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Featured
A global reference tool to fight Alzheimer's
Medicine (Neurology)
Date of upload:
02.07.2018
Co-author:
Caption:
euronews knowledge brings you a fresh mix of the world's most interesting know-hows, directly from space and sci-tech experts. Made by euronews, the most watched news channel in Europe.
How a robot in deep water can bring enlightenment
Engineering (Civil engineering)
Date of upload:
04.07.2018
Co-author:
Caption:
Made by euronews: the most watched news channel in Europe
Reaching for the Sun
Natural Sciences (Astrophysics and Astrononmy)
Date of upload:
14.01.2019
Co-author:
Caption:
A teaser for the European Solar Telescope (EST)
BepiColombo sets off to solve the mysteries of Mercury
Natural Sciences (Astrophysics and Astrononmy)
Date of upload:
17.07.2019
Co-author:
Caption:
Made by euronews: the most watched news channel in Europe.
Comparison of damping mechanisms for transverse waves in coronal loops.
Natural Sciences (Astrophysics and Astrononmy)
Date of upload:
22.01.2017
Co-author:
I. Arregui
Abstract:
Damping of transverse waves in different solar coronal structures is a commonly observed property and a source of information about coronal conditions. Although resonant damping seems to be the most accepted mechanism for damping of transverse waves, there are other possible mechanisms. We have carried out a Bayesian analysis comparing three different models which could explain the damping in coronal loops. Our results indicate that resonant absorption is the most probable mechanism for low ratios between damping time and wave period, while the wave leakage mechanism is the best candidate for high ratios. Nonetheless, the evidence for one model against another shows a strong dependence on the data errors.
Flux Emergence in the Quiet Sun From the Photosphere to the Corona
Natural Sciences (Astrophysics and Astrononmy)
Date of upload:
20.09.2018
Co-author:
Georgia Tsiropoula, Kostas Tziotziou
Abstract:
We report preliminary results on the evolution of a small-scale bipolar magnetic feature, from its emergence at the photosphere to its brightening at the corona. We use imaging and spectral observations from the space-born Hinode (SOT/BFI, SOT/SP, EIS & XRT), TRACE (1550 Å, 1600 Å, 1700 Å) and SoHO (MDI hi-res) as well as the ground-based Dutch Open Telescope (G-band, CaII H and five positions along the Hα profile). The small-scale feature emerges, adjacent to the chromospheric network and shows all morphological characteristics of a small-scale magnetic bubble. The magnetic flux density increases, reaching a maximum value while fine-scale CaII H brightenings coalesce forming clusters of positive and negative polarity footpoints of a bipolar feature. The corresponding emerging magnetic flux tubes make their way to the chromosphere, pushing aside the ambient magnetic field, producing Doppler-shifted absorption features. At the upper chromosphere and transition region, imaged by EIS, the emission gradually increases. The connectivity of the quiet-Sun network gradually changes and part of the existing network connects to the newly emerged bipole. A few minutes after the bipole has reached its maximum magnetic flux density, the bipole brightens in soft X-rays forming a coronal bright point. The brightening is observed in all EIS transition region and coronal windows and is accompanied by Doppler-shifted Hα features.
Testing the Gallavotti-Cohen Fluctuation Theorem on the Solar Photosphere
Natural Sciences (Astrophysics and Astrononmy)
Date of upload:
19.06.2018
Co-author:
F. Berrilli, G. Consolini, D. Del Moro, F. Giannattasio, L. Giovannelli
Abstract:
The understanding of fluctuations in systems far from equilibrium is one of the key issues of non-equilibrium statistical thermodynamics. The Fluctuation Theorem of Gallavotti and Cohen (1995) [GCFT] portrays some symmetry features of entropy production rate and deviations in non-linear and far from equilibrium regime. In this framework, the turbulent solar convection, observed in the photosphere and viewed as a dissipative non-equilibrium system near a steady state, provides an incomparable laboratory where to attempt a test the GCFT. In fact, solar convection flows emerge in the photosphere in terms of a structured pattern: the granulation. High resolutions spectro-polarimetric data acquired with Interferometric BIdimensional Spectropolarimeter (IBIS) instrument installed at the Dunn Solar Telescope (DST) are used to perform this analysis. Here, we present a preliminary analysis of the validity of the GCFT in the solar convection field. The statistical features of entropy production rate, which is at the core of the irreversibility, is estimated through the vertical heat flux. The vertical heat flux along the line of sight (LOS), in its turn, is evaluated using temperature and LOS velocity map obtained with spectro-polarimetric inversion using the NICOLE code and with the simplest center of gravity method.
The CoMP-S and SCD spectropolarimeters at the Lomnicky Peak Observatory as supporting instrumentation to EST.
Natural Sciences (Astrophysics and Astrononmy)
Date of upload:
22.06.2018
Co-author:
Gömöry, P., Rybák, J., Schwartz, P., Kučera, A., Ambróz, J., Kozák, M., Koza, J., Tomczyk, S., Sewell, S., Aumiller, P., Gallagher, D., Summers, R., Sutherland, L., Watt , A.
Abstract:
We present actual status and observing possibilities of the Coronal Multi-channel Polarimeter (CoMP-S) and Solar Chromospheric Detector (SCD) installed at the Lomnicky Peak Observatory. The CoMP-S is a dual beam spectropolarimeter developed to detect full Stokes parameters of prominent coronal and chromospheric spectral lines in order to estimate magnetic and velocity fields in the solar corona and in prominences. The SCD is a single beam spectropolarimetric instrument designed for on disk measurements of Stokes parameters in the chromosphere. Both instruments were designed and manufactured by HAO/NCAR (Boulder, USA). We present technical parameters of the instruments and the acquired data which can serve as complementary observing material to high resolution measurements taken by the European Solar Telescope (EST).
Development of instrumentation for solar observations at the Brazilian National Institute for Space
Natural Sciences (Physics)
Date of upload:
15.11.2018
Co-author:
Abstract:
The solar electromagnetic and corpuscular emissions are strongly modulated by the evolution of the magnetic structure of the solar atmosphere, which is imprinted in the solar surface. The evolution of the magnetic structure leads to gradual changes in the solar activity (space climate) as well as violent events (space weather) that affect the whole Heliosphere. In particular, the solar output affects the ionized and neutral components of the Earth’s atmosphere that have a direct impact on human activities from agriculture to high-technological systems. The solar magnetism is driven by the energy transport from the inner layers to the solar atmosphere. Although systematic observations have revealed several features related to the evolution of solar activity, there is not a complete explanation of the physical processes that lead to solar activity cyclic variability and its long-term changes. Here we present a brief description of the development of a magnetograph and visible-light imager instrument to study the solar dynamo processes through observations of the solar surface magnetic field distribution. The instrument will provide measurements of the vector magnetic field and the line-of-sight velocity in the solar photosphere. As the magnetic field anchored at the solar surface produces most of the structures and energetic events in the upper solar atmosphere and significantly influences the Heliosphere, the development of this instrument plays an essential role in reaching the scientific goals of The Atmospheric and Space Science Coordination (CEA) at the Brazilian National Institute for Space Research (INPE). In particular, the INPE’s Space Weather program will benefit most from the development of this technology. Additionally, we expect that this project will be the starting point to establish a robust research program on Solar System Research at INPE. The proposed instrument has been designed to operate on the ground, but with a conceptual design flexible enough to be adapted to work on a balloon and space-based platforms. In this way, our main aim is acquiring know-how progressively to build state-of-art solar vector magnetograph and visible-light imagers for space-based platforms to contribute to the efforts of the solar-terrestrial physics community to address the main unanswered questions on how our nearby Star works.
'Old Shatterhand' auf christlichsozialen Pfaden. War Karl May ein Sympathisant der christlichsozialen Bewegung Österreichs?
Humanities (Literature)
Date of upload:
25.11.2018
Co-author:
Abstract:
Der Schriftsteller Karl May pflegte eine Vielzahl von Beziehungen zu Repräsentanten der christlichsozialen Partei Österreichs. Diese katholisch-soziale aber auch antisemitische Bewegung war in den deutschen Gebieten der Donaumonarchie eine Massenbewegung. Die Achse der Verbindung Mays zu christlichsozialen Persönlichkeiten und Zeitungen läuft über den Wiener Prälaten Josef Heidenreich, eine schillernde Persönlichkeit mit wechselvoller Geschichte. Anhand der Freundschaft May-Heidenreich entsteht ein lebendiges Bild der ersten politischen katholischen Massenbewegung Österreichs.
Physics and Diagnostics of Magnetic Flux Emergence
Natural Sciences (Astrophysics and Astrononmy)
Date of upload:
03.12.2018
Co-author:
Abstract:
Magnetic flux emergence from the solar convection zone into the atmosphere drives dynamic phenomena observable over a range of temperatures and spatiotemporal scales. In this talk, we review the fundamental physical processes important for flux emergence and relate these processes to observables accessible to ground-based and space borne observatories. We illustrate how continuous spectropolarimetric observations enabled the recent development of data-driven simulations of emerging flux, and how such simulations will improve our understanding of the solar atmosphere. We give suggestions for coordinated studies involving observations by existing and next generation solar telescopes (European Solar Telescope, Daniel K. Inouye Solar Telescope, ALMA and future space missions) and data-driven models. We also explore how machine learning techniques can be applied to perform physical diagnostics of the solar atmosphere.
Deep Learning for Multi-Site Solar Observations: from Quality Estimation to Image Reconstruction
Natural Sciences (Astrophysics and Astrononmy)
Date of upload:
02.05.2019
Co-author:
Astrid Veronig, Werner Pötzi, Tatiana Podladchikova
Abstract:
In recent years deep learning had a major impact in various disciplines. New state-of-the-art results have been achieved in image processing, voice recognition, decision making and many other domains. Deep learning has proven to be robust and capable of solving complex tasks. In contrast to other algorithms deep learning benefits from large amounts of data and the inference times are typically short. Under these aspects deep learning is also of interest for tasks within the SOLARNET H2020 project. We will discuss the potential benefits and applications of deep learning for SPRING. Adequate data filtering and merging of simultaneous observations from multiple observation sites need suitable measure for single-site image quality. Recent approaches with neural networks have proven to perform well on image quality assessment. For full-disk solar observations additional effects, like local atmospheric and seeing conditions, complicate the situation. We propose a customized neural network, to account for the image quality assessment. As a baseline we use the currently operating quality estimation of the Kanzelhöhe Observatory for Solar and Environmental Research (KSO), which is based on a combination of parameters that describe local and global properties extracted from each recorded image. The dataset will consist of manually annotated H-alpha images between 2008 and 2019, covering a wide range of solar activity conditions. The advantage of this approach is that additional observation sites can be included with reduced effort by reusing the pre-trained neural network. Additionally, we are investigating reconstruction and homogenization methods to compensate for local seeing conditions. This can be accomplished by a neural network which translates between high- and low-quality images. The architecture is based on generative adversarial networks (GANs). We use high quality images as conditional input for generating a neural network to create realistic low quality solar images. In parallel a second generator is trained to reproduce the original image. With this approach a dataset of paired ground-truth and degraded images is created. This will be of further use for artificial scenarios of multi-site observation with mixed qualities and for performance estimation of the reconstruction algorithms. To enforce the generation of artificial low-quality images a discriminating network is used to identify the differences between low- and high-quality images. With further training on the full augmented dataset, this network serves as an image quality classifier.
A Comprehensive Approach to Privacy in the Cloud-based Internet of Things
Computer Sciences (Security and cryptography)
Date of upload:
10.01.2019
Co-author:
Lars Hermerschmidt, Daniel Kerpen, Roger Häußling, Bernhard Rumpe, Klaus Wehrle
Abstract:
In the near future, the Internet of Things is expected to penetrate all aspects of the physical world, including homes and urban spaces. In order to handle the massive amount of data that becomes collectible and to offer services on top of this data, the most convincing solution is the federation of the Internet of Things and cloud computing. Yet, the wide adoption of this promising vision, especially for application areas such as pervasive health care, assisted living, and smart cities, is hindered by severe privacy concerns of the individual users. Hence, user acceptance is a critical factor to turn this vision into reality. To address this critical factor and thus realize the cloud-based Internet of Things for a variety of different application areas, we present our comprehensive approach to privacy in this envisioned setting. We allow an individual user to enforce all her privacy requirements before any sensitive data is uploaded to the cloud, enable developers of cloud services to integrate privacy functionality already into the development process of cloud services, and offer users a transparent and adaptable interface for configuring their privacy requirements.
EFFECT OF BED ROUGHNESS DISTRIBUTION AND CHANNEL SLOPE ON RECTANGULAR FREE OVERFALL
Engineering (Civil engineering)
Date of upload:
10.12.2018
Co-author:
Abstract:
In this paper, the free overfall in rectangular channel with a different slopes and bed rough distribution was studied. Bed roughness was made of wood allocated in three different cases: two, three and zigzag rows. The aim of this study is to obtain discharge equations for free overfall depending on brink depth and slope. Three empirical equations proposed for calculating discharge. These equations influenced by slope, channel bed roughness as well as method of roughness distribution. Three rows bed roughness having grater effect on these relationships at steeper slopes. the average values of hc/he at smooth bed is greater by (4%) with respect to that for bed rough at two rows, by (19%) with respect to that for bed rough at zigzag rows and by (24%) with respect to that for bed rough at three rows, so that values for three rows rough and horizontal channel is greater by (4%) with respect to that for channel slope at (1/200) and by (14%) with respect to that for channel slope at (1/100).
How-To MLT_4
Natural Sciences (Astrophysics and Astrononmy)
Date of upload:
14.08.2018
Co-author:
Abstract:
Short How-To about how to call the MLT_ 4 recognition code.
Design of a next generation synoptic solar observing network: solar physics research integrated network group (SPRING)
Natural Sciences (Astrophysics and Astrononmy)
Date of upload:
18.05.2018
Co-author:
Sanjay Gosain, Frank Hill, Alexei Pevtsov, Valentin M. Pillet, Michael Thompson
Abstract:
Long-term synoptic observations of the Sun in different wavelength regions are essential to understand its secular behavior. Such observations have proven very important for discovery of 11 year solar activity cycle, 22 year magnetic cycle, polar eld reversals, Hale's polarity law, Joy's law, that helped Babcock and Leighton to propose famous solar dynamo model. In more recent decades, the societal impact of the secular changes in Sun's output has been felt in terms of solar inputs to terrestrial climate-change and space-weather hazards. Further, it has been realized that to better understand the activity phenomena such as flares and coronal mass ejections (CMEs) one needs synoptic observations in multiple spectral lines to enable tomographic inference of physical parameters. Currently, there are both space and ground based synoptic observatories. However, given the requirements for the long-term stability and reliability of such synoptic datasets, ground-based facilities are more preferable. Also, the ground based observatories are easy to maintain or upgrade while detailed and frequent calibrations are easily possible. The only ground-based facility that currently provides full-disk velocity and magnetic eld maps of the Sun around the clock and at good cadence, is the Global Oscillations Network Group (GONG) network of National Solar Observatory (NSO) which is operational since the mid 90s. Due to its aging instrumentation, operating for nearly three decades, and new requirements to obtain multiwavelength observations, a need is felt in the solar community to build a next generation synoptic observatory network. A group of international observatories have come together under the auspices of SOLARNET program, funded by European Union (EU), to carryout a preliminary design study of such a synoptic solar observing facility called "SPRING", which stands for Solar Physics Research Integrated Network Group. In this article we will present concept of SPRING and the optical design concept of its major instruments.
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