164 research outputs found

    Decolonizing, conviviality and convivial conservation : towards a convivial SDG 15, life on land?

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    In their article 'Towards convivial conservation' (2019), Büscher and Fletcher propose a vision for conservation which partly builds on Ivan Illich's 1973 book Tools for conviviality. Given a growing chorus of voices calling for decolonizing conservation to address the ramifications of racialized mindsets and biases,this article asks: what role could conviviality play in envisioning alternative, decolonizing conservation ideas, particularly for Sustainable Development Goal (SDG) 15? The article first reflects on the case for decolonizing conservation. It then conducts an in-depth analysis of Illich's radical ideas as well as subsequent understandings of conviviality, before juxtaposing Illich's ideas with Büscher and Fletcher's suggestions through a decolonizing lens. Finally,the article reviews SDG 15, 'Life on Land', against the backdrop of the prior decolonizing and convivial perspectives. The article argues that Illich's conviviality and related ideas have much to offer in envisioning alternative, decolonizing conservation ideas by promoting grassroots, democratic decision-making, living within bounds by the rich, emphasizing interdependencies between and within people and the environment, yet need to avoid imposition and incorporate intergenerational and marginalized viewpoints adequately

    Global decisions versus local realities: sustainability standards, priorities and upgrading dynamics in agricultural global production networks

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    Voluntary sustainability standards (VSSs) in global production networks (GPNs) have grown significantly in prominence. Existing research largely assumed that VSSs create linear upgrading outcomes for all GPN actors and has studied VSSs from the point of adoption in the GPNs, rather than a broader range of stages in their lifecycle. To address these limitations, and building on literature around power and agency in GPNs, we develop the constellation of priorities (CoP) model to unpack the diverse and often diverging boardroom (Northern lead firm) and local (Southern supplier) priorities involved in such standards. Through in-depth fieldwork on horticulture in Kenya and cocoa in Nicaragua across the VSS lifecycle, we find significant divergences in priorities between farmer groups in both countries and lead firms in the UK and Germany. We demonstrate analytically and empirically that diverging priorities coupled with power asymmetries produced contestations, leading to simultaneous economic and environmental downgrading, and social upgrading

    Axion-photon Couplings in Invisible Axion Models

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    We reexamine the axion-photon couplings in various invisible axion models motivated by the recent proposal of using optical interferometry at the ASST facility in the SSCL to search for axion. We illustrate that the assignment of U(1)PQU(1)_{PQ} charges for the fermion fields plays an important role in determining the couplings. Several simple non-minimal invisible axion models with suppressed and enhanced axion-photon couplings are constructed, respectively. We also discuss the implications of possible new experiments to detect solar axions by conversion to XX-rays in a static magnetic apparatus tracking the sun.Comment: 14 pages, LaTeX fil

    A 5D non compact and non Ricci flat Kaluza-Klein Cosmology

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    A model universe is proposed in the framework of 5-dimensional noncompact Kaluza-Klein cosmology which is not Ricci flat. The 4D part as the Robertson-Walker metric is coupled to conventional perfect fluid, and its extra-dimensional part is coupled to a dark pressure through a scalar field. It is shown that neither early inflation nor current acceleration of the 4D universe would happen if the non-vacuum states of the scalar field would contribute to 4D cosmology.Comment: 13 pages, major revision, published online in GR

    Bringing research alive through stories: reflecting on research storytelling as a public engagement method

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    Stories are vital in making sense of our lives – and research. Consequently, 12 researchers from the University of Sheffield underwent a three-month training process from September to November 2019 to learn how to shape their research experiences into accessible, ten-minute, spoken stories. This culminated in a storytelling evening as part of the Economic and Social Research Council’s Festival of Social Science, at which researchers from different disciplines discussed various nature–society dynamics in diverse field sites in the Global South. By reflecting on the training process and the performance through qualitative interviews with storytellers and audience members, our study answers the research question: What lessons emerge from an interdisciplinary group of researchers engaging with research storytelling for public engagement? Our study addresses gaps in the literature by focusing on interdisciplinary research storytelling, spoken ten-minute stories, bringing together storytellers’ and audience’s viewpoints, and providing practical recommendations for researchers and practitioners. We argue that research storytelling can have diverse benefits for both researchers and listeners by promoting learning in an accessible format, boosting self-confidence and helping (un/re)learn scholarly communication. However, professional guidance and peer support, as well as ethical sensitivity, are crucial

    Discrete symmetries, invisible axion and lepton number symmetry in an economic 3-3-1 model

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    We show that Peccei-Quinn and lepton number symmetries can be a natural outcome in a 3-3-1 model with right-handed neutrinos after imposing a Z_11 x Z_2 symmetry. This symmetry is suitably accommodated in this model when we augmented its spectrum by including merely one singlet scalar field. We work out the breaking of the Peccei-Quinn symmetry, yielding the axion, and study the phenomenological consequences. The main result of this work is that the solution to the strong CP problem can be implemented in a natural way, implying an invisible axion phenomenologically unconstrained, free of domain wall formation and constituting a good candidate for the cold dark matter.Comment: 17 pages, Revtex

    Diffuse inverse Compton and synchrotron emission from dark matter annihilations in galactic satellites

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    Annihilating dark matter particles produce roughly as much power in electrons and positrons as in gamma ray photons. The charged particles lose essentially all of their energy to inverse Compton and synchrotron processes in the galactic environment. We discuss the diffuse signature of dark matter annihilations in satellites of the Milky Way (which may be optically dark with few or no stars), providing a tail of emission trailing the satellite in its orbit. Inverse Compton processes provide X-rays and gamma rays, and synchrotron emission at radio wavelengths might be seen. We discuss the possibility of detecting these signals with current and future observations, in particular EGRET and GLAST for the gamma rays.Comment: 13 pages, 5 figure

    Surface preparation of powder metallurgical tool steels by means of wire electrical discharge machining

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    The surface of two types of powder metallurgical (PM) tool steels (i.e., with and without nitrogen) was prepared using wire electrical discharge machining (WEDM). From each grade of tool steel, seven surfaces corresponding to one to seven passes of WEDM were prepared. The WEDM process was carried out using a brass wire as electrode and deionized water as dielectric. After eachWEDM pass the surface of the tool steels was thoroughly examined. Surface residual stresses were measured by the X-ray diffraction (XRD) technique. The measured stresses were found to be of tensile nature. The surface roughness of the WEDM specimens was measured using interference microscopy. The surface roughness as well as the residual stress measurements indicated an insignificant improvement of these parameters after four passes of WEDM. In addition, the formed recast layer was characterized by means of scanning electron microscopy (SEM), XRD, and X-ray photoelectron spectroscopy (XPS). The characterization investigation clearly shows diffusion of copper and zinc from the wire electrode into the work material, even after the final WEDM step. Finally, the importance of eliminating excessive WEDM steps is thoroughly discussed

    The cosmic ray positron excess and neutralino dark matter

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    Using a new instrument, the HEAT collaboration has confirmed the excess of cosmic ray positrons that they first detected in 1994. We explore the possibility that this excess is due to the annihilation of neutralino dark matter in the galactic halo. We confirm that neutralino annihilation can produce enough positrons to make up the measured excess only if there is an additional enhancement to the signal. We quantify the `boost factor' that is required in the signal for various models in the Minimal Supersymmetric Standard Model parameter space, and study the dependence on various parameters. We find models with a boost factor greater than 30. Such an enhancement in the signal could arise if we live in a clumpy halo. We discuss what part of supersymmetric parameter space is favored (in that it gives the largest positron signal), and the consequences for other direct and indirect searches of supersymmetric dark matter.Comment: 11 pages, 6 figures, matches published version (PRD

    Dark energy as a mirage

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    Motivated by the observed cosmic matter distribution, we present the following conjecture: due to the formation of voids and opaque structures, the average matter density on the path of the light from the well-observed objects changes from Omega_M ~ 1 in the homogeneous early universe to Omega_M ~ 0 in the clumpy late universe, so that the average expansion rate increases along our line of sight from EdS expansion Ht ~ 2/3 at high redshifts to free expansion Ht ~ 1 at low redshifts. To calculate the modified observable distance-redshift relations, we introduce a generalized Dyer-Roeder method that allows for two crucial physical properties of the universe: inhomogeneities in the expansion rate and the growth of the nonlinear structures. By treating the transition redshift to the void-dominated era as a free parameter, we find a phenomenological fit to the observations from the CMB anisotropy, the position of the baryon oscillation peak, the magnitude-redshift relations of type Ia supernovae, the local Hubble flow and the nucleosynthesis, resulting in a concordant model of the universe with 90% dark matter, 10% baryons, no dark energy, 15 Gyr as the age of the universe and a natural value for the transition redshift z_0=0.35. Unlike a large local void, the model respects the cosmological principle, further offering an explanation for the late onset of the perceived acceleration as a consequence of the forming nonlinear structures. Additional tests, such as quantitative predictions for angular deviations due to an anisotropic void distribution and a theoretical derivation of the model, can vindicate or falsify the interpretation that light propagation in voids is responsible for the perceived acceleration.Comment: 33 pages, 2 figs; v2: minor clarifications, results unchanged; v3: matches the version published in General Relativity and Gravitatio
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