Time-lapse sonic logs reveal patchy CO2 saturation in-situ

Based on time-lapse sonic and neutron porosity logs from the Nagaoka CO2 sequestration experiment, a P-wave velocity-saturation relation at reservoir depth is retrieved. It does not coincide with either of the end-member models of uniform and patchy saturation but falls in between even if realistic error estimates for the host rock properties are considered. Assuming a random distribution of CO2 patches it is shown that the mechanism of wave-induced flow can be evoked to explain this velocity-saturation relation. Characteristic CO2 patch size estimates range from 1 to 5 mm. Such mesoscopic heterogeneity can be responsible for attenuation and dispersion in the well logging frequency band

Direct laboratory observation of patchy saturation and its effects on ultrasonic velocities

Maximizing the recovery of known hydrocarbon reserves is one of the biggest challenges facing the petroleum industry today. Optimal production strategies require accurate monitoring of production-induced changes of reservoir saturation and pressure over the life of the field. Time-lapse seismic technology is increasingly used to map these changes in space and time. However, until now, interpretation of time-lapse seismic data has been mostly qualitative. In order to allow accurate estimation of the saturation, it is necessary to know the quantitative relationship between fluid saturation and seismic characteristics (elastic moduli, velocity dispersion, and attenuation). The problem of calculating acoustic properties of rocks saturated with a mixture of two fluids has attracted considerable interest (Gist, 1994; Mavko and Nolen-Hoeksema, 1994; Knight et al., 1998. For a comprehensive review of theoretical and experimental studies of the patchy saturation problem see Toms et al., 2006)

Adrenocorticotropic hormone levels before treatment predict recurrence of Cushing's disease

Background/PurposeCushing's disease (CD) is the most common cause of endogenous Cushing's syndrome. Transsphenoidal surgery (TSS) is the first choice of treatment. Predicting prognosis after treatment can benefit further strategies of management, but currently there is no convenient predictor. This study aims to investigate characteristic changes after treatment and to identify potential prognostic predictors.MethodsWe retrospectively studied the records of CD patients presenting to the National Taiwan University Hospital, Taipei, Taiwan between 1992 and 2011. They were categorized according to treatment response. Clinical features and examination findings were compared between groups.ResultsForty-one patients with CD were included. The follow-up time was 0.26–19.3 years. The time interval between the onset of symptoms and diagnosis was 2.1–120.0 months. The initial remission rate of CD after the first treatment was 82.9%. Mean body mass index (BMI) was 27.4 kg/m2 before treatment and 26.0 kg/m2 3 months after treatment. The patients in remission had a greater decrease in BMI after treatment and lower dehydroepiandrosterone sulfate (DHEAS) levels before treatment, compared with the recurrent group (both p < 0.05). Adrenocorticotropic hormone (ACTH) levels before treatment showed a significant positive correlation with recurrent diseases (p < 0.05).ConclusionA larger decrease in BMI after treatment and lower DHEAS levels before treatment were noted for the patients who stayed in CD remission. Higher ACTH levels before treatment predicted a recurrence of CD. These are potentially simple and practical predictors of prognosis

PHEME : computing veracity : the fourth challenge of big social data

The veracity of information spreading through social media can sometimes be hard to establish and the deliberate or accidental spread of false information, especially during natural disasters or emergencies, is quite common. We coined the term phemes to describe fast spreading memes which are enhanced with truthfulness information. The PHEME project (http://www.pheme.eu) attempts to identify in real-time four kinds of phemes: controversy, speculation, misinformation and disinformation. This brings challenges in modelling the social network spread of and the online conversations around phemes; developing rumour detection methods; and using historical data to model trustworthiness of the information source

Better post-operative prediction and management of chronic pain in adults after total knee replacement:the multidisciplinary STAR research programme including RCT

Background: The treatment of osteoarthritis with knee replacement aims to reduce pain and disability. However, some people experience chronic pain. Objectives: To improve outcomes for people with chronic pain after knee replacement by identifying post-surgical predictors and effective interventions, characterising patient pathways and resource use, developing and evaluating a new care pathway, and exploring non-use of services. Design: The programme comprised systematic reviews, national database analyses, a cohort study, intervention development, a randomised controlled trial, health economic analyses, qualitative studies and stakeholder engagement. Extensive and meaningful patient and public involvement underpinned all studies. Setting: NHS, secondary care, primary care. Participants: People with, or at risk of, chronic pain after knee replacement and health-care professionals involved in the care of people with pain. Interventions: A care pathway for the management of people with pain at 3 months after knee replacement. Main outcome measures: Patient-reported outcomes and cost-effectiveness over 12 months. Data sources: Literature databases, the National Joint Registry, Hospital Episode Statistics, patient- reported outcomes, the Clinical Practice Research Datalink, the Clinical Outcomes in Arthroplasty Study, the Support and Treatment After joint Replacement randomised trial, interviews with 90 patients and 14 health-care professionals, and stakeholder events. Review methods: Systematic reviews of cohort studies or randomised trials, using meta-analysis or narrative synthesis. Results: In the Clinical Outcomes in Arthroplasty Study cohort, 14% of people experienced chronic pain 1 year after knee replacement. By 5 years, 65% reported no pain, 31% fluctuated and 4% remained in chronic pain. People with chronic pain had a worse quality of life, higher primary care costs, and more frequent analgesia prescriptions, particularly for opioids, than those not in chronic pain. People with chronic pain after knee replacement who made little or no use of services often felt nothing more could be done, or that further treatments may have no benefit or cause harm. People described a feeling of disconnection from their replaced knee. Analysis of UK databases identified risk factors for chronic pain after knee replacement. Pre- operative predictors were mild knee pain, smoking, deprivation, body mass index between 35 and 40 kg/m2 and knee arthroscopy. Peri- and post-operative predictors were mechanical complications, infection, readmission, revision, extended hospital stay, manipulation under anaesthetic and use of opioids or antidepressants. In systematic reviews, pre-operative exercise and education showed no benefit in relation to chronic pain. Peri-operative interventions that merit further research were identified. Common peri- operative treatments were not associated with chronic pain. There was no strong evidence favouring specific post-operative physiotherapy content. We evaluated the Support and Treatment After joint Replacement care pathway in a multicentre randomised controlled trial. We randomised 363 people with pain at 3 months after knee replacement from eight NHS Trusts in England and Wales. At 12 months’ follow-up, the intervention group had lower mean pain severity (adjusted difference –0.65, 95% confidence interval –1.17 to -0.13; p = 0.014) and pain interference (adjusted difference –0.68, 95% confidence interval –1.29 to -0.08; p = 0.026), as measured on the Brief Pain Inventory subscales (scale 0–10). People receiving the Support and Treatment After joint Replacement pathway had lower NHS and Personal Social Services costs (–£724, 95% confidence interval –£150 to £51) and higher quality-adjusted life-years (0.03, 95% confidence interval –0.008 to 0.06) than those with usual care. The Support and Treatment After joint Replacement pathway was cost-effective with an incremental net monetary benefit at the £20,000 per quality-adjusted life-year threshold of £1256 (95% confidence interval £164 to £2348), indicating a 98.79% probability that the intervention is the cost-effective option. Participants found the Support and Treatment After joint Replacement pathway acceptable, with opportunities to receive information and discuss concerns while ensuring further treatment and support. In systematic reviews considering treatments for chronic pain after surgery we identified some unifactorial interventions that merit further research after knee replacement. Health-care professionals delivering and implementing the Support and Treatment After joint Replacement pathway valued its focus on neuropathic pain and psychosocial issues, enhanced patient care, formalised referrals, and improved pain management. Stakeholders supported pathway implementation. Limitations: Database analyses were limited to factors recorded in data sets. Pain was only measured 6 months after surgery. However, analyses including large numbers of centres and patients should be generalisable across the NHS. In many studies found in systematic reviews, long-term pain was not a key outcome. Conclusions: The Support and Treatment After joint Replacement pathway is a clinically effective and cost-effective, acceptable intervention for the management of chronic pain after knee replacement. Unifactorial interventions merit further study before inclusion in patient care. People with pain should be empowered to seek health care, with the support of health-care professionals. Future work: Future work should include research relating to the implementation of the Support and Treatment After joint Replacement pathway into the NHS, an assessment of its long-term clinical effectiveness and cost-effectiveness and wider application, and an evaluation of new interventions for incorporation in the pathway. It will also be important to design and conduct research to improve communication between patients and health-care professionals before surgery; explore whether or not education and support can enable earlier recognition of chronic pain; consider research that may identify how to support people’s feelings of disconnectedness from their new knee; and design and evaluate a pre-surgical intervention based on risk factors. Study registration: All systematic reviews were registered on PROSPERO (CRD42015015957, CRD42016041374 and CRD42017041382). The Support and Treatment After joint Replacement randomised trial was registered as ISRCTN92545361. Funding: This project was funded by the National Institute for Health and Care Research (NIHR) Programme Grants for Applied Research programme and will be published in full in Programme Grants for Applied Research; Vol. 11, No. 3. See the NIHR Journals Library website for further project information

Theoretical Derivation of a Brie-like Fluid Mixing Law

Prediction of the velocity of acoustic waves in partially saturated rocks is very important in geophysical applications. The need to accurately predict acoustic velocities has resulted in a widespread popularity of Brie's effective fluid mixing law. This empirical model together with Gassmann's formula are used routinely in fluid substitution problems in petroleum geophysics and seismic monitoring of carbon capture and storage. Most attempts to justify Brie's model have been focused on interpretation in terms of patchy saturation models and attaching meaning to the Brie parameter in terms of the patch size. In this paper, using a microstructural description of the rock and a parameter relating to capillary pressure, we calculate an effective fluid modulus that is very similar to Brie's law. The fluid mixing law we propose is independent of frequency and has a solid theoretical foundation. This proposed law produces analytically harmonic and arithmetic averaging at the endpoints. Our results indicate that Brie-like behaviour may not necessarily be related to frequency- and patch-size- dependent phenomena

Measurements of fiducial and differential cross sections for Higgs boson production in the diphoton decay channel at s√=8 TeV with ATLAS

Measurements of fiducial and differential cross sections are presented for Higgs boson production in proton-proton collisions at a centre-of-mass energy of s√=8 TeV. The analysis is performed in the H → γγ decay channel using 20.3 fb−1 of data recorded by the ATLAS experiment at the CERN Large Hadron Collider. The signal is extracted using a fit to the diphoton invariant mass spectrum assuming that the width of the resonance is much smaller than the experimental resolution. The signal yields are corrected for the effects of detector inefficiency and resolution. The pp → H → γγ fiducial cross section is measured to be 43.2 ±9.4(stat.) − 2.9 + 3.2 (syst.) ±1.2(lumi)fb for a Higgs boson of mass 125.4GeV decaying to two isolated photons that have transverse momentum greater than 35% and 25% of the diphoton invariant mass and each with absolute pseudorapidity less than 2.37. Four additional fiducial cross sections and two cross-section limits are presented in phase space regions that test the theoretical modelling of different Higgs boson production mechanisms, or are sensitive to physics beyond the Standard Model. Differential cross sections are also presented, as a function of variables related to the diphoton kinematics and the jet activity produced in the Higgs boson events. The observed spectra are statistically limited but broadly in line with the theoretical expectations

Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal

Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV

The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of √s = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pT≥20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60≤pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2≤{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration

Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

This paper presents measurements of the $W^+ \rightarrow \mu^+\nu$ and $W^- \rightarrow \mu^-\nu$ cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13