A general framework for unbiased tests of gravity using galaxy clusters

We present a Markov chain Monte Carlo pipeline which can be used for unbiased large-scale tests of gravity using galaxy cluster observations. The pipeline, which currently uses cluster number counts to constrain the present-day background scalar field $f_{R0}$ of Hu-Sawicki $f(R)$ gravity, fully accounts for the effects of the fifth force on cluster properties including the dynamical mass, the halo concentration and the observable-mass scaling relations. This is achieved using general models which have been calibrated over a wide and continuous mass range ($10^{11}M_{\odot}\lesssim M\lesssim10^{15}M_{\odot}$) using a large suite of cosmological simulations, including the first to simultaneously incorporate both screened modified gravity and full baryonic physics. We show, using mock cluster catalogues, that an incomplete treatment of the observable-mass scaling relations in $f(R)$ gravity, which do not necessarily follow the usual power-law behaviour, can lead to unbiased and imprecise constraints. It is therefore essential to fully account for these effects in future cosmological tests of gravity that will make use of vast cluster catalogues from ongoing and upcoming galaxy surveys. Our constraint framework can be easily extended to other gravity models; to demonstrate this, we have carried out a similar modelling of cluster properties in the normal-branch Dvali-Gabadadze-Porrati model (nDGP), which features a very different screening mechanism. Using our full-physics simulations, we also study the angular power spectra of the thermal and kinetic Sunyaev-Zel'dovich effects in $f(R)$ gravity and nDGP, and demonstrate the potential for precise constraints of gravity using data from upcoming CMB experiments. Finally, we present a retuned baryonic physics model, based on the IllustrisTNG model, which can be used for full-physics simulations within large cosmological volumes. This can be used to study the properties of galaxy groups and clusters in screened modified gravity over the mass range $10^{13}M_{\odot}\leq M\lesssim10^{15}M_{\odot}$

Sustainable financing of permanent CO2 disposal through a Carbon Takeback Obligation

Unless there is immediate, unprecedented, reduction in global demand for carbon-intensive energy and products, then capture and permanent storage of billions of tonnes of carbon dioxide (CO2) annually will be needed before mid-century to meet Paris Agreement goals. Yet competition from cheaper, temporary, carbon storage means that permanent disposal remains starved of investment, currently representing about 0.1% of Energy and Industrial Process (EIP) emissions. This stored fraction must reach 100% to stop EIPs causing global warming. Here we show that a cost-effective transition can occur by mandating an increasing stored fraction through a progressive Carbon Takeback Obligation (CTO) on fossil fuel producers and importers. Projected costs of storage to the consumer are lower than pricing carbon emissions in conventional 1.5{\deg}C scenarios until the 2040s, and comparable or lower thereafter. A CTO combined with measures to reduce CO2 production would deliver the lowest-risk pathway to achieving net zero.Comment: 10 pages, 1 figure, SI available on reques

Learning French in the UK setting: Policy, classroom engagement and attainable learning outcomes

Due to the contemporary dominance of English as global lingua franca, all other “foreign languages” face a number of challenges in formal education. This paper describes the recent evolution of policy and practice regarding foreign language education in England, with a particular focus on early language learning. Evidence from a classroom study of French as foreign language is used to illustrate primary school instructional practices and children’s engagement in this setting, and their learning outcomes. Conclusions are drawn concerning sustainable approaches to the teaching of languages other than English in the early school years, in an English-dominated linguistic landscape

The Esperance Nyungars, at the Frontier: An archaeological investigation of mobility, aggregation and identity in late- Holocene Aboriginal society, Western Australia

This thesis documents the results of an Aboriginal community-based archaeological research project in the Esperance region, southern Western Australia. It is based on analysis of rock art, stone arrangements and flaked stone artefacts. The aim is to understand the role of the study sites – Belinup and Marbaleerup – within patterns of movement that underpinned society and economy in this region during the late-Holocene. The research explores concepts of identity (Jones 1997; Meskell and Preucel 2004) relating to the local Esperance Nyungar people, and the broader Noongar and Western Desert cultural blocs. It has been suggested that negotiations over territory, law and identity during the recent past were directly related to the expansion of the Western Desert cultural bloc (Gibbs and Veth 2002), which situates the study area at a dynamic frontier of cultural change. Exploration of these questions leads to a discussion about the historical construction of Esperance Nyungar identity. The study sites are hypothesised to have functioned in the past as aggregation locales (Conkey 1980). Investigation of this hypothesis is illuminative; firstly, for understanding more about the study sites; and secondly about the application of the aggregation concept, and its limitations for archaeology. The results inform a discussion of how mobility (Binford 1980; Kelly 1992) and aggregation can be usefully applied together to investigate the intersections of social and economic elements in hunter-gatherer settlement. As a conceptual tool for archaeology, identity is challenging because it cannot be directly interpreted from material culture in a simple way. Despite the challenges, identity is an important tool for understanding past societies. Identity is investigated here by mapping the occurrence of symbols across landscapes and considering how these may, or may not, relate to notions of identity and connections to place. The approach begins with what is known (contemporary identity and connection), and works backwards through time and outwards through space towards the unknown. Identity is a powerful way to link the archaeological past with the contemporary descendent community. The process of undertaking a community-based research partnership is discussed, with critical reflection on the challenges and successes. An argument is presented for how and why community input and ownership is critical to the success of archaeological research into Aboriginal pasts in Australia and abroad. The results demonstrate the inherent dynamism in Aboriginal society in southern Western Australia and highlight a historical legacy to the processes of cultural change underpinning Esperance Nyungar identity today. Those processes predate the colonial interruption, and continue into the post-Native Title era. This leads to a discussion and critique of the Native Title system, which often neglects to acknowledge the nuanced realities of Aboriginal societies and the inherent mutability of identity and connections across time and space. It is argued that the internal social dynamics of Aboriginal society are an important part of identity, as people continually negotiate who they are and how they relate to people and places. This constant process of identity-making is a fundamental part of Aboriginal culture and society now and into the distant past

Left Supraclavicular Spindle Cell Lipoma

Background. Spindle cell lipoma (SCL) is a benign lipomatous tumour, typically occurring in the posterior neck, shoulder or upper back of elderly males. They compose of fat, CD34 positive spindle cells, and ropey collagen on a myxoid matrix. This case highlights a rare presentation of SCL and the need for pre-operative diagnosis. Case Report. A 63-year-old gentleman presented with a pre-existing left supraclavicular mass that had recently increased in size. FNA and CT Scans were performed and results discussed in the mutidisciplinary team meeting. Excisional biopsy was recommended. Radiology. CT neck showed a left supraclavicular mass of fatty density with fine internal septations. A low-grade liposarcoma could not be excluded. Histopathology. FNA was indeterminate. Histology of specimen showed bland spindle cells with no evidence of malignancy. Immuno-histochemistry showed SCL with CD34 positivity and negative staining on CDK4 and p16. Management. Excision biopsy of the mass was performed which was technically difficult as the mass invaginated around the brachial plexus. The patient recovered well post-operatively with no neurological deficits. Conclusion. Spindle cell lipoma is a rare benign tumour and a pre-operative diagnosis based on the clinical context, imaging and immuno-histochemistry is crucial to management

Upstream decarbonization through a carbon takeback obligation: An affordable backstop climate policy

In the absence of immediate, rapid, and unprecedented reduction in global demand for carbon-intensive energy and products, the capture and permanent storage of billions of tons of carbon dioxide (CO2) annually will be needed before mid-century to meet Paris Agreement goals. Yet the focus on absolute emission reductions and cheaper, more temporary forms of carbon storage means that permanent CO2 disposal remains starved of investment, currently deployed to capture only about 0.1% of global Energy and Industrial Process (EIP) emissions. This stored fraction, the percentage of fossil EIP emissions that are captured and permanently stored, must reach 100% to stop EIP emissions causing further global warming. Here, we show that a cost-effective transition can occur by mandating an increasing stored fraction through a progressive carbon takeback obligation (CTBO) on fossil carbon producers and importers. By emulating the behavior of an integrated assessment model (IAM) and employing conservative assumptions for the costs of permanent carbon storage, we show that projected economy-wide costs of a CTBO policy are comparable to the costs associated with achieving similarly ambitious climate goals in IAMs employing a global carbon price, or potentially lower if the perceived policy risk cost associated with a CTBO is lower than that associated with a politically determined carbon price. Compared with a global carbon price, an upstream CTBO has advantages of simple governance, speed, and controllability: equivalent carbon prices under a CTBO are reliably capped by the cost of direct air capture and storage, by ensuring deployment keeps pace with continued fossil fuel use, reducing the risk of punitive carbon prices or more draconian measures being needed to drive out the final tranche of emissions. When combined with measures to reduce CO2 production in the near-term, a CTBO could deliver a viable pathway to achieving net-zero emissions consistent with 1.5°C by mid-century

The myriad challenges of the Paris Agreement

The much awaited and intensely negotiated Paris Agreement was adopted on 12 December 2015 by the Parties to the United Nations Framework Convention on Climate Change. The agreement set out a more ambitious long-term temperature goal than many had anticipated, implying more stringent emissions reductions that have been under-explored by the research community. By its very nature a multidisciplinary challenge, filling the knowledge gap requires not only climate scientists, but the whole Earth system science community, as well as economists, engineers, lawyers, philosophers, politicians, emergency planners and others to step up. To kick start cross-disciplinary discussions, the University of Oxford's Environmental Change Institute focused its 25th anniversary conference upon meeting the challenges of the Paris Agreement for science and society. This theme issue consists of review papers, opinion pieces and original research from some of the presentations within that meeting, covering a wide range of issues underpinning the Paris Agreement