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.     

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.     

The Relationship Between Pathological Gambling and Sensation Seeking: The Role of Subscale Scores

Research investigating the relationship between gambling and sensation seeking has yet to establish conclusively whether pathological gamblers (PGs) are more or less sensation seeking than nonpathological gamblers (NPGs). Sensation seeking is usually measured with the Zuckerman et al. (J Consult Clin Psychol 46:139–149, 1978) SS Scale form V (SSS-V). Whereas previous studies relied on the SSS-V total score, the current study uses two samples to demonstrate the importance of the SSS-V subscales, which include Thrill and Adventure Seeking (TA), Experience Seeking (ES), Disinhibition (DS), and Boredom Susceptibility (BS). In two samples, strong intrascale correlations between DS and BS, and between TA and ES, suggest that certain subscales reflect similar underlying characteristics. In both samples PGs displayed higher scores than NPGs on the DS and BS subscales, with mean differences in Sample 2 reaching significant levels for both DS and BS. Results support the notion that the SSS-V can be divided into concepts reflecting actual behavior, based on the DS and BS subscales, and hypothetical behavior, based on the TA and ES subscales. Furthermore, PGs appear to have a preference for the more behavioral subscales while NPGs show a preference for the more hypothetical subscales. Reasons for the subscale divisions and preferences are discussed.     

Drivers of Change in the Democratic Republic of Congo: The Role of China in Re-Shaping the Country

Africa has always been potentially one of the richest continents in the world, but, due to a series of causes (colonization and decolonization process, wars, dictatorships etc.) it has never reached its full potential. The fight against poverty has been carried out by different institutions at the multilateral and bilateral level during the last 30 years, but the route toward economic development seems to be still long for African countries. This paper will focus on the analysis of the new approach to international cooperation introduced by the People’s Republic of China in order to exchange rights of exploitation of Africa’s mining and natural resources with large amounts of capital without any conditionality. The case-study which will be considered is the agreement concluded between the People’s Republic of China and the Democratic Republic of Congo.     

Managing Contradiction: Stockholder and Stakeholder Views of the Firm as Paradoxical Opportunity

Stockholder and stakeholder perspectives have been positioned in the literature as being in tension, and thus a potential source of innovation and change. However, researchers have overlooked a systematic examination of this presumption in theory and in practice. This study explores the ways that stockholder and stakeholder assumptions are presented by theorists and compares these with expressions of stockholder and stakeholder perspectives used by firms in practice. We argue that theoretical entrenchment dichotomizing these perspectives has disrupted the ability of researchers to leverage this tension. While scholarship remains trapped in a vicious cycle, we also argue that firms in practice express only the acceptance dimension of a virtuous cycle. Our empirical research demonstrates that firms accept and accommodate the paradoxical tension between managing for stockholders versus balancing the interests of stakeholders. This is evidenced by strategies we identify as book‐ending, cadence, continuous and simultaneous co‐mingling, and hybridization. We find that in practice these tensions are more integrated whereas in theory they are treated as more distinct and, often, in conflict. We suggest ways in which both scholarship and practice can better leverage tension as paradoxical opportunity.     

University Presidents’ Perceptions and Practice Regarding the Carrying of Concealed Handguns on College Campuses

Abstract

Objective: To assess the perceptions and practices of a national sample of college and university presidents regarding their support for concealed handguns being carried on college campuses. Participants: The sample for this study consisted of a national random sample of 900 college or university presidents. Methods: In the spring of 2013, a 3-wave mailing procedure was used to ensure an adequate response rate to a valid and reliable questionnaire. Results: The response rate was 46%, more than what was needed based on the power analysis. The vast majority (95%) of respondents were not supportive of carrying concealed handguns on campuses. They perceived there to be more disadvantages than advantages to handguns on campus. However, college administrators were not focused enough on the primary prevention of campus firearm trauma. Conclusions: The findings of this study suggest a number of activities that could be implemented to enhance safety on college and university campuses.     

Access Barriers to Mental Health Services for Older Adults from Diverse Populations: Perspectives of Leaders in Mental Health and Aging

This project is based on the results of telephone surveys with 52 local, state, and national informed respondents including policymakers, county leaders, planners, and advocates in mental health and aging with a particular focus on the states of California and Florida. This article addresses challenges to access to mental health services for diverse older adults including barriers related to race and ethnicity, socioeconomic status, location, age, gender, immigrant status, language, sexual orientation, and diagnosis. The article also highlights broad themes that emerged including (1) the importance of outreach and transportation tailored to diverse elders, and (2) recruitment of diverse staff and training related to diversity. The article concludes with policy and practice recommendations to reduce these disparities in access to mental health services for diverse populations of older adults.     

Toddlers Activate Lexical Semantic Knowledge in the Absence of Visual Referents: Evidence from Auditory Priming

Language learners rapidly acquire extensive semantic knowledge, but the development of this knowledge is difficult to study, in part because it is difficult to assess young children's lexical semantic representations. In our studies, we solved this problem by investigating lexical semantic knowledge in 24‐month‐olds using the Head‐turn Preference Procedure. In Experiment 1, looking times to a repeating spoken word stimulus (e.g., kitty‐kitty‐kitty) were shorter for trials preceded by a semantically related word (e.g., dog‐dog‐dog) than trials preceded by an unrelated word (e.g., juice‐juice‐juice). Experiment 2 yielded similar results using a method in which pairs of words were presented on the same trial. The studies provide evidence that young children activate of lexical semantic knowledge, and critically, that they do so in the absence of visual referents or sentence contexts. Auditory lexical priming is a promising technique for studying the development and structure of semantic knowledge in young children.