Infinite Distances and the Axion Weak Gravity Conjecture

The axion Weak Gravity Conjecture implies that when parametrically increasing the axion decay constants, instanton corrections become increasingly important. We provide strong evidence for the validity of this conjecture by studying the couplings of R-R axions arising in Calabi-Yau compactifications of Type IIA string theory. Specifically, we consider all possible infinite distance limits in complex structure moduli space and identify the axion decay constants that grow parametrically in a certain path-independent way. We then argue that for each of these limits a tower of D2-brane instantons with decreasing actions can be identified. These instantons ensure that the convex hull condition relevant for the multi-axion Weak Gravity Conjecture cannot be violated parametrically. To argue for the existence of such instantons we employ and generalize recent insights about the Swampland Distance Conjecture. Our results are general and not restricted to specific examples, since we use general results about the growth of the Hodge metric and the sl(2)-splittings of the three-form cohomology associated to each limit.Comment: 40 pages, 2 figure

Explaining Regional and Local Differences in Organic Farming in England and Wales: A Comparison of South West Wales and South East England

Explaining regional and local differences in organic farming in England and Wales: a comparison of South West Wales and South East England, Regional Studies, Few studies explain the concentration of organic farming in specific regions of England and Wales. This paper compares the development of organic farming in South West Wales and South East England. While the focus in the former is on the use of mainly national marketing channels and the movement of organic produce more than 60 min from the farm, in the latter greater use is made of local and direct marketing channels to distribute organic food within 30 min of the farm. The overriding importance of demand appears to provide a key explanation for regional differentiation in organic farming. 解释英格兰与威尔斯有机农业的区域及地方差异：西南威尔斯与东南英格兰的比较研究，区域研究。显少有研究解释有机农业在英格兰及威尔斯特定区域中的集中现象。本文比较有机农业在西南威尔斯与东南英格兰的发展。西南威尔斯的发展重点，主要在于利用全国行销通路，以及距离农场超过六十分钟的有机产品运送路程，东南英格兰则较着重运用在地且直接的行销通路，在距离农场三十分钟以内的运送路程中分派有机食品。需求的压倒性重要性，似乎提供了有机农业中的区域差异的关键解释。 Expliquer les disparités régionales dans l'agriculture biologique en Angleterre et au pays de Galles: une comparaison du sud-ouest du pays de Galles et du sud-est de l'Angleterre, Regional Studies. Rares sont les études qui expliquent la concentration de l'agriculture biologique dans des zones spécifiques de l'Angleterre et du pays de Galles. Cet article cherche à comparer le développement de l'agriculture biologique du sud-ouest du pays de Galles à celle du sud-est de l'Angleterre. Tandis que celle-là met l'accent sur l'emploi des circuits commerciaux principalement nationaux et sur la distribution de la production agricole biologique à plus de 60 minutes de la ferme, celle-ci exploite davantage les circuits commerciaux locaux et directs pour distribuer les denrées alimentaires organiques dans un rayon de 30 minutes de la ferme. Il semble que l'importance primordiale de la demande constitue un facteur déterminant de la différenciation régionale de l'agriculture biologique. Erklärung der regionalen und lokalen Unterschiede bei der ökologischen Landwirtschaft in England und Wales: ein Vergleich zwischen Südwestwales und Südostengland, Regional Studies. Die Konzentration der ökologischen Landwirtschaft in bestimmten Regionen von England und Wales wird nur in wenigen Studien erklärt. In diesem Beitrag vergleichen wir die Entwicklung der ökologischen Landwirtschaft in Südwestwales mit der von Südostengland. Während in Südwestwales der Schwerpunkt auf den größtenteils landesweiten Absatzkanälen und dem Transport von ökologischen Lebensmitteln an mehr als 60 Minuten vom landwirtschaftlichen Betrieb entfernte Orte liegt, werden in Südostengland öfter lokale und direkte Absatzkanäle genutzt und die ökologischen Lebensmittel an bis zu 30 Minuten vom landwirtschaftlichen Betrieb entfernte Orte transportiert. Die wichtigste Erklärung für die regionalen Unterschiede bei der ökologischen Landwirtschaft scheinen in der vorrangigen Bedeutung der Nachfrage zu liegen. Explicación de las diferencias regionales y locales en la agricultura biológica de Inglaterra y Gales: comparación entre el suroeste de Gales y el sureste de Inglaterra, Regional Studies. En pocos estudios se explica la concentración de la agricultura biológica en regiones específicas de Inglaterra y Gales. En este artículo comparamos el desarrollo de la agricultura biológica en el suroeste de Gales y el sureste de Inglaterra. Mientras que en el suroeste de Gales se hace hincapié en el uso de canales mercantiles principalmente nacionales y el movimiento de productos biológicos a una distancia de más de 60 minutos de la explotación agrícola, en el sureste de Inglaterra se utilizan más los canales mercantiles locales y directos para distribuir alimentos biológicos a no más de 30 minutos de la explotación agrícola. Parece ser que la demanda es el motivo más importante para explicar las diferencias regionales en la agricultura biológica

Microwave Synthesis and Characterisation of Zinc Sulfide Nanomaterials for Photocatalytic and Anti-Bacterial Applications

This thesis is focused on the development of a novel ambient pressure microwave synthesis of ZnS based materials for photocatalytic and anti-bacterial technologies. Chapter 1 introduces the problems with anti-biotic resistant bacteria and the impact that these species are causing within healthcare systems. One of the approaches to tackling these problems is the development of self-cleaning materials to replace the harsh cleaning agents currently in use to sterilize the surfaces of buildings and materials used in healthcare environments. Chapter 1 also introduces semiconductors, semiconductor photocatalysis and the mechanism of action, improving photocatalytic action and how to semiconductor photocatalysts have been used for anti-bacterial activities. Chapter 1 discusses zinc sulfide and its various properties that make it attractive as a platform for photocatalytic materials with its wide band gap that can be modified to make it work in an indoor environment where UV light is not present. Chapter 2 describes the synthesis techniques employed in developing ZnS and doped ZnS materials using an ambient pressure aqueous method. This chapter also explores the techniques employed to characterise the materials prepared by the microwave technique. Chapter 3 covers to development of the ambient pressure aqueous microwave synthesis method including the variation of reagents, microwave irradiation power, irradiation time and volume of reagents and how these factors impacted the characteristics of the material. These characteristics include the crystallinity, size of the material, absorbance profile and its photocatalytic and antibacterial properties. The work of this chapter was published in Applied Catalysis B: Environmental in 2013 and was the subject of a talk which won the best Applied Chemistry talk at the Irish Universities Chemistry Colloquium at Queens University Belfast in 2010. Chapter 4 is a study on effect of metal doping of the Group 13 metals – aluminium, gallium and indium – on ZnS. The optimum conditions for microwave synthesis established in chapter 3 were used with varying amounts of dopant levels to determine the optimum doping concentration to enhance the photocatalytic activity and antibacterial activity under indoor light conditions. Luminescence spectroscopy and X-ray photoelectron spectroscopy were employed to determine the mechanism of doping by the three different metals and the difference of the ionic radii of the metals was shown to affect how the metals interact with the ZnS crystal. The work of this chapter is prepared for publication and will be submitted in late 2018. Chapter 5 presents a study of silver and indium co-doped ZnS prepared by microwave synthesis. The materials were characterised and shown to have a slight improved photocatalytic activity in comparison to indium doped ZnS and a greatly improved activity toward undoped ZnS prepared under the same conditions. There is also a study on the effect of silver doping concentrations on the crystallisation of ZnS and how the level of silver determines whether cubic blende or wurtzite phase material is formed. The work in chapter 5 was published in the Nanotechnology in 2013

Exercise redox biochemistry:conceptual, methodological and technical recommendations

Exercise redox biochemistry is of considerable interest owing to its translational value in health and disease. However, unaddressed conceptual, methodological and technical issues complicate attempts to unravel how exercise alters redox homeostasis in health and disease. Conceptual issues relate to misunderstandings that arise when the chemical heterogeneity of redox biology is disregarded which often complicate attempts to use redox-active compounds and assess redox signalling. Further, that oxidised macromolecule adduct levels reflect formation and repair is seldom considered. Methodological and technical issues relate to the use of out-dated assays and/or inappropriate sample preparation techniques that confound biochemical redox analysis. After considering each of the aforementioned issues, we outline how each issue can be resolved and provide a unifying set of recommendations. We specifically recommend that investigators: consider chemical heterogeneity, use redox-active compounds judiciously, abandon flawed assays, carefully prepare samples and assay buffers, consider repair/metabolism, use multiple biomarkers to assess oxidative damage and redox signalling

Systematic review of the current status of cadaveric simulation for surgical training

Background: There is growing interest in and provision of cadaveric simulation courses for surgical trainees. This is being driven by the need to modernize and improve the efficiency of surgical training within the current challenging training climate. The objective of this systematic review is to describe and evaluate the evidence for cadaveric simulation in postgraduate surgical training. Methods: A PRISMA‐compliant systematic literature review of studies that prospectively evaluated a cadaveric simulation training intervention for surgical trainees was undertaken. All relevant databases and trial registries were searched to January 2019. Methodological rigour was assessed using the widely validated Medical Education Research Quality Index (MERSQI) tool. Results: A total of 51 studies were included, involving 2002 surgical trainees across 69 cadaveric training interventions. Of these, 22 assessed the impact of the cadaveric training intervention using only subjective measures, five measured impact by change in learner knowledge, and 23 used objective tools to assess change in learner behaviour after training. Only one study assessed patient outcome and demonstrated transfer of skill from the simulated environment to the workplace. Of the included studies, 67 per cent had weak methodology (MERSQI score less than 10·7). Conclusion: There is an abundance of relatively low‐quality evidence showing that cadaveric simulation induces short‐term skill acquisition as measured by objective means. There is currently a lack of evidence of skill retention, and of transfer of skills following training into the live operating theatre