Recently, the possible coexistence of a first family composed of "normal" neutron stars (NSs) with a second family of strange quark stars (QSs) has been proposed as a solution of problems related to ...the maximum mass and to the minimal radius of these compact stellar objects. In this paper, we study the mass distribution of compact objects formed in binary systems and the relative fractions of quark and NSs in different subpopulations. We incorporate the strange QS formation model provided by the two-families scenario, and we perform a large-scale population synthesis study in order to obtain the population characteristics. According to our results, the main channel for strange QS formation in binary systems is accretion from a secondary companion on an NS. Therefore, a rather large number of strange QSs form by accretion in low-mass X-ray binaries and this opens the possibility of having explosive GRB-like phenomena not related to supernovae and not due to the merger of two NSs. The number of double strange QS systems is rather small, with only a tiny fraction that merge within a Hubble time. This drastically limits the flux of strangelets produced by the merger, which turns out to be compatible with all limits stemming from Earth and lunar experiments. Moreover, this value of the flux rules out at least one relevant channel for the transformation of all NSs into strange QSs by strangelets' absorption.
Short-range forecasts of variations in the level of the Sea of Azov with a lead time of 48 hours are computed with a three-dimensional hydrodynamic model (a grid spacing is 0.5 nautical miles) twice ...a day at 00:00 and 12:00 using wind speed and air pressure fields on the sea surface from the COSMO model (a grid spacing is 7 km). To eliminate differences between the sea-level simulations and observations, a correction is introduced, that is defined as a difference in the mean level of the Sea of Azov according to observations at coastal stations and model simulations. After introducing the correction of the mean level of the Sea of Azov in the automatic mode, the operational model simulates not only surges but also seasonal sea level variations, for example, a gradual sea level drop in May–December 2020.
ABSTRACT
The newly discovered Be/X‐ray binary in the Small Magellanic Cloud, SXP 1062, provides the first example of a robust association with a supernova remnant (SNR). The short age estimated for ...the SNR qualifies SXP 1062 as the youngest known source in its class, . As such, it allows us to test current models of magnetorotational evolution of neutron stars in a still unexplored regime. Here we discuss possible evolutionary scenarios for SXP 1062 in an attempt to reconcile its long spin period, , and short age. Although several options can be considered, like an anomalously long initial period or the presence of a fossil disc, our results indicate that SXP 1062 may host a neutron star born with a large initial magnetic field, typically in excess of ∼ 1014 G, which then decayed to ∼ 1013 G.
A theorem about the behavior of Cauchy-type integrals at the endpoints of the integration contour and at discontinuity points of the density is stated, and its application to boundary value problems ...for 2
n-
order parabolic equations with a changing direction of time are described. The theory of singular equations, along with the smoothness of the initial data, makes it possible to specify necessary and sufficient conditions for the solution to belong to Hölder spaces. Note that, in the case
n =
3, the smoothness of the initial data and the solvability conditions imply that the solution belongs to smoother spaces near the ends with respect to the time variable.
We demonstrate mode-locking of a thulium-doped fiber laser operating at 1.94 μm, using a graphene-polymer based saturable absorber. The laser outputs 3.6 ps pulses, with ~0.4 nJ energy and an ...amplitude fluctuation ~0.5%, at 6.46 MHz. This is a simple, low-cost, stable and convenient laser oscillator for applications where eye-safe and low-photon-energy light sources are required, such as sensing and biomedical diagnostics.
In rats anesthetized with α-chloralose, coronary artery occlusion (45 min) and reperfusion (120 min) were modeled. The selective δ
2
-opioid receptor agonist deltorphin II was administered 5 min ...before reperfusion. Protein kinase C inhibitor chelerythrine, AMP-activated protein kinase inhibitor compound C, and ATP-sensitive K
+
channel blockers glibenclamide, 5-hydroxydecanoate, and HMR 1098 were administered 10 min before reperfusion. It was found that the infarct-limiting effect of deltorphin II is associated with activation of protein kinase C and opening of sarcolemmal ATP-sensitive K
+
channel.
We perform population synthesis studies of different types of neutron stars (NSs) (thermally emitting isolated NSs, normal radio pulsars, magnetars) taking into account the magnetic field decay and ...using results from the most recent advances in NS cooling theory. For the first time, we confront our results with observations using simultaneously the log N–log S distribution for nearby isolated NSs, the log N–log L distribution for magnetars, and the distribution of radio pulsars in the diagram. For this purpose, we fix a baseline NS model (all microphysics input), and other relevant parameters to standard values (velocity distribution, mass spectrum, birth rates, etc.), allowing us to vary the initial magnetic field strength. We find that our theoretical model is consistent with all sets of data if the initial magnetic field distribution function follows a lognormal law with 〈log (B0/G)〉∼ 13.25 and . The typical scenario includes about 10 per cent of NSs born as magnetars, significant magnetic field decay during the first million years of a NS life (only about a factor of 2 for low-field NSs but more than an order of magnitude for magnetars), and a mass distribution function dominated by low-mass objects. This model explains satisfactorily all known populations. Evolutionary links between different subclasses may exist, although robust conclusions are not yet possible.
The article 1 is devoted to the conjugation problems for different physical processes such as the heat propagation in nonhomogeneous media, diffraction type problems, interaction of filtration and ...channel flows of a fluid, filtration in a borehole, reverse flows in a boundary layer after a separation point, etc. These conjugation problems are supplemented with examples of their realization including existence and uniqueness theorems of the corresponding boundary value problems. In the present article we consider counter concurrent flows with general conjugation conditions in the conjugation models and contact boundary value problems proposed.
This paper presents an algorithm and description of its software implementation for detection of lineaments (ground erosions or cracks) in aerial images of open pits. The proposed approach is based ...on the apparatus of convolutional neural networks for semantic classification of binarized images of lineament objects, as well as graph theory for determining the geometric location of linearized lineament objects with subsequent calculation of their lengths and areas. As source data, three-channel RGB images of high-resolution aerial photography (10×10 cm) are used. The software module of the model is logically divided into three levels: preprocessing, detection, and post-processing. The first level implements the preprocessing of input data to form a training sample based on successive transformations of RGB images into binary images by using the OpenCV library. A neural network of the U-Net type, which includes convolutional (Encoder) and scanning (Decoder) blocks, represents the second level of the information model. At this level, automatic detection of objects is implemented. The third level of the model is responsible for calculating their areas and lengths. The result provided by the convolutional neural network is passed to it as input data. The lineament area is calculated by summing the total number of points and multiplying by the pixel size. The lineament length is calculated by linearizing the areal object into a segmented object with node pixels and, then, calculating the lengths between them while taking into account the resolution of the source image. The software module can work with fragments of the source image by combining them. The module is implemented in Python and its source code is available at
https://gitlab.ict.sbras.ru/popov/lineaments/-/tree/master/lineaments-cnn
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