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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ejor.2005.11.021 Byline: Christos J. Emmanouilides (a), Richard B. Davies (b) Keywords: Marketing; Multi-agent systems; Social interactions; Innovation diffusion; Choice models Abstract: We present a new product choice model in which individual agents are assumed to interact with each other across spatial hierarchies under random Gaussian laws. A restricted form that allows estimation of the model and inference on the random interaction structure on available data is then derived. This is essentially a random coefficients model which we estimate on repeated cross-sectional data for the adoption of video cassette recorders in Britain. It is argued that the random coefficient approach, based on economic and social-theoretic arguments allows for more accurate inference on the structure of social interactions, and thus may provide a useful way to help alleviate the inferential problem caused by the identification issues stated in the literature. This very same problem has for long been at the core of the debate between alternative economic and marketing theories of new product diffusion. Author Affiliation: (a) Department of Economics, Aristotle University of Thessaloniki, P.O. Box 170, 546 21 Thessaloniki, Greece (b) University of Wales Swansea, Singleton Park, Swansea SA2 88P, Wales, UK Article History: Received 1 February 2005; Accepted 1 November 2005

Several treatment strategies for avoiding post-operative ileus have been evaluated in randomised controlled trials. This network meta-analysis aimed to explore the relative effectiveness of these different therapeutic interventions on ileus outcome measures. A systematic literature review was performed to identify randomized controlled trials (RCTs) comparing treatments for post-operative ileus following colorectal surgery. A Bayesian network meta-analysis was performed using the Markov chain Monte Carlo method. Direct and indirect comparisons of all regimens were simultaneously compared using random-effects network meta-analysis. A total of 48 randomised controlled trials were included in this network meta-analysis reporting on 3614 participants. Early feeding was found to be the best treatment for time to solid diet tolerance and length of hospital stay with a probability of P = 0.96 and P = 0.47, respectively. Early feeding resulted in significantly shorter time to solid diet tolerance (Mean Difference (MD) 58.85 h; 95% Credible Interval (CrI) −73.41, −43.15) and shorter length of hospital stay (MD 2.33 days; CrI −3.51, −1.18) compared to no treatment. Epidural analgesia was ranked best treatment for time to flatus (P = 0.29) and time to stool (P = 0.268). Epidural analgesia resulted in significantly shorter time to flatus (MD -18.88 h; CrI −33.67, −3.44) and shorter time to stool (MD -26.05 h; 95% CrI −66.42, 15.65) compared to no intervention. Gastrograffin was ranked best treatment to avoid the requirement for post-operative nasogastric tube insertion (P = 0.61) however demonstrated limited efficacy (OR 0.50; CrI 0.143, 1.621) compared to no intervention. Nasogastric and nasointestinal tube insertion, probiotics, and acupuncture were found to be least efficacious as interventions to reduce ileus. This network meta-analysis identified early feeding as the most efficacious therapeutic intervention to reduce post-operative ileus in patients undergoing colorectal surgery, in addition to highlighting other therapies that require further investigation by high quality study. In patients undergoing colorectal surgery, emphasis should be placed on early feeding as soon as can be appropriately initiated to support the return of gastrointestinal motility. [ABSTRACT FROM AUTHOR]

Background: Clinical Endpoint Classification (CEC) in clinical trials allows FOR standardized, systematic, blinded, and unbiased adjudication of investigator-reported events. We quantified the agreement rates in the STABILITY trial on 15,828 patients with stable coronary heart disease.Methods: Investigators were instructed to report all potential events. Each reported event was reviewed independently by 2 reviewers according to prespecified processes and prespecified end point definitions. Concordance between reported and adjudicated cardiovascular (CV) events was evaluated, as well as event classification influence on final study results.Results: In total, CEC reviewed 7,096 events: 1,064 deaths (696 CV deaths), 958 myocardial infarctions (MI), 433 strokes, 182 transient ischemic attacks, 2,052 coronary revascularizations, 1,407 hospitalizations for unstable angina, and 967 hospitalizations for heart failure. In total, 71.8% events were confirmed by CEC. Concordance was high (>80%) for cause of death and nonfatal MI and lower for hospitalization for unstable angina (25%) and heart failure (50%). For the primary outcome (composite of CV death, MI, and stroke), investigators reported 2,086 events with 82.5% confirmed by CEC. The STABILITY trial treatment effect of darapladib versus placebo on the primary outcome was consistent using investigator-reported events (hazard ratio 0.96 [95% CI 0.87-1.06]) or adjudicated events (hazard ratio 0.94 [95% CI 0.85-1.03]).Conclusions: The primary outcome results of the STABILITY trial were consistent whether using investigator-reported or CEC-adjudicated events. The proportion of investigator-reported events confirmed by CEC varied by type of event. These results should help improve event identification in clinical trials to optimize ascertainment and adjudication. [ABSTRACT FROM AUTHOR]

Methane can be released from the vast marine hydrate reservoirs that surround continents into oceans and perhaps the atmosphere. But how these pathways work within the global carbon cycle now and during a warmer world is only partially understood. Here we use 3-D seismic data to identify what we interpret to be a gas venting system that bypasses the hydrate stability zone (HSZ) offshore of Mauritania. This venting is manifested by the presence of the acoustic wipe-out (AWO) across a densely faulted succession above a salt diapir and a set of morphological features including a substantial, ∼260 m wide and ∼32 m deep, pockmark at the seabed. The base of the HSZ is marked by a bottom simulating reflector (BSR) which deflects upwards above the diapir, rather than mimicking the seabed. We use a numerical modelling to show that this deflection is caused by the underlying salt diapir. It creates a trapping geometry for gas sealed by hydrate-clogged sediment. After entering the HSZ, some methane accumulated as hydrate in the levees of a buried canyon. Venting in this locality probably reduces the flux of gas to the landward limit of feather edge of hydrate, reducing the volume of gas that would be susceptible for release during a warmer world. [ABSTRACT FROM AUTHOR]

To what extent methane liberated from marine hydrate will enter the ocean during a warmer world is unknown. Although methane release due to hydrate dissociation has been modelled, it is unclear whether or not methane will reach the seafloor during a warmer world and therefore contribute to oceanic and atmospheric budgets. Here we show, using a new three-dimensional (3-D) seismic dataset, that some hydrate deposits surround the gas chimneys passing through the HSZ. Bottom water warming since the last glacial maximum (LGM) is interpreted to cause hydrate dissociation but critically some of the released methane was not vented to the ocean. The released gas caused seal failure and free gas entered the hydrate stability zone (HSZ) through vertical gas chimneys to where new hydrate accumulations formed. This process is a new evidence for methane recycling and could account in part for the lack of methane in ice core records that cover warming events during the late Quaternary. This research provides new insight into how methane could be recycled rather than vented during a warmer world. [ABSTRACT FROM AUTHOR]

We examine the effect of time-varying investment barriers on the pricing of UK closed-end emerging market country funds. We find that a direct measure of capital market segmentation is significantly negatively related to both country fund stock return and Net Asset Value (NAV) return of the fund, but there is no relation to the premium. Also we find some evidence of a positive relation for an indirect barrier (inflation variability) and stock return, NAV return and the premium. Overall our results support an information hypothesis of the impact of investment barriers on closed-end fund pricing. [ABSTRACT FROM AUTHOR]

Phosphoflow cytometry is increasingly being used as a tool for the discovery of biomarkers used in the treatment and monitoring of disease and therapy. The ability to measure numerous phospho-protein targets simultaneously at a single cell level accurately and rapidly provides significant advantages over other methods. We here discuss important considerations required to successfully implement these methods. Three different blood collection tubes (lithium-heparin tubes, CPT with sodium citrate and CPT with sodium heparin) were evaluated, with PBMC isolated through lithium-heparin tubes/lymphoprep displaying reduced basal and increased stimulation induced phosphorylation compared to the other two methods. Further, we provide a protocol outlining an 8 color assay developed for the study of intracellular signaling in peripheral blood mononuclear cells. The assay allows for the quantitative measurement of the phospho-proteins ERK1/2, NF-κB p65, Stat1 (Y701), Stat1 (S727), Stat3 (Y705), Stat3 (S727), Stat4 (Y693), p38 and Stat5 (Y694), as well as the identification of T cells, B cells, natural killer cells and monocytes. The assay additionally incorporates fluorescent cell barcoding, reducing assay costs and increasing throughput while increasing data robustness. Inter-assay precision was assessed over a month long period for all experimental variables (phospho-protein measured, cell type and stimulant). Coefficient of variations (CVs) calculated from process triplicates of normalized median fluorescence intensity (MFI) of the phospho-proteins displayed median CVs under 10% when grouped according to cell type, stimulation agent and phospho-protein measured, while the CV for each triplicate did not exceed 20%. [ABSTRACT FROM AUTHOR]

We review the distribution, timing and probable causes of ∼8000 onshore UK seismic events between the years 1970–2012. Of 1769 onshore seismic events with local magnitudes (M L ) ≥ 1.5, we estimate at least ∼21% of these have an anthropogenic origin, at least ∼40% were natural and ∼39% have an undetermined, anthropogenic or natural origin. The majority of the anthropogenic related earthquakes were caused by coal mining and the decline in their numbers from the 1980s to the 2000s was concurrent with a decline in UK coal production. To date, two earthquakes with M L ≥ 1.5 have been caused by hydraulic fracturing. We have a high level of confidence that the mean number of anthropogenic related earthquakes (M L ≥ 1.5) per year onshore in the UK since 1999 is at least three with an annual range of between zero and eight. If we assumed that 50% of the undetermined events had an anthropogenic origin the mean per year increases to twelve. Although there are inherent uncertainties in assigning an anthropogenic versus natural cause for historical earthquakes, these values provide a baseline for the UK, the first of its kind for any nation state, in advance of the presently planned shale gas and oil exploitation. [ABSTRACT FROM AUTHOR]

Abstract: Data from around the world (Australia, Austria, Bahrain, Brazil, Canada, the Netherlands, Poland, the UK and the USA) show that more than four million onshore hydrocarbon wells have been drilled globally. Here we assess all the reliable datasets (25) on well barrier and integrity failure in the published literature and online. These datasets include production, injection, idle and abandoned wells, both onshore and offshore, exploiting both conventional and unconventional reservoirs. The datasets vary considerably in terms of the number of wells examined, their age and their designs. Therefore the percentage of wells that have had some form of well barrier or integrity failure is highly variable (1.9%–75%). Of the 8030 wells targeting the Marcellus shale inspected in Pennsylvania between 2005 and 2013, 6.3% of these have been reported to the authorities for infringements related to well barrier or integrity failure. In a separate study of 3533 Pennsylvanian wells monitored between 2008 and 2011, there were 85 examples of cement or casing failures, 4 blowouts and 2 examples of gas venting. In the UK, 2152 hydrocarbon wells were drilled onshore between 1902 and 2013 mainly targeting conventional reservoirs. UK regulations, like those of other jurisdictions, include reclamation of the well site after well abandonment. As such, there is no visible evidence of 65.2% of these well sites on the land surface today and monitoring is not carried out. The ownership of up to 53% of wells in the UK is unclear; we estimate that between 50 and 100 are orphaned. Of 143 active UK wells that were producing at the end of 2000, one has evidence of a well integrity failure. [Copyright &y& Elsevier]

Abstract: Interpretation of 3D seismic data from offshore Mauritania reveals many localized high amplitude anomalies (HAAs) above mass transport complexes (MTCs). These HAAs are located at ∼400−600 m burial depth, and have circular or elongate shapes in map view. The reflections at the tops of these HAAs are of negative polarity. We divide these HAAs into two populations, aligned and non-aligned. The aligned HAAs comprise three linear groups above the structural lineaments of underlying MTCs, suggesting a genetic link. The aligned HAAs in the western group are often located in depressions, and are interpreted to be caused by both gas migration and coarser-grained sediments. The other two groups of aligned HAAs are interpreted to be caused by residual gas after gas migration fed along the margins of underlying MTCs. In contrast, the non-aligned HAAs are generally smaller, located above the MTC bodies. They are interpreted to be caused by gas which migrated from underlying MTC bodies rather than along the margins, without any evidence for lithology change. We propose that the locations of the HAAs, both aligned and non-aligned, indicate gas migration pathways up MTC margins or local faults associated with the underlying MTCs. One possible gas source could be from hydrate dissociation due to the upward resetting of the base of gas hydrates. Since buried MTCs and gas hydrates can coexist in marine environments, the model of buried MTCs channelling fluids upwards may occur widely which can supply gas to the hydrate systems. [Copyright &y& Elsevier]

Abstract: We compile published examples of induced earthquakes that have occurred since 1929 that have magnitudes equal to or greater than 1.0. Of the 198 possible examples, magnitudes range up to 7.9. The potential causes and magnitudes are (a) mining (M 1.6–5.6); (b) oil and gas field depletion (M 1.0–7.3); (c) water injection for secondary oil recovery (M 1.9–5.1); (d) reservoir impoundment (M 2.0–7.9); (e) waste disposal (M 2.0–5.3); (f) academic research boreholes investigating induced seismicity and stress (M 2.8–3.1); (g) solution mining (M 1.0–5.2); (h) geothermal operations (M 1.0–4.6) and (i) hydraulic fracturing for recovery of gas and oil from low-permeability sedimentary rocks (M 1.0–3.8). Reactivation of faults and resultant seismicity occurs due to a reduction in effective stress on fault planes. Hydraulic fracturing operations can trigger seismicity because it can cause an increase in the fluid pressure in a fault zone. Based upon the research compiled here we propose that this could occur by three mechanisms. Firstly, fracturing fluid or displaced pore fluid could enter the fault. Secondly, there may be direct connection with the hydraulic fractures and a fluid pressure pulse could be transmitted to the fault. Lastly, due to poroelastic properties of rock, deformation or ‘inflation’ due to hydraulic fracturing could increase fluid pressure in the fault or in fractures connected to the fault. The following pathways for fluid or a fluid pressure pulse are proposed: (a) directly from the wellbore; (b) through new, stimulated hydraulic fractures; (c) through pre-existing fractures and minor faults; or (d) through the pore network of permeable beds or along bedding planes. The reactivated fault could be intersected by the wellbore or it could be 10s to 100s of metres from it. We propose these mechanisms have been responsible for the three known examples of felt seismicity that are probably induced by hydraulic fracturing. These are in the USA, Canada and the UK. The largest such earthquake was M 3.8 and was in the Horn River Basin, Canada. To date, hydraulic fracturing has been a relatively benign mechanism compared to other anthropogenic triggers, probably because of the low volumes of fluid and short pumping times used in hydraulic fracturing operations. These data and analysis should help provide useful context and inform the current debate surrounding hydraulic fracturing technology. [Copyright &y& Elsevier]

Abstract: Using three-dimensional (3D) seismic data, we establish a simple model for the development of vertical fluid flow pipes in the deepwater western Niger Delta. We analyse two examples of fluid flow pipes that form vertical seismic chimneys that are 400–600 m wide and ∼2000–2500 m in height, terminate at the current seabed and have bases located at the crest of rollover anticlines. In both cases we identify buried deepwater channels-complexes located below the pipes that formed prior to the growth of the rollover anticlines. The development of the anticlines caused tilting of these channel complexes and differential loading. We propose the channel complexes represent connected permeable reservoir intervals and that lateral pressure transfer caused the pore pressure at the crest of the structures to reach critical levels, leading to hydraulic fracturing of the overburden. Although hydrocarbons may migrate upwards through the chimney systems, they are not necessarily indicators that the channel complexes were gas or oil charged. [Copyright &y& Elsevier]

Abstract: Soil collected from 38 sites on Kangaroo Island in South Australia, containing small remnants of senescent Eucalyptus cneorifolia-dominated mallee, was subject ex situ to both smoke aerosol and heat treatment to simulate burning. Further soil from a subset of 29 of the sites was left untreated as a control. A total of 113 native plant species and 50 introduced species germinated across all sites. Fifty-three of the native plant species that germinated were absent in the above-ground vegetation, including twelve rare or threatened species, and three species previously unrecorded from Kangaroo Island. Fourteen native species and six introduced species germinated in heat plus smoke treated soil but not in untreated soil from the same sites. Non-metric multidimensional scaling ordination indicated differences in native species composition between sites with a long history of sustained livestock grazing (“grazed” sites) and largely ungrazed sites (“ungrazed” sites). On average, significantly more native species germinated from treated soil sampled from “ungrazed” sites than were found in the standing vegetation, while for “grazed” sites this difference was not significant. This indicates the greater potential for post-fire regeneration of native vegetation from the soil seed bank of ungrazed sites than from that of long grazed sites. Both “ungrazed” and “grazed” sites contained weeds in their soil seed banks, including some species which were stimulated by heat plus smoke. This indicated that competition from weeds is potentially a problem when fire is used as a management tool to regenerate senescent understoreys. [Copyright &y& Elsevier]

Abstract: The maximum reported height of an upward propagating hydraulic fracture from several thousand fracturing operations in the Marcellus, Barnett, Woodford, Eagle Ford and Niobrara shale (USA) is ∼588 m. Of the 1170 natural hydraulic fracture pipes imaged with three-dimensional seismic data offshore of West Africa and mid-Norway it is ∼1106 m. Based on these empirical data, the probability of a stimulated and natural hydraulic fracture extending vertically >350 m is ∼1% and ∼33% respectively. Constraining the probability of stimulating unusually tall hydraulic fractures in sedimentary rocks is extremely important as an evidence base for decisions on the safe vertical separation between the depth of stimulation and rock strata not intended for penetration. [Copyright &y& Elsevier]