443 research outputs found

    Tidewater glaciers as feeding spots for the Black-legged Kittiwake (Rissa tridactyla): A citizen science approach

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    Thirty-one tidewater glacier bays in Spitsbergen Island were visited by yachts in August 2011, 2015, 2016 and 2017. Surface water samples were taken by volunteers, the members of the yacht crews, to measure concentrations of suspended matter, salinity, and temperature. Secchi disc measurements were used to measure water transparency. A series of photographs along the glacier fronts were taken and used to count seabirds that were present near the glacier cliff. Basic topographic features (depth, presence of a sill, exposure, glacier width) were obtained from sea charts and analysed. The number of preying Black-legged Kittiwakes (Rissa tridactyla; a target species) ranged from zero to over 2000 birds during 89 visits. High concentrations of individuals (above 100) were observed in 20% of the visits, while no birds were recorded in 42% of the visits. There was no statistical correlation between the topographic features of the glacier and bird concentrations. To our present knowledge, Black-legged Kittiwake feeding spots are random and temporary in time in which (or soon after) the juveniles are leaving the colony. They are a recurrent phenomenon related to krill abundance and simultaneous jet-like meltwater discharges

    Machine Learning methods for simulating particle response in the Zero Degree Calorimeter at the ALICE experiment, CERN

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    Currently, over half of the computing power at CERN GRID is used to run High Energy Physics simulations. The recent updates at the Large Hadron Collider (LHC) create the need for developing more efficient simulation methods. In particular, there exists a demand for a fast simulation of the neutron Zero Degree Calorimeter, where existing Monte Carlo-based methods impose a significant computational burden. We propose an alternative approach to the problem that leverages machine learning. Our solution utilises neural network classifiers and generative models to directly simulate the response of the calorimeter. In particular, we examine the performance of variational autoencoders and generative adversarial networks, expanding the GAN architecture by an additional regularisation network and a simple, yet effective postprocessing step. Our approach increases the simulation speed by 2 orders of magnitude while maintaining the high fidelity of the simulation

    End-to-end Sinkhorn Autoencoder with Noise Generator

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    In this work, we propose a novel end-to-end sinkhorn autoencoder with noise generator for efficient data collection simulation. Simulating processes that aim at collecting experimental data is crucial for multiple real-life applications, including nuclear medicine, astronomy and high energy physics. Contemporary methods, such as Monte Carlo algorithms, provide high-fidelity results at a price of high computational cost. Multiple attempts are taken to reduce this burden, e.g. using generative approaches based on Generative Adversarial Networks or Variational Autoencoders. Although such methods are much faster, they are often unstable in training and do not allow sampling from an entire data distribution. To address these shortcomings, we introduce a novel method dubbed end-to-end Sinkhorn Autoencoder, that leverages sinkhorn algorithm to explicitly align distribution of encoded real data examples and generated noise. More precisely, we extend autoencoder architecture by adding a deterministic neural network trained to map noise from a known distribution onto autoencoder latent space representing data distribution. We optimise the entire model jointly. Our method outperforms competing approaches on a challenging dataset of simulation data from Zero Degree Calorimeters of ALICE experiment in LHC. as well as standard benchmarks, such as MNIST and CelebA

    Utilization of sulphidic mine tailings in alkali-activated materials

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    Disposal of mine tailings is one of the most important environmental issues during the mining lifetime. Especially sulphidic tailings can cause environmental and ecological risks because of their tendency to oxidize in the presence of water or air. Because of small particle size and harmful chemical properties, utilization possibilities of sulphidic mine tailings are limited. The aim of the present study was to develop technologies to utilize sulphidic mine tailings in alkali activated materials. Alkali-activated materials also known as geopolymers are nanosized zeolite type or slightly amorphous materials comparable to traditional Portland cement concrete, which can physically encapsulate or chemically stabilize the hazardous elements such as heavy metals into the 3D structure. Mine tailing based geopolymer aggregates were successfully produced from sulphidic mine tailings with good physical properties. The geopolymer aggregates performed as a concrete aggregate comparable to commercial lightweight aggregates. In addition, geopolymer mortars were prepared from mine tailings. In mortar application, there is a need to add some co-binder such as blast furnace slag in order to achieve high strength for the material. The mine tailing based geopolymer structure has an ability to stabilize a large number of cationic species into the structure while some anionic species were not able to immobilize by alkaline activation

    Experiences with surgical treatment of ventricle septal defect as a post infarction complication

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    <p>Abstract</p> <p>Background</p> <p>Complications of acute myocardial infarction (AMI) with mechanical defects are associated with poor prognosis. Surgical intervention is indicated for a majority of these patients. The goal of surgical intervention is to improve the systolic cardiac function and to achieve a hemodynamic stability. In this present study we reviewed the outcome of patients with post infarction ventricular septal defect (PVSD) who underwent cardiac surgery.</p> <p>Methods</p> <p>We analysed retrospectively the hospital records of 41 patients, whose ages range from 48 to 81, and underwent a surgical treatment between 1990 and 2005 because of PVSD.</p> <p>Results</p> <p>In 22 patients concomitant coronary artery bypass grafting (CAGB) was performed. In 15 patients a residual shunt was found, this required re-op in seven of them. The time interval from infarct to rupture was 8.7 days and from rupture to surgery was 23.1 days. Hospital mortality in PVSD group was 32%. The mortality of urgent repair within 3 days of intractable cardiogenic shock was 100%. The mortality of patients with an anterior VSD and a posterior VSD was 29.6% vs 42.8%, respectively. All patients who underwent the surgical repair later than day 36 survived.</p> <p>Conclusion</p> <p>Surgical intervention is indicated for a majority of patients with mechanical complications. Cardiogenic shock remains the most important factor that affects the early results. The surgical repair of PVSD should be performed 4–5 weeks after AMI. To improve surgical outcome and hemodynamics the choice of surgical technique and surgical timing as well as preoperative management should be tailored for each patient individually.</p

    Total arterial revascularization coronary artery bypass surgery in patients with atrial fibrillation

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    Background: Atrial fibrillation (AF) is a relatively common comorbidity among patients referred for coronary artery bypass grafting (CABG) associated with poorer prognosis. However, little is known about how surgical technique influences survival in this population.Aim: The aim of the current analysis was to determine whether total arterial revascularization (TAR) is associated with improved long-term outcomes in patients with preoperative AF.Methods: We analyzed patient’s data from a HEIST (HEart surgery In atrial fibrillation and Supraventricular Tachycardia) registry. The registry, to date, involves five tertiary high-volume centers in Poland. Between 2006 and 2019, 4746 patients presented with pre-operative AF and multivessel coronary artery disease and underwent CABG. We identified cases of TAR and used propensity score matching to determine non-TAR controls. Median follow-up was 4.1 years (IQR, 1.9–6.8).Results: Propensity matching resulted in 295 pairs of TAR vs. non-TAR. The mean (standard deviation [SD]) number of distal anastomoses was 2.5 (0.6) vs. 2.5 (0.6) (P = 0.94) respectively. Operative and 30-day mortality were not different between TAR and non-TAR patients (hazard ratio [HR] and 95% confidence intervals [CIs], 0.17 (0.02–1.38); P = 0.12 and 0.74 [0.40–1.35]; P = 0.33), respectively. On contrary, TAR was associated with a nearly 30% improved late survival: HR, 0.72 (0.55–0.93); P = 0.01. This benefit was sustained in subgroup analyses, yet most appraised in low-risk patients (&lt;70 years old; EuroSCORE II &lt;2; no diabetes) and when off-pump CABG was performed.Conclusions: TAR in patients with pre-operative AF is safe and associated with improved survival with particular survival benefit in younger low-risk patients undergoing off-pump CABG

    Citizen-Science for the Future: Advisory Case Studies From Around the Globe

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    The democratization of ocean observation has the potential to add millions of observations every day. Though not a solution for all ocean monitoring needs, citizen scientists offer compelling examples showcasing their ability to augment and enhance traditional research and monitoring. Information they are providing is increasing the spatial and temporal frequency and duration of sampling, reducing time and labor costs for academic and government monitoring programs, providing hands-on STEM learning related to real-world issues and increasing public awareness and support for the scientific process. Examples provided here demonstrate the wide range of people who are already dramatically reducing gaps in our global observing network while at the same time providing unique opportunities to meaningfully engage in ocean observing and the research and conservation it supports. While there are still challenges to overcome before widespread inclusion in projects requiring scientific rigor, the growing organization of international citizen science associations is helping to reduce barriers. The case studies described support the idea that citizen scientists should be part of an effective global strategy for a sustained, multidisciplinary and integrated observing system

    An investigation in the correlation between Ayurvedic body-constitution and food-taste preference

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    CO<sub>2</sub> Mineralization Methods in Cement and Concrete Industry

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    Production of Portland clinker is inherently associated with CO2 emissions originating from limestone decomposition, the irreplaceable large-scale source of calcium oxide needed. Besides carbon capture and storage, CO2 mineralization is the only lever left to reduce these process emissions. CO2 mineralization is a reversal reaction to clinker production—CO2 is bound into stable carbonates in an exothermic process. It can be applied in several environmentally and economically favorable ways at different stages of clinker, cement and concrete life cycle. These possibilities are assessed and discussed in this contribution. The results demonstrate that when combined with concrete recycling, the complete circularity of all its constituents, including the process CO2 emissions from the clinker, can be achieved and the overall related CO2 intensity significantly reduced

    The use of alternative fuels in the cement industry as part of circular economy

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    The alternative waste fuels have a significant share in the fuel mix of the cement industry in Poland. The conditions inside cement kilns are favorable enough for environmentally-friendly use of waste fuels. In the article, the authors discuss the current situation concerning the use of alternative fuels in Poland, from difficult beginning in the 1990s to the present time, different kinds of fuels, and the amounts of used fuels. The use of fuels in Poland is presented against the global and EU consumption (including Central European countries and companies). The increased use of waste-derived fuels, from the level of about 1% at the end of the 1990s to the present level of about 70%, allowed for the limitation of waste storage, including avoidance of greenhouse gas emissions and consumption of conventional energy sources; those effects also contributed to the implementation of the sustainable development and circular economy conceptions. The experiences of the cement plants worldwide prove that the use of waste fuels is ecological and economical. The examples showed in the article confirm that cement plants are greatly interested in using waste fuels from waste, as they invest in the infrastructure allowing to store bigger amounts of waste and dose them more efficiently. Thus, the cement industry has become an important element of the country’s energy economy and waste management system
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