The MAPI method—Its effects on productivity: An alternative is needed

This paper examines the question of whether “cookbook” methods of equipment replacement and capital investment analysis have had an adverse effect on productivity. The MAPI method is scrupulously examined for this purpose. It is shown that MAPI is constructed around some rather binding assumptions that cannot be considered as valid in today's economic environment. A more traditional approach is advocated in this paper that will provide more accurate and reliable measures than MAPI. The proposed method requires that economic service lives be determined for all alternatives and an Annual Worth (AW) analysis be performed on each competing project's aftertax cash flow.     

Seasonal Phosphate Demand for Lake Erie Plankton

From April to mid-October 1979, in the eastern and central basins of Lake Erie, the pattern for phosphate demand was assessed by four independent methods: conventional monitoring, measurements of polyphosphate, phosphate turnover time, and a newly developed phosphate deficiency index. Thermal stratification and P limitation occurred faster in the central than in the eastern basin and the plankton remained P limited throughout most of the stratified season. This condition relaxed as the thermocline deepened in the central basin, exposing the epilimnion to a greater area of sediments. In September, when mixing of the entire water column occurred, the plankton were no longer P limited. In contrast, as the thermocline deepened in the eastern basin, metalimnetic water was entrained but the plankton remained P limited until mid-October. These observations support the view that a reduction of phosphorus in Lake Erie would probably affect the phytoplankton biomass during the periods of P limitation.     

Impermeant maleimides. Identification of an exofacial component of the human erythrocyte hexose transport mechanism

The facilitated diffusion of D-glucose across human erythrocyte membranes requires an exofacial (outer surface) sulfhydryl group which can be alkylated by the impermeant reagents glutathione-maleimide and dextran-maleimide. The irreversible inhibition produced by these reagents is asymmetric; inhibition of glucose efflux considerably exceeds that of influx when transport is assayed in the absence of glucose on the opposite side of the membrane. Both D-glucose and cytochalasin B protect the exofacial transport site from alkylation by the impermeant maleimides. This masking effect provides the basis for a two-step procedure for differential labeling of the outer transport site with radioactive glutathione-maleimide. The method labels clearly and consistently a component of the membrane proteins which migrates in sodium dodecyl sulfate-polyacrylamide gels between Coomassie brilliant blue-stained Bands 4.2 and 5, corresponding to an apparent molecular weight of 65,000 to 70,000. Transport studies after inhibition with N-ethylmaleimide suggest that the hexose mechanism also requires a second sulfhydryl group which is not accessible at the cell surface.     

Ionically bonded filler–elastomer composites

Tertiary amine-modified corn starches were converted to their basic or hydroxide form and combined with carboxylated butadiene–acrylonitrile copolymer and butadiene–styrene–sulfonic acid polymer to produce ionically bonded filler–elastomer composites. An increasing percentage of the elastomer fraction in the starch–elastomer composite is insolubilized as the starch-to-elastomer ratio increases. In addition to ionic bonding, a significant amount of elastomer is believed to be physically adsorbed onto the filler. The resulting composites are reprocessible, and some have sufficient tensile properties at room temperature for making rubber goods.     

Choosing between predictable and unpredictable shock conditions: Data and theory.

Reviews the literature on predictability and describes the factors that affect choice. Emphasis is given to the reliability of basic findings, including replications and failures to replicate. Behavioral measures related to choice are reviewed, and some physiological correlates of predictable and unpredictable shock are noted. The data allow several firm conclusions regarding preference, notably that (a) rats (albino, hooded, male, female) prefer predictable shock conditions; (b) they prefer predictable conditions whether shock is avoidable, escapable, or inescapable and whether it is scrambled or unscrambled grid shock; (c) this preference occurs with different procedures, apparatus, and shock delivery systems, such as water electrodes or electrodes attached to the tail, back, ears, or pubis bone; (d) fish and birds also prefer the signaled condition; and (e) although the preference is robust, it is affected by shock intensity, signal duration, intershock intervals, amount of training, and the dependability of shock-free periods. Other factors that may affect preference are also noted. Finally, the theoretical views of conditioned reinforcement, of information, of preparation, and of safety are evaluated, and their strengths and weaknesses are described (4 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Flame-Retarded polypropylene: A comparison of large- and small-scale tests

This paper describes work carried out on flame-retarded polypropylene comparing results on selected small-scale laboratory fire tests with those obtained on a larger-scale test designed to simulate the typical real life hazard situation. In the latter test a number of important parameters such as heat build-up, Hame spread, smoke development and gas evolution were assessed. The results indicate that there is need to use both types of tests to gain a fuller understanding prior to using new materials. An assessment based on small-scale tests alone could be misleading and allow the use of potentially hazardous material in the particular application involved.     

Model Induction with Support Vector Machines: Introduction and Applications

The rapid advance in information processing systems in recent decades had directed engineering research towards the development of intelligent systems that can evolve models of natural phenomena automatically—“by themselves,” so to speak. In this respect, a wide range of machine learning techniques like decision trees, artificial neural networks (ANNs), Bayesian methods, fuzzy-rule based systems, and evolutionary algorithms have been successfully applied to model different civil engineering systems. In this study, the possibility of using yet another machine learning paradigm that is firmly based on the theory of statistical learning, namely that of the support vector machine (SVM), is investigated. An interesting property of this approach is that it is an approximate implementation of a structural risk minimization (SRM) induction principle that aims at minimizing a bound on the generalization error of a model, rather than minimizing only the mean square error over the data set. In this paper, the basic ideas underlying statistical learning theory and SVM are reviewed, and the potential of the SVM for feature classification and multiple regression (modeling) problems is demonstrated by applying the method to two different cases of model induction from empirical data. The relative performance of the SVM is then analyzed by comparing its results with that of ANNs on the same data sets.     

Motion detection and stochastic resonance in noisy environments

Several motion detection schemes are considered and their responses to noisy signals investigated. The schemes include the Reichardt correlation detector, shunting inhibition and the Horridge template model. These schemes are directionally selective and independent of the direction of change in contrast. They function by using spatial information and comparing it at successive time intervals. A rudimentary noise analysis is performed on the Reichardt and inhibition detectors to compare their natural robustness against noise. Using these detectors, stochastic resonance (SR) is applied, which is characterised by an improvement in response when noise is added to the input signal. It is found that the performance of the detectors degrades with the addition of noise. Employing Stocks' suprathreshold SR, an improvement can be gained when considering a network of detectors. Furthermore, when using an incorrect threshold setting for the template model, SR can be displayed.