A new method of measuring coastal surface currents with markers and dyes dropped from an aircraft

This paper describes a new low-cost method of measuring coastal surface currents with markers dropped from a light aircraft at each of a series of stations. Each marker consists of a cloth bag containing floats and a different dye. One marker, with anchor attached, remains stationary while a second marker, with drogue attached, moves with the current. The specific dye with each marker disperses slowly and contjnuously through the cloth into the water and aids in the subsequent location of each marker...

An Economic analysis of the potential for precision farming in UK cereal production

The results from alternative spatial nitrogen application studies are analysed in economic terms and compared to the costs of precision farming hardware, software and other services for cereal crops in the UK. At current prices, the benefits of variable rate application of nitrogen exceed the returns from a uniform application by an average of £22 ha−1 The cost of the precision farming systems range from £5 to £18 ha−1 depending upon the system chosen for an area of 250 ha. The benefits outweigh the associated costs for cereal farms in excess of 80 ha for the lowest price system to 200–300 ha for the more sophisticated systems. The scale of benefits obtained depends upon the magnitude of the response to the treatment and the proportion of the field that will respond. To be cost effective, a farmed area of 250 ha of cereals, where 30% of the area will respond to variable treatment, requires an increase in crop yield in the responsive areas of between 0·25 and 1.00 t ha−1 (at £65 t−1) for the basic and most expensive precision farming systems, respectively

Particles in RSOS paths

We introduce a new representation of the paths of the Forrester-Baxter RSOS models which represents the states of the irreducible modules of the minimal models M(p',p). This representation is obtained by transforming the RSOS paths, for the cases p> 2p'-2, to new paths for which horizontal edges are allowed at certain heights. These new paths are much simpler in that their weight is nothing but the sum of the position of the peaks. This description paves the way for the interpretation of the RSOS paths in terms of fermi-type charged particles out of which the fermionic characters could be obtained constructively. The derivation of the fermionic character for p'=2 and p=kp'+/- 1 is outlined. Finally, the particles of the RSOS paths are put in relation with the kinks and the breathers of the restricted sine-Gordon model.Comment: 15 pages, few typos corrected, version publishe

Offside goals and induced breaches of contract

An analysis of Global Resources Group Ltd v Mackay which explores the possibility of building links between the offside goals rule and nominate delict of inducing breach of contract

Regulation of protein kinase B and glycogen synthase kinase-3 by insulin and beta-adrenergic agonists in rat epididymal fat cells - Activation of protein kinase B by wortmannin-sensitive and -insensittve mechanisms

Previous studies using L6 myotubes have suggested that glycogen synthase kinase-3 (GSK-3) is phosphoryl ated and inactivated in response to insulin by protein kinase B (PKB, also known as Akt or RAG) (Cross, D, A, E., Alessi, D, R., Cohen, P., Andjelkovic, M., and Hemmings, B, A. (1995) Nature 378, 785-789), In the present study, marked increases in the activity of PKB have been shown to occur in insulin-treated rat epididymal fat cells with a time course compatible with the observed decrease in GSK-3 activity, Isoproterenol, acting primarily through beta(3)-adrenoreceptors, was found to decrease GSK-3 activity to a similar extent (approximately 50%) to insulin, However, unlike the effect of insulin, the inhibition of GSK by isoproterenol was not found to be sensitive to inhibition by the phosphatidylinositol 3'-kinase inhibitors, wortmannin or LY 294002, The change in GSK-3 activity brought about by isoproterenol could not be mimicked by the addition of permeant cyclic AMP analogues or forskolin to the cells, although at the concentrations used, these agents were able to stimulate lipolysis. Isoproterenol, but again not the cyclic AMP analogues, was found to increase the activity of PKB, although to a lesser extent than insulin. While wortmannin abolished the stimulation of PKB activity by insulin, it was without effect on the activation seen in response to isoproterenol, The activation of PKB by isoproterenol was not accompanied by any detectable change in the electrophoretic mobility of the protein on SDS-polyacrylamide gel electrophoresis. It would therefore appear that distinct mechanisms exist for the stimulation of PKB by insulin and isoproterenol in rat fat cells

On the fundamental group of the complement of a complex hyperplane arrangement

We construct two combinatorially equivalent line arrangements in the complex projective plane such that the fundamental groups of their complements are not isomorphic. The proof uses a new invariant of the fundamental group of the complement to a line arrangement of a given combinatorial type with respect to isomorphisms inducing the canonical isomorphism of the first homology groups.Comment: 12 pages, Latex2e with AMSLaTeX 1.2, no figures; this last version is almost the same as published in Functional Analysis and its Applications 45:2 (2011), 137-14

Faunal assemblages and multi–scale habitat patterns in headwater tributaries of the South Fork Trinity River – an unregulated river embedded within a multiple–use landscape

Las cabeceras pueden representar el 80% de los kilómetros de recorrido en una cuenca fluvial y poseen unas propiedades físicas y biológicas únicas, cuya importancia hasta hace poco no se habían reconocido para el sostenimiento de un funcionamiento sano de las redes de cuencas y sus servicios ecológicos. Tomamos muestras de 60 cabeceras de los afluentes del río South Fork Trinity, una cuenca de 2.430 km2, boscosa en su mayor parte y de múltiples usos, situada en el noroeste de California. Nuestros objetivos eran: (1) diferenciar tipos de cabeceras únicos utilizando 69 variables abióticas y vegetales, medidas a tres escalas espaciales, y luego reducirlos a subconjuntos informativos; (2) determinar si distintos biotas ocupaban los distintos tipos de afluentes; (3) determinar las características medioambientales asociadas con la presencia y abundancia de dichas comunidades bióticas; y (4) utilizando una modelización de nichos, determinar los umbrales de los atributos claves para ilustrar cómo estos biotas podrían emplearse para la medición de la integridad del sistema y los servicios ecológicos. Varios taxones fueron suficientemente abundantes y extendidos para utilizarlos como bioindicadores; la presencia y abundancia de la trucha arco iris (Oncorhynchus mykiss), la riqueza en especies de la herpetofauna (reptiles y anfibios) y el cangrejo señal (Pacifastacus leniusculus) representaban diferentes posiciones tróficas, el valor como recursos comerciales (la trucha arco iris), la sensibilidad al estrés ambiental (anfibios), e indicadores de la biodiversidad (riqueza de especies de la herpetofauna). La riqueza de especies de la herpetofauna no difirió, pero la abundancia de la trucha arco iris, del cangrejo señal, la riqueza de anfibios, difirieron significativamente entre los tipos de afluentes. Los modelos de los nichos indicaron que los patrones de distribución y abundancia, tanto en los ambientes acuáticos como en los ribereños, estaban asociados con atributos físicos y estructurales a multiples escalas espaciales, tanto dentro como alrededor de los tramos acuáticos. Los bioindicadores respondieron a series únicas de atributos, reflejando la elevada heterogeneidad ambiental en las cabeceras de los afluentes en toda esta gran cuenca. Dichos atributos de los nichos representaban una amplia gama de ambientes de cabeceras fluviales, indicando respuestas a una serie de condiciones naturales y antropogénicas. Se demostró el valor de utilizar una serie de bioindicadores para elucidar las condiciones de las cabeceras y para examinar las numerosas perturbaciones que pueden influir sobre la integridad ecológica. Palabras clave: Cabeceras de afluentes, Bioindicadores, Multiescala, Integridad ecológica.Las cabeceras pueden representar el 80% de los kilómetros de recorrido en una cuenca fluvial y poseen unas propiedades físicas y biológicas únicas, cuya importancia hasta hace poco no se habían reconocido para el sostenimiento de un funcionamiento sano de las redes de cuencas y sus servicios ecológicos. Tomamos muestras de 60 cabeceras de los afluentes del río South Fork Trinity, una cuenca de 2.430 km2, boscosa en su mayor parte y de múltiples usos, situada en el noroeste de California. Nuestros objetivos eran: (1) diferenciar tipos de cabeceras únicos utilizando 69 variables abióticas y vegetales, medidas a tres escalas espaciales, y luego reducirlos a subconjuntos informativos; (2) determinar si distintos biotas ocupaban los distintos tipos de afluentes; (3) determinar las características medioambientales asociadas con la presencia y abundancia de dichas comunidades bióticas; y (4) utilizando una modelización de nichos, determinar los umbrales de los atributos claves para ilustrar cómo estos biotas podrían emplearse para la medición de la integridad del sistema y los servicios ecológicos. Varios taxones fueron suficientemente abundantes y extendidos para utilizarlos como bioindicadores; la presencia y abundancia de la trucha arco iris (Oncorhynchus mykiss), la riqueza en especies de la herpetofauna (reptiles y anfibios) y el cangrejo señal (Pacifastacus leniusculus) representaban diferentes posiciones tróficas, el valor como recursos comerciales (la trucha arco iris), la sensibilidad al estrés ambiental (anfibios), e indicadores de la biodiversidad (riqueza de especies de la herpetofauna). La riqueza de especies de la herpetofauna no difirió, pero la abundancia de la trucha arco iris, del cangrejo señal, la riqueza de anfibios, difirieron significativamente entre los tipos de afluentes. Los modelos de los nichos indicaron que los patrones de distribución y abundancia, tanto en los ambientes acuáticos como en los ribereños, estaban asociados con atributos físicos y estructurales a multiples escalas espaciales, tanto dentro como alrededor de los tramos acuáticos. Los bioindicadores respondieron a series únicas de atributos, reflejando la elevada heterogeneidad ambiental en las cabeceras de los afluentes en toda esta gran cuenca. Dichos atributos de los nichos representaban una amplia gama de ambientes de cabeceras fluviales, indicando respuestas a una serie de condiciones naturales y antropogénicas. Se demostró el valor de utilizar una serie de bioindicadores para elucidar las condiciones de las cabeceras y para examinar las numerosas perturbaciones que pueden influir sobre la integridad ecológica. Palabras clave: Cabeceras de afluentes, Bioindicadores, Multiescala, Integridad ecológica.Headwaters can represent 80% of stream kilometers in a watershed, and they also have unique physical and biological properties that have only recently been recognized for their importance in sustaining healthy functioning stream networks and their ecological services. We sampled 60 headwater tributaries in the South Fork Trinity River, a 2,430 km2, mostly forested, multiple–use watershed in northwestern California. Our objectives were: (1) to differentiate unique headwater types using 69 abiotic and vegetation variables measured at three spatial scales, and then to reduce these to informative subsets; (2) determine if distinct biota occupied the different tributary types; (3) determine the environmental attributes associated with the presence and abundance of these biotic assemblages; and (4) using niche modeling, determine key attribute thresholds to illustrate how these biota could be employed as metrics of system integrity and ecologi¬cal services. Several taxa were sufficiently abundant and widespread to use as bio–indicators: the presence and abundance of steelhead trout (Oncorhynchus mykiss), herpetofauna (reptile and amphibian) species richness, and signal crayfish (Pacifastacus leniusculus) represented different trophic positions, value as commercial resources (steelhead), sensitivity to environmental stress (amphibians), and indicators of biodiversity (herpetofauna species richness). Herpetofauna species richness did not differ, but abundances of steelhead trout, signal crayfish, and amphibian richness all differed significantly among tributary types. Niche models indicated that distribution and abun¬dance patterns in both riparian and aquatic environments were associated with physical and structural attributes at multiple spatial scales, both within and around reaches. The bio–indicators responded to unique sets of attributes, reflecting the high environmental heterogeneity in headwater tributaries across this large watershed. These niche attributes represented a wide range of headwater environments, indicating responses to a number of natural and anthropogenic conditions, and demonstrated the value of using a suite of bio–indicators to elucidate watershed conditions, and to examine numerous disturbances that may influence ecological integrity. Key words: Headwater tributaries, Bio–indicators, Multi–scale, Ecological integrity

Towards More Data-Aware Application Integration (extended version)

Although most business application data is stored in relational databases, programming languages and wire formats in integration middleware systems are not table-centric. Due to costly format conversions, data-shipments and faster computation, the trend is to "push-down" the integration operations closer to the storage representation. We address the alternative case of defining declarative, table-centric integration semantics within standard integration systems. For that, we replace the current operator implementations for the well-known Enterprise Integration Patterns by equivalent "in-memory" table processing, and show a practical realization in a conventional integration system for a non-reliable, "data-intensive" messaging example. The results of the runtime analysis show that table-centric processing is promising already in standard, "single-record" message routing and transformations, and can potentially excel the message throughput for "multi-record" table messages.Comment: 18 Pages, extended version of the contribution to British International Conference on Databases (BICOD), 2015, Edinburgh, Scotlan

A tree-decomposed transfer matrix for computing exact Potts model partition functions for arbitrary graphs, with applications to planar graph colourings

Combining tree decomposition and transfer matrix techniques provides a very general algorithm for computing exact partition functions of statistical models defined on arbitrary graphs. The algorithm is particularly efficient in the case of planar graphs. We illustrate it by computing the Potts model partition functions and chromatic polynomials (the number of proper vertex colourings using Q colours) for large samples of random planar graphs with up to N=100 vertices. In the latter case, our algorithm yields a sub-exponential average running time of ~ exp(1.516 sqrt(N)), a substantial improvement over the exponential running time ~ exp(0.245 N) provided by the hitherto best known algorithm. We study the statistics of chromatic roots of random planar graphs in some detail, comparing the findings with results for finite pieces of a regular lattice.Comment: 5 pages, 3 figures. Version 2 has been substantially expanded. Version 3 shows that the worst-case running time is sub-exponential in the number of vertice