Ultrasonic Doppler measurement of renal artery blood flow

An extensive evaluation of the practical and theoretical limitations encountered in the use of totally implantable CW Doppler flowmeters is provided. Theoretical analyses, computer models, in-vitro and in-vivo calibration studies describe the sources and magnitudes of potential errors in the measurement of blood flow through the renal artery, as well as larger vessels in the circulatory system. The evaluation of new flowmeter/transducer systems and their use in physiological investigations is reported

Simulation of the Process Step Polymer Removal in Indirect Metal Laser Sintering

With the Indirect Metal Laser Sintering and by means of a heat treatment in an oven process metal components can be produced. In the first step the polymer is transformed from the solid state into the gas phase. This takes place all over the component at different velocities depending on the local temperatures and temperature gradients. The creation of the gas phase develops a pressure inside of the component because the diffusion of the polymer within the part has a finite velocity. The pressure may contribute to a damage of the component. This essay deals with the procedure to simulate the gas pressure on the basis of the implementation of kinetic models in the Finite-Element-Analysis.Mechanical Engineerin

Ultrasonic Doppler measurement of renal artery blood flow

Studies were made of (1) blood flow redistribution during lower body negative pressure (LBNP), (2) the profile of blood flow across the mitral annulus of the heart (both perpendicular and parallel to the commissures), (3) testing and evaluation of a number of pulsed Doppler systems, (4) acute calibration of perivascular Doppler transducers, (5) redesign of the mitral flow transducers to improve reliability and ease of construction, and (6) a frequency offset generator designed for use in distinguishing forward and reverse components of blood flow by producing frequencies above and below the offset frequency. Finally methodology was developed and initial results were obtained from a computer analysis of time-varying Doppler spectra

Assessing early literacy skills to prevent problems in reading and writing

Ursachen für Probleme im Schriftspracherwerb sind nicht erst im Anfangsunterricht zu suchen, sondern bereits in familiären Illiteralitätserfahrungen. Insbesondere das Wissen über Schrift und die Erzählfähigkeit sind als Prädiktoren des späteren Schriftspracherwerbs gut belegt. Ein geeignetes Verfahren zu deren reliabler und valider Erfassung fehlt aber im deutschen Sprachraum. Diese Lücke soll mit dem Verfahren EuLe 3-5 (Meindl & Jungmann, in Vorb.) geschlossen werden, dessen Konzeption theoriebasiert und orientiert an anerkannten Verfahren aus dem anglo-amerikanischen Sprachraum erfolgte. Zur Überprüfung seiner Einsetzbarkeit und Güte wurde eine Stichprobe von insgesamt N=658 Kindern aus Kindertageseinrichtungen in Mecklenburg-Vorpommern und Berlin untersucht. In Teilstichproben kamen zur Ermittlung der Konstruktvalidität das SSV bzw. der SETK 3-5 sowie die nonverbalen Skalen der K-ABC zum Einsatz. Die Itemkennwerte (rit= .40 - .61) belegen ebenso wie die Befunde zu den Hauptgütekriterien Objektivität (ICCunjust, einfakt = .96), Reliabilität (Cronbachs aGesamttest= .91) und Validität die Eignung des EuLe 3-5 für präventive Förderentscheidungen im Vorschulalter. Weitere Studien zur inkrementellen und prognostischen Validität des Verfahrens sind notwendig und laufen derzeit. (DIPF/Orig.)Problems in reading and writing acquisition are not rooted in elementary school instruction but often in lacking literacy experiences in the family of origin. Although knowledge of print and narrative skills are well-documented predictors of later literacy acquisition in school, reliable und valid diagnostic instruments are missing in Germany. The EuLe 3-5 (Meindl & Jungmann, in prep.) is supposed to fill this gap. Its conception is grounded in theory and based on established Anglo-American tests. We tested its applicability and quality on a construction sample of N = 658 preschool children in Mecklenburg-West Pomerania and Berlin. To determine construct validity, we administered the SSV or the SETK 3-5 and the nonverbal scales of the K-ABC additionally in subsamples. Item analysis (rit= .40 - .61) and results on objectivity (ICCone-way, random = .96), reliability (Cronbachs atotal test = .91) and validity prove the adequacy of the EuLe 3-5 for intervention decisions at preschool age. Further studies concerning the incremental and predictive validity are necessary and run currently. (DIPF/Orig.

An Open Source Approach for Modern Teaching Methods: The Interactive TGUI System

In order to facilitate teaching complex topics in an interactive way, the authors developed a computer-assisted teaching system, a graphical user interface named TGUI (Teaching Graphical User Interface). TGUI was introduced at the beginning of 2009 in the Austrian Journal of Statistics (Dinges and Templ 2009) as being an effective instrument to train and teach staff on mathematical and statistical topics. While the fundamental principles were retained, the current TGUI system has been undergone a complete redesign. The ultimate goal behind the reimplementation was to share the advantages of TGUI and provide teachers and people who need to hold training courses with a strong tool that can enrich their lectures with interactive features. The idea was to go a step beyond the current modular blended-learning systems (see, e.g., Da Rin 2003) or the related teaching techniques of classroom-voting (see, e.g., Cline 2006). In this paper the authors have attempted to exemplify basic idea and concept of TGUI by means of statistics seminars held at Statistics Austria. The powerful open source software R (R Development Core Team 2010a) is the backend for TGUI, which can therefore be used to process even complex statistical contents. However, with specifically created contents the interactive TGUI system can be used to support a wide range of courses and topics. The open source R packages TGUICore and TGUITeaching are freely available from the Comprehensive R Archive Network at http://CRAN.R-project.org/.

Feedback-based integration of the whole process of data anonymization in a graphical interface

The interactive, web-based point-and-click application presented in this article, allows anonymizing data without any knowledge in a programming language. Anonymization in data mining, but creating safe, anonymized data is by no means a trivial task. Both the methodological issues as well as know-how from subject matter specialists should be taken into account when anonymizing data. Even though specialized software such as sdcMicro exists, it is often difficult for nonexperts in a particular software and without programming skills to actually anonymize datasets without an appropriate app. The presented app is not restricted to apply disclosure limitation techniques but rather facilitates the entire anonymization process. This interface allows uploading data to the system, modifying them and to create an object defining the disclosure scenario. Once such a statistical disclosure control (SDC) problem has been defined, users can apply anonymization techniques to this object and get instant feedback on the impact on risk and data utility after SDC methods have been applied. Additional features, such as an Undo Button, the possibility to export the anonymized dataset or the required code for reproducibility reasons, as well its interactive features, make it convenient both for experts and nonexperts in R – the free software environment for statistical computing and graphics – to protect a dataset using this app

Consistency of PPP GPS and strong-motion records: case study of Mw9.0 Tohoku-Oki 2011 earthquake

GPS and strong-motion sensors are broadly used for the monitoring of structural health and Earth surface motions, focusing on response of structures, earthquake characterization and rupture modeling. Several studies have shown the consistency of the two data sets within at certain frequency (e.g., 0.03<f<0.2Hz). The compatibility of Precise Point Positioning (PPP) GPS and strong-motion data was assessed by comparing their respective displacement waveforms for several frequency bands (f<0.3Hz). For this purpose, there are used GPS and strong-motion records of the Mw9.0 Tohoku 2011 earthquake at 23 very close spaced sites and conclude that the agreement between the two datasets depends on the frequency of the excitation, the direction of the excitation signal and the distance from the excitation source

Simulation of synthetic complex data: The R package simPop

The production of synthetic datasets has been proposed as a statistical disclosure control solution to generate public use files out of protected data, and as a tool to create "augmented datasets" to serve as input for micro-simulation models. Synthetic data have become an important instrument for ex-ante assessments of policy impact. The performance and acceptability of such a tool relies heavily on the quality of the synthetic populations, i.e., on the statistical similarity between the synthetic and the true population of interest. Multiple approaches and tools have been developed to generate synthetic data. These approaches can be categorized into three main groups: synthetic reconstruction, combinatorial optimization, and model-based generation. We provide in this paper a brief overview of these approaches, and introduce simPop, an open source data synthesizer. simPop is a user-friendly R package based on a modular object-oriented concept. It provides a highly optimized S4 class implementation of various methods, including calibration by iterative proportional fitting and simulated annealing, and modeling or data fusion by logistic regression. We demonstrate the use of simPop by creating a synthetic population of Austria, and report on the utility of the resulting data. We conclude with suggestions for further development of the package