Arbuscular mycorrhizal associations in plant nutrition and health

Plants and arbuscular mycorrhizal fungi have co-evolved over a period of at least 450 million years. This fungal-plant association involves the transfer of carbon to the obligate biotropic fungus, in return for a wide range of beneficial functions. Although this is usually a mutualistic relationship, it can become parasitic to the plant under adverse conditions. Here, the research examining mechanisms by which mycorrhizal associations improve plant fitness is reviewed. Although there is strong evidence that a number of beneficial functions are performed by mycorrhizae, the mechanisms behind these are often not clear. There are numerous factors which influence these mechanisms and their outcomes, one or more of which can be affecting the association simultaneously. The knowledge we have on arbusular mycorrhizal associations with plants could be applied to various land management practices in order to improve soil degradation brought about by anthropogenic activities. These include erosion, drought, nutrient stress and salinization, and are often a result of poor land management. In order to use mycorrhizal fungi as a biomanagement tool, more research is required, particularly in mature field communities over long timescales. There is a need to invest in the development of sustainable agroecological management methods and to design future policy and legislation that encourages large organizations to incorporate more sustainable practices whilst protecting small-scale farmers

What is the evidence for harm minimisation measures in gambling venues?

What techniques are currently being used for electronic gambling machine harm minimisation, and do they work? Overview The use of electronic gambling machines (EGMs) in Australia and New Zealand constitutes the largest sector of the gambling industry. The costs arising from the harms of gambling detract significantly from its benefits, and in all Australian jurisdictions various policy measures have been implemented to reduce these harms. If successful, these would maximise the net benefits associated with EGM gambling. This article reviews the available evidence for a range of these practices, particularly those implemented within EGM venues via ‘codes of practice’. These codes of practice are intended to give effect to the principles of ‘responsible gambling’ within EGM venues. These measures are: self-exclusion, signage, messages, interaction with gamblers, the removal of ATMs from gambling venues, and ‘responsible gambling’ assessed overall in a venue context. In addition, we review the evidence in support of two major recommendations of the Productivity Commission’s 2010 report into gambling, pre-commitment and one-dollar maximum wagers. We conclude that there is a modest level of evidence supporting some measures, notably self-exclusion and, to a greater extent, the removal of ATMs. There is also some evidence that ‘responsible gambling’ measures have, collectively, reduced the harms associated with gambling. However, there is limited evidence available to confirm the effectiveness of most individual ‘responsible gambling’ measures actually implemented in venues. Further, policy measures implemented outside the control of venues (such as ATM removal, reduction in bet limits, and the prohibition of smoking) appear to be associated with more significant effects, based on analysis of EGM revenue data in Victoria. The evidence for prospective measures is necessarily limited since the ultimate test is post-implementation efficacy, but there is growing evidence to suggest that pre-commitment, one-dollar maximum bets or other machine design changes may yield significantly more effective harm minimisation effects than in-venue practices such as signage or, indeed, self-exclusion. In considering evidence about the effects of existing or prospective measures it is important to emphasise that packages of measures might be more effective than single ones, and that an inability to confirm a statistically significant effect does not mean that no effect exists. Evidence Base, issue 2, 201

The Coal Mines Council

This paper is intended as an introduction to a disputes resolving procedure peculiar to the New Zealand mining industry. To the best of the writer's knowledge no previous attempt has been made to describe this mdustrial tribunal (Coal Mines Council). I could find no trace of any in-depth study on the value of this and other industrial decision-making bodies in New Zealand. It has not been possible therefore to draw comparisons. The opinions expressed are those of the writer, and not necessarily those of the Mines Department, Coal Mine Owners or Miners' Unions

Southern Ocean currents and climate

The Antarctic Circumpolar Current (ACC) carries about 130 to 150 x 106 m3 S-l along a 20 000 km path circling Antarctica, making it the largest current in the world ocean. The flow of the ACC connects the ocean basins, allowing water, heat, and other properties to be carried from one basin to another. The interbasin connection provided by the ACC is a key link in a global ocean circulation, sometimes called the "great ocean conveyor", which strongly influences the climate of the Earth on time-scales of years to centuries. Unlike most other regions of the ocean, fluctuations of the currents play a central role in the heat and momentum budget of the Southern Ocean. The fluctuations carry momentum, supplied by the strong winds, down to where pressure forces against seafloor topography can compensate the wind forcing, and also carry heat poleward to balance the heat lost by the ocean to the cold atmosphere south of the ACC. While the circumpolar current is the dominant circulation feature of the Southern Ocean, there are important flows in the north-south and vertical planes. Deep water shoals as it spreads south across the Southern Ocean, ultimately reaching the sea surface near Antarctica. Strong interactions with the atmosphere and sea-ice modify the upwelled water where it reaches the surface: some water is made lighter by warming md freshening due to rainfall and sea-ice melt, while some is made more dense by cooling and addition of salt rejected during freezing of sea-ice. The water mass transformations driven by air-sea exchange in the Southern Ocean allow deep water to be converted to lighter intermediate water, as required to complete the loop of the global conveyor

Curricula models for teaching critical and contextual studies

This article is a review of my book ‘Integrating Critical and Contextual Studies in Art and Design: possibilities for post-compulsory education’, in which I examine, at post-16, the relationship between studio practice and critical and contextual studies (CCS). I argue for discrete delivery of CCS as a support to, rather than a deterrent to, integration.Rintoul, J (2018) Curricula models for teaching Critical and Contextual Studies in Leach, S (Ed) AD magazine (NSEAD), issue 22, April 2018, pp.16-1

Robert Southey: a critical biography

Robert Southey ranks among the great English writers, secure of the fame he so eagerly anticipated. Yet, who now reads Southey? Nelson is not so significant a work that the author's name should rank high on its account alone; the Doctor has few readers. Most people indeed know Southey's works only from the Golden Treasury - After Blenheim, and My Days amok the Dead are Past: most of the works here examined have, as individual contributions to literature, no real importance. Of the students who so glibly refer to Southey's prose in examination papers, hardly one in a score could explain his reputation, for that reputation is unheld not by a handful of titles, but by a lifetime's writing.Southey's letters introduce us to one of the most remarkable personalities who have ever borne part in the sustentation. of English literature. Student and recluse as he was, things happened to Southey. Offered the editorship of a government journal, central figure of a scene in the House of Commons, elected member of parliament for a rotten borough, poet -laureate, and had he chosen, baronet of the realm - these were contemporary tributes which, accorded to a man of letters with no other public contacts whatsoever, mark him as of no small importance. He was almost incredibly industrious, and though in many ways a stupid man, was enormously informed. Within the limits set by his religious and political opinions he was prepared to write - and did write - on everything. The respect in which he was held and the mass of his writings make it impossible for any student of the 19th century to overlook Southey. Read or unread, he will always be remembered as one of the really conspicuous figures of his age. That he is known now despite the paucity of biographical study, is one more tribute to him.The importance of his writings is mainly in the importance of the writer. Wrong in nearly every judgement he formed and lacking originality or cogency in argument, he will certainly not be read for guidance. His essays illustrate the state of society and may have a value to the historian, but that equally is not our concern. Yet he will be read with interest for the excellence of his prose style. This is not confined to any one book, nor is any book devoid of blemish: if this belated survey of his prose works has any value it may be in emphasing that however prejudiced, illogical, or ill -informed Southey may have been, he never forgot altogether how to write fine English. Life is too short that readers to-day should waste time on the Colloquies, but even in this masterpiece of folly there is good writing: that is why the 19th century read it.Southey's prose writing had three moodes. In narrative he wrote short sentences, built into closely worked paragraphs with . no heightening or colouring whatever. His aim was to pack in as much detail as possible without spoiling the porportion of the story, and sometimes these long close paragraphs contain odd juxtapositions, as has been shown. He was seldom much excited by mere events, so that for adventures and scenes of battle he had no graphic style, and the most stirring encounters are badly enough related; but by shifting the focus, as described elsewhere, he maintained an atmosphere of tension. In the Peninsular War, his battles lose by comparison with Napier, who was undoubtedly a very gifted writer. Southey's style was well calculated to provide clarity with economy; and was used to good effect in Nelson, the Admirals, and narrative parts of other works. The following passage from the battle of Trafalgar is typical:"The Victory had not yet returned a single gun: fifty of her men had by this time been killed or wounded, and her main-topmast, with all her stunning sails and their booms, shot away. Nelson declared that, in all his battles, he had seen nothing which surpassed the cool courage of his crew on this occasion.At four minutes after twelve she opened her fire from both sides of her deck. It was not possible to break the enemy's line without running on board one of their ships; Hardy informed him of this, and asked which he would prefer. Nelson replied: 'Take your choice, Hardy, it does not signify much.' The master was then ordered to put the helm to port, and the Victory ran on board the Redoubtable, just as her tiller ropes were shot away."Southey's passion was best kindled by more abstract forces. Throughout and after the Napoleonic wars he was very deeply moved by emotional patriotism; hypocrisy and scatology always roused his fighting temper; he could be very violent in defence of his own opinions. In this mood he wrote a more highly coloured style. He favoured long paragraphs built up of compound sentences, in which the main thought was repeated, and elaborated by illustration, and i9ts application extended sometimes by reference or illusion. He was apt to overpunctuate, and favoured too frequently the 'pompous triads' of which Macauley complained in Johnson, but his sentences were well balanced and seldom laboured. At his best, this style has a resonance and rhythmic flow not often equalled, and it is un- failingly perspicuous. "All who read shall understand me," said Southey. At his worst, he became hysterical and resonance was lost in high-pitched abuse, very unlovely. Sufficient examples of this style rae given in the text.In meditative mood , the style retained its rhythmic quality, but lost its violence. There are pages in The Doctor permeated with homely sentiment, but sustained by the dignity of these rhythmic flowing paragraphs which stamp the author as a master of English prose. Much of Cowper and many letters illustrate this style; a late development from the aggressiveness of his most active period.As a satirist Southey was impossible, and his ponderous jocosity gives little pleasure. He tells many good tales in The Doctor, and tells them well, so he was not utterly without a sense of humour,but his own witticisms are pitiful. The worst faults of his style are due to too much aggressiveness and too little genuine humour. He was obviously deficient in imagination . and drove his way through difficulties by sheer self assertion; a method which makes no converts. If Burke defended his side like a philosopher, Southey did so like a soldier. His style lacks the figurative colourfulness of Burke's, and though more continuously clear and hard hitting, was apt to get out of control. Deficient in logic and humour, he was no match for Macaulay in mordant criticism, and his narrative is certainly less colourful. Though in prejudice and self confidence they were equal, Macaulay must be admitted the more entertaining, if more mannered in style. Absolute equality with Sterne is probably to be denied Southey on the score of originality and absence of characterisation, though he writes better. With the 19th century essayists he lid not compete.Southey's position seems to be a little lower than any of these writers; but it must be remembered always that though his separate works are poor supporters of his fame, the aggregate bulk of his good writing is very considerable. It is unjust to rank him by the success or failure of his books - he was not a writer of books, but of prose: passage for passage, he will stand comparison with the best in our literature.To examine his books is at best a poor way of estimating the status of a man whose life and character contribute so largely to his greatness. So far Southey has been unfortunate in his biographers: the time is ripe for a new estimate

Mass, heat and nutrient fluxes in the Atlantic Ocean determined by inverse methods

Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution March 1988Inverse methods are applied to historical hydrographic data to address two aspects of the general circulation of the Atlantic Ocean. The method allows conservation statements for mass and other properties, along with a variety of other constraints, to be combined in a dynamically consistent way to estimate the absolute velocity field and associated property transports. The method is first used to examine the exchange of mass and heat between the South Atlantic and the neighboring ocean basins. The Antarctic Circumpolar Current (ACC) carries a surplus of intermediate water into the South Atlantic through Drake Passage which is compensated by a surplus of deep and bottom water leaving the basin south of Africa. As a result, the ACC loses .25±.18x1015 W of heat in crossing the Atlantic. At 32°S the meridional flux of heat is .25±.19x1015 W equatorward, consistent in sign but smaller in magnitude than other recent estimates. This heat flux is carried primarily by a meridional overturning cell in which the export of 17 Sv of North Atlantic Deep Water (NADW) is balanced by an equatorward return flow equally split between the surface layers, and the intermediate and bottom water. No "leak" of warm Indian Ocean thermocline water is necessary to account for the equatorward heat flux across 32°S; in fact, a large transfer of warm water from the Indian Ocean to the Atlantic is found to be inconsistent with the present data set. Together these results demonstrate that the Atlantic as a whole acts to convert intermediate water to deep and bottom water, and thus that the global thermohaline cell associated with the formation and export of NADW is closed primarily by a "cold water path," in which deep water leaving the Atlantic ultimately returns as intermediate water entering the basin through Drake Passage. The second problem addressed concerns the circulation and property fluxes across 24°and 36°N in the subtropical North Atlantic. Conservation statements are considered for the nutrients as well as mass, and the nutrients are found to contribute significant information independent of temperature and salinity. Silicate is particularly effective in reducing the indeterminacy of circulation estimates based on mass conservation alone. In turn, the results demonstrate that accurate estimates of the chemical fluxes depend on relatively detailed knowledge of the circulation. The zonal-integral of the circulation consists of an overturning cell at both latitudes, with a net export of 19 Sv of NADW. This cell results in a poleward heat flux of 1.3±.2x1015 Wand an equatorward oxygen flux of 2900±180 kmol S-l across each latitude. The net flux of silicate is also equatorward: 138±38 kmol s-1 and 152±56 kmol s -1 across 36°and 24° N, respectively. However, in contrast to heat and oxygen, the overturning cell is not the only important mechanism responsible for the net silicate transport. A horizontal recirculation consisting of northward flow of silica-rich deep water in the eastern basin balanced by southward flow of low silica water in the western basin results in a significant silicate flux to the north. The net equatorward flux is thus smaller than indicated by the overturning cell alone. The net flux of nitrate across 36°N is n9±35 kmol 8- 1 to the north and is indistinguishable from zero at 24°N (-8±39 kmol 8-1 ), leading to a net divergence of nitrate between these two latitudes. Forcing the system to conserve nitrate leads to an unreasonable circulation. The dominant contribution to the nitrate flux at 36°N results from the correlation of strong northward flow and relatively high nitrate concentrations in the sub-surface waters of the Gulf Stream. The observed nitrate divergence between 24°and 36°N, and convergence north of 36°N, can be accounted for by a shallow cell in which the northward flow of inorganic nitrogen (nitrate) in the Gulf Stream is balanced by a southward flux of dissolved organic nitrogen in the recirculation gyre. Oxidation of the dissolved organic matter during its transit of the subtropical gyre supplies the required source of regenerated nitrate to the Gulf Stream and consumes oxygen, consistent with recent observations of oxygen utilization in the Sargasso Sea.This research was supported by NASA under contract NAG5-534 and NSF under contract OCE-8521685

Conductivity Exponent and Backbone Dimension in 2-d Percolation

We present high statistics simulations for 2-d percolation clusters in the "bus bar" geometry at the critical point, for site and for bond percolation. We measured their backbone sizes and electrical conductivities. For all sets of measurements we find large corrections to scaling, most of which do not seem to be described by single powers. Using single power terms for the corrections to scaling of the backbone masses, we would obtain fractal dimensions which are different for site and bond percolation, while the correct result is $D_b = 1.6432(8)$ for both. For the conductivity, the corrections to scaling are strongly non-monotonic for bond percolation. The exponent $t' = t/\nu$ is measured as 0.9826(8), in disagreement with the Alexander-Orbach and other conjectures.Comment: 15 pages, including 5 figures and 2 tables; minor change