Components and processes affecting producibility and commerciality of shale resource systems

Unconventional shale resource systems have provided North America with abundant energy supplies and reserves for present and future decades. This energy resource was largely overlooked until the new millennium. Prior 2000 only a few small oil and gas companies were pursuing such plays led by independent, Mitchell Energy and Development Corporation of The Woodlands, TX. Mitchell's successful commercial development of the Mississippian Barnett Shale of the Ft. Worth Basin, Texas spawned an energy renaissance in North America. In the last decade the development of unconventional shale resource systems has been phenomenal in the United States with abundant new supplies of natural gas and oil. These resource systems are all associated with petroleum source rocks, either within the source rock itself or in juxtaposed, non-source rock intervals. Three key characteristics of these rocks, apart from being associated with organic-rich intervals, are their low porosity (less than 15%), ultra-low permeability (<0.1mD), and brittle or non-ductile nature. These characteristics play a role in the storage, retention, and the requirement of high-energy stimulation to obtain petroleum fl ow. Organic richness and hydrogen content certainly play a role in petroleum generation, but they also play a role in retention and expulsion fractionation of generated petroleum. Often a substantial portion of the porosity evolves from the decomposition of organic carbon that creates organoporosity in addition to any matrix porosity. Open fracture-related porosity is seldom important. Hybrid systems, i.e., organic-lean intervals overlying, interbedded, or underlying the petroleum source rock, are the best producing shale resource systems, particularly for oil due to their limited adsorptive affi nities and the retention of polar constituents of petroleum in the source rock. Paradoxically, the best shale gas systems are those where the bulk of the retained oil in the source rock has been converted to gas by cracking. Such conversion cracks the retained polar constituents of petroleum as well as saturated and aromatic hydrocarbons to condensate-wet gas or dry gas at high thermal maturity. Such high level conversion also creates the maximum organoporosity, while enhancing pore pressure. Bitumen (petroleum)-free total organic carbon (TOC) is comprised of two components, a generative and a non-generative portion. The generative organic carbon (GOC) represents the portion of organic carbon that can be converted to petroleum, whereas the non-generative portion does not yield any commercial amounts of petroleum due to its low hydrogen content. Organoporosity is created by the decomposition of the generative organic carbon as recorded in volume percent. In the oil window, this organoporosity is fi lled with petroleum (bitumen, oil and gas) and is diffi cult to identify, whereas in the gas window any retained petroleum has been converted to gas and pyrobitumen making such organoporosity visible under high magnification microscopy. Production decline analysis shows the variable production potential of many North American shale gas and oil systems and their high decline rates. The most productive North American shale gas systems are shown to be the Marcellus and Haynesville shales, whereas the best shale oil systems are the hybrid Bakken and Eagle Ford systems

Effects of neo-adjuvant chemotherapy for oesophago-gastric cancer on neuro-muscular gastric function

Delayed gastric emptying symptoms are often reported after chemotherapy. This study aims to characterise the effects of chemotherapy on gastric neuro-muscular function. Patients undergoing elective surgery for oesophago-gastric cancer were recruited. Acetylcholinesterase, nNOS, ghrelin receptor and motilin expressions were studied in gastric sections from patients receiving no chemotherapy (n = 3) or oesophageal (n = 2) or gastric (n = 2) chemotherapy. A scoring system quantified staining intensity (0–3; no staining to strong). Stomach sections were separately suspended in tissue baths for electrical field stimulation (EFS) and exposure to erythromycin or carbachol; three patients had no chemotherapy; four completed cisplatin-based chemotherapy within 6 weeks prior to surgery. AChE expression was markedly decreased after chemotherapy (scores 2.3 ± 0.7, 0.5 ± 0.2 and 0 ± 0 in non-chemotherapy, oesophageal- and gastric-chemotherapy groups (p < 0.03 each) respectively. Ghrelin receptor and motilin expression tended to increase (ghrelin: 0.7 ± 0.4 vs 2.0 ± 0.4 and 1.2 ± 0.2 respectively; p = 0.04 and p = 0.2; motilin: 0.7 ± 0.5 vs 2.2 ± 0.5 and 2.0 ± 0.7; p = 0.06 and p = 0.16). Maximal contraction to carbachol was 3.7 ± 0.7 g and 1.9 ± 0.8 g (longitudinal muscle) and 3.4 ± 0.4 g and 1.6 ± 0.6 (circular) in non-chemotherapy and chemotherapy tissues respectively (p < 0.05 each). There were loss of AChE and reduction in contractility to carbachol. The tendency for ghrelin receptors to increase suggests an attempt to upregulate compensating systems. Our study offers a mechanism by which chemotherapy markedly alters neuro-muscular gastric function

Opportunities, challenges and concerns for the implementation and uptake of pelvic floor muscle assessment and exercises during the childbearing years: protocol for a critical interpretive synthesis

This is the final version of the article. Available from the publisher via the DOI in this record.BACKGROUND: Pregnancy and childbirth are important risk factors for urinary incontinence (UI) in women. Pelvic floor muscle exercises (PFME) are effective for prevention of UI. Guidelines for the management of UI recommend offering pelvic floor muscle training (PFMT) to women during their first pregnancy as a preventive strategy. The objective of this review is to understand the relationships between individual, professional, inter-professional and organisational opportunities, challenges and concerns that could be essential to maximise the impact of PFMT during childbearing years and to effect the required behaviour change. METHODS: Following systematic searches to identify sources for inclusion, we shall use a critical interpretive synthesis (CIS) approach to produce a conceptual model, mapping the relationships between individual, professional, inter-professional and organisational factors and the implementation, acceptability and uptake of PFME education, assessment and training during the childbearing years. Purposive sampling will be used to identify potentially relevant material relating to topics or areas of interest which emerge as the review progresses. A wide range of empirical and non-empirical sources will be eligible for inclusion to encompass the breadth of relevant individual, professional, inter-professional and organisational issues relating to PFME during childbearing years. Data analysis and synthesis will identify key themes, concepts, connections and relationships between these themes. Findings will be interpreted in relation to existing frameworks of implementation, attitudes and beliefs of individuals and behaviour change. We will collate examples to illustrate relationships expressed in the conceptual model and identify potential links between the model and drivers for change. DISCUSSION: The CIS review findings and resulting conceptual model will illustrate relationships between factors that might affect the implementation, acceptability and uptake of PFME education, assessment and training during the childbearing years. The model will inform the development and evaluation of a training package to support midwives with implementation and delivery of effective PFME during the antenatal period. The review forms part of the first phase of the United Kingdom National Institute for Health Research funded 'Antenatal Preventative Pelvic floor Exercises And Localisation (APPEAL)' programme (grant number: RP-PG-0514-20002) to prevent poor health linked to pregnancy and childbirth-related UI. SYSTEMATIC REVIEW REGISTRATION: PROSPERO: CRD42016042792.The APPEAL project is funded by a National Institute for Health Research (NIHR) programme grant for applied research (RP-PG-0514-20002). MP and SD were supported in their contribution to the development of the research proposal by the NIHR Collaboration for Leadership in Applied Health Research and Care (CLAHRC) for the South West Peninsula. CM is part-funded by the CLAHRC West Midlands, and DB is part-funded by the CLAHRC South London

Low-temperature gas from marine shales

Thermal cracking of kerogens and bitumens is widely accepted as the major source of natural gas (thermal gas). Decomposition is believed to occur at high temperatures, between 100 and 200°C in the subsurface and generally above 300°C in the laboratory. Although there are examples of gas deposits possibly generated at lower temperatures, and reports of gas generation over long periods of time at 100°C, robust gas generation below 100°C under ordinary laboratory conditions is unprecedented. Here we report gas generation under anoxic helium flow at temperatures 300° below thermal cracking temperatures. Gas is generated discontinuously, in distinct aperiodic episodes of near equal intensity. In one three-hour episode at 50°C, six percent of the hydrocarbons (kerogen & bitumen) in a Mississippian marine shale decomposed to gas (C1–C5). The same shale generated 72% less gas with helium flow containing 10 ppm O2 and the two gases were compositionally distinct. In sequential isothermal heating cycles (~1 hour), nearly five times more gas was generated at 50°C (57.4 μg C1–C5/g rock) than at 350°C by thermal cracking (12 μg C1–C5/g rock)

Natural gas at thermodynamic equilibrium Implications for the origin of natural gas

It is broadly accepted that so-called 'thermal' gas is the product of thermal cracking, 'primary' thermal gas from kerogen cracking, and 'secondary' thermal gas from oil cracking. Since thermal cracking of hydrocarbons does not generate products at equilibrium and thermal stress should not bring them to equilibrium over geologic time, we would not expect methane, ethane, and propane to be at equilibrium in subsurface deposits. Here we report compelling evidence of natural gas at thermodynamic equilibrium. Molecular compositions are constrained to equilibrium

Glasgow 2014, the media and Scottish politics – the (post)imperial symbolism of the Commonwealth Games

This article critically examines print media discourses regarding the 2014 Glasgow Commonwealth Games. The forthcoming analysis considers the political symbolism of the Commonwealth Games with regards to the interlinkages between the British Empire, sport and the global political status of the UK, with specific consideration given to the UK’s declining global power as well as the interconnections between the 2014 Games and the Scottish independence referendum. Hechter’s (1975) ‘internal colonialism’ thesis, which portrays Scotland’s marginalised status within the UK, is drawn upon to critically explore the political symbolism of sport for Scottish nationalism, before discussion focuses upon the extent to which the modern Commonwealth is symptomatic of the UK’s declining status as a global power. Finally, the existence of these narrative tropes in print media coverage of the Commonwealth Games is examined, allowing for critical reflections on the continuing interconnections between the media, sport, nationalism and post-imperial global politics

Sport for Yes? The role of sporting issues in pro-independence political discourse during the Scottish independence referendum campaign

This article critically considers the extent to which sporting issues were harnessed by pro-independence political campaigners during the Scottish independence referendum campaign. Developments such as the inclusion of sport within the Scottish Government’s White Paper on Scottish independence, the establishment of the ‘Working Group on Scottish Sport’ and the establishment of the ‘Sport for Yes’ campaign group demonstrate the harnessing of sporting issues as an additional, if somewhat peripheral, debate point in the referendum campaigns (Lafferty 2014, Scottish Government 2013, Working Group on Scottish Sport and Scottish Government 2013, 2014). The latter of these developments, the establishment of the ‘Sport for Yes’ campaign group, is of particular interest, offering evidence of the explicit political mobilisation of past and present athletes in support of the ‘Yes Scotland’ pro-independence campaign. The use of sport within pro-independence political discourse is therefore scrutinised, drawing upon the principles of critical discourse analysis to explore the ideological assumptions underpinning the discursive representation of sport in relation to Scottish independence

Riverbed sediments buffer phosphorus concentrations downstream of sewage treatment works across the River Wensum catchment, UK

Purpose: Wastewater effluent discharged into rivers from sewage treatment works (STWs) represents one of the most important point sources of soluble reactive phosphorus (SRP) pollution and is a major driver of freshwater eutrophication. In this study, we assess the ability of riverbed sediments to act as a self-regulating buffering system to reduce SRP dissolved in the water column downstream of STW outflows. Materials and methods: River water and riverbed sediment samples were collected from 10 tributary outlets across the River Wensum catchment, Norfolk, UK, at monthly intervals between July and October 2016, such that 40 sediment and 40 water samples were collected in total. Of these locations, five were located downstream of STWs and five were on tributaries without STWs. Dissolved SRP concentrations were analysed and the Equilibrium Phosphorus Concentration (EPC0) of each sediment sample was measured to determine whether riverbed sediments were acting as net sources or sinks of SRP. Results and discussion: The mean SRP concentration downstream of STWs (382 µg P L-1) was double that of sites without a STW (185 µg P L-1), whilst the mean EPC0 for effluent impacted sites (105 µg P L-1) was 70% higher than that recorded at unaffected sites (62 µg P L-1). Regardless of STW influence, riverbed sediments across all 10 sites almost always acted as net sinks for SRP from the overlying water column. This was particularly true at sites downstream of STWs which displayed enhanced potential to buffer the river against increases in SRP released in sewage effluent. Conclusions: Despite EPC0 values revealing riverbed sediments were consistently acting as sinks for SRP, elevated SRP concentrations downstream of STWs clearly demonstrate the sediments have insufficient SRP sorption capacity to completely buffer the river against effluent discharge. Consequently, SRP concentrations across the catchment continue to exceed recommended standards for good chemical status, thus emphasising the need for enhanced mitigation efforts at STWs to minimise riverine phosphorus loading

Advances in prevention and therapy of neonatal dairy calf diarrhoea : a systematical review with emphasis on colostrum management and fluid therapy

Neonatal calf diarrhoea remains the most common cause of morbidity and mortality in preweaned dairy calves worldwide. This complex disease can be triggered by both infectious and non-infectious causes. The four most important enteropathogens leading to neonatal dairy calf diarrhoea are Escherichia coli, rota-and coronavirus, and Cryptosporidium parvum. Besides treating diarrhoeic neonatal dairy calves, the veterinarian is the most obvious person to advise the dairy farmer on prevention and treatment of this disease. This review deals with prevention and treatment of neonatal dairy calf diarrhoea focusing on the importance of a good colostrum management and a correct fluid therapy

‘Team GB’ or ‘Team Scotland’? Media representations of ‘Britishness’ and ‘Scottishness’ at London 2012 and Glasgow 2014

This article critically reflects upon media coverage of the 2012 London Olympic Games and the 2014 Glasgow Commonwealth Games, scrutinising the emergent discursive constructions of ‘Britishness’ and ‘Scottishness’ through an examination of both London-based (English) and Scotland-based publications. Drawing upon Dayan and Katz’s (1992) portrayal of ‘media events’, the article explores how both events presented competing sites of symbolic struggle during a period of constitutional and political turmoil. Consideration is given to the existence of a ‘hegemonic Britishness’ in print media narratives of these events, as evident in the emergent connotations associated with ‘British nationalism’ and ‘Scottish separatism’