mittelstreifen reduziert. 24 Jahre nach der letzten Befahrung liegen die CO2-Konzentrationen auf der Rückegasse bei 2000 ppm und entsprechen wieder denen im ungestörten Bereich
BF/M-Spiegel : Journal des Betriebswirtschaftlichen Forschungszentrums für Fragen der mittelständischen Wirtschaft e. V. an der Universität Bayreuth, 2015, Heft 2
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