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Supra-threshold Contrast Perception in Augmented Reality
No full textWhen an image is seen on an optical see-through augmented reality (AR) display, the light from the display is mixed with the background light from the environment. This can severely limit the available contrast in AR, which is often orders of magnitude below that of traditional displays. Yet, the presented images appear sharper and show more details than the reduction in physical contrast would indicate. In this work, we hypothesize two effects that are likely responsible for the enhanced perceived contrast in AR: background discounting, which allows observers focused on the display plane to partially discount the light from the environment; and supra-threshold contrast perception, which explains the differences in contrast perception across luminance levels. In a series of controlled experiments on an AR high-dynamic-range multi-focal haploscope testbed, we found no statistical evidence supporting the effect of background discounting on contrast perception. Instead, the increase of visibility in AR is better explained with models of supra-threshold contrast perception. Our findings can be generalized to incorporate an image input, and this model serves to design better algorithms and hardware for display systems affected by additive light, such as AR
Unpacking the penetration of agrochemicals in China: The commodification of agricultural inputs and the invisible dispossession of smallholders
No full textChina has transitioned from a negligible user of agrochemicals to one of the world’s largest consumers, producers and exporters within just a few decades. The rapid increase in agrochemical use– often amounting to overuse – has raised significant concerns about food safety and environmental degradation. Despite its importance, the underlying dynamics driving the swift expansion of China’s agrochemical sector remain insufficiently studied. How have traditional farming practices of smallholders, sustained for millennia, shifted so quietly yet dramatically in recent decades? What are the implications of agrochemicals’ penetration into rural society in China? Drawing on field research conducted across sites from 2012 to 2023, this article addresses these questions. It demonstrates that agrochemicals were initially introduced in China under a planned economy, provided by the state as public goods rather than commodities, and were eagerly embraced by agricultural producers. Inputs were effectively distributed to producers through top-down networks. However, following market-oriented reforms and the commodification of these inputs, agrochemical companies leveraged and cultivated these networks into a ‘hierarchical exclusive distribution network’ targeting smallholders. Alongside these top-down networks, rural social networks were also mobilized in input distribution, facilitating smallholders’ acceptance of agrochemicals. Consequently, while smallholders retain their land, they are invisibly dispossessed as ‘producers’ and retained as ‘consumers’ for inputs
Estimating post-operative complication rates in patients with primary brain tumours from routine administrative data: A national cohort study.
No full textINTRODUCTION: Neurosurgery is an important element of brain tumour treatment but carries with it the risk of complications. Previous work has defined a narrow set of general post-operative complications which are used as Patient Safety Indicators (PSIs), but these are not brain tumour specific and do not capture the full range of complications. As a result, there is no way of measuring post-operative complications in neurosurgery at a national level. METHODS: We conducted a retrospective, observational cohort study using a comprehensive national administrative dataset from England on adult brain or spinal tumour patients to better define post-operative complications. We generated and validated a new list of post-operative complications - ICL list. The ICL list contains codes selected specifically from our Gliocova dataset combined with general OECD-defined PSI list. The ICL list is novel as it can assess brain tumour patient complications using an administrative dataset at a national level and captures more specific brain tumour related complications. RESULTS: In our study, 30-day readmission after surgery was 12.7% and 30-day mortality was 2.3%. The ICL list of complications identified many more patients with complications (N = 3,274 (11.3%)) compared to OECD-defined PSI list (N = 568 (2.0%)) without reducing model performance. 30-day mortality was 6.5% in those with complications and 1.8% in those without. DISCUSSION: We have identified a much wider set of complications than the OECD-defined PSIs and shown that patients developing these have worse outcomes than those without complications. This enables us to estimate the risk of post-operative complications in brain tumour patients using national administrative data. It forms the basis for planned further work, allowing us to explore the predictors of and consequences of post-operative complications
Regionally distinct threats from polycyclic aromatic hydrocarbons in global reservoirs
No full textPolycyclic aromatic hydrocarbons pose inconsistent yet increasing threats to freshwater reservoirs worldwide, with implications for ecosystem health and water security. Although local-scale contamination has been widely documented, a comprehensive global synthesis of polycyclic aromatic hydrocarbon occurrence and drivers in reservoirs remains lacking. Here we developed a framework of data compilation, arrangement and statistics to integrate existing data to determine the geographical distribution and potential sources of polycyclic aromatic hydrocarbon pollution in reservoirs globally. Statistical analyses revealed spatial heterogeneity in dominant components and pollution levels across continents. Almost 38% of water samples exceeded an ecologically relevant threshold (0.20 μg l−1), and 42% of sediment samples surpassed the threshold effect concentration, indicating widespread ecological risks. Cluster analysis and source apportionment of the reservoir-level data identified three distinct polycyclic aromatic hydrocarbon patterns, each shaped by region-specific land-use practices, combustion sources and climatic factors. These findings emphasize and inform the need for region-specific monitoring and management strategies, such as expanding monitoring in subtropical and temperate regions, with a focus on polycyclic aromatic hydrocarbon accumulation in aquatic organisms
A cross-sectional study into the prevalence and conformational risk factors of BOAS across fourteen brachycephalic dog breeds.
No full textBrachycephalic Obstructive Airway Syndrome (BOAS) is known to occur as a common condition in short-skulled (brachycephalic) dogs, but has been intensively studied only in three breeds: the Bulldog, French Bulldog and Pug. This study investigates the frequency and severity of BOAS in a further 14 breeds in the UK pet population: Affenpinscher, Boston Terrier, Boxer, Cavalier King Charles Spaniel, Chihuahua, Dogue de Bordeaux, Griffon Bruxellois, Japanese Chin, King Charles Spaniel, Maltese, Pekingese, Pomeranian, Shih Tzu and Staffordshire Bull Terrier. The respiratory functional grading (RFG) assessment was adapted for use in these breeds, noting respiratory characteristics for 898 dogs in this study. Conformational parameters were measured to analyse the association with BOAS risk. Statistical analysis was performed both comparatively across the 14 breeds and within each breed. Almost every breed in this study had some detectable level of breathing abnormality. Only the Maltese and Pomeranian had no dogs with clinically significant disease. The Pekingese and Japanese Chin, had the highest rates of BOAS with only 10.9% and 17.4% being Grade 0 respectively. Across the whole study population, three factors were significantly correlated with BOAS: higher body condition score, nostril stenosis, and lower craniofacial ratio (more extreme facial hypoplasia). These parameters accounted for 20% of the variation in BOAS status when modelled in multiple logistic regression. It was noted that some extremely flat-faced breeds, for example the King Charles Spaniel, had lower rates of BOAS than expected based on their conformation. Overall, the frequency of BOAS varies considerably by breed. Broadly speaking, more extreme brachycephaly, nostril stenosis and high body condition score are associated with increased BOAS risk. However, with variation of phenotype between the breeds, the findings of this study advocate for a breed-specific approach when tackling the reduction of the disease on a population level
Beyond Waterlogging: Evaluating the Impact of Extreme Rainfall on the Road Network
No full textExisting research of extreme rainfall impact on transport networks primarily examines the effect of waterlogging. Although the other two main factors-reduced visibility and traffic-signal power outages-have been shown to significantly affect road operation, their contributions at the network scale remain underexplored. Taking a macroscopic approach, this study gauges the impacts of these three factors on the road network connectivity and efficiency during extreme rainfall through a case study of 26 Local Government Areas in and around Greater London. The result shows that focusing solely on waterlogging while disregarding reduced visibility and traffic signal power failures overestimates road capacities by 15-30% and underestimates network efficiency impacts by 1–23% under different rainfall scenarios. Particularly, the largest impact underestimation is observed for 1-in-30-year rainfall risk, where waterlogging is less dominant, while poor visibility considerably contributes to the impacts. The analysis also suggests that signal power failures during rainfall have limited, localised effects at the network level
A Universal Method for Comparing Open Rotors and Ducted Fans in Hover
No full textFor vertical take-off and landing capable aircraft, designers must choose between open rotors
and ducted fans. Vertical take-off and hover is energy-intensive, so propulsor performance must
be maximised in this mode of flight. Despite this, the best method of assessing hover performance
in previous literature remains unclear, particularly for ducted fans and their comparison with
open rotors. Ducted fan designers typically re-use hover performance metrics derived for open
rotors, but this frequently causes confusion and can result in misleading conclusions, caused by
a flawed choice of reference area in the normalisation of the size of the machine. This paper
presents a novel performance metric which allows direct, fair comparison between open rotors
and ducted fans and correctly takes into account their size impact on the aircraft. The cause
of confusion with existing performance metrics is explained, and a case study from previous
literature is used to demonstrate how a different conclusion is drawn using the new metric. The
new metric is used to produce a method to compare different propulsors with weight effects
included. Finally, an analysis framework is presented that allows engineers to investigate real
flows and break down the causes of excess power consumption to make better-informed design
decisions
Myc linked to dysregulation of cholesterol transport and storage in nonsmall cell lung cancer.
Full text linkNonsmall cell lung cancer (NSCLC) is a leading cause of cancer-related deaths. While mutations in Kras and overexpression of Myc are commonly found in patients, the role of altered lipid metabolism in lung cancer and its interplay with oncogenic Myc is poorly understood. Here we use a transgenic mouse model of Kras-driven lung adenocarcinoma with reversible activation of Myc combined with surface analysis lipid profiling of lung tumors and transcriptomics to study the effect of Myc activity on cholesterol homeostasis. Our findings reveal that the activation of Myc leads to the accumulation of cholesteryl esters (CEs) stored in lipid droplets. Subsequent Myc deactivation leads to further increases in CEs, in contrast to tumors in which Myc was never activated. Gene expression analysis linked cholesterol transport and storage pathways to Myc activity. Our results suggest that increased Myc activity is associated with increased cholesterol influx, reduced efflux, and accumulation of CE-rich lipid droplets in lung tumors. Targeting cholesterol homeostasis is proposed as a promising avenue to explore for novel treatments of lung cancer, with diagnostic and stratification potential in human NSCLC
A Deep Chandra View of A2597: Bubbles, Shocks, Cold Fueling, and a Plasma Depletion Layer
Full text linkTo examine how active galactic nucleus (AGN) feedback shapes the intracluster medium (ICM) and fuels black hole accretion in the cool-core galaxy cluster A2597, we present deep (∼600 ks) Chandra X-ray observations complemented by archival GMRT radio and SINFONI near-infrared data. Radio-mode AGN activity has inflated seven X-ray cavities and driven one to three potential weak shocks ( M∼1.05−1.14 ) extending to ∼150 kpc, suggesting recurrent outbursts occurring on ∼107 yr timescales. We also detect a narrow, ∼57 kpc X-ray surface brightness deficit—a potential plasma depletion layer—likely shaped by residual sloshing motions that amplified magnetic fields and/or displaced gas within the cluster core. Although the AGN injects ∼1044 erg s−1 of energy, comparable to the cluster’s cooling luminosity, radiative cooling persists at ∼15 M⊙ yr−1, replenishing the billion-solar-mass cold gas reservoir at the heart of the brightest cluster galaxy. Sustaining this level of activity requires a continuous fuel supply, yet the estimated Bondi accretion power (∼2 × 1043 erg s−1) falls an order of magnitude short of the observed cavity power, suggesting that “hot” gas fueling is insufficient. Instead, archival Atacama Large Millimeter/submillimeter Array observations continue to support a chaotic cold accretion scenario, where turbulence-driven condensation fuels the AGN at rates exceeding Bondi accretion, sustaining a self-regulated feedback cycle that repeatedly shapes the core of A2597