1,095 research outputs found

    Value added: modes of sustainable recycling in the modernisation of waste management systems

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    For many centuries urban waste management in Europe and Northern America consisted of private – to – private arrangements to remove waste from the city centre and so restrain the spread of cholera and other diseases, odour and nuisances. The agricultural and industrial value chains provided a destination and a motivation to extract and valorise rags, ashes, dust, excreta, metals, food scraps, and many other forms of secondary resources which had some value to someone. The business of recycling developed alongside of municipal waste management, and absorbed many discarded materials, but remained a separate sector with its own practices, institutions, and economic rationality. The management of solid waste management became primarily focused on dumping waste outside the city boundaries. The ‘discovery’ of the relationship between open dumping and groundwater contamination in the 1960s set the stage for a round of modernisation of waste management practices and institutions in high-income countries. The widely recognised and celebrated result was the shift from open dumping and open burning of waste to the engineered “regional sanitary landfill” as a large technical facility that concentrates waste, isolates it from population centres, protects ground-water and thus allows for safe modern disposal of increasingly complex materials. This proved to be a costly affair though, and triggered a process of ecological modernisation in solid waste management characterised by institutional and financial reforms, which elevated the cost of removal. Disposal became costly, and as cities expanded, land to dump became a scarce resource. This set the stage for incorporating valorisation into the modernised waste management landscape as an alternative to modernised disposal. The ecological modernisation process that took place in Northern Europe and North America in the 1980s and early 1990s changed the policies and practices of waste management in fundamental but seldom understood ways. Pricing of disposal in high-income countries represents a core financial reform which in turn stimulates local authorities to invest in their own recycling (composting, reuse) infrastructure as a lower-cost and environmentally attractive alternative. Municipal recycling emerges as a key modernised institution in the landscape of integrated waste management, where investment in recycling produces higher and higher recovery rates and a virtuous circle of more investment, more recovery, less waste, co-operation with the value chains which have been re-constituted as “recycling markets,” and lower system costs. In municipal recycling, the agricultural and industrial value chains function as alternative and lower-cost sinks, complementing the landfill and lowering costs for the whole waste management system. In low- and middle-income countries, in contrast, the ecological modernisation of solid waste is problematic and incomplete, and ‘recycling’ becomes a key new area of global conflict. Priced disposal does not come about, either because of low levels of disposable income or unwillingness of elected officials to impose a burden on tax- and rate-payers, or because the motivation to modernise disposal comes from global institutions and is insufficiently embedded in genuinely local policymaking. Without it the system-internal benefits of diverting materials from disposal to valorisation are missing. Municipal recycling does not emerge, and the virtuous cycle of increasing recovery ambitions and performance is replaced by a vicious cycle of interrupted private value chain transactions, declining valorisation rates, and increasing volumes of materials requiring expensive disposal. City authorities in low- and middle-income countries seeking to gain the financial benefits of selling materials compete with private (informal) waste pickers, recyclers, and livestock feeding operations, claim monopoly rights to materials, and criminalise value chain activities. But they are unable to organise effective valorisation themselves, as they lack knowledge and commercial channels to reach the value chains. The value chain actors are blamed for not buying materials, but also for exploiting poor workers in miserable working conditions. Valorisation businesses are unwilling to do business with municipalities who supply low-quality materials, so the value chain transactions fail, and both avoided costs of disposal and offsetting revenues from valorisation remain elusive. Municipalities, waste system users, and the environment lose in this situation when local authorities are unable to pay landfill operating costs, and the expensive sanitary landfill infrastructure reverts to the status of a pre-modern dumpsite, which has to handle more and more waste. Agricultural and industrial value chains also suffer, because the thousands of individual and family enterprises in waste picking, recycling, and animal feeding are at risk to lose their livelihoods, or see reduced returns on their efforts due to monopoly behaviour, criminalisation, or harassment from the formal waste system actors. Mid-level value chain enterprises get fewer materials, and increasing volumes of potentially recoverable resources end up in the dump. But there are already some examples of how changing the model can produce improved results. In a small number of cities in low- and middle-income countries, the ecological modernisation of the waste management system appears to be leading to the emergence of a new model for institutionalised valorisation, provisionally called inclusive recycling. Inclusive recycling is a model for public sector acceptance of private value chain activities of valorisation. It is a model of shared ownership, risks, and benefits, where each set of actors does what they are best at. While it builds upon the techniques for participatory planning and stakeholder engagement, as well as on technical innovations for separate collection, processing, and environmental education that characterised the development of municipal recycling in the 1980s in OECD countries, inclusive recycling does not rely on the institutional reform of priced disposal. Rather, it maintains the centre of gravity of valorisation activities in the industrial or agricultural value chains, where the knowledge and infrastructure exists to receive, process, and market materials. Instead of re-inventing recycling as a part of the municipal solid waste department’s responsibilities, inclusive recycling looks to intermediary institutions such as labour unions or recycling co-operatives to facilitate shared risks and responsibilities between local authorities and value chain actors. Inclusive recycling can be seen in some of its emerging forms in Asia and Latin America, particularly in situations where there is a tradition of co-operation between civil society and local authorities, large numbers of waste pickers at the base of the value chain pyramid, and where the paper and metal value chains are long, healthy, and deeply rooted. In place of a single municipal recycling system, inclusive recycling is a mixed system where there are many different types of actors, economic niches, and business models. The results may be high levels of recovery and diversion from disposal, making it comparable to municipal recycling as a modernised institution. Like municipal recycling, inclusive recycling contributes to the pluralism of the modernised system, with a proliferation of actors, activities, and economic niches, which qualify it as what ecological modernization scholars have called a ‘modernised mixture’. However, inclusive recycling is not municipal recycling, and in the absence of priced disposal, the risks for both local authorities and value chain actors remain high. Combining global knowledge with local control of ecological modernisation processes is one approach to keeping the risks limited and enlarging the space for the virtuous circle of inclusive recycling to take root and flourish. </p

    Sustainable valorisation of organic urban wastes : insights from African case studies

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    Understanding the problems and potentials of the organic waste stream is perhaps the single most important step that city authorities in Africa could take in moving towards sustainable, affordable, effective and efficient waste management. This publication presents four examples of recent attempts to manage organic waste sustainably in the African context. The participants in the ‘Nairobi organic urban waste’ project have structured this case exercise in order to use the case studies as object lessons, to harvest genuine insights into the feasibility of a variety of ways to successfully and sustainably valorise urban organic waste streams. Three contemporary case examples of compost production are presented. These include composting by a community-based organisation in the Kenyan private sector and by a public-private partnership in Malawi. In all three cases, the project and case study focus is on the relations between city waste and the agricultural supply chain. A fourth case study describes the technical and economic potential to produce and use biogas from urban organic waste

    Biosimilars in rheumatology: what the clinician should know

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    Biosimilars are now a reality in rheumatology. Although analytical and non-clinical procedures to establish similarity have evolved significantly, clinical trials demonstrating equivalent efficacy and safety are absolutely required for all biosimilars. The design of such trials, including equivalence and non-inferiority statistical approaches, are discussed. Clinical evidence on biosimilars that have been approved recently or are presently being developed for use in rheumatology is also reviewed and contrasted with that available for biomimics (or intended copies), which are non-innovator biologics that are marketed in several countries but have not undergone review according to a regulatory pathway for biosimilars

    Some Problems in Probabilistic Tomography

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    Given probability distributions F1 , F2 , . . ., Fk on R and distinct directions θ1, . . ., θk, one may ask whether there is a probability measure μ on R2 such that the marginal of μ in direction θj is Fj, j = 1, . . ., k. For example for k = 3 we ask what the marginal of μ at 45° can be if the x and y marginals are each say standard normal? In probabilistic language, if X and Y are each standard normal with an arbitrary joint distribution, what can the distribution of X + Y or X - Y be? This type of question is familiar to probabilists and is also familiar (except perhaps in that μ is positive) to tomographers, but is difficult to answer in special cases. The set of distributions for Z = X - Y is a convex and compact set, C, which contains the single point mass Z ≡ 0 since X ≡ Y, standard normal, is possible. We show that Z can be 3-valued, Z=0, ±a for any a, each with positive probability, but Z cannot have any (genuine) two-point distribution. Using numerical linear programming we present convincing evidence that Z can be uniform on the interval [-ε, ε] for ε small and give estimates for the largest such ε. The set of all extreme points of C seems impossible to determine explicitly. We also consider the more basic question of finding the extreme measures on the unit square with uniform marginals on both coordinates, and show that not every such measure has a support which has only one point on each horizontal or vertical line, which seems surprising

    ORB5: a global electromagnetic gyrokinetic code using the PIC approach in toroidal geometry

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    This paper presents the current state of the global gyrokinetic code ORB5 as an update of the previous reference [Jolliet et al., Comp. Phys. Commun. 177 409 (2007)]. The ORB5 code solves the electromagnetic Vlasov-Maxwell system of equations using a PIC scheme and also includes collisions and strong flows. The code assumes multiple gyrokinetic ion species at all wavelengths for the polarization density and drift-kinetic electrons. Variants of the physical model can be selected for electrons such as assuming an adiabatic response or a ``hybrid'' model in which passing electrons are assumed adiabatic and trapped electrons are drift-kinetic. A Fourier filter as well as various control variates and noise reduction techniques enable simulations with good signal-to-noise ratios at a limited numerical cost. They are completed with different momentum and zonal flow-conserving heat sources allowing for temperature-gradient and flux-driven simulations. The code, which runs on both CPUs and GPUs, is well benchmarked against other similar codes and analytical predictions, and shows good scalability up to thousands of nodes

    The clonal composition of human CD4+CD25+Foxp3+ cells determined by a comprehensive DNA-based multiplex PCR for TCRB gene rearrangements

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    The characterization of the T-cell receptor (TCR) repertoire of CD4+ regulatory T cells (TR) have been limited due to the RNA degradation that results following permeabilization and fixation as routinely used for intracellular staining of Foxp3. In the present study the clonal composition of human umbilical cord blood (UCB) and adult peripheral blood mononuclear cells (PBMC) CD4+ TR and non-TR was characterized by a DNA-based multiplex PCR which allowed for the consistent clonotypic characterization of cells that have undergone fixation and permeabilization. To validate this method, CD8+ T cells from two HLA A*0201 individuals were sorted and compared clonotypically based upon their ability either to secrete interferon-γ in response to a CMV pp65 epitope or to bind to the corresponding pMHC I tetramer. In the UCB and PBMCs clonotypes shared between the CD4+CD25+Foxp3+ and CD4+CD25+Foxp3− was observed in all 3 UCB and in one adult PBMCs, suggesting that naïve and memory CD4+ TR can share the same clonotypes as CD4+ non-TR in humans

    Amenability of algebras of approximable operators

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    We give a necessary and sufficient condition for amenability of the Banach algebra of approximable operators on a Banach space. We further investigate the relationship between amenability of this algebra and factorization of operators, strengthening known results and developing new techniques to determine whether or not a given Banach space carries an amenable algebra of approximable operators. Using these techniques, we are able to show, among other things, the non-amenability of the algebra of approximable operators on Tsirelson's space.Comment: 20 pages, to appear in Israel Journal of Mathematic
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