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INTRODUCTION/PURPOSE: To compare knee arthrocentesis first‐attempt success using landmark‐guided, ultrasound‐localised and ultrasound‐guided techniques when performed by third‐year medical students. METHODS: In this prospective, crossover study with randomised order of events, medical students performed three different arthrocentesis techniques on knee models: landmark‐guided, ultrasound‐localised and ultrasound‐guided. Each subject attempted the techniques in a randomly assigned permutation at both high‐ and low‐volume simulated knee effusions. The data were analysed with general estimating equations, which produced odds ratios comparing first‐attempt success between different techniques at all effusion volumes. RESULTS: Ninety four of 111 third‐year medical students were enrolled. Proportions of first‐attempt success for the landmark‐guided, US‐localised and US‐guided were 72%, 86% and 75%, respectively. For all effusion volumes, US‐localised demonstrated a statistically significant increase in first‐attempt success over the landmark‐guided technique, OR = 2.38 (95% CI: 1.52–3.70). There was a greater increase in first‐attempt success at low‐volume effusions, OR = 2.86 (95% CI: 1.47–5.56), but no significant increase at high‐volume effusions: OR = 1.85 (95% CI: 1.00–3.45). For all effusion volumes, US‐guided demonstrated no difference to first‐attempt success compared with landmark, OR = 1.15 (95% CI: 0.71–1.85). At low‐volume effusions, US‐guided demonstrated a statistically significant increase in first‐attempt success over landmark‐guided, OR = 2.17 (95% CI: 1.10–4.35), with no significant difference at high volumes, OR: 0.55 (95% CI: 0.28–1.06). DISCUSSION: The data presented here suggest that in this simulated knee model of arthrocentesis, ultrasound‐guided approaches tend to have best efficacy at lower volume effusions, while ultrasound localized tends to do best at higher volume effusions, and both tended to perform better than the landmark technique. This study specifically looked at novices to both arthrocentesis and ultrasound, so extrapolating these results to other groups would require more study, but suggests that ultrasound incorporation into arthrocentesis benefits may offer some benefits for success rates and first attempt success. CONCLUSION: In simulated knee arthrocentesis, ultrasound‐guided techniques increased first‐attempt success over landmark‐guided techniques among medical students. This increase was most evident for arthrocentesis of smaller volume effusions.

Legend for raw response data

raw combination response data; response is represented as fractional viability

Supplementary figure, table and data legend

We ran 8 titration point curves (shown in gray) and then picked 4 concentration points that cover best the response curve for all cell lines (shown in red). The first point is the top plateau, the last is the bottom plateau and the other 2 are in between.

raw single agent response data; response is represented as fractional viability

Hierarchical clustering was performed on the response data across the cell line panel to the single agent treatments. Drugs with similar mechanisms of action clustered together.

RAS mutation/signature does not predict response to mTOR/Wee1 combination.

This article provides a survey overview of the techniques, mechanisms, algorithms, and test and validation strategies required for the design of robotic grappling vehicles intended to approach and grapple free-flying client satellites. We concentrate on using a robotic arm to grapple a free-floating spacecraft, as distinct from spacecraft docking and berthing, where two spacecraft directly mate with each other. Robotic grappling of client spacecraft is a deceptively complex problem: It entails designing a robotic system that functions robustly in the visually stark, thermally extreme orbital environment, operating near massive and extremely expensive yet fragile client hardware, using relatively slow flight computers with limited and laggy communications. Spaceflight robotic systems are challenging to test and validate prior to deployment and extremely expensive to launch, which significantly limits opportunities to experiment with new techniques. These factors make the design and operation of orbital robotic systems significantly different from those of their terrestrial counterparts, and as a result, only a relative handful of systems have been demonstrated on orbit. Nevertheless, there is increasing interest in on-orbit robotic servicing and assembly missions, and grappling is the core requirement for these systems. Although existing systems such as the Space Station Remote Manipulator System have demonstrated extremely reliable operation, upcoming missions will attempt to expand the types of spacecraft that can be safely and dependably grappled and berthed.

Purpose: The aim was this study was to test the effectiveness of the Mexican User Satisfaction Index of Circular and Social Economy (MUSI-CSE) methodology to improve user acceptance and the adoption of biodiesel from the Cowichan Bio-Diesel Co-op (CB-DC), a social enterprise that upcycles cooking oil waste. Approach: The external strategy is to study factors of user experience with products and/or services and internal processes. This type of economy tends to build its value chain independently to avoid barriers in the economic structure. Methodology/Techniques: MUSI-CSE presents a model of satisfaction (present acceptance) and loyalty (future acceptance) factors and a measurement system comprising the same factors. It also identifies and monitors interventions in key factors and evaluates their effectiveness. Here, MUSI-CSE has been tested through a longitudinal and prospective study. In-depth interviews, surveys, SEM, and PLS were used. Findings/originality/applicability: User acceptance and adoption are based on self-benefits and the achievement of specific sustainable local development goals. Satisfaction did not change. Loyalty did experience a statistically significant increase at a 95% confidence level, and sales increased by 26%. It can be concluded that MUSI-CSE innovation contributed to improving users’ future acceptance and adoption. In the future, MUSI-CSE will be adjusted based on other case studies and will support the co-creation of an international methodology and index of circular and social economy.

Three experiments explored the effects of abrupt changes in stimulus properties on streaming dynamics. Listeners monitored 20-s-long low- and high-frequency (LHL-) tone sequences and reported the number of streams heard throughout. Experiments 1 and 2 used pure tones and examined the effects of changing triplet base frequency and level, respectively. Abrupt changes in base frequency (±3-12 semitones) caused significant magnitude-related falls in segregation (resetting), regardless of transition direction, but an asymmetry occurred for changes in level (±12 dB). Rising-level transitions usually decreased segregation significantly, whereas falling-level transitions had little or no effect. Experiment 3 used pure tones (unmodulated) and narrowly spaced (±25 Hz) tone pairs (dyads); the two evoke similar excitation patterns, but dyads are strongly modulated with a distinctive timbre. Dyad-only sequences induced a strongly segregated percept, limiting scope for further build-up. Alternation between groups of pure tones and dyads produced large, asymmetric changes in streaming. Dyad-to-pure transitions caused substantial resetting, but pure-to-dyad transitions sometimes elicited even greater segregation than for the corresponding interval in dyad-only sequences (overshoot). The results indicate that abrupt changes in timbre can strongly affect the likelihood of stream segregation without introducing significant peripheral-channeling cues. These asymmetric effects of transition direction are reminiscent of subtractive adaptation in vision.

Lexical bias is the tendency to perceive an ambiguous speech sound as a phoneme completing a word; more ambiguity typically causes greater reliance on lexical knowledge. A speech sound ambiguous between /g/ and /k/ is more likely to be perceived as /g/ before /ɪft/ and as /k/ before /ɪs/. The magnitude of this difference—the Ganong shift—increases when high cognitive load limits available processing resources. The effects of stimulus naturalness and informational masking on Ganong shifts and reaction times were explored. Tokens between /gɪ/ and /kɪ/ were generated using morphing software, from which two continua were created (“giss”–“kiss” and “gift”–“kift”). In experiment 1, Ganong shifts were considerably larger for sine- than noise-vocoded versions of these continua, presumably because the spectral sparsity and unnatural timbre of the former increased cognitive load. In experiment 2, noise-vocoded stimuli were presented alone or accompanied by contralateral interferers with constant within-band amplitude envelope, or within-band envelope variation that was the same or different across bands. The latter, with its implied spectro-temporal variation, was predicted to cause the greatest cognitive load. Reaction-time measures matched this prediction; Ganong shifts showed some evidence of greater lexical bias for frequency-varying interferers, but were influenced by context effects and diminished over time.

Masking experienced when target speech is accompanied by a single interfering voice is often primarily informational masking (IM). IM is generally greater when the interferer is intelligible than when it is not (e.g., speech from an unfamiliar language), but the relative contributions of acoustic-phonetic and linguistic interference are often difficult to assess owing to acoustic differences between interferers (e.g., different talkers). Three-formant analogues (F1+F2+F3) of natural sentences were used as targets and interferers. Targets were presented monaurally either alone or accompanied contralaterally by interferers from another sentence (F0 = 4 semitones higher); a target-to-masker ratio (TMR) between ears of 0, 6, or 12 dB was used. Interferers were either intelligible or rendered unintelligible by delaying F2 and advancing F3 by 150 ms relative to F1, a manipulation designed to minimize spectro-temporal differences between corresponding interferers. Target-sentence intelligibility (keywords correct) was 67% when presented alone, but fell considerably when an unintelligible interferer was present (49%) and significantly further when the interferer was intelligible (41%). Changes in TMR produced neither a significant main effect nor an interaction with interferer type. Interference with acoustic-phonetic processing of the target can explain much of the impact on intelligibility, but linguistic factors-particularly interferer intrusions-also make an important contribution to IM.

Background: The addition of an addiction medicine consult service has been shown to improve mortality and decrease hospital costs but its impact on the proportion of patients discharged against medical advice (DAMA) and in-hospital initiation of medication for opioid use disorder (MOUD) has not been examined. Methods: A retrospective before-after cohort study was performed at an urban, academic medical center between January 1, 2015 and November 1, 2019. We included adult patients with infective endocarditis and injection drug use determined by admitting diagnosis ICD-9 or ICD-10 codes or documentation within the history section of electronic health recordEHR. Our institution implemented a formal addiction medicine consult service on July 1, 2018. We determined the proportion of patients DAMA and the proportion of patients started on MOUD among patients in the pre-intervention (i.e. hospitalized before July 1, 2018) and intervention (i.e. hospitalized July 1, 2018 or after) groups. Results: A total of 171 patients among hospitalized patients with injection drug use-associated infective endocarditis were included with 119 patients in the pre-intervention group and 52 patients in the intervention group. There was no statistically significant difference in patients DAMA [19% vs 15%, absolute risk difference 4.6% (95% confidence interval -8.6% to 17.7%)] between the intervention and pre-intervention groups. However, there was an increase in the proportion of inpatient MOUD initiation in the intervention group compared to the pre-intervention group [56% vs 21%, absolute risk difference 35% (95% confidence interval 19% to 50%)]. Conclusions: The initiation of an addiction medicine consult service was associated with a higher proportion of MOUD initiation but there was no statistically significant association with the proportion of patients DAMA.

Speech-on-speech informational masking arises because the interferer disrupts target processing (e.g., capacity limitations) or corrupts it (e.g., intrusions into the target percept); the latter should produce predictable errors. Listeners identified the consonant in monaural buzz-excited three-formant analogues of approximant-vowel syllables, forming a place of articulation series (/w/-/l/-/j/). There were two 11-member series; the vowel was either high-front or low-back. Series members shared formant-amplitude contours, fundamental frequency, and F1+F3 frequency contours; they were distinguished solely by the F2 frequency contour before the steady portion. Targets were always presented in the left ear. For each series, F2 frequency and amplitude contours were also used to generate interferers with altered source properties—sine-wave analogues of F2 (sine bleats) matched to their buzz-excited counterparts. Accompanying each series member with a fixed mismatched sine bleat in the contralateral ear produced systematic and predictable effects on category judgments; these effects were usually largest for bleats involving the fastest rate or greatest extent of frequency change. Judgments of isolated sine bleats using the three place labels were often unsystematic or arbitrary. These results indicate that informational masking by interferers involved corruption of target processing as a result of mandatory dichotic integration of F2 information, despite the grouping cues disfavoring this integration.

Background Updatable estimates of COVID-19 onset, progression, and trajectories underpin pandemic mitigation efforts. To identify and characterise disease trajectories, we aimed to define and validate ten COVID-19 phenotypes from nationwide linked electronic health records (EHR) using an extensible framework. Methods In this cohort study, we used eight linked National Health Service (NHS) datasets for people in England alive on Jan 23, 2020. Data on COVID-19 testing, vaccination, primary and secondary care records, and death registrations were collected until Nov 30, 2021. We defined ten COVID-19 phenotypes reflecting clinically relevant stages of disease severity and encompassing five categories: positive SARS-CoV-2 test, primary care diagnosis, hospital admission, ventilation modality (four phenotypes), and death (three phenotypes). We constructed patient trajectories illustrating transition frequency and duration between phenotypes. Analyses were stratified by pandemic waves and vaccination status. Findings Among 57 032 174 individuals included in the cohort, 13 990 423 COVID-19 events were identified in 7 244 925 individuals, equating to an infection rate of 12·7% during the study period. Of 7 244 925 individuals, 460 737 (6·4%) were admitted to hospital and 158 020 (2·2%) died. Of 460 737 individuals who were admitted to hospital, 48 847 (10·6%) were admitted to the intensive care unit (ICU), 69 090 (15·0%) received non-invasive ventilation, and 25 928 (5·6%) received invasive ventilation. Among 384 135 patients who were admitted to hospital but did not require ventilation, mortality was higher in wave 1 (23 485 [30·4%] of 77 202 patients) than wave 2 (44 220 [23·1%] of 191 528 patients), but remained unchanged for patients admitted to the ICU. Mortality was highest among patients who received ventilatory support outside of the ICU in wave 1 (2569 [50·7%] of 5063 patients). 15 486 (9·8%) of 158 020 COVID-19-related deaths occurred within 28 days of the first COVID-19 event without a COVID-19 diagnoses on the death certificate. 10 884 (6·9%) of 158 020 deaths were identified exclusively from mortality data with no previous COVID-19 phenotype recorded. We observed longer patient trajectories in wave 2 than wave 1. Interpretation Our analyses illustrate the wide spectrum of disease trajectories as shown by differences in incidence, survival, and clinical pathways. We have provided a modular analytical framework that can be used to monitor the impact of the pandemic and generate evidence of clinical and policy relevance using multiple EHR sources. Funding British Heart Foundation Data Science Centre, led by Health Data Research UK.

OBJECTIVES To determine recent trends in: (1) human immunodeficiency virus (HIV) diagnoses, (2) the proportion of patients newly diagnosed with HIV with injection drug use (IDU) and (3) patients' patterns of healthcare utilization in the year before diagnosis at an urban, academic medical center. METHODS We performed a cross sectional study of patients newly diagnosed with HIV at a healthcare system in southern New Jersey between January 1st, 2014 and December 31st, 2019. Patients 18 years or older with HIV diagnosed during the study period were included. Demographics, comorbidities, HIV test results, and healthcare utilization data were collected from the electronic medical record. RESULTS Of 192 patients newly diagnosed with HIV, 36 (19%) had documented IDU. New HIV diagnoses doubled from 22 to 47 annual cases between 2014 and 2019. The proportion of patients with newly diagnosed HIV and documented IDU increased from 9% in 2014 to 32% in 2019, chi-square test for linear trend P value = 0.001. Eighty-nine percent of patients with IDU had at least one contact with the healthcare system in the year before diagnosis compared to 63% of patients without IDU, P value 0.003. The median (interquartile range IQR) number of healthcare visits was 7 [2-16] for patients with IDU versus 1 [0-3] for patients without IDU, P

SUBCULTURES, CULTURES AND CLASS John Clarke Stuart Hall Tony Jefferson Brian Roberts Our subject in this volume is Youth Cultures: our object, to explain them as a phenomenon, and their appearance in the post-war period. The subject has, of course, been massively treated, above all in the mass media. Yet, many of these surveys and analyses seem mainly to have multiplied the confusions and extended the mythologies surrounding the topic. By treating it in terms of its spectacular features only, these surveys have become part of the very phenomenon we want to explain. First, then, we must clear the ground, try to get behind the myths and explanations which cover up, rather than clarify, the problem. We have to construct the topic first-partly by demolishing certain concepts which, at present, are taken as adequately defining it. Necessarily, this exercise of penetrating beneath a popular construction must be done with care, lest we discard the ‘rational kernel’ along with its overpublicised husk.

The impact of an extraneous formant on intelligibility is affected by the extent (depth) of variation in its formant-frequency contour. Two experiments explored whether this impact also depends on masker spectro-temporal coherence, using a method ensuring that interference occurred only through informational masking. Targets were monaural three-formant analogues (F1+F2+F3) of natural sentences presented alone or accompanied by a contralateral competitor for F2 (F2C) that listeners must reject to optimize recognition. The standard F2C was created using the inverted F2 frequency contour and constant amplitude. Variants were derived by dividing F2C into abutting segments (100–200 ms, 10-ms rise/fall). Segments were presented either in the correct order (coherent) or in random order (incoherent), introducing abrupt discontinuities into the F2C frequency contour. F2C depth was also manipulated (0%, 50%, or 100%) prior to segmentation, and the frequency contour of each segment either remained time-varying or was set to constant at the geometric mean frequency of that segment. The extent to which F2C lowered keyword scores depended on segment type (frequency-varying vs constant) and depth, but not segment order. This outcome indicates that the impact on intelligibility depends critically on the overall amount of frequency variation in the competitor, but not its spectro-temporal coherence.

Offshore oil and gas production platforms are complex and hazardous process facilities which are usually attended by a permanent human crew to run the daily operations. In recent years, the oil and gas industry has demonstrated strong commitment to change this traditional operations approach and move towards inherently safer philosophy in offshore facilities design and operations, i.e. removing human crew from the facility and operating it remotely from a safe location over extended periods. This paper aims to demonstrate the readiness of robotics technologies coupled with digitalization technologies in process control and facility automation in transforming offshore oil and gas production platforms into smart unmanned installations. This paper is focused on the application of smart robotics, with highly dexterous capabilities and equipped with multiple sensing instruments, in maintaining an offshore oil and gas production facility in full operation without a permanent human crew, and with planned visits to the platform at 12-week intervals, in a case study. The robots are developed to be remotely operated from an onshore control center and/or may be programmed to function autonomously for routine missions on the offshore facility.

A variable transmission thin film for visible light is proposed based on a mechanically actuated origami structure coated with metallic nanoparticles. The transmissivity can be tuned continuously from 0 to > 90 % for unpolarized incident light. Power is only required for switching and is not necessary to maintain the desired transmittance state. The asymmetric metal nanorods create two distinct plasmon resonances. Controlling the orientation of the nanorods with respect to the direction of the incident light changes the optical transmittance. The switching speed is only limited by the mechanical actuation and not by the optical response of the materials. The applicability of the proposed film for smart glass applications is investigated. Good image transmission clarity with minimal distortion is shown.

Stream segregation for a test sequence comprising high-frequency (H) and low-frequency (L) pure tones, presented in a galloping rhythm, is much greater when preceded by a constant-frequency induction sequence matching one subset than by an inducer configured like the test sequence; this difference persists for several seconds. It has been proposed that constant-frequency inducers promote stream segregation by capturing the matching subset of test-sequence tones into an on-going, pre-established stream. This explanation was evaluated using 2-s induction sequences followed by longer test sequences (12–20 s). Listeners reported the number of streams heard throughout the test sequence. Experiment 1 used LHL– sequences and one or other subset of inducer tones was attenuated (0–24 dB in 6-dB steps, and 1). Greater attenuation usually caused a progressive increase in segregation, towards that following the constant-frequency inducer. Experiment 2 used HLH– sequences and the L inducer tones were raised or lowered in frequency relative to their test-sequence counterparts (DfI¼ 0, 0.5, 1.0, or 1.5 DfT). Either change greatly increased segregation. These results are concordant with the notion of attention switching to new sounds but contradict the stream-capture hypothesis, unless a “proto-object” corresponding to the continuing subset is assumed to form during the induction sequence.

Development of shallow subsurface monitoring systems is important for monitoring the ground stability of shallow formation, and also for conventional deep seismic monitoring because with current techniques, temporal changes in shallow seismic velocities can influence monitoring results for the deep subsurface. We have developed an effective shallow seismic imaging and monitoring system with high spatiotemporal resolution and accuracy using a continuous and controlled source system, the accurately controlled routinely operated signal system (ACROSS). The method applies surface-wave analysis to characterize and monitor the shallow subsurface from the spatiotemporal variation of phase velocities. Because the number of available ACROSS units is usually limited, estimating a shallow subsurface with high spatial resolution is a challenging issue in ACROSS-based monitoring. To overcome this problem, we introduced a 2D spatial window into multichannel analysis of surface waves. We analyzed continuous ACROSS data acquired during seven different data periods from 2014 to 2016 at the Aquistore [Formula: see text] storage site in Canada. As a result, we clearly estimated spatial variations of phase velocities using only a single ACROSS unit. The numerical experiments of our method suggested that the spatial variations could be associated with shallow geologic boundaries in the study area. We identified clear seasonal variations of phase velocities in winter, possibly related to ground freezing in shallow sediments, and we showed the high temporal stability of our monitoring approach in warmer seasons. These results indicated that our approach would have the potential to identify spatiotemporal change in shallow subsurface associated with natural phenomena or fluid leakage.

Venezuelan equine encephalitis virus (VEEV) is a neurotropic arbovirus that is highly infectious as an aerosol and can result in an encephalitic phenotype in infected individuals. VEEV infections are known to be associated with robust inflammation that eventually contributes to neurodegenerative phenotypes. In this study, we utilize the TC-83 strain of VEEV, which is known to induce the expression of IL-6, IL-8, and other pro-inflammatory cytokines. We had previously demonstrated that TC-83 infection resulted in changes in mitochondrial function, eventually resulting in mitophagy. In this manuscript, we provide data that links upstream mitochondrial dysfunction with downstream pro-inflammatory cytokine production in the context of microglia and astrocytoma cells. We also provide data on the role of bystander cells, which significantly contribute to the overall inflammatory load. Use of a mitochondrial-targeted antioxidant, mitoquinone mesylate, greatly reduced the inflammatory cytokine load and ameliorated bystander cell inflammatory responses more significantly than a broad-spectrum anti-inflammatory compound (BAY 11–7082). Our data suggest that the inflammatory mediators, especially IL-1β, may prime naïve cells to infection and lead to increased infection rates in microglial and astrocytoma cells. Cumulatively, our data suggest that the interplay between mitochondrial dysfunction and inflammatory events elicited in a neuronal microenvironment during a TC-83 infection may contribute to the spread of infection.

Purpose The purpose of this paper is to design and test a user satisfaction model to evaluate the contribution of biodiesel production and consumption to the sustainability of a semi-urban community in the Cowichan Valley in British Columbia Canada. This case study is part of a larger research study whose purpose is to create a model for an index of sustainable community production and consumption. Design/methodology/approach The theoretical approach selected was the national indices of consumer satisfaction models. The methodology was qualitative and quantitative, in-depth interviews were used to learn the opinion of active and non-active consumers of biodiesel. The interviews were transcribed and analyzed with specialized software for qualitative studies. A structural equation model, whose innovation is the inclusion of the sustainability variables, was designed and analyzed with statistical technique partial least squares. Findings The designed model and methodology were useful to identify the principal cause variables of consumer satisfaction of biodiesel in two types of users: active users and non-active users. The determination coefficient R2 of the latent variables satisfaction and loyalty for the prediction of biodiesel active users model is 0.82 and 0.72, respectively, while the result for the non-active users model is 0.90 for satisfaction and 0.73 for loyalty. Sustainable consumption at community level is statistically significant as a direct cause of the variable sustainability of the community for both models, and in turn the sustainability of the community variable has a significant impact on loyalty for the active users model. Originality/value This case study is part of a larger research study whose purpose is to create a model for an index of sustainable community production and consumption which will be measured longitudinally to detect changes in the sustainable consumption of the community members.

Magnetotelluric (MT) soundings were conducted in a 4 × 4 km area at the Aquistore CO2 sequestration site at Estevan, Saskatchewan, Canada in 2013, 2014 and 2015, prior to CO2 injection. The MT response is locally one-dimensional but spatially variable at short periods ( 30 s). Responses corresponding to Williston Basin rocks are uniform across the area. A representative MT response was inverted using constraints derived from a resistivity well-log. Beneath the Jurassic Watrous to Vanguard formations (at depths greater than 1240–1600 m), the resistivity of the inversion model is consistently 20–30% lower than in the reference well-log model, consistent with the MT method sensing the longitudinal resistivity of the more strongly stratified units at these depths. Electromagnetic noise in the MT data set includes high-frequency odd harmonics of the 60 Hz source and a broad-band source, spatially associated with the CO2 pipeline, observed only in 2014. Within the period range 10−4 to 102 s, but outside the bands influenced by the broad-band noise, the off-diagonal MT impedance response at Aquistore can be measured with an RMS repeatability of 1% or better.

The Aquistore CO2 Storage Site is located in southeastern Saskatchewan, Canada. CO2 is injected into a brine-filled sandstone formation at ∼3200 m depth immediately above the Precambrian basement. Sustained injection rates of 400-600 tonnes/day were achieved at the site starting in the fall of 2015 with a total of 88 ktonnes having been injected by the end of September, 2016. Seismic monitoring methods have been employed to track the subsurface CO2 plume and to record any injection-induced seismicity. Passive seismic monitoring is being conducted using two orthogonal arrays of short-period geophones, 3 broadband seismographs, and an array of downhole geophones. No significant injection-related seismicity (Mw > -1) has been detected during the first 17 months of CO2 injection. The first post-injection time-lapse 3D seismic surveys (surface and VSP) were conducted at the site in February, 2016. The VSP data were acquired with a distributed acoustic sensing system using a 2750 m casing-conveyed optical fibre cable in the observation well. 3D seismic modelling of fluid flow simulations in conjunction with seismic repeatability estimates obtained from field data indicate that the time-lapse VSP should be capable of imaging the CO2 plume after a total injection of ∼30 ktonnes. In addition, this first monitor survey tests the ability of surface seismic data acquired with a sparse permanent array to detect or image the CO2 plume after limited injection. Time-lapse logging is being conducted on a regular basis to provide in situ measurement of the change in seismic velocity associated with changes in CO2 saturation.

The first post-[Formula: see text]-injection 3D time-lapse seismic survey was conducted at the Aquistore [Formula: see text] storage site in February 2016 using the same permanent array of buried geophones used for acquisition of three previous pre-[Formula: see text]-injection surveys from March 2012 to November 2013. By February 2016, 36 kilotons of [Formula: see text] have been injected within the reservoir between 3170 and 3370 m depth. We have developed time-lapse results from analysis of the first post-[Formula: see text]-injection data and three pre-[Formula: see text]-injection data sets. The objective of our analysis was to evaluate the ability of the permanent array to detect the injected [Formula: see text]. A “4D-friendly simultaneous” processing flow was applied to the data in an effort to maximize the repeatability between the pre- and post-[Formula: see text]-injection volumes while optimizing the final subsurface image including the reservoir. Excellent repeatability was achieved among all surveys with global normalized root-mean-square (G nrms) values of 1.13–1.19 for the raw prestack data relative to the baseline data, which decreased during processing to G nrms values of approximately 0.10 for the final crossequalized migrated data volumes. A zone of high normalized root-mean-square ( nrms) values (0.11–0.25 as compared with background values of 0.05–0.10) is identified within the upper Deadwood unit of the storage reservoir, which likely corresponds to approximately 18 kilotons of [Formula: see text]. No significant nrms anomalies are observed within the other reservoir units due to a combination of reduced seismic sensitivity, higher background nrms values, and/or small quantities of [Formula: see text] residing within these zones.