121 research outputs found
Target template guidance of eye movements during real-world search
Humans must regularly locate task-relevant objects when interacting with the world
around them. Previous research has identified different types of information that the
visual system can use to help locate objects in real-world scenes, including low-level
image features and scene context. However, previous research using object arrays
suggest that there may be another type of information that can guide real-world
search: target knowledge. When a participant knows what a target looks like they
generate and store a visual representation, or template, of it. This template then
facilitates the search process. A complete understanding of real-world search needs
to identify how a target template guides search through scenes.
Three experiments in Chapter 2 confirmed that a target template facilitates realworld
search. By using an eye-tracker target knowledge was found to facilitate both
scanning and verification behaviours during search, but not the search initiation
process. Within the scanning epoch a target template facilitated gaze directing and
shortened fixation durations. These results suggest that target knowledge affects
both the activation map, which selects which regions of the scene to fixate, and the
evaluation process that compares a fixated object to the internal representation of the
target.
With the exact behaviours that a target template facilitates now identified, Chapter 3
investigated the role that target colour played in template-guided search. Colour is
one of the more interesting target features as it has been shown to be preferred by the
visual system over other features when guiding search through object arrays. Two
real-world search experiments in Chapter 3 found that colour information had its
strongest effect on the gaze directing process, suggesting that the visual system
relies heavily on colour information when searching for target-similar regions in the
scene percept. Although colour was found to facilitate the evaluation process too,
both when rejecting a fixated object as a distracter and accepting it as the target, this
behaviour was found to be influenced comparatively less. This suggests that the two
main search behaviours – gaze directing and region evaluation – rely on different sets of template features. The gaze directing process relies heavily on colour
information, but knowledge of other target features will further facilitate the
evaluation process.
Chapter 4 investigated how target knowledge combined with other types of
information to guide search. This is particularly relevant in real-world search where
several sources of guidance information are simultaneously available. A single
experiment investigated how target knowledge and scene context combined to
facilitate search. Both information types were found to facilitate scanning and
verification behaviours. During the scanning epoch both facilitated the eye guidance
and object evaluation processes. When both information sources were available to
the visual system simultaneously, each search behaviour was facilitated additively.
This suggests that the visual system processes target template and scene context
information independently.
Collectively, the results indicate not only the manner in which a target template
facilitates real-world search but also updates our understanding of real-world search
and the visual system. These results can help increase the accuracy of future realworld
search models by specifying the manner in which our visual system utilises
target template information, which target features are predominantly relied upon and
how target knowledge combines with other types of guidance information
Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial
Background
Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy
TOI-132 b: A short-period planet in the Neptune desert transiting a V=11.3 G-type star
The Neptune desert is a feature seen in the radius-period plane, whereby a notable dearth of short period, Neptune-like planets is found. Here, we report the Transiting Exoplanet Survey Satellite (TESS) discovery of a new short-period planet in the Neptune desert, orbiting the G-type dwarf TYC 8003-1117-1 (TOI-132). TESS photometry shows transit-like dips at the level of similar to 1400 ppm occurring every similar to 2.11 d. High-precision radial velocity follow-up with High Accuracy Radial Velocity Planet Searcher confirmed the planetary nature of the transit signal and provided a semi-amplitude radial velocity variation of 11.38(-0.85)(+0.84) m s(-1), which, when combined with the stellar mass of 0.97 +/- 0.06 M-circle dot, provides a planetary mass of 22.40(-1.92)(+1.90) M-circle plus. Modelling the TESS light curve returns a planet radius of 3.42(-0.14)(+0.13) R-circle plus , and therefore the planet bulk density is found to be 3.08(-0.46)(+0.44) g cm(-3). Planet structure models suggest that the bulk of the planet mass is in the form of a rocky core, with an atmospheric mass fraction of 4.3(-2.3)(+1.2) percent. TOI-132 b is a TESS Level 1 Science Requirement candidate, and therefore priority follow-up will allow the search for additional planets in the system, whilst helping to constrain low-mass planet formation and evolution models, particularly valuable for better understanding of the Neptune desert
Interpretation of the evidence for the efficacy and safety of statin therapy
This Review is intended to help clinicians, patients, and the public make informed decisions about statin therapy for
the prevention of heart attacks and strokes. It explains how the evidence that is available from randomised controlled
trials yields reliable information about both the effi cacy and safety of statin therapy. In addition, it discusses how
claims that statins commonly cause adverse eff ects refl ect a failure to recognise the limitations of other sources of
evidence about the eff ects of treatment. Large-scale evidence from randomised trials shows that statin therapy reduces
the risk of major vascular events (ie, coronary deaths or myocardial infarctions, strokes, and coronary revascularisation
procedures) by about one-quarter for each mmol/L reduction in LDL cholesterol during each year (after the fi rst) that
it continues to be taken. The absolute benefi ts of statin therapy depend on an individual’s absolute risk of occlusive
vascular events and the absolute reduction in LDL cholesterol that is achieved. For example, lowering LDL cholesterol
by 2 mmol/L (77 mg/dL) with an eff ective low-cost statin regimen (eg, atorvastatin 40 mg daily, costing about £2 per
month) for 5 years in 10 000 patients would typically prevent major vascular events from occurring in about
1000 patients (ie, 10% absolute benefi t) with pre-existing occlusive vascular disease (secondary prevention) and in
500 patients (ie, 5% absolute benefi t) who are at increased risk but have not yet had a vascular event (primary
prevention). Statin therapy has been shown to reduce vascular disease risk during each year it continues to be taken,
so larger absolute benefi ts would accrue with more prolonged therapy, and these benefi ts persist long term. The only
serious adverse events that have been shown to be caused by long-term statin therapy—ie, adverse eff ects of the
statin—are myopathy (defi ned as muscle pain or weakness combined with large increases in blood concentrations
of creatine kinase), new-onset diabetes mellitus, and, probably, haemorrhagic stroke. Typically, treatment
of 10 000 patients for 5 years with an eff ective regimen (eg, atorvastatin 40 mg daily) would cause about 5 cases of
myopathy (one of which might progress, if the statin therapy is not stopped, to the more severe condition of
rhabdomyolysis), 50–100 new cases of diabetes, and 5–10 haemorrhagic strokes. However, any adverse impact
of these side-eff ects on major vascular events has already been taken into account in the estimates of the absolute
benefi ts. Statin therapy may cause symptomatic adverse events (eg, muscle pain or weakness) in up to about
50–100 patients (ie, 0·5–1·0% absolute harm) per 10 000 treated for 5 years. However, placebo-controlled randomised
trials have shown defi nitively that almost all of the symptomatic adverse events that are attributed to statin therapy in
routine practice are not actually caused by it (ie, they represent misattribution). The large-scale evidence available
from randomised trials also indicates that it is unlikely that large absolute excesses in other serious adverse events
still await discovery. Consequently, any further fi ndings that emerge about the eff ects of statin therapy would not be
expected to alter materially the balance of benefi ts and harms. It is, therefore, of concern that exaggerated claims
about side-eff ect rates with statin therapy may be responsible for its under-use among individuals at increased risk of
cardiovascular events. For, whereas the rare cases of myopathy and any muscle-related symptoms that are attributed
to statin therapy generally resolve rapidly when treatment is stopped, the heart attacks or strokes that may occur if
statin therapy is stopped unnecessarily can be devastating
Procalcitonin Is Not a Reliable Biomarker of Bacterial Coinfection in People With Coronavirus Disease 2019 Undergoing Microbiological Investigation at the Time of Hospital Admission
Abstract Admission procalcitonin measurements and microbiology results were available for 1040 hospitalized adults with coronavirus disease 2019 (from 48 902 included in the International Severe Acute Respiratory and Emerging Infections Consortium World Health Organization Clinical Characterisation Protocol UK study). Although procalcitonin was higher in bacterial coinfection, this was neither clinically significant (median [IQR], 0.33 [0.11–1.70] ng/mL vs 0.24 [0.10–0.90] ng/mL) nor diagnostically useful (area under the receiver operating characteristic curve, 0.56 [95% confidence interval, .51–.60]).</jats:p
Implementation of corticosteroids in treating COVID-19 in the ISARIC WHO Clinical Characterisation Protocol UK:prospective observational cohort study
BACKGROUND: Dexamethasone was the first intervention proven to reduce mortality in patients with COVID-19 being treated in hospital. We aimed to evaluate the adoption of corticosteroids in the treatment of COVID-19 in the UK after the RECOVERY trial publication on June 16, 2020, and to identify discrepancies in care. METHODS: We did an audit of clinical implementation of corticosteroids in a prospective, observational, cohort study in 237 UK acute care hospitals between March 16, 2020, and April 14, 2021, restricted to patients aged 18 years or older with proven or high likelihood of COVID-19, who received supplementary oxygen. The primary outcome was administration of dexamethasone, prednisolone, hydrocortisone, or methylprednisolone. This study is registered with ISRCTN, ISRCTN66726260. FINDINGS: Between June 17, 2020, and April 14, 2021, 47 795 (75·2%) of 63 525 of patients on supplementary oxygen received corticosteroids, higher among patients requiring critical care than in those who received ward care (11 185 [86·6%] of 12 909 vs 36 415 [72·4%] of 50 278). Patients 50 years or older were significantly less likely to receive corticosteroids than those younger than 50 years (adjusted odds ratio 0·79 [95% CI 0·70–0·89], p=0·0001, for 70–79 years; 0·52 [0·46–0·58], p80 years), independent of patient demographics and illness severity. 84 (54·2%) of 155 pregnant women received corticosteroids. Rates of corticosteroid administration increased from 27·5% in the week before June 16, 2020, to 75–80% in January, 2021. INTERPRETATION: Implementation of corticosteroids into clinical practice in the UK for patients with COVID-19 has been successful, but not universal. Patients older than 70 years, independent of illness severity, chronic neurological disease, and dementia, were less likely to receive corticosteroids than those who were younger, as were pregnant women. This could reflect appropriate clinical decision making, but the possibility of inequitable access to life-saving care should be considered. FUNDING: UK National Institute for Health Research and UK Medical Research Council
The Science Performance of JWST as Characterized in Commissioning
This paper characterizes the actual science performance of the James Webb
Space Telescope (JWST), as determined from the six month commissioning period.
We summarize the performance of the spacecraft, telescope, science instruments,
and ground system, with an emphasis on differences from pre-launch
expectations. Commissioning has made clear that JWST is fully capable of
achieving the discoveries for which it was built. Moreover, almost across the
board, the science performance of JWST is better than expected; in most cases,
JWST will go deeper faster than expected. The telescope and instrument suite
have demonstrated the sensitivity, stability, image quality, and spectral range
that are necessary to transform our understanding of the cosmos through
observations spanning from near-earth asteroids to the most distant galaxies.Comment: 5th version as accepted to PASP; 31 pages, 18 figures;
https://iopscience.iop.org/article/10.1088/1538-3873/acb29
A History of Discrete Event Simulation Programming Languages
The history of simulation programming languages is organized as a progression in periods of similar developments. The five periods, spanning 1955-1986, are labeled: The Period of Search (1955-1960); The Advent (1961-1965); The Formative Period (1966-1970); The Expansional Period (1971-1978); and The Period of Consolidation and Regeneration (1979-1986). The focus is on recognizing the people and places that have made important contributions in addition to the nature of the contribution. A balance between comprehensive and in-depth treatment has been reached by providing more detailed description of those languages which have or have had major use. Over 30 languages are mentioned, and numerous variations are described in the major contributors. A concluding summary notes the concepts and techniques either originating with simulation programming languages or given significant visibility by them
The development and validation of a scoring tool to predict the operative duration of elective laparoscopic cholecystectomy
Background: The ability to accurately predict operative duration has the potential to optimise theatre efficiency and utilisation, thus reducing costs and increasing staff and patient satisfaction. With laparoscopic cholecystectomy being one of the most commonly performed procedures worldwide, a tool to predict operative duration could be extremely beneficial to healthcare organisations.
Methods: Data collected from the CholeS study on patients undergoing cholecystectomy in UK and Irish hospitals between 04/2014 and 05/2014 were used to study operative duration. A multivariable binary logistic regression model was produced in order to identify significant independent predictors of long (> 90 min) operations. The resulting model was converted to a risk score, which was subsequently validated on second cohort of patients using ROC curves.
Results: After exclusions, data were available for 7227 patients in the derivation (CholeS) cohort. The median operative duration was 60 min (interquartile range 45–85), with 17.7% of operations lasting longer than 90 min. Ten factors were found to be significant independent predictors of operative durations > 90 min, including ASA, age, previous surgical admissions, BMI, gallbladder wall thickness and CBD diameter. A risk score was then produced from these factors, and applied to a cohort of 2405 patients from a tertiary centre for external validation. This returned an area under the ROC curve of 0.708 (SE = 0.013, p 90 min increasing more than eightfold from 5.1 to 41.8% in the extremes of the score.
Conclusion: The scoring tool produced in this study was found to be significantly predictive of long operative durations on validation in an external cohort. As such, the tool may have the potential to enable organisations to better organise theatre lists and deliver greater efficiencies in care
Genetic mechanisms of critical illness in COVID-19.
Host-mediated lung inflammation is present1, and drives mortality2, in the critical illness caused by coronavirus disease 2019 (COVID-19). Host genetic variants associated with critical illness may identify mechanistic targets for therapeutic development3. Here we report the results of the GenOMICC (Genetics Of Mortality In Critical Care) genome-wide association study in 2,244 critically ill patients with COVID-19 from 208 UK intensive care units. We have identified and replicated the following new genome-wide significant associations: on chromosome 12q24.13 (rs10735079, P = 1.65 × 10-8) in a gene cluster that encodes antiviral restriction enzyme activators (OAS1, OAS2 and OAS3); on chromosome 19p13.2 (rs74956615, P = 2.3 × 10-8) near the gene that encodes tyrosine kinase 2 (TYK2); on chromosome 19p13.3 (rs2109069, P = 3.98 × 10-12) within the gene that encodes dipeptidyl peptidase 9 (DPP9); and on chromosome 21q22.1 (rs2236757, P = 4.99 × 10-8) in the interferon receptor gene IFNAR2. We identified potential targets for repurposing of licensed medications: using Mendelian randomization, we found evidence that low expression of IFNAR2, or high expression of TYK2, are associated with life-threatening disease; and transcriptome-wide association in lung tissue revealed that high expression of the monocyte-macrophage chemotactic receptor CCR2 is associated with severe COVID-19. Our results identify robust genetic signals relating to key host antiviral defence mechanisms and mediators of inflammatory organ damage in COVID-19. Both mechanisms may be amenable to targeted treatment with existing drugs. However, large-scale randomized clinical trials will be essential before any change to clinical practice
- …