223 research outputs found
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Apocalypse yesterday: Posthumanism and comics in the Anthropocene
It is widely recognised that the growing awareness that we are living in the Anthropocene – an unstable geological epoch in which humans and their actions are catalysing catastrophic environmental change – is troubling humanity’s understanding and perception of temporality and the ways in which we come to terms with socio-ecological change. This article begins by arguing in favour of posthumanism as an approach to this problem, one in which the prefix ‘post’ does not come as an apocalyptic warning, but rather signals a new way of thinking, an encouragement to move beyond a humanist perspective, and to abandon a social discourse and a worldview fundamentally centred on the human. The article then explores how the impending environmental catastrophe can be productively reimagined through graphic narratives, arguing that popular culture in general, and comics in particular, emerge as productive sites for geographers to interrogate and develop posthuman methodologies and narratives. Developing our analysis around two comics in particular – Here (McGuire, 2014) and Mad Max: Fury Road (Miller et al., 2015) – we show how graphic narrative can help us to move beyond the nature-society divide that is rendered anachronistic by the Anthropocene
A key role of the mitochondrial citrate carrier (SLC25A1) in TNFα- and IFNγ-triggered inflammation
The chronic induction of inflammation underlies multiple pathological conditions, including metabolic, autoimmune disorders and cancer. The mitochondrial citrate carrier (CIC), encoded by the SLC25A1 gene, promotes the export of citrate from the mitochondria to the cytoplasm, a process that profoundly influences energy balance in the cells. We have previously shown that SLC25A1 is a target gene for lipopolysaccharide signaling and promotes the production of inflammatory mediators. We now demonstrate that SLC25A1 is induced at the transcriptional level by two key pro-inflammatory cytokines, tumor necrosis factor-α (TNFα) and interferon-γ (IFNγ), and such induction involves the activity of the nuclear factor kappa B and STAT1 transcription factors. By studying the down-stream events following SLC25A1 activation during signals that mimic inflammation, we demonstrate that CIC is required for regulating the levels of nitric oxide and of prostaglandins by TNFα or IFNγ. Importantly, we show that the citrate exported from mitochondria via CIC and its downstream metabolic intermediate, acetyl-coenzyme A, are necessary for TNFα or IFNγ to induce nitric oxide and prostaglandin production. These findings provide the first line of evidence that the citrate export pathway, via CIC, is central for cytokine-induced inflammatory signals and shed new light on the relationship between energy metabolism and inflammation
The indentation rolling resistance in belt conveyors: A model for the viscoelastic friction
In this paper, we study the steady-state rolling contact of a linear viscoelastic layer of finite thickness and a rigid indenter made of a periodic array of equally spaced rigid cylinders. The viscoelastic contact model is derived by means of Green’s function approach, which allows solving the contact problem with the sliding velocity as a control parameter. The contact problem is solved by means of an accurate numerical procedure developed for general two-dimensional contact geometries. The effect of geometrical quantities (layer thickness, cylinders radii, and cylinders spacing), material properties (viscoelastic moduli, relaxation time) and operative conditions (load, velocity) are all investigated. Physical quantities typical of contact problems (contact areas, deformed profiles, etc.) are calculated and discussed. Special emphasis is dedicated to the viscoelastic friction force coefficient and to the energy dissipated per unit time. The discussion is focused on the role played by the deformation localized at the contact spots and the one in the bulk of the thin layer, due to layer bending. The model is proposed as an accurate solution for engineering applications such as belt conveyors, in which the energy dissipated on the rolling contact of idle rollers can, in some cases, be by far the most important contribution to their energy consumption
Dynamically induced friction reduction in micro-structured interfaces
We investigate the dynamic behavior of a regular array of in-plane elastic supports interposed between a sliding rigid body and a rigid substrate. Each support is modelled as a mass connected to a fixed pivot by means of radial and tangential elastic elements. Frictional interactions are considered at the interface between the supports and the sliding body. Depending on the specific elastic properties of the supports, different dynamic regimes can be achieved, which, in turn, affect the system frictional behavior. Specifically, due to transverse microscopic vibration of the supports, a lower friction force opposing the macroscopic motion of the rigid body can be achieved compared to the case where no supports are present and rubbing occurs with the substrate. Furthermore, we found that the supports static orientation plays a key role in determining the frictional interactions, thus offering the chance to specifically design the array aiming at controlling the resulting interfacial friction force
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Double exposure to capitalist expansion and climatic change: a study of vulnerability on the Ghanaian coastal commodity frontier
Jason Moore's theory of the commodity frontier serves as a useful framework for demonstrating the socio-ecological upheaval that occurs in the 'frontier' spaces to which capitalism must expand in search of uncommodified 'cheap' nature. Work to date however has failed to consider how the impacts of frontier expansion interact with climate change despite the two phenomena being closely linked in both causes and effects, and largely impacting most severely upon rural communities in the Global South. This article seeks to address this gap with a focus on the coastal commodity frontier: socio-ecological systems within which marine and terrestrial frontier expansion can occur concurrently, while being impacted by climatic change. The research was conducted using an ethnographic, case study approach, centred on an eight-month research visit to Aboadze, a small-scale marine fishing community in the Western Region of Ghana. This community is subject to terrestrial frontier expansion in the form of a thermal power station, marine frontier expansion in the form of industrial overfishing, and is also exposed to the impacts of climate change. The article finds, through a double exposure vulnerability framework, that frontier expansion and climatic change interact to exacerbate food, water and livelihood insecurities in the case study
community, whilst simultaneously reducing the community's capacity to adapt to its changing environment and perpetuating harmful global changes through feedback exposures. This research makes an important conceptual contribution by galvanising a conversation between two thus far disparate fields and invites further research to provide more nuanced analyses of the intersectional vulnerabilities impacting coastal communities
Dynamic political contexts and power asymmetries: the cases of the Blue Nile and the Yarmouk Rivers
This paper explores the evolving patterns of hydropolitical relations in the dynamic contexts of Yarmouk and Blue Nile Rivers in comparison. The analysis aims at shedding light over the complex implications that recent political and social changes have aroused for the water disputes between Jordan and Syria on the one hand, and Ethiopia and Egypt on the other. In both basins, cooperative efforts toward the integrated management of transboundary waters have been only partially effective and largely undermined by the perpetuation of unilateral actions by riparian states. In the case studies, the lack of a basin-wide vision over the control and use of shared waters has resulted in disputes among the basin states and ultimately in an unsustainable, unfair, and unwise utilization of the resources. This paper argues that a substantive and effective integration of national water policies is unlikely to occur, unless power asymmetries are properly addressed in order to overcome the likelihood of hegemonic regimes
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