234 research outputs found

    The quest for axions and other new light particles

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    Standard Model extensions often predict low-mass and very weakly interacting particles, such as the axion. A number of small-scale experiments at the intensity/precision frontier are actively searching for these elusive particles, complementing searches for physics beyond the Standard Model at colliders. Whilst a next generation of experiments will give access to a huge unexplored parameter space, a discovery would have a tremendous impact on our understanding of fundamental physics

    Historical and Geographical Information about the Exploration of the Caspian Sea in Cartographic Materials

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    The article provides a brief overview of the historical and geographical data on the Caspian Sea and traces the change in the name of the sea at different stages of history. The study is based on the work of scientists from Russia, Azerbaijan and Kazakhstan. The purpose of the work was to reveal the reasons for the change of sea names and the history of the formation of the marine scientific map in connection with the expeditions organized by Peter the Great in the early 18th century. The authors analyzed historical research and made an attempt to systematize cartographic materials and data from antiquity, the Middle Ages and modern times. The history of the Caspian and its adjacent territories has been a subject of debate since the time of Greek logographers in the ancient world, and historical research of the Caspian Sea continues to the present day. Since ancient times, the Caspian coast has been inhabited by many peoples, becoming a crossroads for the interaction of various cultures; in the late Middle Ages, the Caspian Sea played an important role, being located along the world trade transit known as the Great Silk Road. In the new era, competition for control over the Caspian Sea between states intensified, but as a result of the military-political actions of Peter I, the sea became a de facto geographical object of the Russian Empire, and then the Soviet Union. However, after the collapse of the USSR at the end of the 20th century, the Caspian Sea, which has a geographically convenient location and rich resources, reappeared on the historical arena as one of the most important geopolitical issues. Copyright © 2022 by Cherkas Global Universit

    Bilateral occipital arteries of internal carotid origin: report of a case and review of the literature

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    The present report describes a patient with bilateral occipital arteries of internal carotid origin, which is an extremely rare variation, and left vertebral artery ostial stenosis diagnosed by selective catheterization and digital subtraction angiography

    Video based wildfire detection at night

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    There has been an increasing interest in the study of video based fire detection algorithms as video based surveillance systems become widely available for indoor and outdoor monitoring applications. A novel method explicitly developed for video based detection of wildfires at night (in the dark) is presented in this paper. The method comprises four sub-algorithms: (i) slow moving video object detection, (ii) bright region detection, (iii) detection of objects exhibiting periodic motion, and (iv) a sub-algorithm interpreting the motion of moving regions in video. Each of these sub-algorithms characterizes an aspect of fire captured at night by a visible range PTZ camera. Individual decisions of the sub-algorithms are combined together using a least-mean-square (LMS) based decision fusion approach, and fire/nofire decision is reached by an active learning method. © 2009 Elsevier Ltd. All rights reserved

    Video fire detection - Review

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    This is a review article describing the recent developments in Video based Fire Detection (VFD). Video surveillance cameras and computer vision methods are widely used in many security applications. It is also possible to use security cameras and special purpose infrared surveillance cameras for fire detection. This requires intelligent video processing techniques for detection and analysis of uncontrolled fire behavior. VFD may help reduce the detection time compared to the currently available sensors in both indoors and outdoors because cameras can monitor "volumes" and do not have transport delay that the traditional "point" sensors suffer from. It is possible to cover an area of 100 km2 using a single pan-tilt-zoom camera placed on a hilltop for wildfire detection. Another benefit of the VFD systems is that they can provide crucial information about the size and growth of the fire, direction of smoke propagation. © 2013 Elsevier Inc. © 2013 Elsevier Inc. All rights reserved

    A multi-sensor network for the protection of cultural heritage

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    The paper presents a novel automatic early warning system to remotely monitor areas of archaeological and cultural interest from the risk of fire. Since these areas have been treasured and tended for very long periods of time, they are usually surrounded by old and valuable vegetation or situated close to forest regions, which exposes them to an increased risk of fire. The proposed system takes advantage of recent advances in multi-sensor surveillance technologies, using optical and infrared cameras, wireless sensor networks capable of monitoring different modalities (e.g. temperature and humidity) as well as local weather stations on the deployment site. The signals collected from these sensors are transmitted to a monitoring centre, which employs intelligent computer vision and pattern recognition algorithms as well as data fusion techniques to automatically analyze sensor information. The system is capable of generating automatic warning signals for local authorities whenever a dangerous situation arises, as well as estimating the propagation of the fire based on the fuel model of the area and other important parameters such as wind speed, slope, and aspect of the ground surface. © 2011 EURASIP

    Ablation-cooled material removal at high speed with femtosecond pulse bursts

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    We report exploitation of ablation cooling, a concept well-known in rocket design, to remove materials, including metals, silicon, hard and soft tissue. Exciting possibilities include ablation using sub-microjoule pulses with efficiencies of 100-mJ pulses. © OSA 2015

    A model for a large investor trading at market indifference prices. I: single-period case

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    We develop a single-period model for a large economic agent who trades with market makers at their utility indifference prices. A key role is played by a pair of conjugate saddle functions associated with the description of Pareto optimal allocations in terms of the utility function of a representative market maker.Comment: Shorten from 69 to 30 pages due to referees' requests; a part of the previous version has been moved to "The stochastic field of aggregate utilities and its saddle conjugate", arXiv:1310.728

    Search for Dark Matter Axions with CAST-CAPP

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    The CAST-CAPP axion haloscope, operating at CERN inside the CAST dipole magnet, has searched for axions in the 19.74 μ\mueV to 22.47 μ\mueV mass range. The detection concept follows the Sikivie haloscope principle, where Dark Matter axions convert into photons within a resonator immersed in a magnetic field. The CAST-CAPP resonator is an array of four individual rectangular cavities inserted in a strong dipole magnet, phase-matched to maximize the detection sensitivity. Here we report on the data acquired for 4124 h from 2019 to 2021. Each cavity is equipped with a fast frequency tuning mechanism of 10 MHz/min between 4.774 GHz and 5.434 GHz. In the present work, we exclude axion-photon couplings for virialized galactic axions down to gaγγ=8×1014g_{a{\gamma}{\gamma}} = 8 \times {10^{-14}} GeV1GeV^{-1} at the 90% confidence level. The here implemented phase-matching technique also allows for future large-scale upgrades.Comment: 24 pages, 5 figures, Published version available with Open Access at https://www.nature.com/articles/s41467-022-33913-
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