bluuebunny/crossref_metadata_2025 huggingface dataset:
Top pair production at ultra-high energies
Authors: Okorokov V A
Published: December 2020

The top quark, the heaviest quark and, indeed, the heaviest elementary particle known today, constitutes a novel probe of the long-lived medium in quark-gluon phase which, as expected, can be produced even in light nuclei collisions at ultra-high energies. Some distinctive features are considered for particle production in the top sector in ultra-high energy domain. The antitop-top pair production is studied within the quantum chromodynamics and effective field theory approach used for calculations of total partonic cross sections. Predictions for all observables are computed at NNLO in quantum chromodynamics and at LO in effective field theory. These quantitative results can be important for both the future collider experiments at center-of-mass energy frontier and the improvement of the phenomenological models for development of the cosmic ray cascades in ultra-high energy domain. Thus the study allows the better understanding of heavy particle production and emphasizes the exciting interrelation between the high-energy physics on accelerators and ultra-high energy cosmic ray measurements.
New Markov-Chain Monte Carlo analyses for the evaluation of the antiproton background
Authors: De la Torre Luque P , Gargano F , Loparco F , Mazziotta M N , Serini D
Published: December 2020

Current measurements of the cosmic ray spectra have reached unprecedented accuracy thanks to the new generation of experiments, and in particular the AMS-02 mission. At the same time, significant progress has been made in the propagation models of galactic cosmic rays. Nevertheless, the current knowledge on spallation cross sections is very poor, impeding a more precise estimation of the diffusion coefficient. In this work we show a new Markov-Chain Monte Carlo algorithm able to derive the propagation parameters from the flux ratios of light secondary cosmic rays (Li, Be, B) to C and O and a new procedure able to combine the flux of these secondary cosmic rays in order to get rid of the uncertainties associated to their production cross sections. Then, we show that the antiproton spectrum inferred from this diffusion model match experimental data much better than with earlier analyses, discarding the excess of data previously explained as a possible signature of antiproton production from dark matter.
Annual variations of the 214Po, 213Po and 212Po half-life values
Authors: Alexeev E N , Gangapshev A M , Gavrilyuk Yu M , Gezhaev A M , Kazalov V V , Kuzminov V V , Panasenko S I , Petrenko O D , Ratkevich S S
Published: December 2020

Results of a comparative analysis of the 214Po (T
1/2 = 163.47 ± 0.03 μs), 213Po (T
1/2 = 3.705 ± 0.001 μs) and 212Po (T
1/2 = 294.09 ± 0.07 ns) half-life annular variation parameters are presented. The sinusoid curve approximated a set of 214Po τ-values obtained at BNO INR RAS has an amplitude A = (5.0 ± 1.5) ⋅ 10−4, period ω = (365 ± 8) days, and phase ϕ = (170 ± 7) days. The one obtained at the KhNU has an amplitude A = (4.9 ± 1.8) ⋅ 10−4, a period ω = (377±13) days and a phase ϕ = (77±10) days. The 213Po τ-value sine approximation has an amplitude A = (3.9 ± 1.2) ⋅ 10−4, a period ω = (370 ± 13) days and a phase ϕ = (130 ± 9) days. The 213Po τ-value set with a time duration of ~ 1700 days can be described by a sinusoidal function with an amplitude A = (3.9 ± 1.2) ⋅ 10−4, a period ω = (370 ± 13) days and a phase ϕ = (130±9) days. The 212Po one has an amplitude A = (7.5±1.6)⋅10−4, a period ω = (375±13) days and a phase ϕ = (40 ± 10) days.
Implementation of the deconvolution method for signal peak detection in read-out ASIC
Authors: Atkin E , Azarov D , Ivanov P , Normanov D , Serazetdinov A , Shumikhin V
Published: December 2020

An application of the deconvolution method for signal peak detection in read-out ASIC for GEM detectors is described. Instead of usage of the conventional analog or digital peak detector, deconvolution technique to define the signal maximum was studied. In this case the digital data coming from the ADC are processed by a digital filter that deconvolves according to the pre-determined transfer function of the analog channel. Such processing allows to identify the signal peak values and also to provide reasonable pileup rejection. That enables higher rates of the incoming signals and reduces the amount of lost data.

Combined with the analog channel employing 10-bit 25 MHz sampling rate ADC and 250 ns time constant 2nd-order shaper, the designed deconvolution block maintains peak detection accuracy within 9 LSBs. Time resolution of peak separation is 4 ADC sampling intervals or 100 ns.
Topological properties of Josephson current between two s- and p-wave superconducting nanowires with Majorana fermions
Authors: Suleymanli Bahruz D , Nakhmedov Enver , Naumov Petr Yu
Published: December 2020

Josephson current between two one-dimensional nanowires with proximity induced either s-wave or p-wave pairing and separated by a narrow dielectric barrier is calculated in the presence of Rashba spin-orbit interaction, in-plane and normal Zeeman magnetic fields. We show that Andreev retro-tunneling is realized by means of two channels. The main contribution to the Josephson current in junction of s- or p-wave superconductors is shown to give Andreev scattering in a conventional particle-hole channel, when an electron-like quasiparticle reflects to a hole-like quasiparticle with opposite spin yielding a current which depends only on the order parameters’ phase differences φ and oscillates with fractional 4π period. Nevertheless Andreev bound state energy in second anomalous particle-hole channel, corresponding to the reflection of an incident electron-like quasiparticle to a hole-like quasiparticle with the same spin orientation, survives only in the presence of the in-plane magnetic field, and oscillates with 4π period not only with φ but also with orientational angle of the in-plane magnetic field θ resulting in a magneto-Josephson effect. In the presence of Rashba spin-orbit coupling (SOC) and normal-to-plane magnetic field h, a forbidden gap is shown to open in the dependence of Andreev bound state energies on the phases φ and θ at several values of SOC strength and magnetic field, where Josephson current seems to vanish. The magnetic fields destroy also the particle-hole symmetry of the mid-gap states around Fermi level.
On perturbative unitarity in the extended MSSM Higgs sector
Authors: Dubinin M N , Fedotova E Yu
Published: December 2020

Higgs sector of the minimal supersymmetric standard model (MSSM) extended by dimension-six operators, which are loop contributions in the expansion of the Coleman-Weinberg type potential, is considered. The presence of such additional contributions allows the reopening of phenomenological MSSM scenarios closed in the previous analysis. In order to restrict respective MSSM parameter regions, perturbative unitarity constraints must be satisfied. We find the analytical formula for quartic and trilinear couplings for the Higgs potential extended by dimension-six operators, compare results with the loop corrected constraints at high or finite

s

with and without additional U
(6)-contributions, and show how the allowed regions in the parameter space are affected in these cases.
D-wave Bc
meson production at LHC
Authors: Berezhnoy A V , Belov I N
Published: December 2020

Hadronic production of D wave states of Bc
are discussed. Preliminary estimations of D-wave Bc
yield are presented for LHC conditions.
Measurements of the like-sign pion and kaon femtoscopic correlations at NICA energies
Authors: Nigmatkulov G , Batyuk P , Khyzhniak Y , Kodolova O , Malinina L , Mikhaylov K
Published: December 2020

The main goal of heavy-ion collision measurements at NICA energies(sNN=4−11GeV)is to study the properties of the quark-gluon matter at high baryon densities. Femtoscopy allows one to probe spatial and temporal characteristics of the particle-emission process at the last stage of the collision evolution - kinetic freeze-out. In this proceedings, we present estimations of like-sign pion and kaon pair femtoscopic observables for NICA energies using the UrQMD model. The dependence of the femtoscopic radii on collision energy, centrality, and pair transverse momentum are shown.
Reconstruction of γγ mass spectra in Ag+Ag collisions at 1.23 and 1.58 AGeV beam energies with ECal detector of the HADES experiment
Authors: Shabanov A , Prozorov A , Chudoba P , Galatyuk T , Guber F , Gumberidze M , Ivashkin A , Kugler A , Lalik R , Morozov S , Pechenov V , Petukhov O , Pietraszko J , Rathod N , Reshetin A , Rost A , Svoboda O , Salabura P , Tlusty P
Published: December 2020

HADES is a high acceptance di-electron spectrometer operating at SIS18, GSI, Germany aimed at study of hadron-proton, hadron-nucleus and nucleus-nucleus collisions at 1-4 AGeV beam energies. The new electromagnetic calorimeter (ECal) was added to the experimental setup in order to measure γ-quanta and thus extend its capabilities in study of π
0-, η-mesons, production of neutral hyperons and to improve electron-to-hadron separation for the partcles with momenta p > 300 MeV/c. The first data taking with the ECal detector was carried out in March 2019 when Ag+Ag collisions at 1.23 AGeV and 1.58 AGeV beam energies were studied. The methods of reconstruction of the γγ invariant mass spectra from these data are discussed. The analysis includes several steps: calibration of each module of the ECal detector, identification of γ-quanta, reconstruction of γγ invariant mass spectra and subtraction of combinatorial background. The obtained results show experimental capabilities of the new detector and, after efficiency corrections, will allow to normalize yields of other particles.
Prospects of non-resonant Higgs pair production at the HL-LHC and HE-LHC
Authors: Adhikary Amit , Banerjee Shankha , Barman Rahool Kumar , Bhattacherjee Biplob , Niyogi Saurabh
Published: December 2020

The prospects of observing the di-Higgs production in the Standard Model (SM) is explored. We choose final states based on considerable production rate and cleanliness. Standard cut-based and multivariate analyses using the Boosted Decision Tree (BDT) algorithm is performed at the high luminosity run of the 14 TeV LHC (HL-LHC) and we got a combined signal significance of ∼ 2.1. For the proposed high energy upgrade of the LHC (HE-LHC) at

s

=
27

TeV

, we do multivariate analyses using BDT algorithm, the XGBoost toolkit and Deep Neural Network (DNN), and we observe a discovery prospect with > 5σ significance for the Higgs pair production.
Production of dijets with large rapidity separation at colliders
Authors: Egorov A Yu , Kim V T
Published: December 2020

Production of dijets with large rapidity separation at collider energies in modified logarithm approximations is considered. The results for resummations of different types of logarithms: soft-gluon, non-global and Sudakov ones are discussed. Calculations for various dijet observables are confronted with LHC data.
Cascade single stage Detector using full convolution network
Authors: Liu Ming , Yu Zhengfa , Fu Kai , Zhou Xiangming
Published: December 2020

For object detection, the two-stage approach always achieves better performance than one-stage. But one-stage is more effective. The main shortcomings of one-stage approach are: class imbalance problem during the training phase and sometimes the correct object score is lower. To address those problems, we propose a novel single-shot detector, called Cascade detection. It is composed of several stages, and each stage is composed of several detection layers. The main point of our method is: we design an anchors to anchors module (A2AM), which gives one-stage approach the ability of training stage by stage. It can not only address the class imbalance problem in the training phase, but also increase the object scores and the Iou between prediction and ground truth in the inference phase. The multitask loss function enables us to train the whole network in an end-to-end way. Experiments on PASCAL VOC 2007, PASCAL VOC 2012 and MS COCO prove that our method achieves state-of-art performance detection accuracy and computation efficiency.
Improved algorithm of decision tree based on neural network
Authors: Zhang Min , Peng Hongwei , Yan Xiaoling
Published: December 2020

Decision trees have been applied to solve many data mining problems due to their superior learning and classification capabilities, and have achieved good results. However, for dealing with big data and complex model problems, decision trees show insufficient accuracy and overfitting. In order to solve these problems, neural network is introduced as a decision tree node, and an improved algorithm based on neural network decision tree is proposed. In the neural network decision tree, the classifier learning consists of two stages: the first stage uses a heuristic algorithm with reduced uncertainty to divide the big data, and stops the growth of the decision tree until the node dividing ability is below a certain threshold; in the second stage, the neural network is used to classify the decision-making leaf node with generalization ability. The experimental results show that compared with the traditional classification learning algorithm, the algorithm has a higher accuracy rate and it can determine the size of decision tree through structural adaptation for the classification problem of identifying big data and complex patterns.
Multi-scale Correlation Filter Tracking Algorithm Based on Feature Fusion
Authors: Ren Xiaokang , Wang Hongxiang , Wang Yongye , Li Xingzhen , Liu Xingxing
Published: December 2020

For the Kernel Correlation Filter (KCF) algorithm using a single feature can not fully describe the tracking target, and is susceptible to the change of the target scale, lacking the estimation of the target scale size, an improved feature fusion and multi-scale correlation filter tracking algorithm based on KCF is proposed. Firstly, in the stage of location prediction, color features and directional gradient histogram hog features are fused by feature series, and feature dimensions are added to realize target location prediction. Then the scale filter is introduced into the predicted target position to estimate the optimal target scale as the tracking result. Experimental results show that the accuracy and success rate of the improved algorithm are significantly improved compared with other classical tracking algorithms, and it can deal with scale change, occlusion, deformation and other complex situations robustly.
The improved mayfly optimization algorithm with opposition based learning rules
Authors: Gao Zheng-Ming , Zhao Juan , Li Su-Ruo , Hu Yu-Rong
Published: December 2020

Literal researches proved that not only the best candidates or the best historical trajectories would perform well in guiding the individuals in swarms to find the best solution, the worst and the worst historical trajectories would also work well in doing so. Such situations could be directly treated as pairs of oppositions, and satisfied the ancient Chinese Yin-Yang philosophy, where the opposition based learning (OBL) rule was directly derived from. In this paper, the improved mayfly optimization (MO) algorithm with OBL rules were proposed, simulation experiments were carried out and results showed that the improved MO algorithm with OBL rules would perform better than usual.
Automatic segmentation of low-grade glioma in MRI image based on UNet++ model
Authors: Xu Dan , Zhou Xidong , Niu Xuefen , Wang Junwei
Published: December 2020

Glioma is one of the common brain tumors, and the prognosis of patients with low-grade glioma is relatively good. Therefore, this paper takes the segmentation of low-grade glioma as the research direction, and proposes an automatic segmentation algorithm of low-grade glioma MRI image based on UNet++. Firstly, the sample data in the data set is normalized, and then the sample data is divided into training set, verification set and test set, and data augmentation is performed on the training set; finally, all the data in the training set is used to train the network model. In the training process, in order to alleviate the over-fitting problem of model training, we draw into the dropout after each convolution layer. In order to verify the effectiveness of the proposed model, all intracranial tumor images of patients in the test sample set are selected for segmentation, and the final average Dice coefficient can reach: 89.1%. Compared with the segmentation algorithm based on U-Net, the average Dice coefficient of this algorithm is increased by 3.89%. The experimental results show that this algorithm can achieve better automatic segmentation results for low-level glioma images, provide effective reference for doctors’ diagnosis and surgery, and alleviate the problems of low accuracy and low efficiency caused by manual annotation of images only based on personal experience of doctors.
Multi-level Qualitative Reasoning Logic
Authors: Qin Zhen , Lu Peng , Liao Yuanxiu
Published: December 2020

Qualitative reasoning is a very efficient method that people often use to solve problems. Recently, the literature about qualitative reasoning as a causal analysis and decision-making tool has been emerging. However, the existing qualitative reasoning methods are mainly used for the modeling of imprecise problems. There are not many studies on formalization tools of qualitative “inference”. This paper proposes a logical system for qualitative reasoning (QRL). The main research contents include: the grammar and semantic structure of QRL are given; the meaning of formula logic truth value in QRL and its assignment rules are discussed; and the reliability and completeness of QRL are proved. Compared with fuzzy logic, probability logic and other uncertain reasoning methods, the advantage of QRL method is that it can use axiomatic reasoning method, and does not need to construct membership functions and collect a large number of samples.
An improved gesture recognition algorithm for human-robot collaboration
Authors: Liu Yiqun , Wang Xiaogang , He Yang , Mu Hua , Bai Yuewei
Published: December 2020

In this paper, an improved gesture recognition algorithm framework based on the improved SSD algorithm and OpenPose model for solving the robot’s mobile grasping problem in human-robot environment is proposed. Improved SSD algorithm by optimizing the front network of SSD algorithm and adjusting the prediction box is designed to identify the position of the hand rapidly, and to reduce the time for the training model. Testing experiments are perfomed for recognizing the hand’s key points information and eight designed gestures are compared with the traditional algorithm. The results show that the method can greatly improve the recognition distance of the original model under the dense environment, and also enhance the robustness and accuracy of the model, and have improved the ability of long-distance human-robot collaboration to a certain extent.
An Algorithm for Coalition Formation of Swarm Aerial Vehicles Considering Communication Constraints
Authors: Zhu Mengyuan , Lv Na , Chen Kefan , Xue Bin , Pan Ying
Published: December 2020

To realize efficient coalition formation of swarm aerial vehicles to attack static and dynamic targets on future battlefields, this study proposes a real-time dynamic network model that takes into consideration constraints in communication range and communication delay. Moreover, by using the improved particle swarm optimization algorithm for decision-making of coalition formation, the SAV resources are made best use of and the size of the coalition is minimized. The simulation result shows that in a dynamic network on the battlefield, the proposed model can realize communication and form coalitions, and the optimized algorithm shows higher efficiency than other algorithms in finding solutions. Monte-Carlo simulation result shows that when the communication delay is small, expanding the communication network to find potential coalition members can effectively reduce the time for task completion and improve the system’s overall performance, but when the communication delay is large, it is better to select coalition members from neighboring SAVs.
Thermo-e.m.f. of hot current carriers in non-doped and doped crystals of a layered semiconductor n-InSe
Authors: Abdinov A Sh , Babayeva R F
Published: December 2020

Thermo-e.m.f. of hot current carriers is experimentally investigated in non-doped n-InSe crystals with a dark specific resistance of 2·103≤ρD0
≤9·106Ω·cm at 77 K and doped with erbium with 10−5≤NEr
≤10−1at.%. It was found that its absolute value (|UT
|), in addition to

E
^

and T0
, also depends on ρD0
and N. In the non-doped samples with ρD0
≤1·104Ω·cm and doped with NEr
>10−2 at.%, the dependence

|

U
T

|
(

E
^

)

consists of successive sections:

|

U
T

|
∼

E
^

2

,
 
|

U
T

|
∼

E
^

and

|

U
T

|
∼

E
^

0.5

. In non-doped with ρD0
≥ 5·104 Ω·cm and alloyed with 10−5≤NEr
≤ 10−2 at.% samples at T0
< 250 K and low-heating

E
^

dependence

|

U
T

|
(

E
^

)

obeys the law

|

U
T

|
∼

E
^

κ

with 2<κ≤5. The value of k monotonously depends on NEr
and reaches its maximum value at NEr
=5·10−4 at.%. At T0
>250 K, in all the samples studied, as well as in non-doped low-resistance and doped with NEr
>10−2 at.% samples for all T0
, the dependence

|

U
T

|
(

E
^

)

follows the theory of thermo-e.m.f. of hot current carriers in spatially homogeneous crystalline semiconductors. To explain the results in non-doped high-resistance and doped with 10−5≤NEt
≤10−2 at.% samples at T0
<250 K, the influence of random macroscopic defects must also be taken into account. A qualitative explanation of the results is proposed.
Modeling of physical processes during the propagation of ultrasonic waves in metallic media
Authors: Mozhayko A A , Davydov V V , Rud V Yu
Published: December 2020

The paper deals with the features of modeling physical processes during the propagation of ultrasonic waves in metallic media. A mathematical model for the propagation of shear vertical (SV) ultrasonic waves generated by a single element of a 32-element electromagnetic acoustic phased array has been developed. The calculation of the acoustic field of the 32-element SV electromagnetic acoustic transducer (EMAT) phased array was made. The total displacements for models with defects and without them were calculated. A computer simulation of the process of reflection of the ultrasonic beam from a defect was made. The developed model allows one to study the influence of shape, size, location of defects in the plate as well as the plate geometric parameters on the formation of the reflected signal.
Dielectric properties of ferroelectric diisopropylammonium bromide embedded in porous glass
Authors: Milinskiy A Yu , Baryshnikov S V , Charnaya E V , Uskova N I
Published: December 2020

The results of studying the dielectric constant σ’ and the third harmonic coefficient γ3ω of a new organic ferroelectric diisopropylammonium bromide (C6H16NBr, DIPAB), embedded in porous glasses with an average pore size of 100 nm are presented. Diffusion and shifting of the phase transition to low temperatures by 5 K were detected in comparison with bulk DIPAB. A decrease in the phase transition temperature in nanocomposites with DIPAB nanoparticles is qualitatively consistent with theoretical models of the size effects on the structural phase transition.
The effect of electrochemical oxidation time on the surface morphology of oxidized indium phosphide
Authors: Chernov E A , Samsonov V A , Grebenshchikova E A , Spivak Y M
Published: December 2020

The surface features of oxide layers (< 100nm) grown on single-crystal n-InP (100) samples in acid electrolyte on initial stage were investigated by atomic force and lateral force microscopy. The time of electrochemical oxidation of samples was the variable parameter. There is difference found in the oxide layer phase structure grown in the electrolyte during different time. The initially formed (17 s) islands (a nucleated oxide phase) were divided, then coalescence appeared (26 s), and the occurrence of a second phase was detected. With an increase in the time (40 s) of oxidation, the surface morphology becomes more uniform.
Coarse-grained and ultrafine-grained titanium high-temperature creep
Authors: Narykova M V , Kadomtsev A G , Betekhtin V I , Kolobov Yu R , Manohin S S , Tokmacheva A Yu
Published: December 2020

The publication describes the study of durability in tensile creep of VT1-0 commercial titanium in its two states-coarse-grained and ultrafine-grained. It is shown that the best temperature for log-term testing is 350°C. At this temperature, the ultrafine-grained titanium structure remains stable both during free annealing and durability testing. The obtained data enable retrieving the difference in fracture initiation energies for titanium in its coarse-grained and ultrafine-grained states.
Peculiarities of prismatic input of narrow-band radiation into Ag-ion diffusion waveguide
Authors: Vasileva M V , Lihachev A I , Sokolov R V , Nashchekin A V
Published: December 2020

The peculiarities of prism coupling elements input and output of narrow-band radiation into ion diffusion waveguide are researched. Gradient waveguide with a thickness of 1.67 μm was formed by ion exchange in K8 glass. The output signal intensity dependence on the input and output angles of incidence radiation was measured by developed automatic hardware-software system based on synchronous detection method to improve the signal-to-noise ratio. It was shown the maximum of output signal is reached at equal input and output angles.
Phase sensitive amplification in a periodically poled gradient lithium niobate waveguide
Authors: Galutskiy V V , Ivashko S S , Stroganova E V
Published: December 2020

The article presents a phase sensitive amplifier based on cascaded second harmonic generation and difference frequency generation in a waveguide in the gradient periodically poled lithium niobate. The influence of the composition gradient in periodically poled lithium niobate on phase and spectral dependence of amplification factor is described. The increase of 35% is shown in spectral range of the gradient amplifier in comparison with the gradientless one in the range of 1.55 μm. The dependence of amplification factor of the optical signal from the propagation direction in the waveguide channel in gradient PPLN is also presented.
The dynamics of the spatiotemporal distribution of excited atoms in a nanosecond discharge with a slot cathode
Authors: Ashurbekov N A , Iminov K O , Shakhsinov G S , Zakaryaeva M Z
Published: December 2020

The work is devoted to the study of the spatiotemporal dynamics of the production of excited atoms in an extended nanosecond discharge with a slot cathode in neon at medium gas pressures. The authors experimentally investigated the frame-by-frame dynamics of the spatiotemporal formation of the discharge optical irradiation with an exposure time of 5 ns and time intervals between frames of 2 ns. Under similar conditions, the concentration of excited neon atoms at metastable levels with a time resolution of about 10 ns was measured by laser absorption spectroscopy, and the current-voltage characteristics of the discharge were experimentally determined in a wide range of amplitudes of voltage pulses and gas pressures in the range of 1–60 Torr. To analyze the kinetic processes in the plasma source under study, numerical simulation of ionization processes in the Comsol Multiphysics software environment was performed using a special Plasma module.
Disturbing action of a cubical obstacle on the turbulent vertical-plate free convection boundary layer: RANS-based simulation
Authors: Levchenya A M , Smirnov E M , Smirnovsky A A , Zasimova M A
Published: December 2020

Steady-state RANS simulations were performed to establish disturbing action of a cubical obstacle on the turbulent free convection boundary layer in air along a vertical isothermally heated plate. In the case considered, the size of the cube mounted on the plate is about one-third the full thickness of the incoming boundary layer. Using the k-ω SST turbulence model, refined-grid numerical solutions have been obtained assuming the obstacle surfaces either adiabatic or isothermal. Characteristic three-dimensional features of the free convection flow past the cubical obstacle, such as the horseshoe-like vortex structures and the near-wake recirculation, are analyzed in comparison with the previously studied case dealing with the disturbing action of a circular cylinder of unit aspect ratio. Data on heat transfer augmentation near the obstacle are presented and discussed.
Creating graphene and graphite coatings on metal field electron emitters to improve their characteristics
Authors: Bernatskii Dmitriy , Pavlov Victor
Published: December 2020

The growth of graphene and graphite structures during the catalytic dissociation of benzene molecules on the surface of iridium and rhenium field electron emitters was studied using field electron and desorption microscopy. The emission and operational characteristics of the manufacture emitters were studied. The carbon coating increases the resistance of emitters to adsorption of gas molecules and ion bombardment. The grown graphite crystal allows you to get a beam of electrons localized in a narrow angle when emitting from the angle of the crystal. Metal emitters with a carbon coating in relatively poor vacuum conditions have greater stability and longer lifetime compared to metal emitters.
Refinement of the Rotational Deformation of the Viscoelastic Earth
Authors: Skorobogatyh I.V. , Aung Myo Zo , Perepelkin V.V.
Published: December 2020

Using a modal approach, this work determined the deformations caused by the pole tide for the axisymmetric model of a deformable Earth with a viscoelastic layer. We compared centrifugal moments of inertia variations with generally accepted expressions. The main properties of the theoretical pole tide are considered in comparison with those observed on the basis of processing high-precision measurements of the gravity acceleration.
Evolution of stationary flows of a viscous incompressible fluid in a plane diffuser
Authors: Kumakshev S.A.
Published: December 2020

For the classical formulation of the Jeffery-Hamel problem of the stationary flows of a viscous incompressible fluid in a plane diffuser the solutions are found. The bifurcation of the basic single-mode flow into flows containing sectors of flow and outflow (multi-mode flows) is found. The second bifurcation point (the bifurcation of three mode flow into four and five modes flows) is analyzed as well as the third one. The values of Reynolds number corresponding to the bifurcation points are calculated. The dependence of first bifurcation value vs. the half-expansion angle is presented.
Comparative evaluation of the effectiveness of the separation process with various types of movement of the separating surface
Authors: Blagoveshchensky I G , Shkapov P M
Published: December 2020

An analysis is made of the comparative efficiency of the process of separating spherical particles of finely divided loose product with different types of motion of the separating surface. The influence on the efficiency of the process of separation of the kinematic parameters of the motion of the screen surface is considered. A probabilistic approach to the analysis of sieving efficiency is used.
Study of the influence of the substrate material on the phase composition and thickness of Ti-Pb coatings deposited by a magnetron
Authors: Lozovan A A , Betsofen S Ya , Lyakhovetsky M A , Pavlov Yu S , Grushin I A , Lebedev M A , Sukhova T S , Kubatina E P
Published: December 2020

The structure of coatings deposited by reactive magnetron sputtering of Ti and Pb cathodes on substrates from Mo, 30HGSA and 304 steel was studied by X-ray diffraction. The thickness of the coatings was determined by the difference between the CTE of the coating and the substrate, which is maximum for Mo coating and minimum for 304 steel, for which the thickest coating was found, consisting of tetragonal modifications of PbO.
Bone Marrow and Peripheral Blood Findings in Patients Infected by SARS-CoV-2
Authors: Harris Cynthia K , Hung Yin P , Nielsen G Petur , Stone James R , Ferry Judith A
Published: December 2020

Objectives

Coronavirus disease 19 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is associated with diverse clinical, including hematologic, abnormalities. We describe peripheral blood and bone marrow findings in deceased and living patients with COVID-19.

Methods

We examined bone marrows from 20 autopsies and 2 living patients with COVID-19 using H&E-stained slides and immunohistochemical stains. Clinical history and laboratory values were reviewed. HScore was calculated to estimate risk of hemophagocytic lymphohistocytosis (HLH).

Results

The deceased patients included 12 men and 8 women (aged 32 to >89 years; median, 63 years). Hematologic abnormalities included frequent neutrophilic leukocytosis, lymphopenia, anemia, and thrombocytopenia; one patient showed striking erythrocytosis. The bone marrows were all normocellular to hypercellular, most showing maturing trilineage hematopoiesis with myeloid left shift. In all 19 evaluable bone marrows, hemophagocytic histiocytes were identified. The HScore for secondary HLH ranged from 35 to 269 (median, 125; >169 in 5 patients). Coinfections were identified in 6 patients. In 2 living patients, bone marrow showed maturing trilineage hematopoiesis, including one showing few hemophagocytic histiocytes.

Conclusions

Peripheral blood from deceased patients with COVID-19 frequently showed neutrophilic leukocytosis, lymphopenia, and, rarely, secondary polycythemia; hemophagocytosis was common in their bone marrow. Consistent with other studies, we provide histopathologic evidence of secondary HLH development in patients with COVID-19.
Do Brief Alcohol Interventions Reduce Driving After Drinking Among College Students? A Two-step Meta-analysis of Individual Participant Data
Authors: Mun Eun-Young , Li Xiaoyin , Lineberry Shelby , Tan Zhengqi , Huh David , Walters Scott T , Zhou Zhengyang , Larimer Mary E ,   in Collaboration with Project INTEGRATE Team
Published: December 2020

Aims

College students who drink are at an increased risk of driving after drinking and alcohol-involved traffic accidents and deaths. Furthermore, the persistence of driving after drinking over time underscores a need for effective interventions to prevent future drunk driving in adulthood. The present study examined whether brief alcohol interventions (BAIs) for college students reduce driving after drinking.

Methods

A two-step meta-analysis of individual participant data (IPD) was conducted using a combined sample of 6801 college students from 15 randomized controlled trials (38% male, 72% White and 58% first-year students). BAIs included individually delivered Motivational Interviewing with Personalized Feedback (MI + PF), Group Motivational Interviewing (GMI), and stand-alone Personalized Feedback (PF) interventions. Two outcome variables, driving after two+/three+ drinks and driving after four+/five+ drinks, were checked, harmonized and analyzed separately for each study and then combined for meta-analysis and meta-regression analysis.

Results

BAIs lowered the risk of driving after four+/five+ drinks (19% difference in the odds of driving after drinking favoring BAIs vs. control), but not the risk of driving after two+/three+ drinks (9% difference). Subsequent subgroup analysis indicated that the MI + PF intervention was comparatively better than PF or GMI.

Conclusions

BAIs provide a harm reduction approach to college drinking. Hence, it is encouraging that BAIs reduce the risk of driving after heavy drinking among college students. However, there may be opportunities to enhance the intervention content and timing to be more relevant for driving after drinking and improve the outcome assessment and reporting to demonstrate its effect.
Estimation of the cure rate for distributions in the Gumbel maximum domain of attraction under insufficient follow-up
Authors: Escobar-Bach Mikael , Maller Ross , Van Keilegom Ingrid , Zhao Muzhi
Published: December 2020

Estimators of the cured proportion from survival data which may include observations on cured subjects can only be expected to perform well when the follow-up period is sufficient. When follow-up is not sufficient, and the survival distribution of those susceptible to the event belongs to the Fréchet maximum domain of attraction, a nonparametric estimator for the cure proportion proposed by Escobar-Bach & Van Keilegom (2019) incorporates an adjustment that reduces the bias in the usual estimator. Besides the Fréchet, an important class of limiting distributions for maxima is the Gumbel class. We show that a very wide class of commonly used survival distributions, the generalized Gamma distributions, are in the Gumbel domain of attraction. Extrapolation techniques from extreme value theory are then used to derive, for distributions in this class, a nonparametric estimator of the cure proportion that is consistent and asymptotically normally distributed under reasonable assumptions, and performs well in simulation studies with data where follow-up is insufficient. We illustrate its use with an application to survival data where patients with differing stages of breast cancer have varying degrees of follow-up.
Immunoglobulin-fold containing bacterial adhesins: molecular and structural perspectives in host tissue colonization and infection
Authors: Chatterjee Shruti , Basak Aditya J , Nair Asha V , Duraivelan Kheerthana , Samanta Dibyendu
Published: December 2020

Immunoglobulin (Ig) domains are one of the most widespread protein domains encoded by the human genome and are present in a large array of proteins with diverse biological functions. These Ig domains possess a central structure, the immunoglobulin-fold, which is a sandwich of two β sheets, each made up of anti-parallel β strands, surrounding a central hydrophobic core. Apart from humans, proteins containing Ig-like domains are also distributed in a vast selection of organisms including vertebrates, invertebrates, plants, viruses and bacteria where they execute a wide array of discrete cellular functions. In this review, we have described the key structural deviations of bacterial Ig-folds when compared to the classical eukaryotic Ig-fold. Further, we have comprehensively grouped all the Ig-domain containing adhesins present in both Gram-negative and Gram-positive bacteria. Additionally, we describe the role of these particular adhesins in host tissue attachment, colonization and subsequent infection by both pathogenic and non-pathogenic Escherichia coli as well as other bacterial species. The structural properties of these Ig-domain containing adhesins, along with their interactions with specific Ig-like and non Ig-like binding partners present on the host cell surface have been discussed in detail.
Step-by-Step Evolution of Telomeres: Lessons from Yeasts
Authors: Červenák Filip , Sepšiová Regina , Nosek Jozef , Tomáška Ľubomír
Published: December 2020

In virtually every eukaryotic species, the ends of nuclear chromosomes are protected by telomeres, nucleoprotein structures counteracting the end-replication problem and suppressing recombination and undue DNA repair. Although in most cases, the primary structure of telomeric DNA is conserved, there are several exceptions to this rule. One is represented by the telomeric repeats of ascomycetous yeasts, which encompass a great variety of sequences, whose evolutionary origin has been puzzling for several decades. At present, the key questions concerning the driving force behind their rapid evolution and the means of co-evolution of telomeric repeats and telomere-binding proteins remain largely unanswered. Previously published studies addressed mostly the general concepts of the evolutionary origin of telomeres, key properties of telomeric proteins as well as the molecular mechanisms of telomere maintenance; however, the evolutionary process itself has not been analyzed thoroughly. Here, we aimed to inspect the evolution of telomeres in ascomycetous yeasts from the subphyla Saccharomycotina and Taphrinomycotina, with special focus on the evolutionary origin of species-specific telomeric repeats. We analyzed the sequences of telomeric repeats from 204 yeast species classified into 20 families and as a result, we propose a step-by-step model, which integrates the diversity of telomeric repeats, telomerase RNAs, telomere-binding protein complexes and explains a propensity of certain species to generate the repeat heterogeneity within a single telomeric array.
Hyperplane Arrangements and Mixed Hodge Numbers of the Milnor Fiber
Authors: Kutler Max , Usatine Jeremy
Published: December 2020

For a complex central essential hyperplane arrangement $\mathcal{A}$, let $F_{\mathcal{A}}$ denote its Milnor fiber. We use Tevelev’s theory of tropical compactifications to study invariants related to the mixed Hodge structure on the cohomology of $F_{\mathcal{A}}$. We prove that the map taking an arrangement $\mathcal{A}$ to the Hodge-Deligne polynomial of $F_{\mathcal{A}}$ is locally constant on the realization space of any loop-free matroid. When $\mathcal{A}$ consists of distinct hyperplanes, we also give a combinatorial description for the homotopy type of the boundary complex of any simple normal crossing compactification of $F_{\mathcal{A}}$. As a direct consequence, we obtain a combinatorial formula for the top weight cohomology of $F_{\mathcal{A}}$, recovering a result of Dimca and Lehrer.
Whole-genome sequencing of strains of Vibrio spp. from China reveals different genetic contexts of blaCTX-M-14 among diverse lineages
Authors: Zheng Zhiwei , Ye Lianwei , Li Ruichao , Chen Sheng
Published: December 2020

Objectives

To investigate the prevalence and genetic contexts of the blaCTX-M-14 gene harboured by foodborne isolates of Vibrio spp. in China.

Methods

A total of 1856 Vibrio spp. isolates collected from raw meat and shrimp samples in Guangdong Province of China were screened for blaCTX-M-14 by PCR. The blaCTX-M-14-positive isolates were characterized by MIC, PFGE, MLST, conjugation, S1-PFGE and Southern blotting and WGS using Illumina and Nanopore platforms.

Results

A total of 35 (1.9%) Vibrio isolates were positive for blaCTX-M-14, including 33 Vibrio parahaemolyticus strains and two Vibrio alginolyticus strains. MLST showed that most of the blaCTX-M-14-bearing isolates could be assigned into two major STs, with ST163 being more prevalent (n = 23), followed by ST180 (n = 6). Whole-genome analysis of these 35 isolates revealed that the blaCTX-M-14 gene was associated with ISEcp1 in the upstream region, of which 32 blaCTX-M-14 genes were located in the same loci of chromosome I, 1 blaCTX-M-14 gene was located in a novel chromosomal integrative conjugative element (ICE) belonging to the SXT/R391 family and 2 blaCTX-M-14 genes were located in the same type of plasmid, which belonged to the IncP-1 group. Conjugation experiments showed that only the plasmid-borne blaCTX-M-14 gene could be transferred to the recipient strain Escherichia coli J53.

Conclusions

The emergence of the novel ICE and IncP-1 plasmids has contributed to the variable genetic contexts of blaCTX-M-14 among strains of Vibrio spp. and facilitated the horizontal transfer of such genes between Vibrio spp. and other zoonotic pathogens, resulting in a rapid increase in the prevalence of blaCTX-M-14-bearing bacterial pathogens worldwide.
Perfectly Tired: Perfectionism and Sleep in Adolescents With Chronic Pain
Authors: Clementi Michelle A , Gray Laura S , Bento Samantha P , Jervis Kelsey , Fletcher Angela A , Borner Kelsey , Randall Edin T
Published: December 2020

Objective

Conceptual links between perfectionism and chronic pain have been proposed yet minimal empirical data exists. Poor sleep is associated with high levels of perfectionism and is common among youth with chronic pain. This study explores associations between perfectionism and sleep quality in adolescents with chronic pain while considering levels of functional disability.

Methods

Adolescents (ages 12–18) with chronic pain (N = 423) completed baseline measures of self-oriented perfectionism (SOP), socially prescribed perfectionism (SPP), sleep quality, and functional disability as part of routine clinical care at an outpatient chronic pain clinic and a pain rehabilitation day treatment program. Multivariate multiple regression assessed associations between perfectionism (SOP and SPP) and sleep (falling asleep/reinitiating sleep, returning to wakefulness, and going to bed). Two moderation models explored how relations between perfectionism (SOP and SPP) and sleep quality (total score) varied depending on level of functional disability. All analyses controlled for clinic setting.

Results

Results indicated SPP was associated with more difficulties across all sleep subdomains in adolescents with chronic pain, while SOP was unrelated to sleep quality. Associations between perfectionism and sleep quality were dependent on functional disability; perfectionism was most strongly associated with worse sleep quality for adolescents with less functional disability.

Conclusions

This study highlights the relationship between perfectionism and sleep quality in adolescents with chronic pain and suggests that perfectionistic youth with less disability are at the greatest risk for sleep problems. Longitudinal research is needed to understand how perfectionism, sleep, and disability interact over time in youth with chronic pain.
Moral Entanglement: Taking Responsibility and Vicarious Responsibility
Authors: Goetze Trystan S.
Published: December 2020

Vicarious responsibility is sometimes analysed by considering the different kinds of agents involved—who is vicariously responsible for the actions of whom? In this paper, I discuss vicarious responsibility from a different angle: in what sense is the vicarious agent responsible? I do this by considering the ways in which one may take responsibility for events caused by another agent or process. I discuss three senses of taking responsibility—accepting fault, assuming obligations, and fulfilling obligations—and the forms of vicarious responsibility that correspond to these. I end by explaining how to judge which sense applies in a given case, based on the degree of (what I call) moral entanglement between the agent and what they should take responsibility for.
A Hole in the Box and a Pain in the Mouth
Authors: Casser Laurenz C , Schiller Henry Ian
Published: December 2020

The following argument is widely assumed to be invalid: there is a pain in my finger; my finger is in my mouth; therefore, there is a pain in my mouth. The apparent invalidity of this argument has recently been used to motivate the conclusion that pains are not spatial entities. We argue that this is a mistake. We do so by drawing attention to the metaphysics of pains and holes and provide a framework for their location which both vindicates the argument's validity and explains why it appears invalid. To this end, we show that previously proposed explanations for the apparent invalidity of the argument fail. Moreover, we show that our account accommodates and explains seemingly opposing linguistic data. We conclude that the ‘pain-in-mouth argument’ does not undermine the view that pains are spatial entities.