Efficient Algorithms for Determining 3-D Bi-Plane Imaging Geometry

Biplane projection imaging is one of the primary methods for imaging and visualizing the cardiovascular system in medicine. A key problem in such a technique is to determine the imaging geometry (i.e., the relative rotation and translation) of two projections so that the 3-D structure can be accurately reconstructed. Based on interesting observations and efficient geometric techniques, we present in this paper new algorithmic solutions for this problem. Comparing with existing optimization-based approaches, our techniques yield better accuracy and have bounded execution time, thus is more suitable for on-line applications. Our techniques can easily detect outliers to further improve the accuracy.This research was supported in part by NIH under USPHS grant numbers HL52567.     

Communicative competence in 5- to 8-year-olds with mild or moderate learning difficulties and their classroom peers: referential and negotiation skills

Two studies were run to examine communicative and social aspects of the interaction between 5- to 8-year-old children with mild or moderate learning difficulties (LD) and their classroom peers for whom no such difficulties had been observed (NLD). In the first study, the children's communicative responses to a referential group task were explored, through children describing drawings to each other. In terms of the nature of information exchange, few differences were found between NLD and LD children. Differences were found in terms of the social content of language: in the listener role, LD children tended to be the recipients of more critical and directive speech. The second study, focusing on consensus forming and negotiation processes in a co-operative group task, mirrored the patterns of social aspects found in Study 1. LD children tended to be less influential in affecting the consensus and in directing the course of the task.     

Prüfungshonorare in Deutschland – Determinanten und Implikationen

The audit fees available since 2005 as a consequence of the Bilanzrechtsreformgesetz (commercial code reform act) show an extremely high supplier concentration on the German audit market of publicly listed companies. This justifies the assumption of audit fees above perfect market equilibrium prices. However, the complete collection and multivariate regression analysis of all relevant audit fee and client data document a 24 % decrease in audit fees in 2005 and an average 15 % decrease in the two subsequent years due to auditor changes. This can be interpreted as an indicator for price competition. In addition, the audit fee data shows that the audit fee decreases are only partially compensated by subsequent increases. As a consequence, there is no evidence for lowballing at present. Further time series are necessary to show if the current trend is sustainable.     

Book reviews

E. Kofler, G. Menges: Entscheidungen bei unvollständiger Information. Lecture Notes in Economics and Mathematical Systems 136. Springer-Verlag, Berlin-Heidelberg-NewYork 1976, 357 S., DM 31.

B. S. Everitt: The Analysis ot Contingency Tables. Chapman and Han, London 1977, 128 S., £ 3.75.

O. Barndorff-Nielsen: Information and Exponential Families in Statistical Theory. J. Wiley & Sons, Chichester-New York-Brisbane-Toronto 1978, 247 S., £ 13.50; $ 28.50.

W. Gilchrist: Statisticai Forecasting. J. Wiley & Sons, London-New York-Sydney-Toronto 1976, 321 S., £ 9.50; $ 19.00.

J. M. Chambers: Computational Methods for Data Analysis. J. Wiley & Sons, New York Chichester-Brisbane-Toronto 1977, 279 pp., £ 11.30.

A. Hughes, D. Grawoig: Statistics: A Foundation for Analysis. Addison-Wesley Publishing Company, Reading-Menlo-Park London-Don Mills 1971, 525 S., $ 11.50.

K.Krickeberg, H.Ziezold: Stochastiche Methoden. Springer Verlag, Berlin-Heidelberg-New York 1977, 201 S., 13 Abb., DM 28.

Ch. Schneeweiss: Inventory-Production Theory. A Linear Policy Approach. Lecture Notes in Economics and Mathematical Systems 151. Springer Verlag, Berlin-Heidelberg-NewYork 1977, 122 S., 13 Abb., 9 Tab., DM 18.

S. Dworatschek: Grundlagen der Datenverarbeltung, 6., völlig neu bearb. u. erw. Aufl., Walter de Gruyter, Berlin-New York 1977, 538 S., 200 Abb., 212 Üb.Aufg., 59 Fotos, DM 38.

H. E. Steinhagen, S. Fuchs:Objekterkennung. Einführung in die mathematischen Methoden der Zeichenerkennung. VEB Verlag Technik, Berlin 1976, 436 S., 165 Abb., 32 Tab., 49,–.M.

G. Tinhofer: Mathematik für Studlenanfänger, Carl Hanser Verlag, München 1977, 464 S., 191 Abb., DM 38.     

The Independent Localisations of Interaction and Learning in the Repeated Prisoner's Dilemma

The results of a series of computer simulations demonstrate how the introduction of separate spatial dimensions for agent interaction and learning respectively affects the possibility of cooperation evolving in the repeated prisoner's dilemma played by populations of boundedly-rational agents. In particular, the localisation of learning promotes the emergence of cooperative behaviour, while the localisation of interaction has an ambiguous effect on it.     

Parental Involvement Laws and Minor and Non-Minor Teen Abortion and Birth Rates

The effects of parental notice and consent laws on abortion and birth rates were analyzed for two groups of teens: those 15 to 17 years old (i.e., minor teens) and those 18 to 19 years old (i.e., non-minor teens). Twelve states report abortion and birth statistics at the county level for these two age groups. The sample consists of 597 counties from these twelve states. Residence county abortion and birth rates were regressed against parental notice laws, parental consent laws, and several control variables (i.e., type of state public funding, population density, education and income levels, unemployment rate, family stability, extent of poverty, church membership, and geographic region).An important finding of this study is that both parental consent and notification laws were related to significantly lower abortion rates and to significantly higher birth rates for both minor and non-minor teens. Three measures (i.e., church membership, family stability, and education level) were related negatively and significantly to minor and non-minor teens' abortion rates and birth rates. One other measure (i.e., restrictive public funding) was related significantly to lower abortion rates and higher birth rates for minor and non-minor teens.     

Religion in families 1999 to 2009: A relational spirituality framework

This review examines the role of religion, for better and worse, in marital and parent-child relationships according to peer reviewed studies from 1999-2009. A conceptual framework labeled "relational spirituality" is used to: (a) organize the breadth of findings into the three stages of the formation, maintenance, and transformation of family relationships, and (b) illustrate three in-depth sets of mechanisms to delve into unique ways religion may shape family bonds. Topics include union formation, fertility, spousal roles, marital satisfaction and conflict, divorce, domestic violence, infidelity, pregnancy, parenting children, parenting adolescents, and coping with family distress. Conclusions emphasize moving beyond markers of general religiousness and identifying specific spiritual beliefs and practices that could prevent or intensify problems in traditional and nontraditional families.     

Admissibility of linear estimators with respect to restricted parameter sets

In this paper the admissibility of a linear estimator for a linear regression parameter is characterized for such cases, where the considered parameter varies in an ellipsoid. We obtain a certain subset of the set of all linear estimators which are admissible with respect to the unrestricted parameter set. Furthermore, various linear estimators which have been proposed for improving the least squares estimator in cases of a restricted parameter set are investigated for admissibility. It turns out that only some shrunken estimators and some estimators of ridge type are admissible, whereas the KUKS-OLMAN estimator and all estimators of MARQUARDT type can be improved.