Number of choices and perceived decision freedom as a determinant of satisfaction and consumer behavior.

Studied how the number of choices confronting an individual influences his perceived decision freedom and, consequently, his satisfaction and consumption level. 72 college students, randomly assigned to 1 of 2 experimental conditions, were asked to select one soft drink flavor. Perceived decision freedom and consumption levels were significantly greater for those selecting from an enlarged-choice set, but there was no significant difference in the Ss' stated satisfaction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Polarity dependent oxide defects located using liquid crystals

Liquid crystals have been used to study, non-destructively, the localized regions of high conductivity known to be present in thin layers of silicon dioxide grown thermally on n type silicon. The polarity dependence of the turbulence in the liquid crystals, together with the growth in the number of defects with time suggests that mobile impurity ions play an important role.     

Theoretical spectrum-threshold detector data correlation in EBR-II

An experimental and computer program to further examine the neutron environment in the Experimental Breeder Reactor-II (EBR-II) has been completed. Monte Carlo and S₄ Transport methods were used to determine the neutron spectrum at various positions in the EBR-II core and blanket regions. Response functions for the threshold detectors ⁵⁸Ni (n, p) ⁵⁸Co and ⁵⁴Fe (n, p) ⁵⁴Mn were determined for each position and the corresponding predicted induced activities are compared with experimental results. Based on combinations of calculated neutron spectra, experimental detector responses, and cross section end points an empirical differential cross section was determined for the ⁴⁶Ti (n, p) ⁴⁶Sc threshold reaction. Spectrum averaged cross sections for the three threshold reactions which have been determined at various positions in this facility suggest that significant errors in fast neutron fluences will result if the usual fission spectrum averaged cross sections are used.     

Multifrequency ultrasound transducers for conformal interstitial thermal therapy

Control over the pattern of thermal damage generated by interstitial ultrasound heating applicators can be enhanced by changing the ultrasound frequency during heating. The ability to change transmission frequency from a single transducer through the use of high impedance front layers was investigated in this study. The transmission spectrum of multifrequency transducers was calculated using the KLM equivalent circuit model and verified with experimental measurements on prototype transducers. The addition of a quarter-wavelength thick PZT (unpoled) front layer enabled the transmission of ultrasound at two discrete frequencies, 4.7 and 9.7 MHz, from a transducer with an original resonant frequency of 8.4 MHz. Three frequency transmission at 3.3, 8.4, and 10.8 MHz was possible for a transducer with a half-wavelength thick front layer. Calculations of the predicted thermal lesion size at each transmission frequency indicated that the depth of thermal lesion could be varied by a factor of 1.6 for the quarter-wavelength front layer. Heating experiments performed in excised liver tissue with a dual-frequency applicator confirmed this ability to control the shape of thermal lesions during heating to generate a desired geometry. Practical interstitial Designs that enable the generation of shaped thermal lesions are feasible.     

Fatigue-crack growth in Ti-6Al-4V-0.1Ru in air and seawater: Part II. crack path and microstructure

In Part I of this article, the influence of various testing parameters and environments on the fatigue-crack growth rates in samples of beta-annealed Ti-6Al-4V-0.1Ru (extra-low interstitials) ELI was reported.^[1] A design-of-experiments (DOE) approach was used to survey different combinations of variables, all expected to be important for dynamically loaded offshore oil and gas production risers, and to identify significant effects on the fatigue-crack propagation rate at a stress-intensity range of ΔK=17 MPa . The da/dN vs ΔK curves also were examined for the DOE and supplementary tests, and the results of the two approaches were compared. In this part of the study, the microstructural basis for the robust fatigue-crack growth resistance of beta-annealed Ti-6Al-4V-0.1Ru (ELI) samples was investigated with optical metallography and scanning electron microscopy (SEM). A gradual transition from structure-sensitive (microfacet formation) to structure-insensitive (striation formation) crack propagation centered at ΔK _trans ≅24 MPa , regardless of the combination of testing/environmental conditions examined; the absence of a sharp transition in the slope of the da/dN vs ΔK curves was, therefore, entirely consistent with the fracture-surface morphology. The size of the reversed cyclic plastic zone at the transition ΔK value correlated with the size of the lamella packets, but the number of cycles required to generate a striation ranged between one and ten, suggesting that the crack actively grew over only a portion of its front at any one instant. It is interesting to note that ΔK _trans was the same as the stress range where the da/dN curves at 0.2, 2, and 20 Hz (in seawater) converged to a single curve (refer to Part I of this article): at lower stress ranges, crack growth rates at 20 Hz were significantly higher than those at 0.2 and 2 Hz. The quantitative data showed that fatigue cracks propagated parallel to lamellae interfaces when the long axes of the lamellae made a relatively small angle (<30 deg) to the nominal crack-propagation direction. The crack cut directly across lamellae (i.e., perpendicular to their surfaces) when the long axes of the lamellae were nearly perpendicular to the nominal crack-propagation direction. If the lamellae long axes lay 45 deg to the crack-propagation direction, the crack deflected to run parallel or perpendicular to the lamellae. This behavior occurred regardless of the environment and loading conditions investigated. There was considerable variation in the amount that the cracks deviated from their nominal plane (i.e., the plane normal to the load axis and through the notch tip), with much greater deflections in the cold-rolled than in the parent material, but the angle of the macroscopic crack plane did not exceed 11 deg. Crack branching was observed both at the center and outer surfaces of the samples, regardless of ΔK or other parameters. The relationship between micro- and macrobranches was examined, and branching was more prominent below ΔK _trans, which separated the structure-sensitive and continuum-mode crack-propagation regimes. The relative amounts of micro- and microbranches are reported, and this branching may explain the large scatter in the measurements of the fatigue-crack growth rate often encountered in Ti-6Al-4V and its variants and points to the need for thorough characterization of crack paths, both midplane and surface, as part of the interpretation of da/dN vs ΔK data.     

A hybrid ASM approach for sparse volumetric data segmentation

Three-Dimensional (3D) Active Shape Modeling (ASM) is a straightforward extension of 2D ASM. 3D ASM is robust when true volumetric data is considered. However, when the information in one dimension is sparse, pure 3D ASM tends to be less robust. We present a hybrid 2D + 3D methodology which can deal with sparse 3D data. 2D and 3D ASMs are combined to obtain a “global optimal” segmentation of the 3D object embedded in the data set, rather than the “locally optimal” segmentation on separate slices. Experimental results indicate that the developed approach shows equivalent precision on separate slices but higher consistency for whole volumes when compared to 2D ASM, while the results for whole volumes are improved when compared to the pure 3D ASM approach. The text was submitted by the authors in English. Stuart Michael Williams, born in 1967, graduated with BAHons in 1989, BMBCh in 1992 from Oxford University, UK; MRCP (1995), FRCR(1999); Stuart Michael Williams is currently the Consultant Radiologist of Norfolk and Norwich University Hospital, Norwich, UK. His research areas include oncological radiology with an interest in image analysis and medical education. Stuart Michael Williams has 24 publications (monographs and articles). He is a member of the Royal College of Radiologists; member of the European Congress of Radiology; and a member of the European Society of Magnetic Resonance in Medicine and Biology. Yanong Zhu, born in 1975, graduated with B. Sci. in 1997 and M. Sci. in 2002 from Northwest University, China and PhD in 2006 from the University of East Anglia, Norwich, UK. His research areas include computer vision, medical image understanding, and analysis. Yanong Zhu has eight publications (monographs and articles). Reyer Zwiggelaar, born in 1963, graduated with B. Sci. from State University Groningen, the Netherlands in 1989. He was awarded his PhD in 1993 by University College London, UK. Reyer Zwiggelaar is currently the Senior Lecturer at the University of Wales Aberystwyth, UK. Dr. Zwiggelaar has more than 80 publications (monographs and articles). His research areas include medical image understanding, especially concentrating on mammographic data, pattern recognition, statistical methods, and feature detection techniques.     

The evidence missing from evidence-based practice.

Comments on the report by the APA Presidential Task Force on Evidence-Based Practice (see record 2006-05893-001) entitled Evidence-based practice in psychology. Regrettably, the task force report was largely silent on three critical issues. As a consequence, it omitted much of the evidence necessary for a complete picture of evidence-based practice. First, the task force report did not operationalize "evidence." Second, the task force report did not address the crucial problem of iatrogenic treatments. Third, the task force report said little about the necessity for ongoing objective evaluation of clinical cases, which is critical to ethically responsible services. Current debate centers on how research findings should be factored into interventions, not on whether it is necessary to do so. Rather than waiting for the resolution of competing views on the matter, psychologists bear an ethical obligation to offer evidence-informed services. Three critical steps that were largely neglected by the task force report can go far toward helping psychologists honor that commitment: (a) providing a clearer operationalization of scientific evidence, (b) using current research to rule out the use of potentially harmful methods, and (c) using objective criteria to evaluate all of their cases on an ongoing basis. These steps, in turn, clarify the menu of options available to therapists, help protect clients from harm, and offer the advantage of allowing clinicians to contribute to the growing body of knowledge about what does and does not work in psychotherapy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

THE SCIENCE OF CYBERNETICS AND THE CYBERNETICS OF SCIENCE

Recent developments in cybernetics have challenged key tenets in the philosophy of science. The philosophy of science constitutes a theory of knowledge that is often called realism. However, the philosophy of science is not a unified field, there are a variety of points of view. Contemporary cybernetics, meanwhile, is developing a philosophy called constructivism. This paper compares cybernetics with two important schools of thought within the philosophy of science, lists several different assumptions that lead to misunderstandings between scientists and cyberneticians, and then suggests a way of resolving the differences not by rejecting science but by enlarging it.     

On the role of search for learning from examples

Gold (1967) discovered a fundamental enumeration technique, the socalled identification-by-enumeration, a simple but powerful class of algorithms for learning from examples (inductive inference). We introduce a variety of more sophisticated (and more powerful) enumeration techniques and characterize their power. We conclude with the thesis that enumeration techniques are even universal in that each solvable learning problem in inductive inference can be solved by an adequate enumeration technique. This thesis is technically motivated and discussed.     

Remote sensing of phytoplankton pigments: A comparison of empirical and theoretical approaches

Algorithms that have been used on a routine basis for remote sensing of the phytoplankton pigment, chlorophyll- a, from ocean colour data from satellite sensors such as the CZCS (Coastal Zone Color Scanner), SeaWiFS (Sea Viewing Wide Field-of-View Sensor) and OCTS (Ocean Colour and Temperature Scanner) are all of an empirical nature. However, there exist theoretical models that allow ocean colour to be expressed as a function of the inherent optical properties of seawater, such as the absorption coefficient and the backscattering coefficient. These properties can in turn be expressed as functions of chlorophyll- a, at least for the so-called Case 1 waters in which phytoplankton may be considered to be the single, independent variable responsible for most of the variations in the marine optical properties. Here, we use such a theoretical approach to model variations in ocean colour as a function of chlorophyll- a concentration, and compare the results with some empirical models in routine use. The parameters of phytoplankton absorption necessary for the implementation of the ocean colour model are derived from our database of over 700 observations of phytoplankton absorption spectra and concurrent measurements of phytoplankton pigments by HPLC (High Performance Liquid Chromatography) techniques. Since there are reports in the literature that significant differences exist in the performance of the algorithms in polar regions compared with lower latitudes, the model is first implemented using observations made at latitudes less than 50. It is then applied to the Labrador Sea, a high-latitude environment. Our results show that there are indeed differences in the performance of the algorithm at high latitudes, and that these differences may be attributed to changes in the optical characteristics of phytoplankton that accompany changes in the taxonomic composition of their assemblages. The sensitivities of the model to assumptions made regarding absorption by coloured dissolved organic matter (or yellow substances) and backscattering by particles are examined. The importance of Raman scattering on ocean colour and its influence on the algorithms are also investigated.