Evaluation of the EVA Descriptor for QSAR Studies: 3. The use of a Genetic Algorithm to Search for Models with Enhanced Predictive Properties (EVA_GA)

The EVA structural descriptor, based upon calculated fundamental molecular vibrational frequencies, has proved to be an effective descriptor for both QSAR and database similarity calculations. The descriptor is sensitive to 3D structure but has an advantage over field-based 3D-QSAR methods inasmuch as structural superposition is not required. The original technique involves a standardisation method wherein uniform Gaussians of fixed standard deviation (σ) are used to smear out frequencies projected onto a linear scale. This smearing function permits the overlap of proximal frequencies and thence the extraction of a fixed dimensional descriptor regardless of the number and precise values of the frequencies. It is proposed here that there exist optimal localised values of σ in different spectral regions; that is, the overlap of frequencies using uniform Gaussians may, at certain points in the spectrum, either be insufficient to pick up relationships where they exist or mix up information to such an extent that significant correlations are obscured by noise. A genetic algorithm is used to search for optimal localised σ values using crossvalidated PLS regression scores as the fitness score to be optimised. The resultant models are then validated against a previously unseen test set of compounds. The performance of EVA_GA is compared to that of EVA and analogous CoMFA studies

Representations of the homotopy surface category of a simply connected space

We introduce the homotopy surface category of a space which generalizes the 1+1-dimensional cobordism category of circles and surfaces to the situation where one introduces a background space. We explain how for a simply connected background space, monoidal functors from this category to vector spaces can be interpreted in terms of Frobenius algebras with additional structure.Comment: 9 pages, 2 figure

The BSE Crisis and the Price of Red Meat in the UK

This paper presents estimates of price functions for beef, lamb and pork for the UK economy which allow for the effects of the 1996 BSE crisis. Our estimates illustrate the importance of allowing for the joint endogeneity of prices in these markets. We show that the effects of this crisis had a significant negative effect on the price of beef and a positive and significant effect on the price of lamb. However, there appears to have been little effect on the price of pork

The EVA spectral descriptor

The EVA descriptor is derived from fundamental IR- and Raman range molecular vibrational frequencies. EVA is sensitive to 3D structure but has an advantage over field-based 3D-QSAR methods inasmuch as it is invariant to both translation and rotation of the structures concerned and thus structural superposition is not required. The latter property and the demonstration of the effectiveness of the descriptor for QSAR means that EVA has been the subject of a great deal of interest from the modelling community. This review describes the derivation of the descriptor, details its main parameters and how to apply them, and provides an overview of the validation that has been done with the descriptor. A recent enhancement to the technique is described which involves the localised adjustment of variance in such a way that enhanced internal and external predictivity may be obtained. Despite the statistical quality of EVA QSAR models the main draw-back to the descriptor at present is the difficulty associated with back-tracking from a PLS model to an EVA pharmacophore. Brief comment is made on the use of the EVA descriptor for diversity studies and the similarity searching of chemical structure databases

Convergence and Diversity in International and Comparative Industrial Relations

[Excerpt] In this essay, we reexamine a critical paradox in international and comparative industrial relations, a paradox that already decades ago demonstrated its ability to intrigue scholarly curiosity (Galenson, 1952,1963; Kerr et al, 1960). As we see it, convergence along a number of important dimensions, such as labor law and organizational and bargaining structure, is occurring simultaneously with widespread cross-national and local divergence, or diversity, in industrial relations practices and outcomes. Along with economic and political interdependence and with intensifications of market competition, convergence and diversity both appear to be product of an increasing spread of markets and ideas sometimes referred to as globalization. In employing this term, we intend to make the point that the conduct of global business is no longer confined to the sort of international trading and related activities that have been carried on for centuries already. In the modern era, the production and exchange of both goods and services occur increasingly on a global scale (Reich, 1991). At this level, as capital mobility expands and trade agreements proliferate (NAFTA, CATT, the single European market), national governments find it increasingly difficult to regulate markets. This globalization of markets, we suggest, is the dominant force driving change (whether toward convergence or diversity) in the contemporary period. Our observations are especially applicable to the advanced industrial countries of the Organization for Economic Cooperation and Development (OECD), the primary focus of this paper, although the trends identified here probably also hold to some extent for newly industrialized countries and less developed societies as well

Estimating Quarterly GDP for the Interwar UK Economy: An Application to the Employment Function

Chow and Lin (1971) set out a procedure for the generation of higher frequency estimates for series for which data is available at a low frequency using data on a related series at the higher frequency. In this paper we set out a simple algorithm for the generation of quarterly estimates for a series for which annual data is available and quarterly data is available for the related series. We apply this to data for interwar Gross Domestic Product using Industrial Production as the related series. Using this approach we generate quarterly GDP figures for the period 1920.1 to 1938.4. This series is valuable in that it can be used to estimate a cointegrating relationship between employment, real wages and aggregate output which is not possible when we use industrial production directly as our quarterly measure of aggregate demand

BGS Sigma 2012 open source user guide

The British Geological Survey began developing digital field mapping systems in 1989. However, it was apparent that the commercially available hardware was not suitable at that time. In 2001, we revisited the topic under the System for Integrated Geoscience Mapping (SIGMA) programme. By 2003, BGS had developed a PDA (personal digital assistant) field system, which was superseded in 2005, when we began deploying a beta system on rugged Tablet PCs. The Tablet PC system, which we called BGS•SIGMAmobile was used by BGS in mapping projects across the UK as well as overseas. It first became available in Open Source form, in June 2009 via the BGS website, www.bgs.ac.uk, under an agreement which stipulates that updates and modifications must be supplied to BGS in order to stimulate further developments. In 2011/2012, BGS•SIGMAmobile was rewritten in .NET and combined with our office based mapping software BGS•SIGMAdesktop within ArcGIS 10.x to create BGS•SIGMA 2012. It is envisaged that future releases will be made available from the BGS website incorporating new modules, modifications and upgrades supplied by BGS and external users of the system. This document has been written to guide users through the installation and use of BGS•SIGMA 2012 (mobile and desktop), which is the third free release. We are happy to receive feedback and modifications emailed to [email protected]

Interacting Unities: An Agent-Based System

Recently architects have been inspired by Thompsonis Cartesian deformations and Waddingtonis flexible topological surface to work within a dynamic field characterized by forces. In this more active space of interactions, movement is the medium through which form evolves. This paper explores the interaction between pedestrians and their environment by regarding it as a process occurring between the two. It is hypothesized that the recurrent interaction between pedestrians and environment can lead to a structural coupling between those elements. Every time a change occurs in each one of them, as an expression of its own structural dynamics, it triggers changes to the other one. An agent-based system has been developed in order to explore that interaction, where the two interacting elements, agents (pedestrians) and environment, are autonomous units with a set of internal rules. The result is a landscape where each agent locally modifies its environment that in turn affects its movement, while the other agents respond to the new environment at a later time, indicating that the phenomenon of stigmergy is possible to take place among interactions with human analogy. It is found that it is the environmentis internal rules that determine the nature and extent of change

Creatine and glycerol hyperhydration in trained subjects prior to exercise in the heat.

The authors examined the effects of combined creatine (Cr) and glycerol (Gly) supplementation on responses to exercise in the heat. Subjects (N = 24) were matched for body mass and assigned to either a Cr or placebo (Pl) group. Twice daily during two 7-d supplementation regimens, the Cr group received 11.4 g of Cr·H2O and the Pl group received 11.4 g of glucose. Subjects in both groups also ingested 1 g of Gly/kg body mass (twice daily) in either the first or the second supplementation regimen. This design allowed 4 possible combinations of supplements to be examined (Pl/Pl, Pl/Gly, Cr/Pl, and Cr/Gly). Exercise trials were conducted pre- and postsupplementation at 30 °C and 70% relative humidity. In the Pl group, total body water (TBW) increased by 0.50 ± 0.28 L after Gly and in the Cr group by 0.63 ± 0.33 L after Pl and by 0.87 ± 0.21 L after Gly. Both Cr/Pl and Cr/Gly resulted in significantly attenuated heart rate, rectal temperature, and perceived effort during exercise, although no regimen had any effect on performance. The addition of Gly to Cr significantly increased TBW more than Cr alone (P = 0.02) but did not further enhance the attenuation in HR, Tre, and RPE during exercise. These data suggest that combined Cr and Gly is an effective method of hyperhydration capable of reducing thermal and cardiovascular strain