A genetic algorithm for railway scheduling with environmental considerations

A genetic algorithm is a randomized optimization technique that draws its inspiration from the biological sciences. Specifically, it uses the idea that genetics determines the evolution of any species in the natural world. Integer strings are used to encode an optimization problem and these strings are subject to combinatorial operations called reproduction, crossover and mutation, which improve these strings and cause them to ‘evolve’ to an optimal or nearly optimal solution. In this paper, the general machinations of genetic algorithms are described and a performance-enhanced algorithm is proposed for solving the important practical problem of railway scheduling. The problem under consideration involves moving a number of trains carrying mineral deposits across a long haul railway line with both single and double tracks in either direction. Collisions can only be avoided in sections of the line with double tracks. Constraints reflecting practical requirements to reduce environmental impacts from mineral transport, such as avoidance of loaded trains traversing populated areas during certain time slots, have to be satisfied. This is an NP-hard problem, which usually requires enumerative, as opposed to constructive, algorithms. For this reason, an ‘educated’ random search procedure like the genetic algorithm is an alternative and effective technique. The genetic algorithm is given difficult test problems to solve and the algorithm was able to generate feasible solutions in all cases.     

Dynamics of social interactive behavior: A computerized procedure for analyzing trends, patterns, and sequences.

Describes procedures that use detailed and sequential observations of monkey mother-infant interactive behavior to make a coordinated analysis of development. Computer programs provide for (1) organizing the behavioral data into frequency tables and developmental curves, (2) making analyses of variance and trends comparing groups of Ss, and (3) determining statistically the patterns of simultaneous behavior and the sequences of patterns that characterize individual Ss and groups. This treatment of a large volume of data is economically feasible. The computer programs have been generalized for application in various kinds of behavioral research. Analyses provide bases in concrete behavioral terms for deriving hypotheses about the dynamics of social behavior and development. This approach promises a more complete and developmental view of complex interactive processes. Greater sophistication in the use of computer capabilities and in the application of mathematical models and treatments can increase its effectiveness. (19 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Business sans frontieres? Cultural diversity and the engineer inEurope

Business relationships between people of differing cultures, even within the confines of Europe, are fraught with opportunities for misunderstanding. The UK engineer doing business with mainland Europe is likely to be confronted with many differences in business customs, conventions and etiquette. Many of these are cultural. Indeed, it is said that about 20% of a business relationship is based on cultural human and interpersonal aspects. This 20% can make a negotiation succeed or fail. Time is one of these aspects. Will the British engineer be able to organise his/her business and schedule appointments in the same way as at home? The Spanish or French business partner may well have a completely different perception of time and working style. In many respects the cultural divergence corresponds to the geographic north/south divide in Europe. The author concentrates on a number of the social, cultural and linguistic factors, and offer some conclusions and solutions for the engineer     

It ain't over till it's over: fashioning durable settlements

Vivian Berger , of New York, examines hard‐earned settlements that nearly evaporated. In order to better serve mediation participants' interests, she presents six problems that hinder or prevent a mediation agreement, and discusses precautions to avoid getting derailed.     

Intertek天祥20年护航中国制造 支持全球贸易

百年认证机构Intertek天祥集团进入中国20周年,其在中国的本地化服务之道是什么？Intertek天祥集团首席执行官Wolfhart Hauser博士认为,是贴近客户的创新精神。来自倍科国际贸易有限公司的童灵博士一语传神——Intertek天祥提供给我们的服务就像写小说的最高境界＂意料之外,情理之中＂。     

Accumulation of eicosapentaenoic acid in plasma phospholipids of subjects fed canola oil

The metabolism of α-linolenic acid from canola oil was studied in eight normolipidemic men. The 42-day study was divided into three periods: a 6-day pre-experimental and two 18-day experimental. Approximately 75% of the dietary fat (28% of total energy) was provided by a mixture of fats during the pre-experimental period and either canola oil (CO) or sunflower oil (SO) during the experimental periods. The CO and SO diets were fed in a cross-over design. The ratios of linoleic to linolenic acid were 2.6∶1 and 73.9∶1 in the CO and SO diets, respectively. Dietary fat source had an effect on plasma phospholipid fatty acids: 18∶1n−9, 18∶3n−3 and 20∶5n−3 were higher (p<0.05), and 18∶2n−6 was lower in the phosphatidylcholine fraction; 18∶1n−9 was higher and 20∶4n−6 lower in the phosphatidyl-ethanolamine fraction; and 18∶1n−9 and 20∶5n−3 were higher and 20∶4n−6 and 22∶6n−3 were lower in the alkenylacyl-ethanolamine phospholipid fraction on the CO diet as compared to the SO diet. Consumption of the canola oil diet resulted in higher n−3 fatty acid levels and lower n−6 fatty acid levels in plasma phospholipids than consumption of the sunflower oil diet.     

Design of luminescent sulfur-containing polynuclear gold(I) complexes for advanced nanomaterials and chemosensors

A series of high-nuclearity gold(I) sulfido complexes with bridging diphosphine ligands have been synthesized and isolated, with the general formulae of [Au₁₀(μ-P^P)₄(μ₃-S)₄]X₂ and [Au₁₂(μ-P^P)₄(μ₃-S)₄]X₄ (P^P = diphosphine; X = PF₆ or ClO₄). Intense green and orange emissions were observed upon excitation at λ > 350 nm both in the solid state and in solutions. The green emission has been attributed to originate from excited states derived from the metal-perturbed intraligand (IL) transition while the orange emission arises from the ligand-to-metal-metal bond charge-transfer (LMMCT; S(Au...Au) states. The switching on and off of the LMMCT emission in a series of dinuclear gold(I) thiolate complexes with crown ether pendants induced by ion-binding has been demonstrated, and this provides a new strategy for the design of luminescence signalling and chemosensing devices in optoelectronics and sensor technology.     

Do arsenosugars pose a risk to human health? The comparative toxicities of a trivalent and pentavalent arsenosugar

Seafood frequently contains high concentrations of arsenic (approximately 10-100 mg/kg dry weight). In marine algae (seaweed), this arsenic occurs predominantly as ribose derivatives known collectively as arsenosugars. Although it is clear that arsenosugars are not acutely toxic, there is a possibility of arsenosugars having slight chronic toxicity. In general, trivalent arsenicals are more toxic than their pentavalent counterparts, so in this work we examine the hypothesis that trivalent arsenosugars might be significantly more toxic than pentavalent arsenosugars in vitro. We compared the in vitro toxicity of (R)-2,3-dihydroxypropyl-5-deoxy-5-dimethylarsinoyl-beta-D-riboside, a pentavalent arsenosugar, to that of its trivalent counterpart, (R)-2,3-dihydroxypropyl-5-deoxy-5-dimethylarsino-beta-D-riboside. The trivalent arsenosugar nicked plasmid DNA, whereas the pentavalent arsenosugar did not. The trivalent arsenosugar was more cytotoxic (IC50 = 200 microM, 48 h exposure) than its pentavalent counterpart (IC50 > 6000 microM, 48 h exposure) in normal human epidermal keratinocytes in vitro as determined via the neutral red uptake assay. However, both the trivalent and the pentavalent arsenosugars were significantly less toxic than MMA(III), DMA(III), and arsenate. Neither the pentavalent arsenosugar nor the trivalent arsenosugar were mutagenic in Salmonella TA104. The trivalent arsenosugar was readily formed by reaction of the pentavalent arsenosugar with thiol compounds, including, cysteine, glutathione, and dithioerythritol. This work suggests that the reduction of pentavalent arsenosugars to trivalent arsenosugars in biology might have environmental consequences, especially because seaweed consumption is a significant environmental source for human exposure to arsenicals.