994 research outputs found

    Continuous correlated beta processes

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    In this paper we consider a (possibly continuous) space of Bernoulli experiments. We assume that the Bernoulli distributions are correlated. All evidence data comes in the form of successful or failed experiments at different points. Current state-ofthe-art methods for expressing a distribution over a continuum of Bernoulli distributions use logistic Gaussian processes or Gaussian copula processes. However, both of these require computationally expensive matrix operations (cubic in the general case). We introduce a more intuitive approach, directly correlating beta distributions by sharing evidence between them according to a kernel function, an approach which has linear time complexity. The approach can easily be extended to multiple outcomes, giving a continuous correlated Dirichlet process, and can be used for both classification and learning the actual probabilities of the Bernoulli distributions. We show results for a number of data sets, as well as a case-study where a mixture of continuous beta processes is used as part of an automated stroke rehabilitation system.

    Scale-dependence of lithological control on topography: Bedrock channel geometry and catchment morphometry in western Scotland

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    We propose that a scale-dependent topographic signature of erodibility arises due to fluvial and glacial erosion acting on different parts of the landscape at different times. For 14 catchments in western Scotland, we define three levels of substrate erodibility in order of decreasing resistance: quartzite rocks, nonquartzite rocks, and zones of fault-related fracture. Then, using digital topographic and planimetric data coupled with field measurements, we identify regression based scaling relationships between substrate erodibility and morphometric parameters at two spatial scales. Catchment-scale morphometry shows a weak to variable relationship with substrate metrics overall. Erodibility can be inferred from catchment steepness indices (i.e., channel steepness index and relief ratio), but the existence of multiple exceptions could confound a more general application of this approach. Nonetheless, major valley troughs trace fault zones and nonquartzite rocks, leaving much of the higher and steeper ground formed in quartzite. At the reach scale, bedrock channel slope is far more sensitive to substrate erodibility than is channel width. Quartzite outcrops steepen bedrock channels by a factor of 1.5–6.0, and in terms of unit stream power, channels increase their erosional capacity by a factor of 2.7–3.5. Yet only 4%–13% of this increase is due to channel narrowing. Based on a large data set of bedrock channel width (n = 5825) from four rivers, we find that width scales with drainage area (in m<sup>2</sup>) as W = 0.01A<sup>0.28</sup>. Our results are consistent with the view that width-area scaling is similar in all single-thread rivers subject to transport-limited conditions but that for increasingly sediment supply limited settings, erosional thresholds at the channel boundary are the key determinants of bedrock channel width

    From patent to patient: analysing access to innovative cancer drugs.

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    Analysis of cancer drugs licensed through the European Medicines Agency (EMA) in 2000-2016 shows that the number of authorisations increased over that timeframe. The median number of licensed drugs each year rose from six for 2000-2008 to 13.5 for 2009-2016. Over 2000-2016, there were 64 drug authorisations for haematological, 15 for breast, and 12 for skin cancer, but none for oesophageal, brain, bladder, or uterine cancer. Only 6% of authorisations included a paediatric indication. The average time for a drug to progress from patent priority date to availability on the National Health Service (NHS) increased from 12.8 years for drugs first licensed in 2000-2008 to 14.0 years for those licensed in 2009-2016. There was evidence that the most innovative drugs were not being prioritised for EMA licensing and NICE approval

    Mass movement susceptibility mapping using satellite optical imagery compared with InSAR monitoring: Zigui County, Three Gorges region, China

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    Mass movements on steep slopes are a major hazard to communities and infrastructure in the Three Gorges region, China. Developing susceptibility maps of mass movements is therefore very important in both current and future land use planning. This study employed satellite optical imagery and an ASTER GDEM (15 m) to derive various parameters (namely geology; slope gradient; proximity to drainage networks and proximity to lineaments) in order to create a GIS-based map of mass movement susceptibility. This map was then evaluated using highly accurate deformation signals processed using the Persistent Scatterer (PS) InSAR technique. Areas of high susceptibility correspond well to points of high subsidence, which provides a strong support of our susceptibility map

    Evolving Role of Endoscopic Retrograde Cholangiopancreatography in Management of Extrahepatic Hepatic Ductal Injuries due to Blunt Trauma: Diagnostic and Treatment Algorithms

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    Extrahepatic hepatic ductal injuries (EHDIs) due to blunt abdominal trauma are rare. Given the rarity of these injuries and the insidious onset of symptoms, EHDI are commonly missed during the initial trauma evaluation, making their diagnosis difficult and frequently delayed. Diagnostic modalities useful in the setting of EHDI include computed tomography (CT), abdominal ultrasonography (AUS), nuclear imaging (HIDA scan), and cholangiography. Traditional options in management of EHDI include primary ductal repair with or without a T-tube, biliary-enteric anastomosis, ductal ligation, stenting, and drainage. Simple drainage and biliary decompression is often the most appropriate treatment in unstable patients. More recently, endoscopic retrograde cholangiopancreatography (ERCP) allowed for diagnosis and potential treatment of these injuries via stenting and/or papillotomy. Our review of 53 cases of EHDI reported in the English-language literature has focused on the evolving role of ERCP in diagnosis and treatment of these injuries. Diagnostic and treatment algorithms incorporating ERCP have been designed to help systematize and simplify the management of EHDI. An illustrative case is reported of blunt traumatic injury involving both the extrahepatic portion of the left hepatic duct and its confluence with the right hepatic duct. This injury was successfully diagnosed and treated using ERCP

    From The Anfield Wrap to Boss Night and the Paris Protests: Football, Politics, Identity and the Cultural Evolution of Fan Media and Supporter Activism in Liverpool

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    There have been significant recent developments in media produced by football fans, from social media and online magazines to podcasts, YouTube channels and live events. 21st century technologies have facilitated new types of supporter-produced media, rendering the means of production more accessible to fans. In Liverpool, fan channels have emerged, influenced by the city’s musical heritage and political and cultural identity. For instance, modern events such as Boss Night and podcasts produced by The Anfield Wrap (TAW) have helped provide an authentic voice for the city’s contemporary football culture, political identity and connected social activism. Due to globalised media networks, they can also offer an educational mobilising hub for those interested in Liverpool’s current idiosyncratic cultural and political civic context. This research is informed by literature on fan media and activism and draws on collective identity theory and Bourdieu’s notion of habitus. In-depth interviews were conducted with experienced supporters and various individuals closely associated with the production of fan media. Structurally, the paper outlines Liverpool’s historical, cultural, sporting and fan media context. It then analyses data detailing the evolution of Boss Mag to Boss Night events and examining The Anfield Wrap as an innovative site of content creation. Contextually, the paper explores fan activism through the mediatised protest of Liverpool’s ownership and collective expressions of political identity. Finally, it draws on the experiences of supporters at the 2022 Champions League final in Paris and the use of technology and fan media in capturing and responding to the mistreatment of supporters

    Habitat complexity and predator odours impact on the stress response and antipredation behaviour in coral reef fish

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    Mass coral bleaching events coupled with local stressors have caused regional-scale loss of corals on reefs globally. Following the loss of corals, the structural complexity of these habitats is often reduced. By providing shelter, obscuring visual information, or physically impeding predators, habitat complexity can influence predation risk and the perception of risk by prey. Yet little is known on how habitat complexity and risk assessment interact to influence predator-prey interactions. To better understand how prey’s perception of threats may shift in degraded ecosystems, we reared juvenile Pomacentrus chrysurus in environments of various habitat complexity levels and then exposed them to olfactory risk odours before simulating a predator strike. We found that the fast-start escape responses were enhanced when forewarned with olfactory cues of a predator and in environments of increasing complexity. However, no interaction between complexity and olfactory cues was observed in escape responses. To ascertain if the mechanisms used to modify these escape responses were facilitated through hormonal pathways, we conducted whole-body cortisol analysis. Cortisol concentrations interacted with habitat complexity and risk odours, such that P. chrysurus exhibited elevated cortisol levels when forewarned with predator odours, but only when complexity levels were low. Our study suggests that as complexity is lost, prey may more appropriately assess predation risk, likely as a result of receiving additional visual information. Prey’s ability to modify their responses depending on the environmental context suggests that they may be able to partly alleviate the risk of increased predator-prey interactions as structural complexity is reduced

    Hidden giants: The story of Bolbometopon muricatum at ningaloo reef

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    Bolbometopon muricatum (bumphead parrotfish, Valenciennes, 1839) is a conspicuous, iconic and ecologically important coral reef fish species. B. muricatum plays an important role in the bioerosion of the reef framework and as a result has been described as both an ecosystem engineer and keystone species. Despite the complete absence of B. muricatum from 32 years of scientific surveys across the Ningaloo Reef World Heritage Area, we recorded a total of 155 individuals of B. muricatum across 63.2 ha of reef crest surveys, equating to mean density of 2.38 ind/ha. Our observations represent the first record of this iconic species in scientific surveys at Ningaloo and in combination with qualitative observations of B. muricatum by expert witnesses, indicate B. muricatum is likely to have been present in ecologically relevant densities since 2006. The densities of B. muricatum observed at northern Ningaloo in 2021 suggest this species is removing an estimated 13.42 tonnes/ha or 1.34 kg/m2 of calcium carbonate per year, which is broadly comparable with estimates of total parrotfish bioerosion across many reefs in the central Indian and Pacific Oceans. Although not currently afforded elevated conservation status within management plans, B. muricatum possess many life-history characteristics that make them vulnerable to overfishing and may justify consideration for increased protection within the world heritage listed Ningaloo Reef Marine Park
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