bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of the Collective Thomson Scattering System on HL-3 tokamak
Authors: Deng Weichu , Shi Zhongbing , Shi Peiwan , Zhang Feng , Yu Xin , Yang Zengchen , Jiang Min , Zhou Yu , Shen Yuqi , Han Kexi , Hu Liwen , Zhong Wulyu
Published: November 2024

A collective Thomson scattering (CTS) diagnostic system is being developed to measure fastion velocity distribution on HL-3 tokamak. A 140 GHz gyrotron belonging to electron cyclotron resonance heating (ECRH) system would be used to generate probe beam. The scattering spectra among HL-3 parameter ranges are calculated to assess diagnostic feasibility. Scattering signals will be detected by a heterodyne system, which is proposed to optimize diagnostic performance.
Tuning optical properties to optimize microwave absorbers
Authors: Hentrich Andreas , Semmler Christian
Published: November 2024

Microwave absorbing materials are critical for several components including bolometers and beam dumps. Profound knowledge of the material properties and the material-wave interactions is a necessity for both design and use of these components. With the strong focus of the ITER absorbing components on ceramic materials, a systematic study was performed to methodically investigate the optical properties of the aluminium oxide-titanium oxide material system.
Splitting scheme for gyro-kinetic equations with Semi-Lagrangian and Arakawa substeps
Authors: Bell Dominik , Pinto Martin Campos , Kumozec Davor , Schnack Frederik , Bourne Emily , Sonnendrücker Eric
Published: November 2024

The gyro-kinetic model is an approximation of the Vlasov-Maxwell system in a strongly magnetized magnetic field. We propose a new algorithm for solving it combining the Semi-Lagrangian (SL) method and the Arakawa (AKW) scheme with a time-integrator. Both methods are successfully used in practice for different kinds of applications, in our case, we combine them by first decomposing the problem into a fast (parallel) and a slow (perpendicular) dynamical system. The SL approach and the AKW scheme will be used to solve respectively the fast and the slow subsystems. Compared to the scheme in [1], where the entire model is solved using only the SL method, our goal is to replace the method used in the slow subsystem by the AKW scheme, in order to improve the conservation of the physical constants.
Entwöhnungsbehandlung (Sucht-Rehabilitation) der
Alkoholabhängigkeit
Authors: Enke Martin , Wallenwein Elke , Weber Tillmann
Published: November 2024

Die ambulante, tagesklinische und stationäre Alkoholentwöhnungsbehandlung (AEB)
ermöglicht eine effektive Behandlung der Alkoholabhängigkeit mit hohen
Abstinenzquoten. Nach bewilligtem Reha-Antrag können abstinente Rehabilitanden
mit einem multimodalen, interdisziplinären, primär psychotherapeutischen
Behandlungskonzept an den zugrunde liegenden Ursachen ihrer
Abhängigkeitsentwicklung, ihrer Abstinenzmotivation und Rückfallprophylaxe
arbeiten.
Einflussfaktoren auf die Bereitschaft von Psychologie-Studierenden
für eine Tätigkeit in der Versorgung von Substanzkonsumstörungen: Welche Rolle
spielen stigmatisierende Einstellungen?
Authors: Christiansen Lara , Buchholz Angela
Published: November 2024

Ziel der Studie Maßnahmen zur Entstigmatisierung von
Substanzkonsumstörungen (SKS) sollten möglichst frühzeitig in Ausbildung und
Studium adressiert werden. Bisherige Studien zeigten einen positiven Einfluss
von Berufserfahrungen auf die spätere Arbeitsbereitschaft im Zusammenhang mit
SKS. Diese Studie untersucht, inwieweit stigmatisierende Einstellungen gegenüber
Menschen mit SKS die Berufsinteressen von Studierenden der Psychologie
beeinflussen und welche weiteren Faktoren mit einer Bereitschaft für eine
spätere Tätigkeit im Suchtbereich assoziiert sind. Des Weiteren stellt sich die
Frage, ob und in welchem Maße der eigene Alkoholkonsum stigmatisierende
Einstellungen gegenüber Menschen mit einer Alkoholkonsumstörung (AKS)
beeinflusst.

Methodik Es wurde eine Online-Befragung mit 157 Psychologiestudierenden in
Deutschland durchgeführt. Die Stichprobe umfasst Bachelor- und Masterstudierende
jeglicher Studiengänge, die der Psychologie zugeordnet werden können und wurde
im Schneeballverfahren in sozialen Medien erhoben. Die Rekrutierung dauerte 3
Wochen. In einem von den Autorinnen zusammengestellten Fragebogen wurden
bisherige Berufserfahrung und –Interessen erhoben. Als potenzielle
Einflussfaktoren wurden praktische und private Erfahrungen mit SKS. Der
Alkoholkonsum wurde mit dem AUDIT-C und das Ausmaß stigmatisierender
Einstellungen mit dem OMS-HC erhoben.

Ergebnisse Eigener Alkoholkonsum (AUDIT-C; p=,021) hatte einen positiven,
während das Ausmaß stigmatisierender Einstellungen (OMS-HC; p<,001) einen
negativer Einfluss auf die Bereitschaft zeigte, später im Suchtbereich zu
arbeiten. Der AUDIT-C zeigte sich zudem als signifikanter Prädiktor für die
Stigma-Ausprägung (p<,001). Die Studiendauer, Vorliegen und Dauer praktischer
Erfahrung, Erfahrung mit SKS im engeren Umfeld zeigten keinen signifikanten
Einfluss auf die Bereitschaft. Die Psychologie-Studierenden der vorliegenden
Untersuchung wiesen im Mittel eine höhere Stigma-Ausprägung auf als eine
Vergleichsstichprobe von Psycholog*innen und Medizinstudierenden in der
Literatur zur OMS-HC.

Schlussfolgerung Sowohl der eigene Alkoholkonsum als auch das Ausmaß
stigmatisierender Einstellungen konnten als signifikante Prädiktoren für eine
Tätigkeit in der Versorgung von SKS identifiziert werden. Zudem wurde
festgestellt, dass der Alkoholkonsum der Studierenden ein signifikanter
Prädiktor für die stigmatisierende Einstellungen ist. Maßnahmen zur
Entstigmatisierung sollten frühzeitig adressiert werden, da die Stichprobe
bereits zum Zeitpunkt der Erhebung ein erhöhtes Maß an stigmatisierenden
Einstellungen aufweisen.
Assoziation von Selbststigmatisierung und
Abstinenz-Selbstwirksamkeitserwartung bei Patientinnen und Patienten mit
Drogengebrauchsstörung
Authors: Herter Manuel , Rumpf Hans-Jürgen , Bischof Anja , Lange Nikolaus , Bischof Gallus
Published: November 2024

Hintergrund Während ein negativer Zusammenhang von Selbststigmatisierung
auf die Abstinenzbezogene Selbstwirksamkeitserwartung bei Patientinnen und
Patienten mit einer Alkoholgebrauchsstörung Gut belegt ist, fehlen
entsprechen-de Befunde bei Abhängigkeit von illegalen Substanzen. In der
vorliegenden Arbeit wurde untersucht, wie Selbststigmatisierung bei Patientinnen
und Patienten mit einer Substanzgebrauchsstörung, die illegale Substanzen
konsumieren, asso-ziiert ist.

Methode Es wurden Selbst- und Fremdstigmatisierung mit einer auf Drogen
adaptierten Version der Self-Stigma in Alcohol Dependence Scale (SSAD) und die
drogenbezogene Abstinenz-Selbstwirksamkeitserwartung (DASE) erfasst. Zur
Auswertung der Zusammenhänge wurden Regressionsanalysen durchgeführt.

Ergebnisse Insgesamt nahmen 70 Patientinnen und Patienten (86% männlich)
an der Studie teil. Die Patientinnen und Patienten befanden sich zum Zeitpunkt
der Befragung in Rehabilitationseinrichtungen mit dem Schwerpunkt illegale
Substanzen. Eine Regressionsanalyse mit der
Abstinenz-Selbstwirksamkeitserwartung als abhängige Variable ergab einen
negativen sig-nifikanten Zusammenhang mit der Dauer der Abhängigkeit, der
Depressivität und der Selbststigmatisierung. Die Selbststigmatisierung erwies
sich als der stärkste negative Prädiktor für die
Abstinenz-Selbstwirksamkeitserwartung.

Schlussfolgerung Selbststigmatisierung steht in Zusammenhang mit der
Abstinenz-Selbstwirksamkeitserwartung und sollte bei der Behandlung
berücksichtigt werden. Weitere Forschung zu den Auswirkungen von Stigmatisierung
und zu Interventionsansätzen zur Reduktion von (Selbst-)Stigmatisierung wird
empfohlen.
Integral Dynamic Model for Training in Wrist Arthroscopy
Authors: Torres-Fuentes Carlos Eduardo , Vergel-Martínez María Fernanda , Rojas-Bautista Diego José , Martínez Mallerly Carolina Garzón
Published: November 2024

Introduction Whereas arthroscopic surgery allows for proper control of the surgical area, minimizes surgical risks, and promotes quick functional and occupational recovery, the complex anatomy makes arthroscopy difficult to perform.

Objective We aimed to determine the impact of a hand arthroscopic surgery training model that would impact on the acquisition of skills necessary for hand pathologies treatment.

Methods We conducted a quasi-experimental study before and after, involving 16 plastic surgery residents at Fundacioün Universitaria de Ciencias de la Salud, who had completed at least 2 months of the training program. Before the residents began their training, we measured time and assessed each resident's technique in three exercises using the Arthroscopic Surgery Skills Evaluation Tool (ASSET) scale on a wrist arthroscopy training model that evaluates the skills required for this type of surgical technique. After completing the training program, the training effect was measured using the same three exercises. These variables were tested a second time after training for comparison.

Results An increase in ASSET scale scores was found; we found a significant improvement in safety, arthroscope use, mastery, bimanual dexterity, and movement fluency (p < 0.03), and an improvement in instrument use and procedure completion was not significant.

Conclusion The designed training model allows to acquire and improve skills in hand arthroscopic surgery according to the ASSET scale.
On the zero-temperature properties of matter and the quantum theorem of corresponding states
Authors: Nosanow L. H.
Published: November 2024

The zero-temperature properties of matter with an interaction pair potential of the Lennard–Jones form are studied in the context of the Quantum Theorem of Corresponding States. In particular, the phase transition between the fluid and crystalline phases is studied for systems obeying either Fermi–Dirac or Bose–Einstein statistics. It is found that the solidification pressure of a Fermi system is much lower than that of a Bose system with the same mass and pair potential. We find that it is illuminating to extend the usual thermodynamic variable space to include the corresponding states quantum parameter η=ℏ2m80−2 which is defined in the text. It is shown that phase transitions occur at zero temperature as η is varied. Calculations of several thermodynamic quantities at zero temperature are presented.
Elastic moduli and lattice stability of quantum crystals
Authors: Plakida N. M. , Aksenov V. L.
Published: November 2024

The elastic moduli are calculated on the basis of self-consistent theory, and the stability domain of a quantum crystal is determined for a simple fcc model. It is shown that second-order terms of the theory play an essential role in the solution of the self-consistent equation, and taking them into account is necessary for a correct description of strongly anharmonic crystals. A comparison is given between the elastic moduli obtained and those calculated for this same model in the classical high temperature case.
Quantum effects during plastic straining of solidified noble gases
Authors: Krupskii I. N. , Leont’eva A. V. , Stroilov Yu. S. , Indan L. A.
Published: November 2024

Plastic-strain properties of solid neon, argon, krypton, xenon, and hydrogen (uniaxial extension) are considered. The temperature dependence of plastic strain is shown to obey the law of corresponding states, viz., v=f(Δ2/ΔΠπ2), in a wide range of temperatures: The dependence is determined by a ratio of Δ2=Δ2(T) r. m. s. displacements of atomic particles, and ΔΠπ2, those at the melting point. At high temperatures this dependence goes over to the usual thermal-activation one. Close to zero temperature, the highest plastic strain rate is independent of temperature and is related to the de Boer parameter λ by the equation v∼exp (— c/λ), c = const, which coincides with the known expression for the quantum tunnelling of particles through high energy barriers.
Thermal properties of solid hydrogen and deuterium
Authors: Manzhelii V. G.
Published: November 2024

Discussed are recent measurements of specific heat thermal expansion, heat conductivity, and isothermal compressibility of solid hydrogen and deuterium. The influence of several factors (anharmonicities of lattice vibrations, impurities, ortho-para-composition and quantum diffusion) on the magnitude and temperature dependence of the thermal properties is considered. Experimental data are presented which indicate that a first-order phase transition exists in the premelting region of solid hydrogen.
Light absorption anomalies in the magnetic phase transition of FeCo3
Authors: Eremenko V. V. , Litvinenko Yu. G. , Shapiro V. V.
Published: November 2024

The behavior of exciton and exciton-magnon light absorption bands in magnetic fields up to 300 kOe (H∥C3) is studied in monocrystals of antiferromagnetic (TN = 38°K) rhombohedric (R3¯c) dielectric FeCo3. In the region of the magnetic phase transition (H1 < H < H2, H1 = 148 kOe, H2= 176 kOe) to the state with parallel orientation of the magnetizations of both sublattices (S1∥S2) a number of anomalies were observed: an abrupt change in exciton line splitting in a field H1 and further unusual behavior of this line at H > H1; significant attenuation of integral intensity of the exciton-magnon absorption band upon reaching H1 and almost complete extinction of absorption in fields H > H2. The energy of exciton line components and the integral coefficient of exciton-magnon absorption are calculated in the molecular field model. It is shown that, in the critical field range where a multisublattice structure is realized, three types of ion may be distinguished, to each of which there corresponds a certain excitation energy value. Within the framework of this calculation the behavior of the exciton line component frequencies and the integral coefficient of exciton-magnon absorption correlate completely with crystal magnetization, and are explained by anomalies of the magnetic phase transition in FeCo3.
The paraconductivity of one-dimensional granular systems
Authors: Antsygina T. N.
Published: November 2024

A one-dimensional chain of superconducting granules with Josephson coupling between them is considered. The absence of long-range order in the phase below Tc for such a system leads to the existence of a unique “paraconductivity” due to the superconducting state of the granules, which is calculated exactly for the given model.
Structure and thermodynamic properties of β-CO
Authors: Krupskii I. N. , Prokhvatilov A. I. , Érenburg A. I. , Isakina A. P.
Published: November 2024

An x-ray study of CO lattice parameters is performed over the temperature range 62–68°K. Coefficients of volume expansion were determined, and the heat capacity Cv and isothermal compressibility χT were calculated. Heat capacity related to rotational molecular motion is analyzed. It is shown that in contrast to β-Ν2 the high temperature phase of CO is orientationally disordered.
Effect of the cooling medium on low-temperature deformation of chromium-nickel steels
Authors: Trefilov V. I. , Medvedev Ε. M. , Kirillov E. S. , Zakharchenko A. I.
Published: November 2024

A study was made concerning the plastic deformation of grades 03Khl8N8, 03Khl8N20, and 0Khl8N10T steel during elongation at a strain rate ϵ˙=1⋅10−3−5.5⋅10−4sec−1 in liquid hydrogen (14.5–20.4°K), as well as in gaseous hydrogen (21–25°K) and helium (16–30°K). On the basis of stress-strain curves obtained here, the effect of experimental conditions on the trends in the development of jumpwise plastic deformation is then established. It has thus been found that jumpwise plastic deformation increases when cooling with liquid hydrogen is replaced by cooling with a gaseous medium, when the temperature of liquid hydrogen is lowered, or when the deformation rate is increased. These effects are analyzed, with heat dissipation at the interface between deformed material and cooling medium taken into account. Conclusions are drawn concerning the significant role of thermal processes in the intensification of jumpwise low-temperature plastic deformation of metals.
Nonlinear absorption of sound in gallium
Authors: Fil’ V. D. , Denisenko V. I. , Bezuglyi P. A.
Published: November 2024

The nonlinear effects that occur when an intense sound wave propagates in gallium are studied. They occur due to the trapping of electrons of the effective interaction zone by the potential relief of the wave.
Nonlinear absorption of electromagnetic waves in type-1 superconductors
Authors: Galaiko V. P. , Shumeiko V. S.
Published: November 2024

The resonance absorption of an electromagnetic field by thermal excitations in a superconductor is considered for T≪Δ. It is shown that the absorption is nonlinear for amplitudes above H∼(ω/Δ)Hc. A kinetic equation is derived for the excitations and used to solve the quantum problem of the inelastic scattering of excitations by a local potential; the role of states inside the superconductor energy gap is analyzed. The results are used to calculate the frequency and amplitude dependences of the absorption.
Subthreshold two-magnon absorption anomalies in magnetized low-dimensional ferromagnets
Authors: Pereverzev Yu. V. , Stepanov A. A.
Published: November 2024

Anomalies in subthreshold, two-magnon absorption in ferromagnets due to the low-dimensionality of the magnetic structure are investigated theoretically. Since the exchange integral J' is small along either one or two directions, the singularity in the magnon density of states g(ω), caused by the single point of contact of the constant-energy surface with the boundary of the Brillouin zone, lies close to the magnon activation energy. This results in the appearance of a peak in the absorption coefficient curve Γ(ω, Η) near a frequency on the order of twice the gap in the magnon spectrum.
Temperature-time dependences of the electrical conductivity of metal-ammonia solutions in the solid phase
Authors: Dmitrenko I. M. , Shchetkin I. S. , Osika E. A. , Sil’vestrova T. V. , Tarasenko G. I. , Tsoi G. M.
Published: November 2024

The electrical conductivity of quenched sodium-ammonia solutions with the metal concentration ranging from 1 to 16 at.% was studied as a function of time and of the temperature over the 20–195°K range. Results of x-ray analysis are shown here which cover the 3–16 at.% range of sodium concentration and the 77–170°K temperature range. It is demonstrated that the high electrical conductivity of freshly quenched sodium-ammonia solutions is due to the precipitation, during freezing, of domains with a higher sodium concentration so that high-conductance channels are formed in the solution. The increase in the electrical resistance with time and with increasing temperature is attributed here to the diffusion processes which coagulate the metal into colloidal particles.
Low-temperature plastic deformation of copper and aluminum in magnetic fields up to 27 kOe
Authors: Bol’shutkin D. N. , Verkin B. I. , Desnenko V. A. , Ya. Il’ichev V. , Medvedev E. M.
Published: November 2024

A study was made concerning the low-temperature (T = 4.2°K) plastic deformation of aluminum and copper in constant magnetic fields, outside a magnetic field, and in transient magnetic fields varying exponentially at various rates. It has been established that constant magnetic fields of intensity H0≤27kOe and transient magnetic fields varying at rates H⋅<3.4⋅105Oe/sec do not effect the plastic deformation of aluminum and copper. Transient magnetic fields varying at rates H⋅>3.4⋅105Oe/sec produce a jumpwise hardening as a result of Joule heat generated in specimens by eddy currents.
Intermolecular interactions with excited oxygen B3Σu− in solid solutions of nitrogen and inert gases
Authors: Gimpelevich L. G. , Timchenko L. I. , Ya. Fugol’ I.
Published: November 2024

The features of the matrix shift of the electron-vibrational bands of the Schumann-Runge transition were investigated for molecules of oxygen in matrices of solid inert gases and nitrogen. A calculation and an analysis of the ground X3Σg− state of oxygen in various matrices was carried out. An attempt was made to describe quantitatively the intermolecular interactions of excited O2 molecules with a cryogenic matrix and also to obtain the characteristics of the excited state B3Σu− of oxygen itself. The parameters were determined of the interaction potentials of the excited impurity O2 with Ar, Kr, and Xe atoms and with molecules of N2 and O*2. The magnitudes of the polarizability and the van der Waals constants, characterizing the excited B3Σu− state of molecular oxygen, were estimated.
Fluctuation effects in superconductors below Tc
Authors: Cheishvili O. D.
Published: November 2024

By using Keldysh's technique, the Cooper vertex function below Tc is calculated and employed to study fluctuation contributions to the density of states and to sound attenuation in a gapless superconductor. It is shown that for thin and "dirty" films in a magnetic field parallel to the film surface the fluctuation term contributes significantly to the electron density of states and to sound attenuation.
Energy relaxation in superconducting alloys
Authors: Lisitsyn S. G.
Published: November 2024

It is shown that impurities increase the rate of electron energy relaxation. Experimental data pertaining to the stimulation of Tc by a superhigh-frequency field in films are discussed on the basis of the results obtained.
Weakly superheated states of type I superconductors
Authors: Shikina N. I.
Published: November 2024

Solutions to the Ginzburg-Landau equations are analyzed which correspond to weakly superheated states of type-I superconductors. These solutions are then extended to the case of a finite and sufficiently thick superconducting sample.
Critical fields and lattice structure of “tilted vortices” in a superconductor surface layer and in thin films
Authors: Minenko E. V.
Published: November 2024

The vortex state which corresponds to a lattice of “tilted vortices” (Kulik vortices) is investigated in the surface layer of a Type II superconductor and in thin films in a field which forms a finite angle with the surface. Some inaccuracies are noticed in the calculations carried out by other authors, and an improved variational procedure is suggested, which allows one to determine the type of vortex structure, its space orientation, and the dependence of the critical magnetic field on the tilt angle.
Effect of nonuniformities and the measurement current on the current-voltage characteristics of tunnel junctions
Authors: Chubov P. N.
Published: November 2024

The observed deviations of the I–V characteristics of Al-Insulator-Al tunnel junctions from the theoretical form is shown to be due to the combined action of superconducting inhomogeneities in the films forming the junctions and the measurement current acting on the inhomogeneities. The magnitude of this effect is assumed to be related to the critical parameters (JK and HK) of the film material.
Temperature and hydrostatic-pressure dependence of antiferromagnetic resonance in CuCl2·2H2O in an inclined magnetic field
Authors: Galkin A. A. , Popov V. A. , Polyakov P. I. , Synkov V. G.
Published: November 2024

The dependence of the resonance properties of CuCl2·2H2O at low frequencies ν ≈ 0.7 to 4.9 GHz on hydrostatic pressure (ρ = 0 to 11.2 kbar) and temperature (T = 1.68 to 4.2°K) is investigated. Theory and experiment are compared. Values are obtained for the magentoelastic parameters governing the hydrostatic­-pressure dependence of the exchange and relativistic parameters of antiferromagnets.
Structure of impurity bands and absorption of ultrasound
Authors: Zaitsev R. O. , Malkin I. A.
Published: November 2024

A dielectric is considered containing a small amount of quantum (delocalized) impurities. The case is considered when in one unit cell of an ideal crystal there are several equivalent interstitial positions. It is shown that for low temperatures in this system there are several impurity bands, the number of bands being equal to the product of the number of interstitial positions and the number of states of the impurity atom in each interstitial position. Since the distance between the bands is fairly small, the interband transitions may be observed with the aid of ultrasonic measurements. It is established that the absorption coefficient of sound has a broad minimum as a function of temperature. The calculations are carried out in the tight-binding approximation for the case of low impurity concentration.
Theory of quantum oscillations of the Hall effect in doped semiconductors and semimetals
Authors: Kuleev I. G. , Novokshonov S. G.
Published: November 2024

The Hall component of the conductivity tensor is calculated for the elastic scattering of electrons on impurities with finite radius of action up to the fourth order in the interaction. It is shown that with scattering of electrons on impurities in a quantizing magnetic field, transitions within one Landau level will predominate if the radius of action of the scattering potential r0 is significantly greater than the magnetic length α (or the cyclotron orbit radius in the case of large quantum numbers ζ/ћΩ ⪢ 1. It is established that the phase shift of the oscillations of the transverse magnetic resistance ρ⊥ and the Hall coefficient RH will differ for short-range and long-range impurity potentials.
Theory of superconducting bridges
Authors: Mitsai Yu. N.
Published: November 2024

In a linear approximation, a relation is found between the alternating current amplitudes and the voltages in a short bridge in the presence of a steady current. The stationary Josephson effect is also investigated in such systems for alloys with paramagnetic impurities. Consideration is not restricted to the temperature region near the critical one.
Sound absorption and dispersion in metals with several carrier groups
Authors: Kopelievich A. I. , Usatenko O. V.
Published: November 2024

Ultrasonic absorption in semimetals and metals whose Fermi surface consists of carrier groups, either isolated or bridged by narrow necks, is studied under the assumption that electron-phonon interaction is the principal mechanism of electron relaxation. By proceeding from the exact form of the collision integral, the temperature dependence of the relaxation time is found for electron transitions between different groups of the Fermi surface. It is this relaxation time that determines the temperature dependence of the sound absorption coefficient in the low-frequency limit. The contribution of electron-phonon drag is shown to decrease the absorption coefficient significantly.
Low-temperature plastic deformation of nickel in magnetic fields up to 34 kOe
Authors: Bol’shutkin D. N. , Desnenko V. A. , ll’ichev V. Ya.
Published: November 2024

Low-temperature (T = 4.2°K) plastic deformation in polycrystalline nickel has been studied in constant (H = 34 kOe) and transient (H ≤ 34 kOe) magnetic fields which change exponentially in time at different rates. It has been established that a constant magnetic field H = 34 kOe increases the flow limit of nickel by about 10% while transient magnetic fields cause a change in the deforming stress. It is concluded that the observed effects can be explained by magnetostriction and Joule heating of the nickel samples by eddy currents.
Effects of impurities on the nonuniform state in layered superconductors
Authors: Bulaevskii L N. , Guseinov A. A.
Published: November 2024

The possibility of the existence of a nonuniform state is investigated, and the nature of the phase transition is determined in layered superconductors with Josephson-like interlayer coupling as a function of sample purity and temperature for a field parallel to the layers. The dependence of the upper critical field HK2(‖) on temperature and electron mean free path within the layers is obtained. At temperatures T < 0.55 Tc, it is shown that depending on the purity of the superconductor and the temperature, either a second-order phase transition into a nonuniform superconducting state or a first-order transition into a uniform superconducting state is observed in layered superconductors with Josephson interlayer coupling for a field parallel to the layers.
Antiferromagnetic impurity in a one-dimensional anisotropic ferromagnet
Authors: Gann V. V. , Zazunov L. G.
Published: November 2024

We investigate single-particle localized states of a one-dimensional ferromagnetic system with anisotropic exchange in the presence of an antiferromagnetic impurity with spin S′ = 1/2. We calculate the energies and wave functions of the ground and excited states. We consider the excitation of single-particle local levels by an external microwave field at low temperatures.
Low-symmetry features of the ESR spectra of KY(MoO4)2-KEr⋅(MoO4)2 crystals
Authors: Pshisukha A. M. , Zvyagin A. I. , Chernyi A. S.
Published: November 2024

We have studied the ESR spectrum of crystals of the low-symmetry system KY(MoO4)2-KEr(MoO4)2 at low temperatures and frequencies of 10, 30, and 60 GHz. The resonance absorption band in the spectrum has a triplet structure whose origin is due to the existence in KEr(MoO4)2 of one-dimensional chains of Er3+ ions interacting via strong dipole-dipole coupling along the crystallographic c axis. We discuss the features of the ESR spectrum of KEr(Mo04)2 caused by the presence in the energy spectrum of the Er3+ ion of an excited state lying close to the ground state, as well as by components of the local crystal field whose symmetry is lower than orthorhombic. We make a comparison with the ESR spectra of the other previously studied molybdates, KDy(MoO4)2 and KYb(MoO4)2. We reach a conclusion regarding the significant role of the individual characteristics of rare-earth ions in determining the ESR spectra of low-symmetry concentrated magnetic crystals.
A spatial restriction method in the theory of many-electron systems. I
Authors: Ratner A. M.
Published: November 2024

An efficient method is suggested for calculating the behavior of many-electron systems in which the electron motion is spatially restricted by the wave function permutation symmetry. The method is based on introducing a trial function, satisfying the permutation rules and accounting explicitly for restriction in the one-electron configuration space. Applied to outer shell electrons of an atom, the method allows the inner shells to be taken into account through a vanishing boundary condition on a spherical surface of radius r0. A table of r0 values is constructed for atomic cores of the principal group elements. The energy levels of atoms and ions calculated with the aid of this table are in good agreement with a wide range of spectroscopic data. The results form a basis for ground state calculations of dielectric crystals (see Part II).
A spatial restriction method in the theory of many-electron systems. II. The ground state of dielectric crystals
Authors: Ratner A. M. , Shamfarova O. Ya.
Published: November 2024

The method of spatial restriction, developed in Part I of this work, is used to study crystals consisting of closed-shell atoms and ions. The spatial restriction imposed by permutation relations on the motion of outer shell electrons has been earlier reduced to a zero boundary condition on a spherical surface of radius r0. The r0 values obtained in Part I of this work from the ionization potentials of isolated atoms are used to study 12 alkali halide crystals, with calculated lattice constants differing from the experimental values by less than 2%. Similar calculations are performed for rare-gas crystals, with a pressure dependence of compressibilities in good agreement with experimental data in a wide range of pressures.
Quantum theory of longitudinal transport phenomena in cylindrical conductors in a weak magnetic field
Authors: Bogachek É. N.
Published: November 2024

The behavior of the longitudinal kinetic coefficients of cylindrical conductors placed in a weak magnetic field is studied. It is shown that the electrical and thermal conductivity and thermoelectromotive force periodically vary as the magnetic field flux is varied. The oscillation period is equal to the flux quantum hc/e of a normal metal. The relative oscillation amplitude is found and ways in which they may be experimentally detected are discussed.
Internal friction in multilayer films in the range 4.2−100 °K
Authors: Postnikov V. S. , Miloshenko V. E. , Davydov D. V. , Panteleev I. N.
Published: November 2024

Measurements have been made on the internal friction in multilayer films of S−D−S−D and S−N−S−N types in the temperature range 4.2−100°K; the temperature dependence of the internal friction has various features, which become especially complex near the superconducting transition.
Broadband operation of an X-band high-power relativistic traveling wave tube
Authors: Bao Rong , Wang Hongguang , Li Yongdong , Liu Chunliang
Published: November 2024

Wide-band high-power relativistic traveling wave tubes (RTWTs) in X-band have the potential in phased-array antennas, microwave weapons, and so on. Thorough design and optimization are required to achieve wide-band amplification, especially with invariant beam voltage and interaction length. A corrugated circular waveguide is applied as the slow-wave structure for wide bandwidth. The geometric parameters of the structure are initially chosen by cold analysis and then verified by a nonlinear model and the 2D particle-in-cell simulation. The kinematic mismatch is proved to be vital to the wide-band amplification of the device. Optimization is performed so that high output powers in the bandwidth can be achieved with the same interaction length. With the beam voltage of 625 kV and the beam current of 1.92 kA, the optimized RTWT can deliver more than 100 MW from 8.43 to 9.32 GHz, and the corresponding bandwidth is ∼10%. In the frequency range from 8.65 to 9.32 GHz, the output power and efficiency are larger than 170 MW and 14%, respectively.
Chemistry Nobel honors protein design and modeling
Authors: Lopatka Alex
Published: November 2024

The prizewinning research enhances understanding of nature’s molecular toolkit and enables the construction of novel proteins.
Predecisional information search adaptively reduces three types of uncertainty
Authors: Spektor Mikhail S. , Wulff Dirk U.
Published: November 2024

How do people search for information when they are given the opportunity to freely explore their options? Previous research has suggested that people focus on reducing uncertainty before making a decision, but it remains unclear how exactly they do so and whether they do so consistently. We present an analysis of over 1,000,000 information-search decisions made by over 2,500 individuals in a decisions-from-experience setting that cleanly separates information search from choice. Using a data-driven approach supported by a formal measurement framework, we examine how people allocate samples to options and how they decide to terminate search. Three major insights emerge. First, predecisional information search has at least three drivers that can be interpreted as reducing three types of uncertainty: structural, estimation, and computational. Second, the selection of these drivers of information search is adaptive, sequential, and guided by environmental knowledge that integrates prior expectations, task instructions, and personal experiences. Third, predecisional information search exhibits substantial interindividual heterogeneity, with individuals recruiting different drivers of information search. Together, these insights suggest that human information search is complex in ways that cannot be fully explained by monolithic accounts of information search, including proposals focused on estimation uncertainty or cost–benefit analysis. We conclude that broader theories of human information-search behavior are necessary.
S-adenosyl-L-methionine is the unexpected methyl donor for the methylation of mercury by the membrane-associated HgcAB complex
Authors: Zheng Kaiyuan , Rush Katherine W. , Date Swapneeta S. , Johs Alexander , Parks Jerry M. , Fleischhacker Angela S. , Abernathy Macon J. , Sarangi Ritimukta , Ragsdale Stephen W.
Published: November 2024

Mercury (Hg) is a heavy metal that exhibits high biological toxicity. Monomethylmercury and dimethylmercury are neurotoxins and a significant environmental concern as they bioaccumulate and biomagnify within the aquatic food web. Microbial Hg methylation involves two proteins, HgcA and HgcB. Here, we show that HgcA and HgcB can be heterologously coexpressed, and the HgcAB complex can be purified. We demonstrated that HgcA is a membrane-associated cobalamin-dependent methyltransferase and HgcB is a ferredoxin-like protein containing two [4Fe-4S] clusters. Further, spectroscopic and kinetic results demonstrate that S-adenosyl-L-methionine (SAM) donates the methyl group to Hg in a two-step reaction involving a methylcob(III)alamin intermediate including Co-thiolate ligation from a conserved Cys residue. Our findings uncover a biological role for SAM in microbial Hg methylation.
Targeting PRMT7-mediated monomethylation of MAVS enhances antiviral innate immune responses and inhibits RNA virus replication
Authors: Yang Jingjing , Li Wenjuan , Zhang Zepeng , Gong Xiaohua , Chen Yanchao , Peng Xiaoyu , Hu Guosheng , Dai Xianglong , He Yaohui , Huang Ying , Cao Shiqiang , Yang Yang , Liu Wen
Published: November 2024

RIG-I-like receptors (RLRs)-mitochondrial antiviral signaling protein (MAVS) are crucial for type I interferon (IFN) signaling pathway and innate immune responses triggered by RNA viruses. However, the regulatory molecular mechanisms underlying RNA virus-activated type I IFN signaling pathway remain incompletely understood. Here, we found that protein arginine methyltransferase 7 (PRMT7) serves as a negative regulator of the type I IFN signaling pathway by interacting with MAVS and catalyzing monomethylation of arginine 232 (R232me1) in MAVS. RNA virus infection leads to the downregulation and dissociation of PRMT7 from MAVS as well as the decrease of R232me1 methylation, enhancing MAVS/RIG-I interaction, MAVS aggregation, type I IFN signaling activation, and antiviral immune responses. Knock-in mice with MAVS R232 substituted with lysine (

Mavs
R232K

-KI) are more resistant to Vesicular Stomatitis Virus infection due to enhanced antiviral immune responses. PiPRMT7-MAVS, a short peptide inhibitor designed to interrupt the interaction between PRMT7 and MAVS, inhibits R232me1 methylation, thereby enhancing MAVS/RIG-I interaction, promoting MAVS aggregation, activating type I IFN signaling, and bolstering antiviral immune responses to suppress RNA virus replication. Moreover, the clinical relevance of PRMT7 is highlighted that it is significantly downregulated in RNA virus-infected clinical samples, such as blood samples from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and Ebola virus, as well as H1N1-infected bronchial epithelial cells. Our findings uncovered that PRMT7-mediated arginine methylation plays critical roles in regulating MAVS-mediated antiviral innate immune responses, and targeting arginine methylation might represent a therapeutic avenue for treating RNA viral infection.
Modeling the velocity of evolving lineages and predicting dispersal patterns
Authors: Bastide Paul , Rocu Pauline , Wirtz Johannes , Hassler Gabriel W. , Chevenet François , Fargette Denis , Suchard Marc A. , Dellicour Simon , Lemey Philippe , Guindon Stéphane
Published: November 2024

Accurate estimation of the dispersal velocity or speed of evolving organisms is no mean feat. In fact, existing probabilistic models in phylogeography or spatial population genetics generally do not provide an adequate framework to define velocity in a relevant manner. For instance, the very concept of instantaneous speed simply does not exist under one of the most popular approaches that models the evolution of spatial coordinates as Brownian trajectories running along a phylogeny. Here, we introduce a family of models—the so-called Phylogenetic Integrated Velocity (PIV) models—that use Gaussian processes to explicitly model the velocity of evolving lineages instead of focusing on the fluctuation of spatial coordinates over time. We describe the properties of these models and show an increased accuracy of velocity estimates compared to previous approaches. Analyses of West Nile virus data in the United States indicate that PIV models provide sensible predictions of the dispersal of evolving pathogens at a one-year time horizon. These results demonstrate the feasibility and relevance of predictive phylogeography in monitoring epidemics in time and space.
Observation of Thouless pumping of light in quasiperiodic photonic crystals
Authors: Yang Kai , Fu Qidong , Prates Henrique C. , Wang Peng , Kartashov Yaroslav V. , Konotop Vladimir V. , Ye Fangwei
Published: November 2024

Topological transport is determined by global properties of physical media where it occurs and is characterized by quantized amounts of adiabatically transported quantities. Discovered for periodic potential, it was also explored in disordered and discrete quasiperiodic systems. Here, we report on experimental observation of pumping of a light beam in a genuinely continuous incommensurate photorefractive quasicrystal emulated by its periodic approximants. We observe a universal character of the transport which is determined by the ratio between periods of the constitutive sublattices, by the sliding angle between them, and by Chern numbers of the excited bands (in the time-coordinate space) of the approximant, for which pumping is adiabatic. This reveals that the properties of quasiperiodic systems determining the topological transport are tightly related to those of their periodic approximants and can be observed and studied in a large variety of physical systems. Our results suggest that the links between quasiperiodic systems and their periodic approximants go beyond the pure mathematical relations: They manifest themselves in physical phenomena which can be explored experimentally.
The interplay between liquid–liquid and ferroelectric phase transitions in supercooled water
Authors: Izzo Maria Grazia , Russo John , Pastore Giorgio
Published: November 2024

The distinctive characteristics of water, evident in its thermodynamic anomalies, have implications across disciplines from biology to geophysics. Considered a valid hypothesis to rationalize its unique properties, a liquid–liquid phase transition in water below the freezing point, in the so-called supercooled regime, has nowadays been observed in several molecular dynamics simulations and is being actively researched experimentally. The hypothesis of ferroelectric phase transition in supercooled water can be traced back to 1977, due to Stillinger. In this work, we highlight intriguing and far-reaching implications of water: The ferroelectric and liquid–liquid phase transitions can be designed as two facets of the same underlying phenomenon. Our results are based on the analysis of extensive molecular dynamics simulations and are explained in the context of a classical density functional theory in mean-field approximation valid for a polar liquid, where dipolar interaction is treated perturbatively. The theory underpins the potential role of ferroelectricity in promoting the liquid–liquid phase transition, being the density-polarization coupling inherent in the dipolar interaction potential. The existence of ferroelectric order in supercooled low-density liquid water is confirmed by the observation in molecular dynamics simulations of collective modes in space-time polarization correlation functions, traceable to spontaneous breaking of continuous rotational symmetry. Our work sheds light on water’s supercooled behavior and opens the door to experimental investigations of the static and dynamic behavior of water’s polarization.
Many Little Hacks: Agroecological Plant Protection through Regenerative Potato Cropping
Authors: Junge S.M. , Finckh M.R.
Published: November 2024

Typically potato farming practices are characterized by tight rotations, intensive tillage and fertilization. This leads to soil degradation, increased pest and disease pressure, and use of chemicals, thereby endangering ecosystem health and contaminating water supplies. Agroecological strategies were tested, including the strategic use of cover crops, reduced tillage, and organic fertilization by compost and transferred mulch of green manures. These practices were shown to improve soil structure, increase soil biodiversity, reduce the need for chemical inputs, and enhance crop resilience against pests and diseases. Findings underscore the effectiveness of agroecological management systems in increasing both ecological and economic sustainability in potato farming. The study argues for a change, away from individual measures and solutions and toward an interlocking ecoagricultural system and systemic thinking to reduce or avoid chemical pesticides, high fertilizer input, and tillage.

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© The Authors 2024
A Multi-faceted View of the X-Ray Spectral Variability in Seyfert Galaxy Ark 120
Authors: Ren Lu-Xin , Wang Jun-Xian , Kang Jia-Lai
Published: November 2024

Utilizing a range of techniques including multi-band light curves, softness ratio analysis, structure functions, rms spectra, cross-correlation functions, and ratios of spectra from different intervals, we present a comprehensive study of the complex X-ray spectral variability in Seyfert 1 galaxy Ark 120, through re-analyzing its six XMM-Newton observations taken between 2003 and 2014. We find a clear “softer-when-brighter” trend in the 2–10 keV power-law component over long timescales, with this trend being timescale dependent, as it is much weaker on shorter timescales, similar to that previously detected in NGC 4051. Notably, a rare “harder-when-brighter” trend is observed during one exposure, indicating dynamic changes in the spectral variability behavior of the power-law component. This exceptional exposure, with the spectral variability indeed marked by a power-law pivoting at an unusually low energy of  ~2 keV, suggests intricate variations in the thermal Comptonization processes within the corona. Furthermore, when the data below 2 keV are included, we identify that the soft excess component adds significant complexity to the spectral variability, such as evidenced by a transition from “harder-when-brighter” to “softer-when-brighter” during another single exposure. Such extra complexity arises because the variability of the soft excess sometimes follows and sometimes does not follow the changes in the power-law component. Our findings underscore the necessity of applying multiple analytic techniques to fully capture the multifaceted spectral variability of AGNs.
Flavor neutrinos as unstable particles: an interaction picture view
Authors: Blasone M , Giacosa F , Smaldone L , Torrieri G
Published: November 2024

This paper reviews the similarities in the behavior of unstable particles and oscillating neutrinos using perturbation theory within the interaction picture of quantum field theory. We begin by examining how decaying systems are studied in the interaction picture and then demonstrate how similar calculations can be performed to determine the transition probabilities for flavor oscillations. Notably, the expressions for neutrino oscillations and particle decays are identical in the short-time range. Furthermore, we show that the flavor oscillation formula derived through this method matches, within the adopted approximation, the one obtained using the flavor Fock space approach.
Improved breakdown strength at high temperatures through annealing of syndiotactic polystyrene
Authors: Wu Xudong , Tan Daniel Q.
Published: November 2024

The improvement of the breakdown strength of polymer films is an essential scientific and applied research topic for high-voltage electrical power applications. Here, syndiotactic polystyrene (sPS) is annealed at different temperatures above the glass transition temperature so as to achieve dielectric improvement in both breakdown strength and dielectric loss. The breakdown strength of the annealed film can be increased by about 19.6% at 120°C compared with the original one. The dielectric loss is reduced by nearly 50% at high temperatures. It demonstrates a generalized phenomenon of annealing treatment of polymer films in facilitating further crystallization through chain packing or orientation, which limits the movement of charge carriers and polarization at high temperatures.