1,764 research outputs found

    Systematic evaluation of radiological findings in the assessment of resectability of peri-ampullary cancer by CT using different contrast phase protocols

    Get PDF
    Aims: To determine the relative significance of radiological signs in determining the resectability of peri-ampullary cancer (PC) and to assess the value of multi-phase imaging in detecting these findings. Materials and Methods: Blinded, double re-reporting of pre-operative imaging from five hospitals was undertaken of 411 patients undergoing surgery for PC over an eight year period, of whom 119 patients were found to be inoperable at the time of surgery. Results: The median tumour size was 26.7 mm and the proportion of patients reported to have regional lymphadenopathy (RL), venous (VI) and arterial involvement (AI) was 24.7%, 11.5% and 3.9% respectively and was similar regardless of the number of contrast phases undertaken. Significant associations were however noted between individual risk factors: VI was closely associated with tumour size (p=0.002) and AI (p< 0.0001). In multi-variable analysis AI, VI and RL were independently associated with resectability (relative risk of resection =0.05, 0.31 and 0.51 respectively). Tumour size however was not associated with resectability when VI was included in the multivariate model

    The Theoretical Astrophysical Observatory: Cloud-Based Mock Galaxy Catalogues

    Full text link
    We introduce the Theoretical Astrophysical Observatory (TAO), an online virtual laboratory that houses mock observations of galaxy survey data. Such mocks have become an integral part of the modern analysis pipeline. However, building them requires an expert knowledge of galaxy modelling and simulation techniques, significant investment in software development, and access to high performance computing. These requirements make it difficult for a small research team or individual to quickly build a mock catalogue suited to their needs. To address this TAO offers access to multiple cosmological simulations and semi-analytic galaxy formation models from an intuitive and clean web interface. Results can be funnelled through science modules and sent to a dedicated supercomputer for further processing and manipulation. These modules include the ability to (1) construct custom observer light-cones from the simulation data cubes; (2) generate the stellar emission from star formation histories, apply dust extinction, and compute absolute and/or apparent magnitudes; and (3) produce mock images of the sky. All of TAO's features can be accessed without any programming requirements. The modular nature of TAO opens it up for further expansion in the future.Comment: 17 pages, 11 figures, 2 tables; accepted for publication in ApJS. The Theoretical Astrophysical Observatory (TAO) is now open to the public at https://tao.asvo.org.au/. New simulations, models and tools will be added as they become available. Contact [email protected] if you have data you would like to make public through TAO. Feedback and suggestions are very welcom

    Collaboration in Truck Appointment System in Container Terminals

    Get PDF
    Due to the continual increase of the global containerized trade, many container terminals face the problem of high demands that their current resource capacity cannot afford. The consequences of such situation are not only the long queues of trucks at the entrance gates and storage yards but also the large turnaround times of trucks. In response, Truck Appointment Systems (TAS) were introduced to schedule truck arrivals in order to alleviate the terminal rush hours, however, the mandatory appointments developed by TASs have a negative impact on the operations as well as resources of the trucking companies. In recent literature, this issue was considered by introducing collaborative TAS in which the trucking companies as well as the container terminals collaborate to set the truck appointments. This work elaborates on the difference between traditional and collaborative TAS and demonstrates how collaborative TAS can improve the performance of the container terminal and reduce the cost of the trucking companies.&nbsp

    Secure Set-Based State Estimation for Linear Systems under Adversarial Attacks on Sensors

    Full text link
    When a strategic adversary can attack multiple sensors of a system and freely choose a different set of sensors at different times, how can we ensure that the state estimate remains uncorrupted by the attacker? The existing literature addressing this problem mandates that the adversary can only corrupt less than half of the total number of sensors. This limitation is fundamental to all point-based secure state estimators because of their dependence on algorithms that rely on majority voting among sensors. However, in reality, an adversary with ample resources may not be limited to attacking less than half of the total number of sensors. This paper avoids the above-mentioned fundamental limitation by proposing a set-based approach that allows attacks on all but one sensor at any given time. We guarantee that the true state is always contained in the estimated set, which is represented by a collection of constrained zonotopes, provided that the system is bounded-input-bounded-state stable and redundantly observable via every combination of sensor subsets with size equal to the number of uncompromised sensors. Additionally, we show that the estimated set is secure and stable irrespective of the attack signals if the process and measurement noises are bounded. To detect the set of attacked sensors at each time, we propose a simple attack detection technique. However, we acknowledge that intelligently designed stealthy attacks may not be detected and, in the worst-case scenario, could even result in exponential growth in the algorithm's complexity. We alleviate this shortcoming by presenting a range of strategies that offer different levels of trade-offs between estimation performance and complexity

    Biliary duodenostomy: a safe and easier biliary drainage procedure after choledochal cyst excision

    Get PDF
    Background/purpose: The treatment of choice for choledochal cyst (CC) is complete excision followed by biliary–enteric anastomosis. Roux-en-Y biliary jejunostomy has been favored by most surgeons for decades, with satisfying results. The use of biliary duodenostomy (BD) is another simple alternative for biliary drainage after CC excision. Our intermediate-term outcomes of both biliary drainage procedures after CC excision are presented.Methods: We carried out a retrospective analysis of the outcome of CC management in children operated at the Pediatric Surgery Department of Ain-Shams University over 5 years, from January 2010.Results: A total of 23 cases (16 females) were included in this study. The mean age at operation was 4.02 ± 2.52 years. Twenty-one cases had type I and two cases had type III CC. Complete excision of the CC was performed in 22 cases, and partial excision with mucosectomy was performed in one case. Biliary–enteric anastomosis was performed with the duodenum in 18 patients (group I, BD) and with the jejunum in five cases (group II, Roux-en-Y biliary jejunostomy). The mean follow-up period was 53± 4.48 months. A patient from group II suffered from ascending cholangitis 6 months postoperatively.Conclusion: BD is a simple technique for biliary drainage after CC excision with no major complications at intermediate-term follow-up.Keywords: biliary obstruction, choledochal cyst, hepaticoduodenostomy, jaundic

    A Simple Angle of Arrival Estimation System

    Get PDF
    We propose a practical, simple and hardware friendly, yet novel and very efficient, angle of arrival (AoA) estimation system. Our intuitive, two-phases cross-correlation based system requires a switched beam antenna array with a single radio frequency chain. Our system cross correlates a reference omni-directional signal with a set of received directed signals to determine the AoA. Practicality and high efficiency of our system are demonstrated through performance and complexity comparisons with multiple signal classification algorithm.Scopu

    Suboptimal correction of low anorectal anomalies: a possible cause for intractable constipation in children

    Get PDF
    Background Constipation is a common problem among patients following the repair of low anorectal anomalies. We present our experience in managing constipation in a group of these patients with reoperation to correct residual anterior anal misplacement.Patients and methods The study included pediatric patients presenting with significant constipation following the repair of low anorectal anomalies. Patients with evidence of residual anterior anal misplacement (either clinically, by means of MRI, or using electrical muscle stimulation) were offered a reoperation to bring their ani backward to an orthotropic position.Results Thirteen patients were included in the study between September 2009 and June 2015. Their ages ranged from 1.5 to 10 years. The primary anomaly was rectoperineal fistula in 10 (seven boys and three girls) and rectovestibular in three girls. Two types of reoperations were performed: a posterior anoplasty with posterior sphincterotomy (five cases), and a limited sagittal anorectoplasty (eight cases). Straining at defecation was relieved in all patients. Of the 13 patients, nine were relieved from their constipation (69%) and had regular bowel movements without medications. The remaining four (31%) showed partial improvement.Conclusion Among patients with low anorectal anomalies, suboptimal correction with residual anterior anal misplacement represents one correctable cause for persistence of constipation
    • …
    corecore