A
bstract
The cross section of the process
e
+
e
−
→ ηπ
+
π
−
is measured using the data collected with the CMD-3 detector at the VEPP-2000 collider in the center-of-mass energy range from 1
.
1 to 2
....
0 GeV. The decay mode
η → γγ
is used for
η
meson reconstruction in the data sample corresponding to an integrated luminosity of 78
.
3 pb
−
1
. The energy dependence of the
e
+
e
−
→ ηπ
+
π
−
cross section is fitted within the framework of vector meson dominance in order to extract the Γ(
ρ
(1450)
→ e
+
e
−
)
B
(
ρ
(1450)
→ ηπ
+
π
−
) and the Γ(
ρ
(1700)
→ e
+
e
−
)
B
(
ρ
(1700)
→ ηπ
+
π
−
) products. Based on conservation of vector current, the analyzed data are used to test the relationship between the
e
+
e
−
→ ηπ
+
π
−
cross section and the spectral function in
τ
−
→ ηπ
−
π
0
ντ
decay. The
e
+
e
−
→ ηπ
+
π
−
cross section obtained with the CMD-3 detector is in good agreement with the previous measurements.
The participation of DNA methylation and histone acetylation in the mechanisms of anterograde amnesia and memory recovery was studied on grape snails trained in conditioned food aversion. Anterograde ...amnesia developed 10 days after memory reconsolidation impairment with an NMDA glutamate receptor antagonist and was characterized by long-term memory formation impairment upon repeated training. DNA methyltransferase inhibitor injections to snails 1 h before repeated training, as well as 15 min or 4 h after repeated training, caused rapid formation of memory that persisted for at least 10 days. Injections of histone deacetylase inhibitor before repeated training also induced the formation of a stable long-term memory. However, administration of histone deacetylase inhibitor 15 min after repeated training initiated a temporary memory recovery. Injections of the inhibitor 4 h after repeated training were ineffective. These results indicate that histone-dependent chromatin remodeling and DNA methylation are selectively involved in the mechanisms of anterograde amnesia and memory recovery.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
—The issues of the causes and factors of manifestation of seismic activity during the extraction of minerals in the deposits of the Khibiny massif, which are mined underground, are considered. Based ...on seismic monitoring data, groups of seismic activity were identified, such as seismicity in the working area, directly related to blasting and natural seismicity, related to other mining and geological factors. The difference in the characteristics of the manifestation of seismicity for these two groups of seismic events is shown.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
An experimental study of the efficiency of solvers of 2D boundary value problems on subgrids of quasi-structured rectangular grids is carried out. A solver means a solution method and its software ...implementation. The following three solvers are considered: a direct solver (Buneman’s cyclic reduction method) and two iterative ones (the alternative direction method of Peaceman and Rachford and the successive overrelaxation method). Characteristic features of the study are as follows: 1) the subgrids have a small number of nodes, namely 8 × 8, 16 × 16, 32 × 32, and 64 × 64; 2) the efficiency is estimated not only for single calculations, but also for series of calculations; in each of them the problem is repeatedly solved with different boundary conditions on the same subgrid. Based on a series of calculations, a combined method is proposed, and recommendations on using the solvers are given.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The results of study of the initial stage of expansion of a collisionless plasma with the electric current into a plane vacuum gap on the basis of kinetic equations for electrons and ions and the ...Poisson equation for the electric field are given. Self-consistent dynamics of a two-component plasma and electric field are theoretically modeled and the fundamental mechanism for establishing superthermal velocities of charged particles is described in detail. The parameters of anode-directed flows of positive ions in the cathode plume plasma are calculated. The expansion velocities of the cathode plume plasma observed in vacuum arcs at the level of (1−5) × 10
6
cm/s can be explained within the framework of the proposed collisionless mechanism.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Posterior fossa tumors (PFT) are the most common tumors in children. Differentiation between the various PFT types is critical, as different tumors have diverse treatment approaches. This study ...proposes the use of fused architecture comprising two neural networks, a pre-trained ResNet-50 Convolutional Neural Network (CNN) and a tabular based network for the classification of PFT. The study included data for 158 MRI scans of 22 healthy controls and 136 pediatric patients with newly diagnosed PFT (63 Pilocytic Astrocytoma, 57 Medulloblastoma and 16 Ependymoma). The input data for classification were from magnetic resonance imaging: post contrast T1-weighted, fluid attenuated inversion recovery and diffusion Trace images, and tabular data: subject's age. Evaluation of the model was performed in a stratified 5-fold cross-validation manner, based on accuracy, precision, recall and F1 score metrics. Model explanation was performed in terms of visual explanation of the CNN by Gradient-weighted Class Activation Mapping (Grad-CAM) and by testing the contribution to the classification results of the different imaging input data sets and the proposed fused architectures relative to CNN only and tabular only architectures. The best classification results were obtained with the fused CNN + tabular data architecture, and based on diffusion Trace images, achieving mean cross-validation accuracy of 0.88 ± 0.04 for the validation and 0.87 ± 0.02 for the test dataset. Overall, the proposed architecture achieved improvement in accuracy and F1 score compared to CNN method for this dataset. The source code is available on the GitHub repository: https://github.com/artzimy/CNNTabular .
The research investigates the structure of a welded joint of a railway rail after local heat treatment and without it. Macro- and microstructural analyses of rail samples were performed using optical ...microscopy methods. The hardness of the rail running surface in the heat-affected zone of butt welds was measured. It has been found that the formation of zones with reduced hardness is inevitable due to the temperature gradient created during the welding process. Moreover, using local induction heat treatment results in the formation of new, more extended zones with reduced hardness. It has been determined that the only solution to this problem is to reduce the extent of heat-affected zones to sizes that do not lead to increased wear and local crushing.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The main principles of using wires with tungsten nanopowder for arc cladding are considered. Special features of production and application of tungsten-modified wires are analyzed. The microstructure ...of the high-strength layer obtained by cladding wires with different tungsten nanopowder contents is investigated. Microhardness of clad specimens is determined.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Abstract Objective The supracerebellar infratentorial (SCIT) paramedian approach in sitting position represents one of the most used surgical route for dealing with pineal region lesions. Purpose of ...our study is to determine the cornerstones to perform this approach in a simple, safe and effective way, so that it could be easily reproduced in other neurosurgical centers, particularly in those with modest resources. Methods We reviewed and analyzed the surgical videos of twenty-four pineal region lesions that were operated on through a SCIT approach between June 2012 and October 2015. The SCIT approach may be divided into three main steps: 1)skin-muscle incision; 2)craniotomy; 3)dura opening and access to the pineal region. Results Complete lesion removal was accomplished in 23 cases, and subtotal removal in one case. The pineal region was effectively and safely reached through the SCIT approach in the sitting position with a mean time of 14 minutes, using a basic set of microsurgical instruments. Cornerstones, as well as potential delaying events, were carefully recorded for each of the three main steps of the approach. Moreover, we present in a short video a step by step guide to perform the SCIT approach in a fast and safe way. Conclusions A correct application of microsurgical principles may allow to safely and rapidly perform the SCIT approach, thus offering an effective and relatively atraumatic route for dealing with pineal region lesions.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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