Pure Significance Tests of the Unit Root Hypothesis Against Nonlinear Alternatives

Abstract. This paper describes artificial neural network based pure significance tests for the unit root hypothesis against nonlinear alternatives. The theoretical properties of the tests are discussed and a Monte Carlo investigation of their small sample properties is undertaken.     

Corrosion and Crack Growth in 33% Na2O-67% SiO2 and 33% Li2O-67% SiO2 Glasses

Environmentally enhanced crack growth data for 33% Na₂O-67% SiO₂ and 33% Li₂O-67% SiO₂ (mol%) were obtained. Corrosion data for the same glasses as determined by infrared reflection spectroscopy and atomic absorption spectroscopy were also measured. It was determined that, of the tested environments, those and only those environments which caused surface corrosion also enhanced crack growth. Crack growth curves were more complicated for these materials than for fused silica. Water-dominated regions occurred even in environments which are known to enhance crack growth.     

Heating Characteristics of Homogeneous Milk-Based Formulas in Cans Processed in an Agitating Retort

Milk-based formulas with proximate analyses similar to infant formulas were heated to determine influence of headspace, reel speed, solids content, and consistency on F_o. Concentrations with 12.5, 25, and 30% solids were heated in three can sizes. Increasing Steritort rpm from 3.4 to 10.9 for 307 × 710 cans (12.5% solids) had greatest effect; the F_o increased from 9.8 to 12.3. The same increase in rpm for a continuous retort would reduce F_o from 9.8 to 2.0 because of reduced processing time. Solids content and consistency influenced heating, but variations in consistency of a given concentration had no measurable effect on F_o. Headspace influenced heating for each concentration, but was not as critical as for more viscous products.     

Growth of the Acid-Tolerant Fungus Scytalidium acidophilum as a Potential Source of Single-Cell Protein

An acid-tolerant fungus, Scytalidium acidophilum, was cultivated in peat extract for potential use as a single-cell protein (SCP) source. In shake flask fermentations with a 0.3% yeast extract diluted peat extract medium, it was found that the best conditions for growth occurred at pH 2.0 and 25°C. The maximum biomass concentration was produced after 10 days, with no significant differences for agitation rates between 100 and 200 rpm. Microbial contamination was not observed in nonaseptic operations. The protein content and amino acid composition of the mycelium produced compares with those reported for S. acidophilum grown in other fermentation media. The advantages of growing S. acidophilum in acid peat extract are presented.     

A City Metaphor to Support Navigation in Complex Information Spaces

A major problem in modern information systems is to locate information and to re-find information one has seen before. Systems like the World Wide Web are heavily interlinked, but do not show structures that help users to navigate the information it contains. The use of appropriate navigation metaphors can help to make the structure of modern information systems easier to understand and therefore easier to use.We propose a conceptual user interface metaphor based on the structure of a city. Cities are very complex spatial environments and people know how to get information, how to reach certain locations in a city, and how to make use of the available infrastructure, etc. Cities provide a rich set of navigational infrastructure that lends itself to creating sub-metaphors for navigational tools. A city metaphor makes this existing knowledge about a structured environment available to the user of a computerized information system.We first focus on several properties necessary for future user interfaces (or user interface metaphors) that will distinguish them from current systems, like the richness of information or the use of visualizations to show the structure of information spaces. We also describe the strengths and problems of spatial user-interface metaphors. Then we present the structure of the information city metaphor, its structuring and navigation metaphors and what we see as its main advantages and problems. We further outline a few scenarios of how an Information City might work. Finally, we compare implementing this metaphor using either a textual or a graphical virtual environment or a combination.     

An investigation of the electrochemical reduction of pentachlorophenol with analysis by HPLC

A study has been made of the electrochemical reduction of pentachlorophenol (PCP) on a lead electrode in both water and propylene carbonate. A combination of voltammetric measurements and analysis of reaction products by high performance liquid chromatography (HPLC) have established that the reduction of PCP in propylene carbonate occurs by two different pathways, depending upon the electrode potential. At -1.9V vs SCE, reduction is mediated by adsorbed hydrogen, whereas at -2.3V vs SCE direct reduction of PCP also occurs. A similar approach has established that the reduction of PCP in water follows only one reaction pathway, namely, direct electron transfer from lead to PCP.     

Strategic management control

Throughout this account, the growing interest in management strategy, as a subject which can be planned, as well as described, by upper-echelon managers has been indicated.

The most important concept that has been outlined is that the need for a planned management strategy arises directly from the task which management sets itself when it tries to control its environment. It is not merely a need which becomes apparent at a high level of management complexity, but is inherently part of the function of management.

The second important idea, implicit throughout this account, and made explicit in §7, is that models of the organization are baaed on axioms which must be outlined at the highest level of control in an organization—by the board of directors : thus, the board have a direct influence, as well as ultimate responsibility, in the modelling activities of managers who construct and carry out planned strategic decisions.     

A guide to analysis and reconstruction of serial block face scanning electron microscopy data

Serial block face scanning electron microscopy (SBF‐SEM) is a relatively new technique that allows the acquisition of serially sectioned, imaged and digitally aligned ultrastructural data. There is a wealth of information that can be obtained from the resulting image stacks but this presents a new challenge for researchers – how to computationally analyse and make best use of the large datasets produced. One approach is to reconstruct structures and features of interest in 3D. However, the software programmes can appear overwhelming, time‐consuming and not intuitive for those new to image analysis. There are a limited number of published articles that provide sufficient detail on how to do this type of reconstruction. Therefore, the aim of this paper is to provide a detailed step‐by‐step protocol, accompanied by tutorial videos, for several types of analysis programmes that can be used on raw SBF‐SEM data, although there are more options available than can be covered here. To showcase the programmes, datasets of skeletal muscle from foetal and adult guinea pigs are initially used with procedures subsequently applied to guinea pig cardiac tissue and locust brain. The tissue is processed using the heavy metal protocol developed specifically for SBF‐SEM. Trimmed resin blocks are placed into a Zeiss Sigma SEM incorporating the Gatan 3View and the resulting image stacks are analysed in three different programmes, Fiji, Amira and MIB, using a range of tools available for segmentation. The results from the image analysis comparison show that the analysis tools are often more suited to a particular type of structure. For example, larger structures, such as nuclei and cells, can be segmented using interpolation, which speeds up analysis; single contrast structures, such as the nucleolus, can be segmented using the contrast‐based thresholding tools. Knowing the nature of the tissue and its specific structures (complexity, contrast, if there are distinct membranes, size) will help to determine the best method for reconstruction and thus maximize informative output from valuable tissue.     

Sequence dependent set-up times and job sequencing

On many machine tools the set-up times are sequence dependent; that is, the time to set-up for the new part is dependent upon the part for -which the machine is currently set-up. In scheduling lots on the machine, the set-up time is often a significant component of the total time required to complete each lot. Set-up times are frequently not available to the production scheduler, and when they are, they frequently are only averages which conceal the sequence dependency of the set-up times. In this paper, we first develop a procedure that classifies set-up operations and predicts the set-up times and we then develop a method for sequencing the jobs so as to minimize the total set-up time. An example using real world data is used to illustrate these procedures