A comparison of screening methods for insect contamination in wheat

In collaboration with the United States Department of Agriculture and a number of major milling companies, the “Insect-Detect” immunoassay for analyzing insect contamination in grains has been compared with three more traditional methods, X-ray analysis, cracking and flotation, and the insect fragment test (IFT). Testing was carried out in blind fashion using clean wheat samples that were spiked with differing numbers of grain kernels infested with late instar larvae of the granary weevil (Sitophilus granarius (L.)). Three different laboratories analyzed the samples for each of the four methods. The collaborative trials showed that the insect immunoassay clearly provided the most accurate measurement of actual insect infestation, followed by X-ray analysis. While both cracking and flotation and IFT procedures provided a general measure of contamination, they showed much greater variability.     

The Concept of Planned Development: A Presentation and Commentaries on the Contribution of Nathaniel Lichfield

This article and the commentaries which accompany it centres on a reflection by consultant-academic Nathaniel Lichfield on his work on planned development and the evaluation of the impacts of such development, over a career spanning the past 60 years. His work, in the UK and across the world, had a formative influence on generations of planners brought up on his texts. In this presentation, David Adams sets the context of his contribution. The heart of the article is a reflective synthesis by Lichfield on his own work from his first major contribution in 1956, to its evolution in the 1960s into the technique of the Planning Balance Sheet, and later, Community Impact Evaluation. His starting point is that there can be urban and regional planning which does not lead to physical development on the ground and there can be such development on the ground that has not been influenced by government led urban and regional planning. Neither of these is planned development. This takes place when the two are fused together in practice: the development and the government led planning. It is this simple concept, with particular emphasis on its economics, which was treated at length in the Economics of Planned Development (1956). In order to fully describe the concept, the book's contents are summarized in the first half of this article following an introduction of the background. Following the publication of the book, Lichfield's professional and academic work took him in many directions, much of which fell loosely under the ambit of the economics of planned development. His contributions were not written up as sequels to the book but rather in related books, papers and articles under an array of topics. He terms these 'the children of EPD'. They are described in the second half of the article, grouped in relation, as appropriate, to each of the main themes of the 1956 book and extensions of it. Lichfield's article is followed by three commentaries. The first, by Mike Teitz, positions his work and its later development in the changing context of the times. The second, by Barrie Needham, provides some critical thoughts on how well the concept of 'planned development' travels transnationally into different institutional contexts. The third, from consultant-planner Alan Wenban-Smith, himself working on policy evaluation in the UK, explores the practical and methodological robustness of Lichfield's concepts. Overall, the piece provides an input to reflections on the relation between state and market in the development process and on the evaluative stance the state should take to its interventions.     

Microstructure/Process Relations in Sol-Gel-Prepared KnbO3 Thin Films on (100) MgO

Epitaxial (110) orthorhombic KNbO₃ thin films were prepared using alkoxide solutions. Single-phase films were produced with stoichiometric sols while slight variations in stoichiometry (52/48 Nb/K or 48/52 Nb/K) created residual second phases. Nucleation and growth of KNbO₃, as a function of process conditions were monitored by observing the KNbO₃ rosettes produced from niobium-rich solutions. Methanolic solutions produced films with the highest rosette density and the highest amount of KNbO₃. Hydrolysis of the sol aided the crystallization of the KNbO₃ phase but also promoted the formation of second phases. Hydrolysis at 0°C reduced second-phase formation.     

Review Article

This paper addresses itself to a problem that faces all cities but which was — and was seen to be — an ever more grave one for the burgeoning cities of nineteenth century Europe: environmental pollution. This problem — and in particular sewage which is the focus of the article — has as yet been little studied by historians. The paper shows, first, that in Paris in the period 1750–1850 the city was confronted by rapidly increasing quantities of sewage and that for complex cultural, class and scientific reasons Parisian elites came to perceive sewage removal as a problem that required solution and to adopt a series of strategies to do so. It shows, secondly, that the city's administration brought about changes which were of greater import than those effected under Haussmann in the 1850s and 1860s. The limits to what it could do were imposed not by short‐sightedness or parsimony, but by long‐term structural constraints of different orders, attitudinal, technological, power relationships in the capitalist city.     

Microbiology of a wetland ecosystem constructed to remediate mine drainage from a heavy metal mine

A pilot passive treatment plant (PPTP) was constructed to evaluate the potential of a composite wetland system to remediate acidic, metal-rich water draining the former Wheal Jane tin, in Cornwall, England. The treatment plant consists of three separate and controllable composite systems, each of which comprises a series of aerobic wetlands for iron oxidation and precipitation, a compost bioreactor for removing chalcophilic metals and to generate alkalinity, and rock filter ponds for removing soluble manganese and organic carbon. To understand the roles of microorganisms in remediating acid mine drainage (AMD) in constructed wetland ecosystems, populations of different groups of cultivatable acidophilic microbes in the various components of the Wheal Jane PPTP were enumerated over a 30-month period. Initially, moderately acidophilic iron-oxidising bacteria (related to Halothiobacillus neapolitanus) were found to be the major cultivatable microorganisms present in the untreated AMD, though later heterotrophic acidophiles emerged as the dominant group, on a numerical basis. Culturable microbes in the surface waters and sediments of the aerobic wetlands were similarly dominated by heterotrophic acidophiles, though both moderately and extremely acidophilic iron-oxidising bacteria were also present in significant numbers. The dominant microbial isolate in waters draining the anaerobic compost bioreactors was an iron- and sulfur-oxidising moderate acidophile that was closely related to Thiomonas intermedia. The acidophiles enumerated at the Wheal Jane PPTP accounted for 1% to 25% of the total microbial population. Phylogenetic analysis of 14 isolates from various components of the Wheal Jane PPTP showed that, whilst many of these bacteria were commonly encountered acidophiles, some of these had not been previously encountered in AMD and AMD-impacted environments.     

Robust backstepping and neural network control of a low-quality nonholonomic mobile robot

A robust motion controller based on neural network and backstepping technique is proposed for a two-DOF low-quality mobile robot (MR). There are two main components in the motion controller. One is the tracking controller, which guarantees the MR follows the reference trajectory; the other one is the wheel-level inverse NN controller, which compensates the dynamics of the MR. Simulation results are provided to validate the proposed controllers. Experiments with a real low-quality MR, which were built from cheap drivelines, have been used to verify the effectiveness and robustness of the motion controller.     

An isomorphism theorem between the 7-adic integers and a ring associated with a hexagonal lattice

The primary goal of this paper is to prove that a ring defined by L. Gibson and D. Lucas is isomorphic to the ring of 7-adic integers. The ring, denoted byR ₂, arises naturally as an algebraic structure associated with a hexagonal lattice. The elements ofR ₂ consist of all infinite sequences in /(7). The addition and multiplication operations are given in terms of remainder and carries tables. The Generalized Balanced Ternary, denoted byG, is the subring ofR ₂ consisting of all the finite sequences ofR ₂. IfI _k is the ideal ofG consisting of all those sequences whose firstk digits are zero, then the second goal of the paper is to show that the inverse limit ofG/I _k is also isomorphic to the 7-adic integers.     

Mass spectrometric identification of silver nanoparticles: the case of Ag32(SG)19

Mass spectrometry has played a key role in identifying the members of a series of gold clusters, which has enabled the development of magic-number cluster theory. The successes of the gold cluster system have yet to be repeated in another metal cluster system, however. Silver clusters in particular have proven to be challenging due to their relative instability compared with gold clusters. Using the well-characterized gold nanocluster, Au(25)(SG)(18), we present optimized electrospray ionization mass spectrometry (ESI-MS) instrumental parameters for the maximal transmission of the intact cluster. Parameters shown to have the largest effect on intact cluster transmission/detection include trap and transfer collision energy, source temperature, and cone gas flow rate. Herein we describe a general strategy to acquire mass spectra of fragile metal clusters with reliable mass assignments. By also optimizing sample solution conditions, high-quality ESI mass spectra of a prototypical silver:glutathione (Ag:SG) cluster were obtained without significant fragmentation. By using gentle conditions and solution conditions designed to stabilize the clusters, fragmentation was dramatically reduced and mass spectra with isotopic resolution were measured. Using this strategy, we have made the first formula assignment for a ligand-protected Ag cluster of Ag(32)(SG)(19).