Ni/Au contacts to corundum α-Ga2O3 Massabuau, Fabien C.-P.; Adams, Francesca; Nicol, David ...
Japanese Journal of Applied Physics,
06/2023, Letnik:
62, Številka:
SF
Journal Article
This systematic review is focusing on the current literature in order to give an overview of the protective role of antioxidants in ram semen preservation. Throughout the sperm conservation process ...the unsaturated fatty acids of the spermatozoa membrane binds oxygen and evolves numerous peroxide bonds. The lipid peroxidation leads to unbalanced oxidative stress that causes different impairments of sperm cells, and acrosome loss. ,,Cold shock” also induces caspase cascade involved in apoptosis, DNA fragmentation and in overall it has a detrimental effect on the fertilizing capacity of spermatozoa. Nowadays the cryopreservation of semen is considered as a routine procedure in cattle. Despite the various advantages of the method, the recovery rate of live and intact spermatozoa still remains low in boar, dog and ram samples. Previously several studies highlighted that the addition of antioxidants could improve the survival and motility rates, because antioxidants acted as free radical scavengers and protected spermatozoa against reactive oxygen species (ROS). Enzymatic antioxidants as superoxide dismutase (SOD), catalase, glutathione peroxidase (GPX) and non-enzymatic antioxidant molecules like tocopherol, ascorbic acid, pyruvate, resveratrol have a protective effect against membrane damage that occurs during semen preservation process.
The alignment of the CMB Cold Spot and the Eridanus supervoid suggests a physical connection between these two relatively rare objects. We use galaxy catalogues with photometric (2MPZ) and ...spectroscopic (6dF) redshift measurements, supplemented by low-redshift compilations of cosmic voids, in order to improve the 3D mapping of the matter density in the Eridanus constellation. We find evidence for a supervoid with a significant elongation in the line of sight, effectively spanning the total redshift range z < 0.3. Our tomographic imaging reveals important substructure in the Eridanus supervoid, with a potential interpretation of a long, fully connected system of voids. We improve the analysis by extending the line-of-sight measurements into the antipodal direction that interestingly crosses the Northern Local Supervoid at the lowest redshifts. Then it intersects very rich superclusters like Hercules and Corona Borealis, in the region of the Coma and Sloan Great Walls, as a possible compensation for the large-scale matter deficit of Eridanus. We find that large-scale structure measurements are consistent with a central matter underdensity δ0 ≈ −0.25, projected transverse radius
$r_{0}^{\perp }\approx 195$
Mpc h
−1 with an extra deepening in the centre, and line-of-sight radius
$r_{0}^{\parallel }\approx 500$
Mpc h
−1, i.e. an ellipsoidal supervoid. The expected integrated Sachs–Wolfe imprint of such an elongated supervoid is at the ΔT
ISW ≈ −40 μK level, thus inappropriate to accounting for the Cold Spot pattern in the CMB.
Stackelberg game models for demand response management in smart electricity grids have been studied extensively in the scientific literature. Still, a barrier to their practical applicability is the ...assumption that the retailer (leader in the game) has perfect knowledge about the consumers’ (followers’) decision model. This paper investigates the possibilities of reconstructing the consumers’ decision model from historic tariff and consumption data. For this purpose, it introduces an inverse optimization approach to eliciting the parameters of electricity consumer models formulated as linear programs from the historic samples. The inverse problem is first transformed into a quadratically constrained quadratic program, and then solved using successive linear programming techniques. The approach is demonstrated on a common consumer model with multiple types of deferrable loads behind a single smart meter. Experimental results are presented, and directions for future research are proposed.
Magnetic skyrmion braids Zheng, Fengshan; Rybakov, Filipp N.; Kiselev, Nikolai S. ...
Nature communications,
09/2021, Letnik:
12, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Abstract
Skyrmions are vortex-like spin textures that form strings in magnetic crystals. Due to the analogy to elastic strings, skyrmion strings are naturally expected to braid and form complex ...three-dimensional patterns, but this phenomenon has not been explored yet. We found that skyrmion strings can form braids in cubic crystals of chiral magnets. This finding is confirmed by direct observations of skyrmion braids in B20-type FeGe using transmission electron microscopy. The theoretical analysis predicts that the discovered phenomenon is general for a wide family of chiral magnets. These findings have important implications for skyrmionics and propose a solid-state framework for applications of the mathematical theory of braids.
We combine photometric information of the Wide-Field Infrared Survey Explorer (WISE) and Two Micron All Sky Survey (2MASS) all-sky infrared data bases, and demonstrate how to produce clean and ...complete galaxy catalogues for future analyses. Adding 2MASS colours to WISE photometry improves star–galaxy separation efficiency substantially at the expense of losing a small fraction of the galaxies. We find that 93 per cent of the WISE objects within W1 < 15.2 mag have a 2MASS match, and that a class of supervised machine learning algorithms, support vector machines (SVM), are efficient classifiers of objects in our multicolour data set. We constructed a training set from the Sloan Digital Sky Survey PhotoObj table with known star–galaxy separation, and determined redshift distribution of our sample from the Galaxy and Mass Assembly spectroscopic survey. Varying the combination of photometric parameters input into our algorithm we show that W1
WISE
− J
2MASS is a simple and effective star–galaxy separator, capable of producing results comparable to the multidimensional SVM classification. We present a detailed description of our star–galaxy separation methods, and characterize the robustness of our tools in terms of contamination, completeness, and accuracy. We explore systematics of the full sky WISE-2MASS galaxy map, such as contamination from moon glow. We show that the homogeneity of the full sky galaxy map is improved by an additional J
2MASS < 16.5 mag flux limit. The all-sky galaxy catalogue we present in this paper covers 21 200 deg2 with dusty regions masked out, and has an estimated stellar contamination of 1.2 per cent and completeness of 70.1 per cent among 2.4 million galaxies with z
med ≈ 0.14. WISE-2MASS galaxy maps with well controlled stellar contamination will be useful for spatial statistical analyses, including cross-correlations with other cosmological random fields, such as the cosmic microwave background. The same techniques also yield a statistically controlled sample of stars as well.
Chiral magnetic skyrmions
are nanoscale vortex-like spin textures that form in the presence of an applied magnetic field in ferromagnets that support the Dzyaloshinskii-Moriya interaction (DMI) ...because of strong spin-orbit coupling and broken inversion symmetry of the crystal
. In sharp contrast to other systems
that allow for the formation of a variety of two-dimensional (2D) skyrmions, in chiral magnets the presence of the DMI commonly prevents the stability and coexistence of topological excitations of different types
. Recently, a new type of localized particle-like object-the chiral bobber (ChB)-was predicted theoretically in such materials
. However, its existence has not yet been verified experimentally. Here, we report the direct observation of ChBs in thin films of B20-type FeGe by means of quantitative off-axis electron holography (EH). We identify the part of the temperature-magnetic field phase diagram in which ChBs exist and distinguish two mechanisms for their nucleation. Furthermore, we show that ChBs are able to coexist with skyrmions over a wide range of parameters, which suggests their possible practical applications in novel magnetic solid-state memory devices, in which a stream of binary data bits can be encoded by a sequence of skyrmions and bobbers.
India has an abundance of solar energy resources. Nearly 90% of the urban dwellers in different parts of India used electricity for heating water. Using electricity for resident water heating not ...only contributes to negative environment impact via the emission of a substantial quantity of carbon dioxide but also places a financial burden on households. The examination of solar irradiance, economic feasibility, and hot water demands is crucial in assessing the potential of solar thermal collector (STC) to fulfill hot water requirement. In order to enhance the value of the STC, it is essential for the collector to effectively manage operations with a focus on minimizing cost. To get an optimal heating effect, the present STC is fastened with an obstruction inside the tube. The collector is examined in three distinct seasons to observe temperature variations and the appropriate use of the device during non-operational hours. The recommended average temperatures for summer, rainy season, and winter are 68, 57, and 47 °C, respectively. Additionally, a thorough examination of the economic analysis and payback period for STC was also conducted.
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