Carbonate records of submarine hydrocarbon venting: northern Gulf of Mexico

Hydrocarbon seep sediments are examined from 3 sites in the Gulf of Mexico (Green Canyon Lease Blocks 232, 185, and 272) to relate the effects of gas hydrates and hydrocarbons on microbial process, pore fluid chemistry, and the processes of authigenic carbonate formation. Hydrocarbon-fueled microbial reactions result in pore fluids with lowered SO42- (all consumed by –10 cm) and enrichments in H2S, alkalinity, and DIC (up to 20 mmol, 30 meq/L, and 18 mmol/L, respectively) which promote carbonate formation. Pore fluid d13CDIC (PDB) is influenced by thermogenic hydrocarbons and crude oil in GC 232 and GC 185 (ranging from –9 to –39‰) and methane formed in situ via fermentation. GC 272 sediments experience seepage from biogenic methane and thermogenic hydrocarbons (d13CDIC as negative as –52‰). Radiocarbon measurements of pore fluid DIC in GC 272 provide evidence of fossil biogenic methane. Pore fluid chloride concentrations influenced by gas hydrate formation and decomposition show that hydrates occupy from 5-30% of the sediment pore space. The calculated saturation state of pore fluids with respect to carbonate minerals show that they are supersaturated with respect to calcite, aragonite and dolomite. Pore fluid calcium, magnesium, and strontium, show the effects of recent carbonate precipitation. The sediments contained elevated carbonate levels (up to 70wt.%) due to either aragonite/Mg-calcite nodules (GC 232 and GC 185) or dolomite/Mg-Calcite nodules (GC 272) formed near the sediment-water interface. The GC 272 mud volcano site represents the first described occurrence in the Gulf of Mexico of pseudomorphs after the carbonate mineral, ikaite. GC 232 and GC 185 carbonate d18O averages 3.4‰ and indicates that the nodules were precipitated from fluids with the present day temperature and stable isotope composition. GC 272 carbonates have d18O indicative of formation at elevated temperatures (as negative as –6.7‰ PDB). The carbonates have d13C that ranges from –12 to -40‰, reflective of the pore fluid d13CDIC and indicates that non-methane hydrocarbons are the ultimate source for the carbonates. Sediments from GC 232 , GC 272 and GC 185 were shown to have sedimentation rates in the top 30 cm of 13 cm/ka, 15 cm/ka, and 27 cm/ka, respectively

Coleman - de Luccia instanton of the second order in a brane world

The second order Coleman - de Luccia instanton and its action in the Randall - Sundrum type II model are investigated and the comparison with the results in Einstein's general relativity is done in the present paper.Comment: 4 pages, accepted in IJT

The Skyrme Energy Functional and Naturalness

Recent studies show that successful relativistic mean-field models of nuclei are consistent with naive dimensional analysis and naturalness, as expected in low-energy effective field theories of quantum chromodynamics. The nonrelativistic Skyrme energy functional is found to have similar characteristics.Comment: 8 pages, REVTeX 3.0 with epsf.sty, plus 2 figure

'Worlds of justification’ in the politics and practices of urban regeneration

A considerable body of research has developed on processes of neoliberal urban regeneration and gentrifi cation. On the one hand, there are many political economy accounts emphasising the role of economic capital in processes of urban change and gentrifi cation. On the other hand, there is a wealth of governmentality studies on the art of government that fail to explain how ungovernable subjects develop. Similarly, within gentrifi cation studies there are many accounts on the role of changing consumer lifestyles and defi ning gentrifi cation, but less concern with the governance processes between actors in urban regeneration and gentrifi cation. Yet such issues are of considerable importance given the role of the state in urban regeneration and dependence on private capital. This paper utilises the French Pragmatist approach of Boltanski and Thévenot to examine a case study state-led gentrifi cation project. Boltanski and Thévenot argue that social coordination occurs by way of actors working through broader value-laden ‘worlds of justifi cation’ that underpin processes of argumentation and coordination. The examined case study is a deprived area within an English city where a major state-led gentrification programme has been introduced. The rationale for the programme is based on the assumption that reducing deprivation relies upon substantially increasing the number of higher income earners. The paper concludes that market values have overridden broader civic values in the negotiation process, with this intensifying as the state internalised market crisis tendencies within the project. More broadly, there is a need for French Pragmatism to be more sensitive to the spatial processes of social coordination, which can be achieved through critical engagement with recent concepts of ‘assemblages’

False vacuum decay with gravity in a critical case

The vacuum decay in a de Sitter universe is studied within semiclassical approximation for the class of effective inflaton potentials whose curvature at the top is close to a critical value. By comparing the actions of the Hawking - Moss instanton and the Coleman - de Luccia instanton(s) the mode of vacuum decay is determined. The case when the fourth derivative of the effective potential at its top is less than a critical value is discussed.Comment: 10 pages, 8 figures, minor changes don

Creating spatial synergies around food in cities

This paper focusses on the phenomenon of multifunctional urban food initiatives (MUFIs) and how, using food as a vehicle, they provide integrative solutions for a number of social, environmental and economic problems in European cities. Through an in-depth investigation of three MUFIs in the UK, Latvia and Belgium, the paper aims to increase understanding on how different activities are combined within MUFIs, leading to the creation and strengthening of synergies: both internal, between the different activities performed within MUFIs, and external synergies between the MUFI and the (peri-) urban environment in which it operates. The three cases illustrate that the dense and complex urban environment in which they are situated provides possibilities to create a wide, diverse network around food, leading to a high potential for synergies to occur. In this way, MUFIs can respond to specific urban needs, which are not addressed by the state, and therefore have an important signalling function. For the MUFIs themselves, although being multifunctional increases opportunities, it is also a challenge to find the right balance between the different functions and not to lose sight of the economic side of the business. Local governments can support MUFIs by providing space for them, room to experiment, adapting regulations to get MUFIs out of the “grey zones” of legislation, and by starting to strategically think about food in their city region

Branding the City: The Democratic Legitimacy of a New Mode of Governance

__Abstract__ Place branding has been used to influence ideas concerning communities and districts, especially in regeneration programmes. This article approaches branding as a new governance strategy for managing perceptions. Considering the popular criticism that branding is a form of spin that prevents the public from gaining a proper understanding of their government's policies, this article focuses on the democratic legitimacy of branding in urban governance. The branding of two urban communities in the Netherlands is examined empirically in terms of input legitimacy, throughput legitimacy and output legitimacy. The research shows how the democratic legitimacy of branding varies in the two cases. In one case, branding largely excluded citizens, whereas in the other case there was limited citizen participation. The article indicates that, although branding can potentially be a participatory process in which the feelings and emotions of citizens are included, this potential is not always fully realised in practice

Radical, Reformist, and Garden-Variety Neoliberal: Coming to Terms with Urban Agriculture’s Contradictions

For many activists and scholars, urban agriculture in the Global North has become synonymous with sustainable food systems, standing in opposition to the dominant industrial agri-food system. At the same time, critical social scientists increasingly argue that urban agriculture programmes, by filling the void left by the rolling back of the social safety net, underwrite neoliberalisation. I argue that such contradictions are central to urban agriculture. Drawing on existing literature and fieldwork in Oakland, CA, I explain how urban agriculture arises from a protective counter-movement, while at the same time entrenching the neoliberal organisation of contemporary urban political economies through its entanglement with multiple processes of neoliberalisation. By focusing on one function or the other, however, rather than understanding such contradictions as internal and inherent, we risk undermining urban agriculture\u27s transformative potential. Coming to terms with its internal contradictions can help activists, policy-makers and practitioners better position urban agriculture within coordinated efforts for structural change, one of many means to an end rather than an end unto itself

Impact of technology-based interventions for children and young people with type 1 diabetes on key diabetes self-management behaviours and prerequisites: A systematic review

Background The role of technology in the self-management of type 1 diabetes mellitus (T1DM) among children and young people is not well understood. Interventions should aim to improve key diabetes self-management behaviours (self-management of blood glucose, insulin administration, physical activity and dietary behaviours) and prerequisites (psychological outcomes and HbA1c) highlighted in the UK guidelines of the National Institute for Health and Care Excellence (NICE) for management of T1DM. The purpose was to identify evidence to assess the effectiveness of technological tools in promoting aspects of these guidelines amongst children and young people. Methods A systematic review of English language articles was conducted using the following databases: Web of Science, PubMed, Scopus, NUSearch, SAGE Journals, SpringerLink, Google Scholar, Science Direct, Sport Discus, Embase, Psychinfo and Cochrane Trials. Search terms included paediatric, type one diabetes, technology, intervention and various synonyms. Included studies examined interventions which supplemented usual care with a health care strategy primarily delivered through a technology-based medium (e.g. mobile phone, website, activity monitor) with the aim of engaging children and young people with T1DM directly in their diabetes healthcare. Studies did not need to include a comparator condition and could be randomised, non-randomised or cohort studies but not single-case studies. Results Of 30 included studies (21 RCTs), the majority measured self-monitoring of blood glucose monitoring (SMBG) frequency, clinical indicators of diabetes self-management (e.g. HbA1c) and/or psychological or cognitive outcomes. The most positive findings were associated with technology-based health interventions targeting SMBG as a behavioural outcome, with some benefits found for clinical and/or psychological diabetes self-management outcomes. Technological interventions were well accepted by children and young people. For the majority of included outcomes, clinical relevance was deemed to be little or none. Conclusions More research is required to assess which elements of interventions are most likely to produce beneficial behavioural outcomes. To produce clinically relevant outcomes, interventions may need to be delivered for at least 1 year and should consider targeting individuals with poorly managed diabetes. It is not possible to determine the impact of technology-based interventions on insulin administration, dietary habits and/or physical activity behaviour due to lack of evidence