Comments on the Interpretation of the Mechanism of Formation of Minor Products Accompanying the Catalytic Cracking of Cumene

The article “The Catalytic Cracking of Cumene” by Corma and Wojciechowski [11 discusses, among other things, mechanisms of formation of minor products accompanying dealkylation of isopro-pylbenzene. The mechanistic schemes advanced by the authors by artfully exhibited drawings seem to violate accepted principles of cationic reactions and ignore known facts of catalytic hydrocarbon conversions.     

Assessment of average,population and individual bioequivalence in two- and four-period crossover studies

The aim of bioequivalence studies is to assess the equivalence of two pharmaceutical formulations of the same active drug substance. Currently three types of bioequivalence are distinguished: average, population and individual bioequivalence. Average and population bioequivalence can be assessed in two-period (non-replicated) crossover studies, whereas individual bioequivalence requires three- or four-period replicated studies, with a preference for four-period studies. The PC-program BIOEQV80 is presented for the statistical analysis of average and population bioequivalence from two-period crossover studies. The program BIOEQ2X2 is presented for the statistical analysis of all three types of bioequivalence from four-period replicated crossover studies. The statistical aspects of population and individual bioequivalence are based on a recent Guidance issued by the US Food and Drug Administration.     

A Web-Based Knowledge Network for Supporting Emerging Internet Applications

Although the Internet and the World Wide Web technologies have gained a tremendous amount of popularity among people and organizations, the network that these technologies created is not much more than a multimedia data network. It provides tools and services for people to browse and search for data but does not provide the facilities for automatically delivering the relevant information for supporting decision–making to the right people or applications at the right time. Nor does it provide the means for users to enter and share their knowledge that would be useful for making the right decisions. In this work, we introduce the concept of a Web–based knowledge network, which allows users and organizations to publish, not only their multimedia data, but also their knowledge in terms of events, parameterized event filters, customizable rules and triggers that are associated with their data and application systems. Operations on the data and application systems may post events over the Internet to trigger the processing of rules defined by both information providers and consumers. The knowledge network is constructed by a number of replicable software components, which can be installed at various network sites. They, together with the existing Web servers, form a network of knowledge Web servers.     

A vehicle routing problem solved by using a hybrid genetic algorithm

The main purpose of this study is to find out the best solution of the vehicle routing problem simultaneously considering heterogeneous vehicles, double trips, and multiple depots by using a hybrid genetic algorithm. This study suggested a mathematical programming model with a new numerical formula which presents the amount of delivery and sub-tour elimination. This model gives an optimal solution by using OPL-STUDIO(ILOG CPLEX). This study also suggests a hybrid genetic algorithm (HGA) which considers the improvement of generation for an initial solution, three different heuristic processes, and a float mutation rate for escaping from the local solution in order to find the best solution. The suggested HGA is also compared with the results of a general genetic algorithm and existing problems suggested by Eilon and Fisher. We found better solutions rather than the existing genetic algorithms.     

An optimal image transform for threshold-based cloud detection using heteroscedastic discriminant analysis

We present a simple image transform that optimally combines four image channels into a greyscale image for threshold-based cloud detection. These image channels, namely blue, green, red and near infrared, are present on many low Earth-orbit resource satellites. Applying a single threshold to a greyscale image is a computationally efficient method suitable for onboard implementation. We used heteroscedastic discriminant analysis (HDA), which is a generalization of the popular dimension-reducing linear discriminant analysis, to transform the image. Comparative tests between HDA, existing transforms from the remote-sensing literature (the haze optimized and D transforms), as well as the single red and blue image channels were conducted. Although thin clouds remain challenging for global threshold-based techniques, the HDA transform consistently gave the best average segmentation errors across the test dataset. This dataset consisted of 32 1 megapixel Quickbird and Landsat images. HDA has not previously been applied to remote-sensing data.     

Three proteins involved in Caenorhabditis elegans vulval invagination are similar to components of a glycosylation pathway

We have molecularly analyzed three genes, sqv-3, sqv-7, and sqv-8, that are required for wild-type vulval invagination in Caenorhabditis elegans. The predicted SQV-8 protein is similar in sequence to two mammalian beta(1,3)-glucuronyltransferases, one of which adds glucuronic acid to protein-linked galactose-beta(1, 4)-N-acetylglucosamine. SQV-3 is similar to a family of glycosyltransferases that includes vertebrate beta(1, 4)-galactosyltransferases, which create galactose-beta(1, 4)-N-acetylglucosamine linkages. One model is therefore that SQV-8 uses a SQV-3 product as a substrate. SQV-7 is similar to members of a family of nucleotide-sugar transporters. The sqv genes therefore are likely to encode components of a conserved glycosylation pathway that assembles a C. elegans carbohydrate moiety, the absence of which perturbs vulval invagination.     

Minimal graphics

Photorealistic rendering of graphical models continues to be a topic of considerable research effort in the computer graphics community. However, photorealism isn't the only criterion for judging an image's value. In visualization, where rendering is the conduit through which abstract, nonrealistic forms (such as isosurfaces or streamtubes) become perceivable to users, photorealism may neither be the most useful nor appropriate property. This article describes our long-term research vision in an area that, in our view, should gain a lot of importance in the future