Function-Orientated Structural Analysis of the Proximal Human Femur

In his model of the biomechanics of the proximal human femur, Friedrich Pauwels assumes a resultant force acting on the femoral head that is created by the partial body weight and the force of the abductor muscles inserting at the greater trochanter. This model suggests a tensile force in the region of the greater trochanter. An exact examination of the muscle insertions at the greater trochanter resulted in a contrasting hypothesis assuming a local compression stress in the region of the greater trochanter. The aim of this study was to examine which hypothesis is favored by the internal architecture of the proximal femur. Based on the architectural software Allplan (R), we performed an extended analysis of the trabecular structure within the proximal femur using CT scans of 10 human cadaver femora altogether. According to our results, both the medial and the trochanteric trabecular systems are orientated approximately perpendicular to the arcuate trabecular system {[}angles between systems ranging from 84.6 to 93.0 degrees (mean angle 90.7 degrees) and from 80.9 to 86.5 degrees, (mean angle 84.9 degrees), respectively]; furthermore, the medial trabecular system is orientated perpendicular to the epiphysis of the femoral head (mean of angles: 94.7). The biomechanical interpretation of these results strongly supports the idea of compressive stress in the region of the greater trochanter and makes a predominant tensile force of the abductor muscles highly unlikely. Copyright (C) 2009 S. Karger AG, Base

Base-rate neglect based on base-rates in experience-based contingency learning

Predicting criterion events based on probabilistic predictor events, humans often lend excessive weight to predictor event information and insufficient weight to criterion event base-rates. Using the matching-to-sample paradigm established in studies on experience-based contingency learning in animals, Goodie and Fantino (1996) showed that human judges exhibit base-rate neglect when sample cues are associated with response options through similarity relations. In conceptual replications of these studies, we demonstrated similar effects when sample cues resemble the response options in terms of base-rates skewed in the same direction rather than physical similarity. In line with the pseudocontingency illusion (Fiedler & Freytag, 2004), predictions were biased toward the more (less) frequently rewarded response option following the more (less) frequently presented sample cue. Thus, what is a demonstration of base-rate neglect from one perspective turns out to reflect the judges' sensitivity to the alignment of skewed base-rate distributions.

From Cross-Organizational Business Process to Public Services

Service-oriented architectures promise flexible process integration in heterogeneous environments, particularly in cross organizational contexts. Therefore, a systematic approach for deriving service definitions from cross-organizational business processes is required. The paper at hand presents a structured, model driven approach that allows for cross-organizational integration with service-oriented concepts and technologies based on a cross-organizational business process. The resulting method is specified by means of a metamodel and a procedure model. Taking into account existing approaches in the research field, the paper focuses on the activities for the service design specification and the subsequent implementation of the public services. Feasibility of the method is shown by applying it in a Business-to-Government (B2G) real-world scenario, namely the collaboration between a consigning company and customs authorities according to the new European harmonized customs procedures

Primary stability of cementless threaded acetabular cups at first implantation and in the case of revision regarding micromotions as indicators

The primary stability of cementless total hip endoprosthesis is of vital importance for proximate, long-term osteointegration. The extent of micromotions between implant and acetabulum is an indicator of primary stability. Based on this hypothesis, different cementless hip joint endoprosthesis were studied with regard to their micromotions. The primary stability of nine different cementless threaded acetabular cups was studied in an experimental setup with blocks of rigid foam. The micromotions between implant and implant bearing were therefore evaluated under cyclic, sinusoidal exposure. The blocks of polymer foam were prepared according to the Paprosky defect classifications. The micromotions increased with the increasing degree of the defect with all acetabuli tested. Occasionally coefficients of over 200 mu m were measured. From a defect degree of 3b according to Paprosky, the implants could no longer be appropriately placed. The exterior form of the spherical implants tended to exhibit better coefficients than the conical/parabolic implants

Der Systemwechsel in Russland als passive Revolution und die Aussichten auf eine demokratische Gegenbewegung

Im ersten Teil dieser Arbeit habe ich versucht die These zu untermauern, dass es sich bei der Systemtransformation in der ehemaligen Sowjetunion auf keinen Fall um eine Revolution des Sowjetvolkes unter der Führung Boris Jelzins gegen die kommunistischen Eliten gehandelt hat, sondern dass es in erster Linie große Teile dieser Eliten selbst waren die diesen System-wechsel organisiert und unterstützt haben. Der Großteil der Bevölkerung selbst spielte dabei keine oder nur eine sehr minimale Rolle. Außerdem wende ich mich auch gegen die Über-schätzung des Einflusses westlicher Regierungen und Berater und Beraterinnen in Bezug auf diese Transformation. Die Basis und Bedingungen des Systemwechsels waren bereits vorhan-den und beschlossen als das Land für westliche Berater und Beraterinnen geöffnet wurde. Im zweiten Teil der Arbeit geht es dann in erster Linie um die Situation von zivilgesellschaftli-chen Akteuren in Russland. Dabei geht es vor allem um die Frage, ob zivilgesellschaftliche Strukturen allmählich mehr Einfluss auf die Politik in Russland erlangen konnten und wie die Staatsmacht auf diese aus der Bevölkerung kommenden Bewegungen reagiert. In diesem Zusammenhang wird deutlich, dass im Moment wenig darauf hinweist, dass die Staatsmacht die Absicht hat der Bevölkerung mehr direkten Einfluss auf das politische System zu ermögli-chen. Im Gegenteil, spätestens seit der Geiselnahme von Beslan versucht Präsident Putin und seine Umgebung sehr erfolgreich unabhängiges zivilgesellschaftliches Engagement unter Ge-neralverdacht zu stellen und auf der anderen Seite staatlich organisierte zivilgesellschaftliche Strukturen zu installieren

Base-rate neglect based on base-rates in experience-based contingency learning

Predicting criterion events based on probabilistic predictor events, humans often lend excessive weight to predictor event information and insufficient weight to criterion event base-rates. Using the matching-to-sample paradigm established in studies on experience-based contingency learning in animals, Goodie and Fantino (1996) showed that human judges exhibit base-rate neglect when sample cues are associated with response options through similarity relations. In conceptual replications of these studies, we demonstrated similar effects when sample cues resemble the response options in terms of base-rates skewed in the same direction rather than physical similarity. In line with the pseudocontingency illusion (Fiedler & Freytag, 2004), predictions were biased toward the more (less) frequently rewarded response option following the more (less) frequently presented sample cue. Thus, what is a demonstration of base-rate neglect from one perspective turns out to reflect the judges' sensitivity to the alignment of skewed base-rate distributions

Pseudocontingencies in stereotype formation : extending illusory correlations

Under the notion of illusory correlations, simple learning paradigms (e.g. Hamilton & Gifford, 1976) have been used to study the formation of stereotypes that discriminate between majorities and minorities. In the present paper, limitations of this approach in terms of theoretical explanations and empirical evidence are addressed. Theoretically, we propose pseudocontingencies (PCs, Fiedler, Freytag & Meiser, 2008) as a more robust mechanism behind illusory correlations. In contrast to previous explanations, PCs can explain illusory correlations when groups are never paired with valence. Empirically, we replicate earlier findings, i.e. that the more frequently observed group, the majority, is evaluated more in line with the more frequently observed valence. Crucially, we extend the empirical evidence in that illusory correlations prove robust over a very large number of observations (320) and under increasingly interactive task conditions, involving predictions of valence (Experiment 2) and reinforcement-learning conditions (Experiment 3). The latter provided evidence for illusory correlations on a new measure, participants’ predictions. These predictions reflect the expectations about the valence associated with majority and minority and might well affect real life behavior. The discussion focuses on possible reasons for why PCs are used in stereotypic judgments