An Alternative Perspective: A Critical Evaluation of the Waddell Threshold Extrapolation Model in Chemical Carcinogenesis

In a recent Perspective article ( Toxicologic Pathology 31: 260—262, 2003) Waddell asserts that he has developed a log linear extrapolation model that can demonstrate a threshold and resolve for once and for all the uncertainies associated with low dose cancer risk extrapolation. However, his method essentially forces, rather than demonstrates, a threshold, and has many serious flaws that result in significant under-estimation of low dose risk. It would be a serious mistake for the scientific community to adopt Waddell's log linear extrapolation model for chemical carcinogenesis risk assessment.

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’n Waardering vir die positiewe! Waarderende betrokkenheid as ‘n gemeentelike- en pastorale lens

HTS Teologiese Studies / Theological Studies ◽

10.4102/hts.v67i2.887 ◽

2011 ◽

Vol 67 (2) ◽

Cited By ~ 1

Author(s):

Kobus Schoeman ◽

Jan Albert Van den Berg

Keyword(s):

Appreciative Inquiry ◽

Practical Theology ◽

Traditional Approach ◽

Critical Evaluation ◽

Pastoral Ministry ◽

Congregational Studies ◽

Alternative Perspective

An appreciation for the positive! Appreciative engagement as congregational process and congregational- and pastoral lens The traditional approach of only solving what is wrong is challenged by newer perspectives emphasising the meaning of an appreciation for the positive. The possible meaning of this alternative perspective for the development of a relevant positive practical theology was explored in investigating the possible meaning of the methodology of appreciative inquiry. The benefit of this model, for congregational studies and pastoral ministry amongst others, was investigated, described and illustrated with a case study. After a critical evaluation of the methodology of appreciative inquiry, suggestions for the development of a relevant positive practical theology, incorporating an appreciation for the positive in an appreciative engagement were mapped.

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Technology, innovation, employment and power: Does robotics and artificial intelligence really mean social transformation?

Journal of Sociology ◽

10.1177/1440783317726591 ◽

2017 ◽

Vol 54 (3) ◽

pp. 331-345 ◽

Cited By ~ 23

Author(s):

Ross Boyd ◽

Robert J. Holton

Keyword(s):

Artificial Intelligence ◽

Technological Innovation ◽

Social Transformation ◽

Critical Evaluation ◽

Future Trends ◽

Technological Determinism ◽

Sociological Approach ◽

Alternative Perspective ◽

Political Economic ◽

Discursive Power

How far do recent innovations in robotics and artificial intelligence herald an unprecedented economic and social transformation? This article provides a critical evaluation of this question, challenging the relentless technological determinism of much debate, and reframing the issues involved within a political-economic and sociological approach. This focuses on the economic, political and historical dynamics of technological innovation, and its consequences for employment and economic re-structuring, mediated through sovereign and discursive power. A range of epistemological and empirical problems with the transformationist position are identified, and an alternative perspective proposed emphasizing complexity and uncertainty around contemporary and future trends.

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Electron Microscopy of Metal-Matrix Composites

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069016 ◽

1970 ◽

Vol 28 ◽

pp. 404-405

Author(s):

A. Lawley ◽

M. R. Pinnel ◽

A. Pattnaik

Keyword(s):

Electron Microscopy ◽

Metal Matrix Composites ◽

Metal Matrix ◽

Critical Evaluation ◽

Elastic Behavior ◽

Matrix Composites ◽

Directionally Solidified ◽

Fracture Characteristics ◽

Broad Program

As part of a broad program on composite materials, the role of the interface on the micromechanics of deformation of metal-matrix composites is being studied. The approach is to correlate elastic behavior, micro and macroyielding, flow, and fracture behavior with associated structural detail (dislocation substructure, fracture characteristics) and stress-state. This provides an understanding of the mode of deformation from an atomistic viewpoint; a critical evaluation can then be made of existing models of composite behavior based on continuum mechanics. This paper covers the electron microscopy (transmission, fractography, scanning microscopy) of two distinct forms of composite material: conventional fiber-reinforced (aluminum-stainless steel) and directionally solidified eutectic alloys (aluminum-copper). In the former, the interface is in the form of a compound and/or solid solution whereas in directionally solidified alloys, the interface consists of a precise crystallographic boundary between the two constituents of the eutectic.

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