1,202 research outputs found

    High purity nanoparticles exceed stoichiometry limits in rebox chemistry: the nano way to cleaner water

    Get PDF
    A potentially cheaper and more effective way of cleaning wastewater has been discovered by scientists at Nazarbayev University and the University of Brighton researching nanotechnology [1]. It is well established that when particles are reduced to the nanoscale unexpected effects occur. Silver, for example, interacts with mercury ions in a fixed ratio of atoms (stoichiometry), typically 2:1, which presents a limit that has never been exceeded. In this project we used an alternative chemical procedure based on modified quartz sand to immobilise silver nanoparticles (NPs) with control over their size. We found that when the size of the silver NPs decreased below 35 nm the amount of mercury ions reacting with silver increased beyond the long-held limit and rose to a maximum of 1:1.2 for 10 nm sized silver

    The social implications of artificial intelligence.

    Get PDF
    For 18 years. I have been publishing books and papers on the subject of the social implications of Artificial Intelligence (AI). This is an area which is has been, and remains, in need of more academic attention of a serious nature than it currently receives. It will be useful to attempt a working definition of the field of AI at this stage. There is a considerable amount of disagreement as to what does and does not constitute AI and this often has important consequences for discussions of the social implications of the field. In brief, I define AI as the study of intelligent behaviour (in humans, animals, and machines) and the attempt to find ways in which such behaviour could be engineered in any type of artefact. My position on the definition of AI as a field of activity is set out in full in various places in the works submitted for this application. Most important are Chapter 2 of Whitby, 1988b, Chapter 3 of Whitby, 1996, and Whitby, 2000. This definition is distinctive (though not unique). For the purposes of discussion of social implications, its most distinctive feature is that it does not require the imitation or replication of human intellectual attributes. Because, under this definition, AI is not limited to the study of and attempt to build human-like intelligence the discussion of its social implications is rendered much broader. Also, because AÏ encompasses the attempt to engineer intelligent behaviour in any type of artefact, discussion of its social implications will need to consider the way in which AI technology, methods, and attitudes can permeate other different areas. This will include a wide range of technologies which include an AI element and a wide range of disciplines which are influenced by AI ideas. Thus the social implications of AI are turned into an immensely important field of study, since AI technology will steadily continue to permeate other technologies and thereby society as a whole. Many of the social implications of this technological process are nonobvious and surprising. If we are to make sensible, timely, and practical policy decisions and legislation then it is important to be as clear as possible about likely technological developments and their social implications. We may initially attempt to characterise various approaches by other authorities on the social implications of AI. Thèse range from the wildly spéculative such as Warwick (1988) and Moravec (1988) to the mainly technical, for example Michie (1986). At the wildly spéculative end of this continuum represented by Professor Warwick there are scare stories involving robots taking over the earth. (See for example Warwick, 1998 pp. 21-38) At the other end of the continuum, there are writers who often see AI as entirely positive, or as having no social implications at all. Most authorities will, or at least should, occupy a position somewhere between these extremes. However, in giving serious académie considération to this area, one needs to respond to this entire range of approaches. That is to say that one must (as a minimum) both be conversant with probable technical developments and also carefully and critically respond to speculations about the nature of future society. In my research I have consistently attempted to do just this. This is obviously a cross-disciplinary exercise and the differing methodologies of different disciplines présent further problems in determining the best (or an approximation to the best) approach. For a number of reasons, which will be fully explored in this statement, my approach has concentrated (mainly, though not exclusively) on the attempt to provide guidance to those actually concerned with the technical and scientific development of AI. The published books and papers submitted as part of this application span a period of 16 years. Thèse works form a cohérent body of research around the area of the social implications of AI. This body both develops the theme of the need for professionalism in AI and answers the criticisms of other writers in the area. They involve a full response to other writers in this area, over the entire continuum described above. This is a large, coherent, important, and generally well-regarded body of work which is in every relevant sense equivalent to that required for a PhD. by research

    Global Atmospheric Aerosol Modeling

    Get PDF
    Global aerosol models are used to study the distribution and properties of atmospheric aerosol particles as well as their effects on clouds, atmospheric chemistry, radiation, and climate. The present article provides an overview of the basic concepts of global atmospheric aerosol modeling and shows some examples from a global aerosol simulation. Particular emphasis is placed on the simulation of aerosol particles and their effects within global climate models

    Robot rights? Towards a social-relational justification of moral consideration \ud

    Get PDF
    Should we grant rights to artificially intelligent robots? Most current and near-future robots do not meet the hard criteria set by deontological and utilitarian theory. Virtue ethics can avoid this problem with its indirect approach. However, both direct and indirect arguments for moral consideration rest on ontological features of entities, an approach which incurs several problems. In response to these difficulties, this paper taps into a different conceptual resource in order to be able to grant some degree of moral consideration to some intelligent social robots: it sketches a novel argument for moral consideration based on social relations. It is shown that to further develop this argument we need to revise our existing ontological and social-political frameworks. It is suggested that we need a social ecology, which may be developed by engaging with Western ecology and Eastern worldviews. Although this relational turn raises many difficult issues and requires more work, this paper provides a rough outline of an alternative approach to moral consideration that can assist us in shaping our relations to intelligent robots and, by extension, to all artificial and biological entities that appear to us as more than instruments for our human purpose

    ruvA Mutants that resolve Holliday junctions but do not reverse replication forks

    Get PDF
    RuvAB and RuvABC complexes catalyze branch migration and resolution of Holliday junctions (HJs) respectively. In addition to their action in the last steps of homologous recombination, they process HJs made by replication fork reversal, a reaction which occurs at inactivated replication forks by the annealing of blocked leading and lagging strand ends. RuvAB was recently proposed to bind replication forks and directly catalyze their conversion into HJs. We report here the isolation and characterization of two separation-of-function ruvA mutants that resolve HJs, based on their capacity to promote conjugational recombination and recombinational repair of UV and mitomycin C lesions, but have lost the capacity to reverse forks. In vivo and in vitro evidence indicate that the ruvA mutations affect DNA binding and the stimulation of RuvB helicase activity. This work shows that RuvA's actions at forks and at HJs can be genetically separated, and that RuvA mutants compromised for fork reversal remain fully capable of homologous recombination

    Dominant aerosol processes during high-pollution episodes over Greater Tokyo

    Get PDF
    This paper studies two high-pollution episodes over Greater Tokyo: 9 and 10 December 1999, and 31 July and 1 August 2001. Results obtained with the chemistry-transport model (CTM) Polair3D are compared to measurements of inorganic PM2.5. To understand to which extent the aerosol processes modeled in Polair3D impact simulated inorganic PM2.5, Polair3D is run with different options in the aerosol module, e.g. with/without heterogeneous reactions. To quantify the impact of processes outside the aerosol module, simulations are also done with another CTM (CMAQ). In the winter episode, sulfate is mostly impacted by condensation, coagulation, long-range transport, and deposition to a lesser extent. In the summer episode, the effect of long-range transport largely dominates. The impact of condensation/evaporation is dominant for ammonium, nitrate and chloride in both episodes. However, the impact of the thermodynamic equilibrium assumption is limited. The impact of heterogeneous reactions is large for nitrate and ammonium, and taking heterogeneous reactions into account appears to be crucial in predicting the peaks of nitrate and ammonium. The impact of deposition is the same for all inorganic PM2.5. It is small compared to the impact of other processes although it is not negligible. The impact of nucleation is negligible in the summer episode, and small in the winter episode. The impact of coagulation is larger in the winter episode than in the summer episode, because the number of small particles is higher in the winter episode as a consequence of nucleation.Comment: Journal of Geophysical Research D: Atmospheres (15/05/2007) in pres

    <i>amoA</i> Gene Abundances and Nitrification Potential Rates Suggest that Benthic Ammonia-Oxidizing Bacteria and Not Archaea Dominate N Cycling in the Colne Estuary, United Kingdom

    Get PDF
    ABSTRACT Nitrification, mediated by ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA), is important in global nitrogen cycling. In estuaries where gradients of salinity and ammonia concentrations occur, there may be differential selections for ammonia-oxidizer populations. The aim of this study was to examine the activity, abundance, and diversity of AOA and AOB in surface oxic sediments of a highly nutrified estuary that exhibits gradients of salinity and ammonium. AOB and AOA communities were investigated by measuring ammonia monooxygenase ( amoA ) gene abundance and nitrification potentials both spatially and temporally. Nitrification potentials differed along the estuary and over time, with the greatest nitrification potentials occurring mid-estuary (8.2 μmol N grams dry weight [gdw] −1 day −1 in June, increasing to 37.4 μmol N gdw −1 day −1 in January). At the estuary head, the nitrification potential was 4.3 μmol N gdw −1 day −1 in June, increasing to 11.7 μmol N gdw −1 day −1 in January. At the estuary head and mouth, nitrification potentials fluctuated throughout the year. AOB amoA gene abundances were significantly greater (by 100-fold) than those of AOA both spatially and temporally. Nitrosomonas spp. were detected along the estuary by denaturing gradient gel electrophoresis (DGGE) band sequence analysis. In conclusion, AOB dominated over AOA in the estuarine sediments, with the ratio of AOB/AOA amoA gene abundance increasing from the upper (freshwater) to lower (marine) regions of the Colne estuary. These findings suggest that in this nutrified estuary, AOB (possibly Nitrosomonas spp.) were of major significance in nitrification. </jats:p

    Research on the Geography of Agricultural Change: Redundant or Revitalized?

    Get PDF
    Future research directions for agricultural geography were the subject of debate in Area in the late 1980s. The subsequent application of political economy ideas undoubtedly revived interest in agricultural research. This paper argues that agricultural geography contains greater diversity than the dominant political economy discourse would suggest. It reviews ‘other’ areas of agricultural research on policy, post-productivism, people, culture and animals, presenting future suggestions for research. They should ensure that agricultural research continues revitalized rather than redundant into the next millennium
    corecore