bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling the dynamics of an exoskeleton link of variable length using the Lagrange – Maxwell system of differential equations of motion
Authors:   Branch of the National Research University ", Blinov Alexander О. ,   MPEI",   in Smolensk, Andrey V. Borisov ,   Branch of the National Research University "MPEI" in Smolensk, Konchina Larisa V. ,   The Branch of National Research University MPEI in Smolensk, Maslova Kseniia S. ,   The Branch of National Research University MPEI in Smolensk, Filippenkov Konstantin D. ,   The Branch of National Research University MPEI in Smolensk
Published: June 2022

The objective of the study is the development of 3D variable-length link model with electric drives to be used in designing of next-generation comfortable exoskeletons. The developed link model has two inertial absolutely rigid sections on its ends and a variable- length section, considered weightless, in between. The mechanical part of the variable-length link model has been implemented in the universal computer math "Wolfram Mathematcia 11.3" environment by building the system of Lagrange – Maxwell differential equations. The electro-mechanical link model with electric drives has been implemented in the MatLab Simulink environment. The implemented model includes the following units: the trajectory synthesis unit per each degree of freedom, the unit for controlling torques calculation based on differential equations of motion, the unit for selecting electric motors with gears, the unit for calculating electric current per each motor and implementing the control system. The electric motors, reducers, rack and pinion gears implementing the specified and programmed link motion have been selected. The inertial and geometrical variable-length link parameters corresponding to the human tibia in the period of the single-support step phase have been selected. The drives implementing the link rotation are situated in the bottom link point in the combination of two orthogonal cylindrical hinges. One of these hinges is fixed to the supporting surface, the other one is fixed to the link end. This hinge combination simulates human ankle joint in the single-support step phase. The drive controlling the link length change is situated at the end of the bottom absolutely rigid weighty link section. The programmed trajectories for generalized coordinates are specified based on the simulation requirements of the anthropomorphic tibia motion. As a result, the electro-mechanical model of a variable- length link with parameters corresponding to the average man’s tibia has been developed. The drives and gears that allow implementing the motion close to anthropomorphic one have been selected. The implementation of this motion based on the developed software in the computer math "Wolfram Mathematica 11.3" environment and in the MatLab Simulink system has been demonstrated. The numerical calculations are presented.
Building and analyzing a machine learning model for short-term bitcoin market forecasting based on recurrent neural networks
Authors:   Synergy University, Trubin Alexander E. , Ozheredov Vadim A. ,   Synergy University; Space Research Institute of the Russian Academy of Sciences, Morozov Artem A. ,   Orel State University named aft I. S. Turgenev, Batishchev Alexander V. ,   Synergy University, Aleksahin Alexander N. ,   Synergy University, Filimonova Elena V. ,   Synergy University
Published: June 2022

In this article, the construction and analysis of machine learning models were performed for short-term forecasting in the cryptocurrency market on the example of bitcoin – one of the most popular cryptocurrencies in the world. The initial data for the study leads to the conclusion that over the long period of its existence, bitcoin has shown a high degree of volatility, especially evident in comparison with traditional financial instruments. The article substantiates that this market is influenced by a multitude of factors. No one can say for sure what makes up the value of a particular cryptocurrency, as it involves a range of reasons, which cannot be fully taken into account. To overcome this problem, we have considered the principle of recurrent neural network. It is described why networks with memory are better at making predictions on the time series than conventional autoregressive model and standard forward propagation networks. The initial data processing algorithm and transformation methods are defined. The sample was reduced in order to increase the speed of the network, by reducing the number of recalculations of weights. The algorithm of the family of recurrent neural networks was built and trained to test the hypothesis about their better adaptivity due to short-term and long-term memory. The model is evaluated on the test data representing the bitcoin exchange rate for 2021–2022, since this period is characterized by high volatility. It is concluded that it is reasonable to use a similar type of models for short-term forecasting of cryptocurrency rates.
Text sentiment analysis in banking
Authors:   Orel State University named aft I. S. Turgenev, Stroev Sergey P. , Zakharov Alexander V. ,   Synergy University, Meksheneva Zhanna V. ,   Synergy University, Shokolov Valentin V. ,   Raiffeisenbank JSC, Nechaev Andrey M. ,   Synergy University, Lyublinskaya Natalia N. ,   Synergy University
Published: June 2022

The paper presents the author's approach to solving the problem of sentiment analysis of online Russian-language messages about the activities of banks. The study data are customer reviews about banks in general and their products, services and quality of service posted on the Banki.ru portal. In this paper, the problem of text sentiment analysis is considered as a binary classification task based on a set of positive and negative reviews. A vector model with a tf-idf weighting scheme was used to represent the collected and preprocessed texts. The following algorithms with the selection of optimal parameters on the grid were used for binary classification task: naive Bayesian classifier, support vector machine, logistic regression, random forest and gradient boosting. Standard statistical metrics, such as accuracy, completeness, and F-measure, were used to evaluate the quality of solving the classification problem. For the indicated metrics, the best results were obtained on the classification model developed with the use of Support Vector Machine. Thematic text modeling was also carried out using the Dirichlet latent placement method to define the most typical topics of customer messages. As a result, it was concluded that the most popular message topics are "cards" and "quality of service". The obtained results can be used in the activities of banks to automate its reputation monitoring in the media and when routing client requests to solve various problems. When solving problems, the features of the Python programming language were actively used, namely, libraries for web scraping, machine learning, and natural language processing.
Alcaraz y la Virgen de Cortes en la fotografía y pintura de Pedro Román
Authors: Sánchez Ferrer José , Andrinal Román Lorenzo
Published: June 2022

Pedro Román Martínez fue un artista que nació en Alcaraz en 1878 y aunque a los doce años tuvo que irse con su familia a vivir a Toledo no dejó de estar vinculado a su pueblo natal, al que volvió en numerosas ocasiones y en el que pasó largas temporadas durante las que fotografió y pintó sus paisajes, monumentos, calles, gentes y tradiciones, dejándonos un extraordinario legado gráfico del Alcaraz del primer cuarto del siglo XX. Buena parte del conjunto de fotografías que hizo tienen como referente a la Virgen de Cortes. Durante un cuarto de siglo fotografió la imagen, siempre vestida, su santuario, las romerías y ferias del 7 y 8 de septiembre y la Coronación del 1 de mayo de 1922, siendo el único fotógrafo, que se sepa, que dejó testimonio visual de los actos, celebraciones y romería de ese día singular; su aportación es esencial para conocer muchos aspectos del importantísimo homenaje y de la honda manifestación de devoción que los miles de fieles de esta Virgen le ofrecieron hace cien años.
Out of COVID
Authors: Ott Konrad
Published: June 2022

Im Zentrum des Beitrags von Konrad Ott steht das Thema der Nachhaltigkeitspolitik nach der Pandemie. Er gliedert sich in drei Teile. Zunächst wendet sich Ott dem ›Vorher‹ zu, das heißt dem Status quo ante vor der Pandemie.
Aus der Pers­pektive eines Zeitzeugens gibt er in diesem Abschnitt einen kursorischen Rückblick auf 40 Jahre Umweltpolitik vor 2019. Im zweiten Teil legt er eine Art Phänomenologie (in einem weiten Verständnis dieser
philo­sophischen Methodik) von Alltags- und Naturerfahrungen im ›Während‹ dar. Der dritte Teil des Beitrags betrifft das ›Danach‹ in normativer und politisch orientierender Absicht.

Konrad Ott's paper focuses on the topic of sustainability policy after the pandemic. It is divided into three parts. First, Ott turns to the ›before‹, i.e. the status quo ante before the pandemic.
From the perspective of a contemporary witness, he gives in this section a cursory review of 40 years of environmental policy before 2019. In the second part, he presents a kind of phenomenology
(in a broad understanding of this philosophical methodology) of everyday and natural experiences in the ›while‹. The third part of the contribution concerns the ›after‹ in normative and
politically orienting intent.
ASSOTIATION OF THE GENETIC POLYMORPHISM E670G OF THE PCSK-9 AND THE SEVERITY OF THE CAROTID ATHEROSCLEROSIS IN PATIENTS WITH HETEROZYGOUS FAMILIAL HYPERCHOLESTEROLEMIA IN UZBEK POPULATION
Authors: Alieva R. B. , Hoshimov S. U. , Ahmedova Sh. S. , Bekmetova F. M. , Shek A. B. , Kurbanov R. D.
Published: June 2022

Objective: to study the severity of carotid artery atherosclerosis in patients with heterozygous familial hypercholesterolemia in the Uzbek population, depending on the level of PCSK-9 and the genetic polymorphism E670G of the PCSK-9 gene.

Material and methods. The study included 57 patients with chronic stable coronary artery disease (SCAD) and familial heterozygous hypercholesterolemia (HeFH, group I). The comparison group consisted of 144 patients with SCAD without HeFH divided into two subgroups: A - statin free before the research (n=63) and B (n=81) who took it as outpatients; control group consisted of 17 healthy people. The level of proprotein convertase subtilisin-kexin type 9 (PCSK-9) was measured with Human Proprotein Convertase 9/PCSK9 ELISA Kit (MULTI SCIENCE, China). The genetic typing of PCSK9 E670G (rs505151) polymorphism was performed by means of the PCR-RFLP method.

Results. A comparison of the results of duplex scanning of carotid arteries in patients with HeFH showed that the carotid intima-media thickness (CIMT) on the left (1.14±0.18 mm, P<0.01) and on the right (1.15±0.16 mm, P<0.01) was higher, than in the comparison group: 1.05±0.17 mm and 1.04±0.18 mm, respectively. The studies revealed a positive correlation between the incidence of Myocardial infarction (MI) in the history in patients with HeFH and the (r=0.38, P<0.05). The CIMT also correlated with an increase in the concentration of PCSK9 (r = 0.31, P <0.05) in the blood and the carriage of the G allele of polymorphism E670G (r = 0.39, P <0.05) of the PCSK9 gene.

Conclusion. Inpatientswithheterozygousfamilialhypercholesterolemia in the Uzbek population a direct correlation was established between Myocardial infarction in the history, the carotid intima-media thickness, an increase in the concentration of PCSK-9 in the blood and the carriage of the G allele of E670G polymorphism of the PCSK9 gene, that allows them to be used as prognostic markers for the risk of development of cardiovascular complications.
THE SEVERITY OF THE CLINICAL MANIFESTATIONS OF CHRONIC VENOUS DISEASES IN MEN, DEPENDING ON THE DEGREE OF ARTERIAL HYPERTENSION
Authors: Baev V. M. , Vagapov T. F.
Published: June 2022

Study of the effect of the degree of arterial hypertension (AH) on the severity of the clinical manifestations of chronic venous disease (CVD) of the lower extremities in men of working age.

Material and methods. A comparative analysis of the clinical severity and severity of CVD (diagnosed by CEAP) was performed using the VCSS scale of two groups of male patients with hypertension aged 3055 years. Group 1 - 40 patients with 1 degree of hypertension (SBP 143 (140-147) mmHg, DBP 92 (90-95) mmHg) and group 2 - 34 patients with 2 and 3 degrees of hypertension (SBP 164 (156-179) mmHg, DBP 107 (101-109) mmHg). Comparison of shares is performed using the contingency table using the X2 criterion.

Results. Symptoms of chronic venous diseases such as pain, varicose veins, edema and hyperpigmentation, have been reported in the observed patients. Signs with greater severity were not noted. Leg pain (p = 0.047) and edema (p = 0.002) were more often diagnosed in patients with grade 2 and 3 hypertension than in patients with grade 1 hypertension.

Conclusion. The severity of hypertension worsens the clinic of chronic venous diseases in men 30-55 years old.
LONG-TERM CARDIOVASCULAR COMPLICATIONS IN ONCOLOGIC PATIENTS AFTER ANTITUMOR THERAPY (>1 YEAR)
Authors: Kazantseva M. L. , Oshchepkova E. V. , Saidova M. A. , Avalyan A. A. , Chazova I. F.
Published: June 2022

Oncological and cardiovascular diseases (CVD) hold a leading position among the causes of mortality in many countries of the world, including the Russian Federation [1]. In recent years, a decrease in mortality due to oncologic diseases (OD) is noted around the world thanks to early diagnostics, as well as to the development and implementation of new technologies and therapeutic treatment strategies (chemotherapy, targeted and radiation therapy). Among patients with OD who received chemotherapy and radiation therapy, CVD is one of the leading causes of poor prognosis, including lethal outcomes [2-5]. The long-term cardiotoxic effects of antitumor therapy (chemotherapy, radiation therapy) reduce the survival rate and quality of life of patients who suffer from cancer. Thus, early diagnostics and timely detection of the cardiotoxic effects that follow antitumor treatment is one of the main tasks of cardio-oncology.
Where to Find Overmassive Brown Dwarfs: New Benchmark Systems for Binary Evolution
Authors: Majidi Dorsa , Forbes John C. , Loeb Abraham
Published: June 2022

Under the right conditions, brown dwarfs that gain enough mass late in their lives to cross the hydrogen-burning limit will not turn into low-mass stars, but rather remain essentially brown dwarf–like. While these objects, called either beige dwarfs or overmassive brown dwarfs, may exist in principle, it remains unclear exactly how they would form astrophysically. We show that accretion from AGB winds, aided by the wind Roche lobe overflow mechanism, is likely to produce a substantial population of observable overmassive brown dwarfs, though other mechanisms are still plausible. Specifically, we predict that Sun-like stars born with a massive brown dwarf companion on an orbit with a semimajor axis of order 10 au will likely produce overmassive brown dwarfs, which may be found today as companions to the donor star's remnant white dwarf. The identification and characterization of such an object would produce unique constraints on binary evolution, because there is a solid upper limit on the brown dwarf's initial mass.
Bursting Bubbles: Feedback from Clustered Supernovae and the Trade-off Between Turbulence and Outflows
Authors: Orr Matthew E. , Fielding Drummond B. , Hayward Christopher C. , Burkhart Blakesley
Published: June 2022

We present an analytic model for clustered supernovae (SNe) feedback in galaxy disks, incorporating the dynamical evolution of superbubbles formed from spatially overlapping SNe remnants. We propose two realistic outcomes for the evolution of superbubbles in galactic disks: (1) the expansion velocity of the shock front falls below the turbulent velocity dispersion of the interstellar medium in the galaxy disk, whereupon the superbubble stalls and fragments, depositing its momentum entirely within the galaxy disk; or (2) the superbubble grows in size to reach the gas scale height, breaking out of the galaxy disk and driving galactic outflows/fountains. In either case, we find that superbubble breakup/breakout almost always occurs before the last Type II SN (≲40 Myr) in the recently formed star cluster, assuming a standard high-end initial mass function slope, and scalings between stellar lifetimes and masses. The threshold between these two cases implies a break in the effective strength of feedback in driving turbulence within galaxies, and a resulting change in the scalings of, for example, star formation rates with gas surface density (the Kennicutt–Schmidt relation) and the star formation efficiency in galaxy disks.
Numerical Modeling of Spectral Hardening at a Finite-width Shock
Authors: Xu Y. D. , Li G. , Yao S.
Published: June 2022

Spectral hardening has been identified in solar flare hard X-ray observations for several decades and remains a puzzle. We examine spectral hardening under the diffusive shock acceleration mechanism using numerical simulations. The hardening is related to the finite width of the shock and is controlled by the shock Péclet number. We implement two different types of Monte Carlo simulations. The first is based on the backward stochastic differential equation method, where the Parker transport equation is solved by casting it to a set of stochastic different equations, and by following the trajectories of individual quasiparticles. In the second approach, we follow real particles and particles are assumed to move freely between scatterings from magnetic turbulence in the plasma. The scattering is modeled as either large-angle hard-sphere elastic collision, or small-angle pitch-angle scattering. We show that the results from these two approaches agree well with each other and agree with analytical results. We also use a Pan-spectrum form to fit the resulting spectra.
The Mechanism of Efficient Electron Acceleration at Parallel Nonrelativistic Shocks
Authors: Shalaby Mohamad , Lemmerz Rouven , Thomas Timon , Pfrommer Christoph
Published: June 2022

Thermal electrons cannot directly participate in the process of diffusive acceleration at electron–ion shocks because their Larmor radii are smaller than the shock transition width: this is the well-known electron injection problem of diffusive shock acceleration. Instead, an efficient pre-acceleration process must exist that scatters electrons off of electromagnetic fluctuations on scales much shorter than the ion gyroradius. The recently found intermediate-scale instability provides a natural way to produce such fluctuations in parallel shocks. The instability drives comoving (with the upstream plasma) ion–cyclotron waves at the shock front and only operates when the drift speed is smaller than half of the electron Alfvén speed. Here we perform particle-in-cell simulations with the SHARP code to study the impact of this instability on electron acceleration at parallel nonrelativistic, electron–ion shocks. To this end, we compare a shock simulation in which the intermediate-scale instability is expected to grow to simulations where it is suppressed. In particular, the simulation with an Alfvénic Mach number large enough to quench the intermediate instability shows a great reduction (by two orders of magnitude) of the electron acceleration efficiency. Moreover, the simulation with a reduced ion-to-electron mass ratio (where the intermediate instability is also suppressed) not only artificially precludes electron acceleration but also results in erroneous electron and ion heating in the downstream and shock transition regions. This finding opens up a promising route for a plasma physical understanding of diffusive shock acceleration of electrons, which necessarily requires realistic mass ratios in simulations of collisionless electron–ion shocks.
ALMA Lensing Cluster Survey: ALMA-Herschel Joint Study of Lensed Dusty Star-forming Galaxies across z ≃ 0.5 – 6
Authors: Sun Fengwu , Egami Eiichi , Fujimoto Seiji , Rawle Timothy , Bauer Franz E. , Kohno Kotaro , Smail Ian , Pérez-González Pablo G. , Ao Yiping , Chapman Scott C. , Combes Francoise , Dessauges-Zavadsky Miroslava , Espada Daniel , González-López Jorge , Koekemoer Anton M. , Kokorev Vasily , Lee Minju M. , Morokuma-Matsui Kana , Muñoz Arancibia Alejandra M. , Oguri Masamune , Pelló Roser , Ueda Yoshihiro , Uematsu Ryosuke , Valentino Francesco , Van der Werf Paul , Walth Gregory L. , Zemcov Michael , Zitrin Adi
Published: June 2022

We present an ALMA-Herschel joint analysis of sources detected by the ALMA Lensing Cluster Survey (ALCS) at 1.15 mm. Herschel/PACS and SPIRE data at 100–500 μm are deblended for 180 ALMA sources in 33 lensing cluster fields that are detected either securely (141 sources; in our main sample) or tentatively at S/N ≥ 4 with cross-matched HST/Spitzer counterparts, down to a delensed 1.15 mm flux density of ∼0.02 mJy. We performed far-infrared spectral energy distribution modeling and derived the physical properties of dusty star formation for 125 sources (109 independently) that are detected at >2σ in at least one Herschel band. A total of 27 secure ALCS sources are not detected in any Herschel bands, including 17 optical/near-IR-dark sources that likely reside at z = 4.2 ± 1.2. The 16th, 50th, and 84th percentiles of the redshift distribution are 1.15, 2.08, and 3.59, respectively, for ALCS sources in the main sample, suggesting an increasing fraction of z ≃ 1 − 2 galaxies among fainter millimeter sources (f
1150 ∼ 0.1 mJy). With a median lensing magnification factor of

μ
=

2.6

−
0.8

+
2.6

, ALCS sources in the main sample exhibit a median intrinsic star formation rate of

94

−
54

+
84

M
⊙ yr−1, lower than that of conventional submillimeter galaxies at similar redshifts by a factor of ∼3. Our study suggests weak or no redshift evolution of dust temperature with L
IR < 1012
L
⊙ galaxies within our sample at z ≃ 0 − 2. At L
IR > 1012
L
⊙, the dust temperatures show no evolution across z ≃ 1–4 while being lower than those in the local universe. For the highest-redshift source in our sample (z = 6.07), we can rule out an extreme dust temperature (>80 K) that was reported for MACS0416 Y1 at z = 8.31.
Generalized Fluid Models of the Braginskii Type
Authors: Hunana P. , Passot T. , Khomenko E. , Martínez-Gómez D. , Collados M. , Tenerani A. , Zank G. P. , Maneva Y. , Goldstein M. L. , Webb G. M.
Published: June 2022

Several generalizations of the well-known fluid model of Braginskii (1965) are considered. We use the Landau collisional operator and the moment method of Grad. We focus on the 21-moment model that is analogous to the Braginskii model, and we also consider a 22-moment model. Both models are formulated for general multispecies plasmas with arbitrary masses and temperatures, where all of the fluid moments are described by their evolution equations. The 21-moment model contains two “heat flux vectors” (third- and fifth-order moments) and two “viscosity tensors” (second- and fourth-order moments). The Braginskii model is then obtained as a particular case of a one ion–electron plasma with similar temperatures, with decoupled heat fluxes and viscosity tensors expressed in a quasistatic approximation. We provide all of the numerical values of the Braginskii model in a fully analytic form (together with the fourth- and fifth-order moments). For multispecies plasmas, the model makes the calculation of the transport coefficients straightforward. Formulation in fluid moments (instead of Hermite moments) is also suitable for implementation into existing numerical codes. It is emphasized that it is the quasistatic approximation that makes some Braginskii coefficients divergent in a weakly collisional regime. Importantly, we show that the heat fluxes and viscosity tensors are coupled even in the linear approximation, and that the fully contracted (scalar) perturbations of the fourth-order moment, which are accounted for in the 22-moment model, modify the energy exchange rates. We also provide several appendices, which can be useful as a guide for deriving the Braginskii model with the moment method of Grad.
New Fe i Level Energies and Line Identifications from Stellar Spectra. III. Initial Results from UV, Optical, and Infrared Spectra
Authors: Peterson Ruth C. , Kurucz Robert L.
Published: June 2022

The spectrum of neutral iron is critical to astrophysics, yet furnace laboratory experiments cannot reach high-lying Fe i levels. Instead, Peterson & Kurucz and Peterson et al. adopted ultraviolet (UV) and optical spectra of warm stars to identify and assign energies for 124 Fe i levels with 1900 detectable Fe i lines, and to derive astrophysical gf values for over 1000 of these. An energy value was assumed for each unknown Fe i level, and confirmed if the wavelengths predicted in updated Kurucz Fe i calculations matched the wavelengths of four or more unidentified lines in the observed spectra. Nearly all these identifications were for LS levels, those characterized by spin–orbit coupling, whose lines fall primarily at UV and optical wavelengths. This work contributes nearly 100 new Fe i level identifications. Thirty-nine LS levels are identified largely by incorporating published positions of unidentified laboratory Fe i lines with wavelengths <2000 Å. Adding infrared (IR) spectra provided 60 Fe i jK levels, where a single outer electron orbits a compact core. Their weak IR lines are searchable, because their mutual energies obey tight relationships. For each new Fe i level, this work again makes publicly available its identification, its energy, and a list of its potentially detectable lines with theoretical gf values, totalling >16,000 lines. For over 2000 of these, this work provides astrophysical gf values adjusted semiempirically to fit the stellar spectra. The potential impact of this work on modeling UV and IR stellar spectra is noted.
A Compound Poisson Generator Approach to Point-source Inference in Astrophysics
Authors: Collin Gabriel H. , Rodd Nicholas L. , Erjavec Tyler , Perez Kerstin
Published: June 2022

The identification and description of point sources is one of the oldest problems in astronomy, yet even today the correct statistical treatment for point sources remains one of the field’s hardest problems. For dim or crowded sources, likelihood-based inference methods are required to estimate the uncertainty on the characteristics of the source population. In this work, a new parametric likelihood is constructed for this problem using compound Poisson generator (CPG) functionals that incorporate instrumental effects from first principles. We demonstrate that the CPG approach exhibits a number of advantages over non-Poissonian template fitting (NPTF)—an existing method—in a series of test scenarios in the context of X-ray astronomy. These demonstrations show that the effect of the point-spread function, effective area, and choice of point-source spatial distribution cannot, generally, be factorized as they are in NPTF, while the new CPG construction is validated in these scenarios. Separately, an examination of the diffuse-flux emission limit is used to show that most simple choices of priors on the standard parameterization of the population model can result in unexpected biases: when a model comprising both a point-source population and diffuse component is applied to this limit, nearly all observed flux will be assigned to either the population or to the diffuse component. A new parameterization is presented for these priors that properly estimates the uncertainties in this limit. In this choice of priors, CPG correctly identifies that the fraction of flux assigned to the population model cannot be constrained by the data.
The R-process Alliance: A Nearly Complete R-process Abundance Template Derived from Ultraviolet Spectroscopy of the R-process-enhanced Metal-poor Star HD 222925*
Authors: Roederer Ian U. , Lawler James E. , Den Hartog Elizabeth A. , Placco Vinicius M. , Surman Rebecca , Beers Timothy C. , Ezzeddine Rana , Frebel Anna , Hansen Terese T. , Hattori Kohei , Holmbeck Erika M. , Sakari Charli M.
Published: June 2022

We present a nearly complete rapid neutron-capture process (r-process) chemical inventory of the metal-poor ([Fe/H] = −1.46 ± 0.10) r-process-enhanced ([Eu/Fe] = +1.32 ± 0.08) halo star HD 222925. This abundance set is the most complete for any object beyond the solar system, with a total of 63 metals detected and seven with upper limits. It comprises 42 elements from 31 ≤ Z ≤ 90, including elements rarely detected in r-process-enhanced stars, such as Ga, Ge, As, Se, Cd, In, Sn, Sb, Te, W, Re, Os, Ir, Pt, and Au. We derive these abundances from an analysis of 404 absorption lines in ultraviolet spectra collected using the Space Telescope Imaging Spectrograph on the Hubble Space Telescope and previously analyzed optical spectra. A series of appendices discusses the atomic data and quality of fits for these lines. The r-process elements from Ba to Pb, including all elements at the third r-process peak, exhibit remarkable agreement with the solar r-process residuals, with a standard deviation of the differences of only 0.08 dex (17%). In contrast, deviations among the lighter elements from Ga to Te span nearly 1.4 dex, and they show distinct trends from Ga to Se, Nb through Cd, and In through Te. The r-process contribution to Ga, Ge, and As is small, and Se is the lightest element whose production is dominated by the r-process. The lanthanide fraction, log X
La = −1.39 ± 0.09, is typical for r-process-enhanced stars and higher than that of the kilonova from the GW170817 neutron-star merger event. We advocate adopting this pattern as an alternative to the solar r-process-element residuals when confronting future theoretical models of heavy-element nucleosynthesis with observations.
NuSTAR Observations of 52 Compton-thick Active Galactic Nuclei Selected by the Swift/Burst Alert Telescope All-sky Hard X-Ray Survey
Authors: Tanimoto Atsushi , Ueda Yoshihiro , Odaka Hirokazu , Yamada Satoshi , Ricci Claudio
Published: June 2022

We present systematic broadband X-ray spectral analysis of 52 Compton-thick (

24
≤
log

N

H

LOS

/

cm

−
2

) active galactic nucleus (CTAGN) candidates selected by the Swift/Burst Alert Telescope all-sky hard X-ray survey observed with Chandra, X-ray Multi-Mirror Mission-Newton (XMM-Newton), Swift/X-Ray Telescope, Suzaku, and NuSTAR. The XMM-Newton data of 10 objects and the NuSTAR data of 15 objects are published for the first time. We use an X-ray spectral model from a clumpy torus (XClumpy) to determine the torus properties. As a result, the hydrogen column density along the line of sight

N

H

LOS

obtained from the XClumpy model indicates that 24 objects are Compton-thin AGNs and 28 objects are CTAGNs in a 90% confidence interval. The main reason is the difference in the torus model applied. The hydrogen column density along the equatorial direction

N

H

Equ

of CTAGNs inferred from the XClumpy model is larger than that of less obscured AGNs. The Compton-thin torus covering factor C
22 obtained from the XClumpy model is consistent with that of Ricci et al. in the low Eddington ratio (

log

R

Edd

≤
−
1.0

), whereas C
22 inferred from the XClumpy model is larger than that of Ricci et al. in the high Eddington ratio (

−
1.0
≤
log

R

Edd

). The average value of the Compton-thick torus covering factor C
24 obtained from the XClumpy model is

36

−
4

+
4

%. This value is larger than that of Ricci et al. (

C

24

≃

27

−
4

+
4

%) based on the assumption that all AGNs have intrinsically the same torus structure. These results suggest that the structure of CTAGNs may be intrinsically different from that of less obscured AGNs.
Three-month Monitoring of the Variability toward W51 IRS2 with Ammonia, Water, and Methanol Transitions
Authors: Zhang Yan-Kun , Chen Xi , Sobolev Andrej M. , Shen Zhi-Qiang , Li Bin , Zhao Zhang
Published: June 2022

A four-epoch monitoring program spanning ∼three months (from 2020 January 8 to April 7) for ammonia, water, and methanol transitions toward the high-mass star-forming region W51 IRS2 was conducted using the Shanghai 65 m Tianma Radio Telescope with its K-band (18–26.5 GHz) receiver. In total, 33 ammonia transitions and 16 methanol transitions were detected toward the target at least once during this monitoring program. Among them, 14 ammonia and 4 methanol transitions show maser emission characteristics. Rapid variabilities (including both increases and decreases) in the ammonia and methanol transitions were detected from both maser and thermal emissions during the three months of the monitoring. In addition, H2O masers with obvious variability were also detected. The results of the rotation diagram analysis for the ammonia and methanol quasi-thermal transitions show the variations in their rotational temperatures during the monitoring. The derived temperatures from the transitions with larger upper energies (E

u
/κ) generally decreased over the whole monitoring period, from January 8 to April 7, but those with smaller E

u
/κ first increased from January 8 to April 1, then rapidly decreased from April 1 to April 7. These findings support the suggestion that an inside-out heatwave propagation in W51 IRS2 was involved with the accretion burst over a short duration (only on the order of months) and caused the drastic variability behaviors of the different line transitions during high-mass star formation.
An Insight-HXMT Dedicated 33 day Observation of SGR J1935+2154. I. Burst Catalog
Authors: Cai Ce , Xue Wang-Chen , Li Cheng-Kui , Xiong Shao-Lin , Zhang Shuang-Nan , Lin Lin , Li Xiao-Bo , Ge Ming-Yu , Zhao Hai-Sheng , Song Li-Ming , Lu Fang-Jun , Zhang Shu , Zhang Yan-Qiu , Xiao Shuo , Tuo You-Li , Yi Qi-Bin , Wei Guo Zhi , Lun Xie Sheng , Zhao Yi , Zhang Zhen , Li Qing-Xin , Liu Jia-Cong , Zheng Chao , Wang Ping
Published: June 2022

Magnetars are neutron stars with an extreme magnetic field and sometimes manifest as soft gamma-ray repeaters (SGRs). SGR J1935+2154 is one of the most prolific bursters and the first confirmed source of a fast radio burst (FRB; i.e., FRB 200428). Encouraged by the discovery of the first X-ray counterpart of FRBs, the Insight-Hard X-ray Modulation Telescope (Insight-HXMT) implemented a dedicated 33-day-long Target of Opportunity observation of SGR J1935+2154 since 2020 April 28. With the HE, ME, and LE telescopes, Insight-HXMT provides a thorough monitoring of burst activity evolution of SGR J1935+2154, in a very broad energy range (1–250 keV) with high temporal resolution and high sensitivity, resulting in a unique valuable data set for detailed studies of SGR J1935+2154. In this work, we conduct a comprehensive analysis of this observation, including detailed burst search, identification, and temporal analyses. After carefully removing false triggers, we find a total of 75 bursts from SGR J1935+2154, out of which 70 are single pulsed. The maximum burst rate is about 56 bursts day−1. Both the burst duration and the waiting time between two successive bursts follow lognormal distributions, consistent with previous studies. We also find that bursts with longer duration (some are multipulsed) tend to occur during the period with relatively high burst rate. There is no correlation between the waiting time and the fluence or duration of either the former or latter burst. It also seems that there is no correlation between burst duration and hardness ratio, in contrast to some previous reports. In addition, we do not find any X-ray burst associated with any reported radio bursts except for FRB 200428.
Dust Extinction Law in Nearby Star-resolved Galaxies. II. M33 Traced by Supergiants
Authors: Wang 王 Yuxi 钰溪 , Gao 高 Jian 健 , Ren 任 Yi 逸 , Chen 陈 Bingqiu 丙秋
Published: June 2022

The dust extinction curves toward individual sight lines in M33 are derived for the first time with a sample of reddened O-type and B-type supergiants obtained from the Local Group Galaxies Survey (LGGS). The observed photometric data are obtained from the LGGS, PS1 Survey, UKIRT, PHATTER Survey, Galaxy Evolution Explorer, Swift/UVOT, and XMM-SUSS. We combine the intrinsic spectral energy distributions (SEDs) obtained from the ATLAS9 and Tlusty stellar model atmosphere extinguished by the model extinction curves from the silicate-graphite dust model to construct model SEDs. The extinction traces are distributed along the arms in M33, and the derived extinction curves cover a wide range of shapes (R

V
≈ 2–6), indicating the complexity of the interstellar environment and the inhomogeneous distribution of interstellar dust in M33. The average extinction curve with R

V
≈ 3.39 and dust size distribution

dn

/

da
∼

a

−
3.45

exp
(
−
a

/

0.25
)

is similar to that of the Milky Way but with a weaker 2175 Å bump and a slightly steeper rise in the far-UV band. The extinction in the V band of M33 is up to 2 mag, with a median value of A

V
≈ 0.43 mag. The multiband extinction values from the UV to IR bands are also predicted for M33, which will provide extinction corrections for future works. The method adopted in this work is also applied to other star-resolved galaxies (NGC 6822 and WLM), but only a few extinction curves can be derived because of the limited observations.
Can We Detect Coronal Mass Ejections through Asymmetries of Sun-as-a-star Extreme-ultraviolet Spectral Line Profiles?
Authors: Yang 杨 Zihao 子浩 , Tian 田 Hui 晖 , Bai Xianyong , Chen Yajie , Guo Yang , Zhu 朱 Yingjie 英杰 , Cheng Xin , Gao 高 Yuhang 宇航 , Xu 徐 Yu 昱 , Chen Hechao , Zhang Jiale
Published: June 2022

Coronal mass ejections (CMEs) are the largest-scale eruptive phenomena in the solar system. Associated with enormous plasma ejections and energy releases, CMEs have an important impact on the solar–terrestrial environment. Accurate predictions of the arrival times of CMEs at the Earth depend on precise measurements of their 3D velocities, which can be achieved by using simultaneous line-of-sight (LOS) and plane-of-sky (POS) observations. Besides the POS information from routine coronagraph and extreme-ultraviolet (EUV) imaging observations, spectroscopic observations could unveil the physical properties of CMEs, including their LOS velocities. We propose that spectral line asymmetries measured by Sun-as-a-star spectrographs can be used for routine detections of CMEs and estimations of their LOS velocities during their early propagation phases. Such observations can also provide important clues for the detection of CMEs on other solar-like stars. However, few studies have concentrated on whether we can detect CME signals and accurately diagnose CME properties through Sun-as-a-star spectral observations. In this work, we construct a geometric CME model and derive the analytical expressions for full disk-integrated EUV line profiles during CMEs. For different CME properties and instrumental configurations, the full disk-integrated line profiles are synthesized. We further evaluate the detectability and diagnostic potential of CMEs from the synthetic line profiles. Our investigations provide important constraints on the future design of Sun-as-a-star spectrographs for CME detections through EUV line asymmetries.
The Binary Black Hole Spin Distribution Likely Broadens with Redshift
Authors: Biscoveanu Sylvia , Callister Thomas A. , Haster Carl-Johan , Ng Ken K. Y. , Vitale Salvatore , Farr Will M.
Published: June 2022

The population-level distributions of the masses, spins, and redshifts of binary black holes (BBHs) observed using gravitational waves can shed light on how these systems form and evolve. Because of the complex astrophysical processes shaping the inferred BBH population, models allowing for correlations among these parameters will be necessary to fully characterize these sources. We hierarchically analyze the BBH population detected by LIGO and Virgo with a model allowing for correlations between the effective aligned spin and the primary mass and redshift. We find that the width of the effective spin distribution grows with redshift at 98.6% credibility. We determine this trend to be robust under the application of several alternative models and additionally verify that such a correlation is unlikely to be spuriously introduced using a simulated population. We discuss the possibility that this correlation could be due to a change in the natal black hole spin distribution with redshift.
KENYA’S MILITARY INTERVENTION IN SOMALIA
Authors: ZWIEFELHOFER Tomáš
Published: June 2022

The case study is focused on the last ten years of Kenyan military involvement in Somalia. It is based on literature review and expert interviews with field researchers and military members, which were conducted by the author. Through the analysis of motives for intervention, achievements, and mishaps, it examines lessons learned from the intervention. The decade long Kenya’s intervention has evolved into one of the pillars of fostering the stability in the Horn of Africa. Located in this region, which is unstable, Kenya finds itself being responsible for future stabilizing efforts, as it is the only stable state left in the Horn of Africa at present days.
Let’s talk about the (lady)birds and the bees: how insects can whisper a multitude of stories
Authors: Chua Physilia , Korlevic Petra , Pereira-da-Conceicoa Lyndall , Ferguson Cameron , Zhao Leia , Lawniczak Mara
Published: June 2022

If you have watched A Bug’s Life, you would have seen that insects come in an assortment of colours, shapes, and sizes. They are the perfect organism that could be used to describe the myriad diversity of all life on earth. These six-legged creatures are one of the most diverse groups of species, accounting for more than 80% of all documented living animals Ødegaard 2008. This huge diversity also makes it extremely time- and labour-intensive to carry out large-scale monitoring of insects. High-throughput sequencing technologies and the use of DNA barcodes for species identification have paved the way for the rapid biomonitoring of insects Hebert et al. 2003. However, millions of insect species are not well-represented in DNA reference databases, making species-level identification challenging for molecular research. Projects such as the Darwin Tree of Life (DToL) aim to cover this gap and generate DNA barcodes for all eukaryotic species found in the UK Blaxter et al. 2022. At the Wellcome Sanger Institute, the BIOSCAN UK for Flying Insects project has two main aims;

Documenting the diversity of UK flying insects

Discovering insect-cobiont interactions

Documenting the diversity of UK flying insects

Discovering insect-cobiont interactions

To meet these aims, we will be documenting the diversity of one million malaise-caught insects from 100 sites across the UK in the next five years. We will be using a non-destructive DNA extraction technique to preserve insect specimen integrity for museum collections or educational purposes Korlević et al. 2021. COI barcoding will be carried out using ONT and/or PacBio long-read technology to identify each insect specimen. To tease apart insect conbiont interactions, we will carry out mini barcoding using primers targeting microbes, parasites, vertebrates, invertebrates, and plants Fig. 1. Together, this molecular dataset consisting of one million specimens collected over space and time in the next five years will allow us to discover how insects interact with the ecosystem and advance insect biomonitoring research in the UK.
First results on the genetic variation of the Bulgarian populations of Morimus asper funereus (Mulsant, 1862) (Coleoptera, Cerambycidae)
Authors: Kostova Rumyana , Bobeva Aneliуa , Bekchiev Rostislav
Published: June 2022

There is an ambiguity about the taxonomic status of Morimus asper funereus (Mulsant, 1862), a saproxylic longhorn beetle, widespread in Bulgaria and other Balkan countries. It is a protected species under the Habitats Directive (Annex II) and under the Bulgarian Biodiversity Act. A recent molecular study, based on the cytochrome C oxidase subunit I (COI) and the second internal transcribed spacer (ITS2) gene se­quences, found that all European and Turkish populations of Morimus should be referred to M. asper (Sulzer, 1776) (Solano et al. 2013). The territory of Bulgaria and some other Balkan countries remain as an unstudied gap in that research. Here we present preliminary results on the genetic divergence and diversity of Morimus populations on the Balkans based on COI gene sequences using material from Bulgaria and Albania and the haplotypes’ sequences of Solano et al. (2013) obtained from GenBank. The material collected from Bulgaria аnd two localities in Albania was identified based on morphology characteristics as M. asper funereus (44 samples), M. verecundus bulgaricus Danilevski et all., 2016 (1 sample from the type locality), Morimus orientalis Reitter, 1894 (1 sample from Strandzha Mts.) and Lamia textor (Linnaeus, 1758) (1 sample) used as an outgroup. All obtained sequences were analyzed and haplotype diversity was estimated. The results show that Bulgarian populations of Morimus demonstrate relatively high haplotype diversity in correspondence to the diversity of the other European populations. Also, a phylogeographical hypothesis of the linkage between Bulgarian and other Balkan populations was developed. Four main lineages of divergence were identified. In addition, our results support the assumption that M. verucundus is a tentative subspecies of the morphologically and genetically variable M. asper.
Full chloroplast sequencing using genome skimming for novel plant DNA barcode discovery in Amaranths
Authors: Galindo Gonzalez Leonardo , Gagnon Marie-Claude , Kyte Sarah , Charron Andréanne , Colville Adam
Published: June 2022

DNA barcoding has been established as an efficient, sensitive and reliable methodology for plant identification. However, in spite of efforts to find a universal DNA plant barcode, some taxa are not sufficiently resolved by typical plant barcoding genes like matK or rbcL. We have used a technique known as genome skimming, which relies on the empiric low coverage sequencing of a full plant genome, resulting in high coverage of the high copy genome fractions such as chloroplast and rDNA. Phylogenetic studies show that these regions are a reservoir of variability which could be further exploited for DNA barcode discovery. We sequenced eight amaranth species using Illumina Next Generation Sequencing technology to test the feasibility of this technique. Amaranths were chosen due to their increasing impact as invasive species bearing multiple herbicide resistance mechanisms. Our results showed that complete chloroplast genomes could be assembled for all of the eight species tested. We obtained an average of 47 million reads for each one of the amaranth nuclear genomes, which range in size between 400-700Mb approximately. These reads provide an average theoretical coverage of 10-15X for each nuclear genome, but resulted in an average chloroplast genome coverage in the range of 500-8000X due to multiple chloroplast genome copies per cell. Alignment of the eight chloroplast genomes shows variability in the single copy regions (Fig. 1), especially on intergenic sections (Fig. 2). Additional preliminary analyses also show variation among different populations of the same species, demonstrating the importance of studying both inter and intraspecific diversity to design reliable and accurate DNA barcodes that can be used in species identification.