Making a difference? Understanding the working lives of learning disability nurses; 30 years of learning disability nursing in England

The study aimed to explore the lived experience of the careers of learning disability nurses in England. The methodology was informed by Hermeneutic Phenomenology, and the study design utilised narrative interviewing techniques based on an adapted model of the Biographic Narrative Interpretive Method (Wengraf 2001) in order to explore the career choices, experiences and beliefs, and values about learning disability nursing. Twenty in-depth qualitative interviews with learning disability nurses, who had been in practice in the 30-year period between 1979 and 2009, were undertaken in 2010 across nine counties in England. The data was interpreted using a narrative analysis approach. Key findings indicated that nurses, working in a diverse range of settings with varying degrees of experience, are motivated by working with people with learning disabilities and narrate their experiences of building relationships with people articulating the meaning of this for them as nurses. The initial reasons for choosing learning disability nursing as a career formed a key theme within the findings, with complex influences on their career choice. Additionally, all participants in this study created a narrative of change, focusing on the ways in which change in policy, practice and in societal views have impacted upon their working lives and their identity. The individual narratives have also been interpreted to form a collective narrative of learning disability nursing to specifically explore the identity of learning disability nurses and nursing in a changing context of health and social care provision

Gas hydrate dynamics at the Green Canyon Site, Gulf of Mexico - recovery prospects based on new 3-D modeling study

Due to their favorable P-T conditions and organic-rich deposits, sub-seafloor sediments in the northern Gulf of Mexico are known to have a large potential for gas hydrate accumulations. The presence of gas hydrates within sediments of the Green Canyon block has been proven by various methods, incl. seismic imaging, geochemical analysis, and drilling conducted mainly as a part of Joint Industry Project (JIP) Phase II. Gas hydrates reported therein usually occur as tens up to hundreds of meters thick sections with moderate to high concentrations within a range of 50 – 70 vol. % of pore space, and hence, seem to offer a considerable natural deposit of methane gas. The main focus of this study was to explore the complex effects of a set of control- parameters responsible for hydrocarbon migration and storage within the Gas Hydrate Stability Zone (GHSZ) on the accumulation of gas hydrates. To investigate the processes of basin formation and its subsidence history, source rock maturation, hydrocarbon migration and expulsion, and to quantify the gas hydrate accumulation potential, 3-D numerical study has been conducted using PetroMod. The area of interest extends over ~14 km x 33 km and covers the edge of the Sigsbee Escarpment representing the main salt mobility front in the region. The simulation contains full depositional history of the Green Canyon block, incl. salt deposition and re-mobilization as well as its further implications for temperature field, fluids migration and sedimentary layers distribution. Methane generation has been resolved by in-situ POC degradation and deep thermogenic mobilization from two distinct hydrocarbon sources. As a result, we present a number of likely scenarios of gas hydrate formation and accumulation in the study area that have been calibrated against available data

Heat Flow Measurements at the Danube Deep-Sea Fan, Western Black Sea

Seafloor heat flow measurements are utilized to determine the geothermal regime of the Danube deep-sea fan in the western Black Sea and are presented in the larger context of regional gas hydrate occurrences. Heat flow data were collected across paleo-channels in water depths of 550–1460 m. Heat flow across levees ranges from 25 to 30 mW m−2 but is up to 65 mW m−2 on channel floors. Gravity coring reveals sediment layers typical of the western Black Sea, consisting of three late Pleistocene to Holocene units, notably red clay within the lowermost unit cored. Heat flow derived from the bottom-simulating reflector (BSR), assumed to represent the base of the gas hydrate stability zone (GHSZ), deviates from seafloor measurements. These discrepancies are linked either to fast sedimentation or slumping and associated variations in sediment physical properties. Topographic effects account of up to 50% of heat flow deviations from average values. Combined with climate-induced variations in seafloor temperature and sea-level since the last glacial maximum large uncertainties in the prediction of the base of the GHSZ remain. A regional representative heat flow value is ~30 mW m−2 for the study region but deviations from this value may be up to 100%

3-D basin-scale reconstruction of natural gas hydrate system of the Green Canyon, Gulf of Mexico

Our study presents a basin-scale 3D modeling solution, quantifying and exploring gas hydrate accumulations in the marine environment around the Green Canyon (GC955) area, Gulf of Mexico. It is the first modeling study that considers the full complexity of gas hydrate formation in a natural geological system. Overall, it comprises a comprehensive basin re-construction, accounting for depositional and transient thermal history of the basin, source rock maturation, petroleum components generation, expulsion and migration, salt tectonics and associated multi-stage fault development. The resulting 3D gas hydrate distribution in the Green Canyon area is consistent with independent borehole observations. An important mechanism identified in this study and leading to high gas hydrate saturation (> 80 vol. %) at the base of the gas hydrate stability zone (GHSZ), is the recycling of gas hydrate and free gas enhanced by high Neogene sedimentation rates in the region. Our model predicts the rapid development of secondary intra-salt mini-basins situated on top of the allochthonous salt deposits which leads to significant sediment subsidence and an ensuing dislocation of the lower GHSZ boundary. Consequently, large amounts of gas hydrates located in the deepest parts of the basin dissociate and the released free methane gas migrates upwards to recharge the GHSZ. In total, we have predicted the gas hydrate budget for the Green Canyon area that amounts to ∼3,256 Mt of gas hydrate which is equivalent to ∼340 Mt of carbon (∼7 x 1011 m3 of CH4 at STP conditions), and consists mostly of biogenic hydrates

Gas hydrate accumulations at the Alaska North Sloge: total assessment based on 3D petroleum system modeling

The Alaska North Slope comprises an area of about 400,000 km2 including prominent gas and oil fields. Gas hydrates occur widely at the Alaska North Slope. A recent assessment by the USGS estimates 0.7-4.47 x 1012 m3 of technically recoverable gas hydrates based on well data and drilled hydrate accumulations. In spring 2012 a production field trial, testing CO2/N2 injection and depressurization, was conducted by USDOE/JOGMEC/ConocoPhillips at the Ignik Sikumi site. The 3D geological model of the Alaska North Slope developed by the USGS and Schlumberger is used to test the new gas hydrate module in the petroleum systems modeling software PetroMod®. Model results of the present extent of the gas hydrate stability zone (GHSZ) are in good agreement with results from well data. The model simulations reveal that the evolution of the GHSZ over time is primarily controlled by the climatic conditions regulating the extent of the permafrost during the last 1 Myr. Preliminary model runs predict the highest gas hydrate saturations near the major faults and at the bottom of the GHSZ, where thermogenic methane gas accumulates after migration through the most permeable stratigraphic layers (e.g. Sag River Sandstone Fm, Ivishak Fm). Gas hydrate saturations predicted for the Mount Elbert Stratigraphic Test Well and the Ignik Sikumi sites are basically controlled by the alternation of layers with different permeability and the fault properties (time of opening, permeability, etc). Further results including a total gas hydrate assessment for the Alaska North Slope will be presented during the conference

In-situ borehole temperature measurements confirm dynamics of the gas hydrate stability zone at the upper Danube deep sea fan, Black Sea

Highlights • In-situ temperature measurements were conducted at the Danube deep sea fan. • Operations were performed with the MARUM-MeBo200 seafloor drill rig. • The BSR is located ∼20 m below the current gas hydrate stability zone. • Seismic data suggest presence of shallower BSR-like events. Abstract Coring, geophysical logging, and in-situ temperature measurements were performed with the MARUM-MeBo200 seafloor rig to characterize gas hydrate occurrences in sediments of the Danube deep sea fan, off Romania, Black Sea. The new drilling data showed no evidence for significant gas hydrate saturations within the sediments but the presence of free gas at the depth of the bottom-simulating reflector (BSR). In-situ temperature and core-derived geochemical data suggest that the current base of the gas hydrate stability zone (BGHSZ) is ∼20 m shallower than the BSR. Investigation of the seismic data around the drill sites shows several locations where free gas previously trapped at a former BGHSZ migrated upwards forming a new reflection above the BSR. This shows that the gas hydrate system in the Danube deep sea fan is still responding to climate changes initiated at the end of the last glacial maximum

Optimal conspicuity of liver metastases in virtual monochromatic imaging reconstructions on a novel photon-counting detector CT—effect of keV settings and BMI

In dual-energy CT datasets, the conspicuity of liver metastases can be enhanced by virtual monoenergetic imaging (VMI) reconstructions at low keV levels. Our study investigated whether this effect can be reproduced in photon-counting detector CT (PCD-CT) datasets. We analyzed 100 patients with liver metastases who had undergone contrast-enhanced CT of the abdomen on a PCD-CT (n = 50) or energy-integrating detector CT (EID-CT, single-energy mode, n = 50). PCD-VMI-reconstructions were performed at various keV levels. Identical regions of interest were positioned in metastases, normal liver, and other defined locations assessing image noise, tumor-to-liver ratio (TLR), and contrast-to-noise ratio (CNR). Patients were compared inter-individually. Subgroup analyses were performed according to BMI. On the PCD-CT, noise and CNR peaked at the low end of the keV spectrum. In comparison with the EID-CT, PCD-VMI-reconstructions exhibited lower image noise (at 70 keV) but higher CNR (for ≤70 keV), despite similar CTDIs. Comparing high- and low-BMI patients, CTDI-upregulation was more modest for the PCD-CT but still resulted in similar noise levels and preserved CNR, unlike the EID-CT. In conclusion, PCD-CT VMIs in oncologic patients demonstrated reduced image noise–compared to a standard EID-CT–and improved conspicuity of hypovascularized liver metastases at low keV values. Patients with higher BMIs especially benefited from constant image noise and preservation of lesion conspicuity, despite a more moderate upregulation of CTDI

GaMin’11 – an International Inter-laboratory Comparison for Geochemical CO2 - Saline Fluid - Mineral Interaction Experiments

Due to the strong interest in geochemical CO2-fluid-rock interaction in the context of geological storage of CO2 a growing number of research groups have used a variety of different experimental ways to identify important geochemical dissolution or precipitation reactions and – if possible – quantify the rates and extent of mineral or rock alteration. In this inter-laboratory comparison the gas-fluid-mineral reactions of three samples of rock-forming minerals have been investigated by 11 experimental labs. The reported results point to robust identification of the major processes in the experiments by most groups. The dissolution rates derived from the changes in composition of the aqueous phase are consistent overall, but the variation could be reduced by using similar corrections for changing parameters in the reaction cells over time. The comparison of experimental setups and procedures as well as of data corrections identified potential improvements for future gas-fluid-rock studies