Statistical procedures for evaluating the practical utility of a moderator approach to prediction.

Describes 3 statistical procedures for evaluating the practical utility of a moderator approach. Each procedure gives tests of significance for the comparison of 3 prediction strategies: (a) using the moderator variable as a basis for subgrouping Ss and computing separate regression equations, (b) using the moderator variable as a predictor variable, or (c) excluding the moderator variable from the prediction model. It is concluded that when job performance is measured along a continuum, the average y score of the selected group (Procedure 1) should be considered. However, when 2 levels of job performance are measured, (e.g., pass-fail grades) then either the number of selection errors (Procedure 2) or the number of selection errors when a selection ratio constraint is present (Procedure 3) should be used. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Women as TV Experts: The Voice of Authority?

Three-yeax study shows more women experts selling products for women but still backed up by the "known quantity" of an authoritative male uoice-over.     

Task difficulty and conformity pressures.

This study using 60 Ss showed that conformity pressures are more easily exerted when the person is poorly informed with respect to questions of general information. When certain of the correct answers, the person is more easily able to resist pressures, but when uncertain he is more prone to use supplemental external information as the basis for making responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A study of the motion and deformation of the heart due to respiration

This paper describes a quantitative assessment of respiratory motion of the heart and the construction of a model of respiratory motion. Three-dimensional magnetic resonance scans were acquired on eight normal volunteers and ten patients. The volunteers were imaged at multiple positions in the breathing cycle between full exhalation and full inhalation while holding their breath. The exhalation volume was segmented and used as a template to which the other volumes were registered using an intensity-based rigid registration algorithm followed by nonrigid registration. The patients were imaged at inhale and exhale only. The registration results were validated by visual assessment and consistency measurements indicating subvoxel registration accuracy. For all subjects, we assessed the nonrigid motion of the heart at the right coronary artery, right atrium, and left ventricle. We show that the rigid-body motion of the heart is primarily in the craniocaudal direction with smaller displacements in the right-left and anterior-posterior directions; this is in agreement with previous studies. Deformation was greatest for the free wall of the right atrium and the left ventricle; typical deformations were 3-4 mm with deformations of up to 7 mm observed in some subjects. Using the registration results, landmarks on the template surface were mapped to their correct positions through the breathing cycle. Principal component analysis produced a statistical model of the motion and deformation of the heart. We discuss how this model could be used to assist motion correction.     

Elevated temperature deformation behavior of dispersion-strengthened Al and Al-Li-Mg alloys

A model describing the behavior of dispersion-strengthened aluminum alloys, when subjected to elevated temperature plastic deformation, is presented. The aims are twofold:

1. to use the model for extrapolation of laboratory data to predict behavior under service conditions where the strain rate is extremely low (<10^?9 s^?1); and
2. to design and fabricate materials having specific elevated temperature properties based on microstructural predictions from the model.

The results of constant strain-rate compression tests covering a range of temperatures from 250 to 550 °C and strain rates of 5 × 10^?5 to 10^?1 s^?1 are presented in conjunction with microstructural investigations using transmission electron microscopy (TEM) and x-ray diffraction. Materials mechanically alloyed with (a) no dispersoids, (b) 23 nm radius TiO₂ dispersoids, and (c) 10 nm diameter Al₂O₃ dispersoids have been studied. The effect of varying the volume fraction of the TiO₂ dispersoids and adding alloying additions of Mg and Li to the matrix Al have been investigated. In addition, the TiO₂ particles are shown to have reacted to form Al₃Ti. An adaptation to the detachment model of Rösler and Arzt has been proposed to account for the behavior of these types of materials and to enable accurate prediction of deformation behavior at elevated temperatures and low strain rates.     

Evidence for Use of Chemical Cues by Male Horseshoe Crabs When Locating Nesting Females (Limulus polyphemus)

Horseshoe crabs come ashore in attached pairs during spring high tides to mate and nest on beaches of the Atlantic and Gulf coasts. Unattached males also come ashore and crowd around the nesting pairs as satellites and engage in sperm competition with the attached male. Females with no satellites and females with large numbers of satellites nest next to one another on the same tide. When females are removed and replaced by a cement model, satellite males continue to be attracted to the same location. Models over sites where females with many satellites had nested are more attractive to males than sites from which a female with no satellites had been removed or a site where no crab had been nesting recently. A second experiment demonstrated that males are responding to chemical cues. A sponge filled with seawater taken from below a female with many satellites and placed under a model female was more attractive to males than a sponge filled with seawater. This is the first demonstration that horseshoe crabs use chemical cues, in addition to visual cues, to locate mates.     

Apoptosis in the mature and developing olfactory neuroepithelium

Neuronal apoptosis is important in the developmental sculpting of a normal nervous system and also in the loss of neurons caused by neurodegenerative disease, ischemia or trauma. In a developing embryo, exquisite mechanisms of regulation exist to balance factors that control neuronal birth and death within a given neuronal group, so that sufficient neurons develop and survive to elicit normal function. Postnatally, the only part of the mammalian nervous system where many of these regulatory balance mechanisms are retained is the olfactory epithelium (OE). During the last 30 years, researchers investigating olfactory receptor neuron cellular and developmental biology have focussed on the regeneration of the neuronal population within the olfactory neuroepithelium, following the induced death of the mature neuronal population. This body of work has thus far overshadowed the equally important and intrinsically linked phenomenon of the death of mature olfactory receptor neurons, which is required to initiate regeneration. The purpose of this review is to reveal what has been established about the different forms of cell death that can occur in neurons of the olfactory epithelium, and highlight the identified pro- and anti-apoptotic pathways that control the normal and induced turnover of olfactory receptor neurons.     

Building a Medical Decision Support System for Colon Polyp Screening by Using Fuzzy Classification Trees

To deal with highly uncertain and noisy data, for example, biochemical laboratory examinations, a classifier is required to be able to classify an instance into all possible classes and each class is associated with a degree which shows how possible an instance is in that class. According to these degrees, we can discriminate the more possible classes from the less possible classes. The classifier or an expert can pick the most possible one to be the instance class. However, if their discrimination is not distinguishable, it is better that the classifier should not make any prediction, especially when there is incomplete or inadequate data. A fuzzy classifier is proposed to classify the data with noise and uncertainties. Instead of determining a single class for a given instance, fuzzy classification predicts the degree of possibility for every class.Adenomatous polyps are widely accepted to be precancerous lesions and will degenerate into cancers ultimately. Therefore, it is important to generate a predictive method that can identify the patients who have obtained polyps and remove the lesions of them. Considering the uncertainties and noise in the biochemical laboratory examination data, fuzzy classification trees, which integrate decision tree techniques and fuzzy classifications, provide the efficient way to classify the data in order to generate the model for polyp screening.     

Securing Statically-verified Communications Protocols Against Timing Attacks

We present a federated analysis of communication protocols which considers both security properties and timing. These are not entirely independent observations of a protocol; by using timing observations of an executing protocol it is possible to calculate encryption keys which were intended to be secret or to deduce derived information about the nature of the communication even in the presence of unbreakable encryption. Our analysis is based on expressing the protocol as a high-level model and deriving from this process calculus models analysable by the Imperial PEPA Compiler and the LySatool.