Propagation of sound in turbulent media

Perturbation methods commonly used to study the propagation of acoustic waves in turbulent media are reviewed. Emphasis is on those techniques which are applicable to problems involving long-range propagation in the atmosphere and ocean. Characteristic features of the various methods are illustrated by applying them to particular problems. It is shown that conventional perturbation techniques, such as the Born approximation, yield solutions which contain secular terms, and which therefore have a relatively limited range of validity. In contrast, it is found that solutions obtained with the aid of the Rytov method or the smoothing method do not contain secular terms, and consequently have a much greater range of validity

In silico identification and characterisation of 17 polymorphic anonymous non-coding sequence markers (ANMs) for red grouse (Lagopus lagopus scotica)

Peer reviewedPostprin

Digging for gold nuggets : uncovering novel candidate genes for variation in gastrointestinal nematode burden in a wild bird species

Acknowledgements This study was funded by a BBSRC studentship (MAWenzel) and NERC grants NE/H00775X/1 and NE/D000602/1 (SB Piertney). The authors are grateful to Marianne James, Mario Roder and Keliya Bai for field-work assistance, Lucy M.I. Webster and Steve Paterson for help during prior development of genetic markers,Heather Ritchie for helpful comments on manuscript drafts and all estate owners, factors and keepers for access to field sites, most particularly MJ Taylor and Mike Nisbet (Airlie), Neil Brown (Allargue), RR Gledson and David Scrimgeour (Delnadamph), Andrew Salvesen and John Hay (Dinnet), Stuart Young and Derek Calder (Edinglassie), Kirsty Donald and DavidBusfield (Glen Dye), Neil Hogbin and Ab Taylor (Glen Muick), Alistair Mitchell (Glenlivet), Simon Blackett, Jim Davidson and Liam Donald (Invercauld), Richard Cooke and Fred Taylor (Invermark), Shaila Rao and Christopher Murphy (Mar Lodge), and Ralph Peters and Philip Astor (Tillypronie)Peer reviewedPostprin

Isabelle/PIDE as Platform for Educational Tools

The Isabelle/PIDE platform addresses the question whether proof assistants of the LCF family are suitable as technological basis for educational tools. The traditionally strong logical foundations of systems like HOL, Coq, or Isabelle have so far been counter-balanced by somewhat inaccessible interaction via the TTY (or minor variations like the well-known Proof General / Emacs interface). Thus the fundamental question of math education tools with fully-formal background theories has often been answered negatively due to accidental weaknesses of existing proof engines. The idea of "PIDE" (which means "Prover IDE") is to integrate existing provers like Isabelle into a larger environment, that facilitates access by end-users and other tools. We use Scala to expose the proof engine in ML to the JVM world, where many user-interfaces, editor frameworks, and educational tools already exist. This shall ultimately lead to combined mathematical assistants, where the logical engine is in the background, without obstructing the view on applications of formal methods, formalized mathematics, and math education in particular.Comment: In Proceedings THedu'11, arXiv:1202.453

The effects of blood preparation for radioimmunoassay and competitive protein binding assay on the stability of progesterone and estrogen concentrations

Competitive protein binding (CPB) assay for progesterone and radioimmunoassay (RIA) for estrogen were used to evaluate the effects of various blood handling techniques from the time of collection to assay on the stability of progesterone and estrogen concentrations in blood. Eight 40 ml samples were collected consecutively in polycarbonate centrifuge tubes from the jugular veins of eight cows and subjected to various treatments. Treatments consisted of collecting samples in pre-cooled heparinized (1000 U/ml) tubes maintained in an ice bath, centrifuging immediately (2400 rpm for 30 minutes) and storing the plasma fraction at -15°C; and collecting samples in heparinized or non-heparinized, pre-cooled and warm (room temperature) tubes, and holding as whole blood either at 4°C for 24 hours or at room temperature for 4 or 24 hours prior to centrifutation and storage of the plasma or serum fraction at -15°C. The last of the eight samples collected from.each cow was handled identically to the first sample to evaluate the effects of animal stress during bleeding and volume of blood collected on hormone concentration. Significant differences in the progesterone concentrations existed between treatments (P \u3c 0.001). Plasma and serum samples held at 4°C for 24 hours were significantly lower in progesterone than plasma samples centrifuged. There was no difference in progesterone concen-trations of plasma and serum samples subjected to similar treatment effects. Samples collected in warm (room temperature) tubes and held as whole blood at room temperature until centrifuged were significantly lower in progesterone content (P \u3c 0.001) than those collected in cool tubes. Warm tube samples held as whole blood at room temperature for 24 hours prior to centrifugation were significantly lower in progesterone than those held as whole blood for 4 hours (P \u3c 0.001). Serum samples held at room temperature for 4 hours and 24 hours prior to centrifugation were 38 percent and 89 percent lower in progesterone content, respectively, than the plasma samples centrifuged immediately. Animal stress or volume of blood collected had no effect on progesterone concentration. Radioimmunoassay for estrogen was conducted on blood from the same cows and subjected to the same treatments used for CPB assay of progesterone. There was no significant difference in estrogen concen-trations between any of the treatments evaluated in this study. Aliquots of pooled plasma samples from a number of cows were subjected to alternate freezing and thawing to a maximum of 6 and 7 times prior to the assay for progesterone and estrogen, respectively. No significant effect of repeated freezing and thawing on the concentra-tion of either progesterone or estrogen was detected. The average recovery of labeled progesterone added to cow plasma was 93.3 ± 0.64 percent. Following the addition of 3 ng of unlabeled progesterone to steer plasma, the average recovery was 96.9 ± 0.45 per cent or 2.9 ng of progesterone. RIA was carried out using one 6 ml extraction and 2 hours lee water Incubation. Recovery of 20 pg and 50 pg of estradiol-17β added to pooled cow plasma averaged 91.0 ± 0.35 per cent and 81.0 ± 0.60 percent, respectively. Average recovery of estradiol-17β3H from a cow being assayed was 89.0 ± 1.5 percent. Based on the data obtained in this study, samples used for CPE assay of progesterone should be centrifuged and the plasma fraction of whole blood removed as soon as possible after collection and frozen until assayed. Estrogen concentrations in samples prepared for RIA of estro-gen are apparently not as susceptible to the effects of various sample preparation methods as is progesterone. However, it is recommended that samples of estrogen assay also be centrifuged and stored at sub zero temperatures as soon as possible

Global land use implications of biofuels: State of the art conference and workshop on modelling global land use implications in the environmental assessment of biofuels

Background, Aims and Scope On 4¿5 June 2007, an international conference was held in Copenhagen. It provided an interdisciplinary forum where economists and geographers met with LCA experts to discuss the challenges of modelling the ultimate land use changes caused by an increased demand for biofuels. Main Features The main feature of the conference was the cross-breeding of experience from the different approaches to land use modelling: The field of LCA could especially benefit from economic modelling in the identification of marginal crop production and the resulting expansion of the global agricultural area. Furthermore, the field of geography offers insights in the complexity behind new land cultivation and practical examples of where this is seen to occur on a regional scale. Results Results presented at the conference showed that the magnitude and location of land use changes caused by biofuels demand depend on where the demand arises. For instance, mandatory blending in the EU will increase land use both within and outside of Europe, especially in South America. A key learning for the LCA society was that the response to a change in demand for a given crop is not presented by a single crop supplier or a single country, but rather by responses from a variety of suppliers of several different crops in several countries. Discussion The intensification potential of current and future crop and biomass production was widely discussed. It was generally agreed that some parts of the third world hold large potentials for intensification, which are not realised due to a number of barriers resulting in so-called yield gaps. Conclusions Modelling the global land use implications of biofuels requires an interdisciplinary approach optimally integrating economic, geographical, biophysical, social and possibly other aspects in the modelling. This interdisciplinary approach is necessary but also difficult due to different perspectives and mindsets in the different disciplines. Recommendations and Perspectives The concept of a location dependent marginal land use composite should be introduced in LCA of biofuels and it should be acknowledged that the typical LCA assumption of linear substitution is not necessarily valid. Moreover, fertiliser restrictions/accessibility should be included in land use modelling and the relation between crop demand and intensification should be further explored. In addition, environmental impacts of land use intensification should be included in LCA, the powerful concept of land use curves should be further improved, and so should the modelling of diminishing returns in crop production

Diabetische Makulopathie und Retinopathie: Funktionelle und sozialmedizinische Bedeutung

Zusammenfassung: Hintergrund: Die diabetische Makulopathie ist in den entwickelten Ländern führende Ursache für eine Erblindung vor dem Erreichen des Rentenalters. Die weltweit zunehmende Zahl von Diabetikern lässt vermuten, dass die Bedeutung der diabetischen Retinopathie und Makulopathie als Ursache einer schweren Sehbehinderung eher noch zunimmt. Methode: Zu den Stichworten in der Kapitelüberschrift zu Epidemiologie, Bedeutung und Ursachen der Sehstörung bei diabetischer Makulopathie wurde eine Literatursuche durchgeführt, um Übersichtsartikel sowie kontrollierte Studien der letzten Jahre zusammenzustellen. Ziel war eine Übersicht über funktionelle und sozioökonomische Konsequenzen der diabetischen retinalen Mikroangiopathie und über neue therapeutische Strategien. Ergebnisse: Erste Veränderungen in Richtung einer diabetischen Mikroangiopathie sind bereits früh nach Auftreten der Hyperglykämie nachweisbar. Langfristig verursacht sie schwere Organschäden. Für deren Behandlung werden wesentlich mehr Ressourcen benötigt als für die Behandlung der Hyperglykämie. Die diabetischen Mikroangiopathie verursacht darüber hinaus einen bemerkenswerten sozialmedizinischen Schaden. Der Früherkennung der vermehrten Gefäßpermeabilität bei Diabetikern kommt ein erheblicher Stellenwert für die Steuerung der Therapie zu. Für ein Hinauszögern der mikrovaskulären Komplikationen steht immer noch die Kontrolle der metabolischen Risikofaktoren Hyperglykämie und Hyperlipidämie sowie der Hypertonie im Vordergrund. Schlussfolgerungen: Moderne therapeutische Möglichkeiten erlauben heute eine medikamentöse Frühintervention mit dem Ziel, das Auftreten irreversibler mikrovaskulärer Schäden, namentlich der diabetischen Retinopathie und Makulopathie, hinauszuzögern. Das ophthalmologische Screening darf nicht mehr bei der Erkennung von Spätschäden diabetischer mikrovaskulärer Komplikationen am Auge beginnen. Eine enge interdisziplinäre Zusammenarbeit mit früher Implementation der neueren Therapieansätze bilden dabei die Grundlage für den therapeutischen Erfolg, bevor sich eine Sehbeeinträchtigung entwickel

Geometric reasoning via internet crowdsourcing

The ability to interpret and reason about shapes is a peculiarly human capability that has proven difficult to reproduce algorithmically. So despite the fact that geometric modeling technology has made significant advances in the representation, display and modification of shapes, there have only been incremental advances in geometric reasoning. For example, although today's CAD systems can confidently identify isolated cylindrical holes, they struggle with more ambiguous tasks such as the identification of partial symmetries or similarities in arbitrary geometries. Even well defined problems such as 2D shape nesting or 3D packing generally resist elegant solution and rely instead on brute force explorations of a subset of the many possible solutions. Identifying economic ways to solving such problems would result in significant productivity gains across a wide range of industrial applications. The authors hypothesize that Internet Crowdsourcing might provide a pragmatic way of removing many geometric reasoning bottlenecks.This paper reports the results of experiments conducted with Amazon's mTurk site and designed to determine the feasibility of using Internet Crowdsourcing to carry out geometric reasoning tasks as well as establish some benchmark data for the quality, speed and costs of using this approach.After describing the general architecture and terminology of the mTurk Crowdsourcing system, the paper details the implementation and results of the following three investigations; 1) the identification of "Canonical" viewpoints for individual shapes, 2) the quantification of "similarity" relationships with-in collections of 3D models and 3) the efficient packing of 2D Strips into rectangular areas. The paper concludes with a discussion of the possibilities and limitations of the approach