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In the morning sector of its near equatorial orbit Equator-S observed large magnetic oscillations in the Pc 5 frequency range. The poloidal part of the observed oscillations is usually interpreted as being caused by surface waves of the magnetopause driven by a Kelvin-Helmholtz instability (KHI). We found, however, that these oscillations are sometimes additionally superposed with reconnection signatures. This occurs during periods of northward interplanetary magnetic field. In fact, the Walen relation as a test for reconnection is satisfied for many short periods of time. This indicates transient and thin layers of reconnection, embedded in the large scale motion. We compared our observations with appropriate magnetohydrodynamic simulations allowing reconnection in the case of shear flows. Comparing the simulation results with the magnetic field and plasma observations we found good agreement of simulations and observations. We conclude that Equator-S has observed reconnection embedded in Kelvin-Helmholtz instability generated vortices in its nonlinear phase. [Copyright &y& Elsevier]

Reconnection is the most efficient way to release the energy accumulated in the tense astrophysical magnetoplasmas. As such it is a basic paradigm of energy conversion in the universe. Astrophysical reconnection is supposed to heat plasmas to high temperatures, it drives fast flows, winds and jets, it accelerates particles and leads to structure formation. Reconnection can take place only after a local breakdown of the plasma ideality, enabling a change of the magnetic connection between plasma elements. After Giovanelli first suggested magnetoplasma discharges in 1946, reconnection has usually been identified with vanishing magnetic field regions. However, for the last ten years a discussion has been going on about the structure of 3 D reconnection, e.g., whether in 3 D it is possible also without magnetic nulls or not. We first shortly review the relevant magnetostatic and kinematic fluid theory results to argue than that a kinetic approach is necessary to reveal the generic three-dimensional structure and dynamics of reconnection in collisionless astrophysical plasmas. We present results about the 3 D structure of kinetic reconnection in initially antiparallel magnetic fields. They were obtained by selfconsistently considering ion and electron inertia as well as dissipative wave-particle resonances. In this approach reconnection is a natural consequence of the instability of thin current sheets. We present the results of a nonlocal linear dispersion theory and describe the nonlinear evolution of the instability using numerical particle code simulations. The decay of thin current sheets directly leads to a configurational instability and three-dimensional dynamic reconnection. We report the resulting generic magnetic field structure. It contains pairs of magnetic nulls, connected by separating magnetic flux surfaces through which the plasma flows and along which reconnection induces large parallel electric fields. Our results are illustrated by virtual reality views and movies, both stored on the attached CD-ROM and also being available from the Internet. [ABSTRACT FROM AUTHOR]

The article presents a study which tests the toxicity of copper on crustacean Daphnia (D.) magna populations. The study uses a parametric model to measure the effects of copper on the population of D. magna and atomic absorption spectrophotometry to analyze the copper concentrations. Results show that individual growth can be an index of toxic stress and that copper is toxic in hard water since it is displaced from binding sites on humic substances.

Although turbulence has been conjectured to be important for magnetic reconnection, still very little is known about its role in collisionless plasmas. Previous attempts to quantify the effect of turbulence on reconnection usually prescribed Alfvénic or other low-frequency fluctuations or investigated collisionless kinetic effects in just two-dimensional configurations and antiparallel magnetic fields. In view of this, we analyzed the kinetic turbulence self-generated by three-dimensional guide-field reconnection through force-free current sheets in frequency and wave-number spaces, utilizing 3D particle-in cell code numerical simulations. Our investigations reveal reconnection rates and kinetic turbulence with features similar to those obtained by current in situ spacecraft observations of MMS as well as in the laboratory reconnection experiments MRX, VTF, and VINETA-II. In particular, we found that the kinetic turbulence developing in the course of 3D guide-field reconnection exhibits a broadband power-law spectrum extending beyond the lower-hybrid frequency and up to the electron frequencies. In the frequency space the spectral index of the turbulence appeared to be close to -2.8 at the reconnection X line. In the wave-number space it also becomes -2.8 as soon as the normalized reconnection rate reaches 0.1. The broadband kinetic turbulence is mainly due to current-streaming and electron-flow-shear instabilities excited in the sufficiently thin current sheets of kinetic reconnection. The growth of the kinetic turbulence corresponds to high reconnection rates which exceed those of fast laminar, nonturbulent reconnection. [ABSTRACT FROM AUTHOR]

A correction to the article "Volcanology, geochemistry and age of the Lausitz Volcanic Field" that was published in the May 24, 2015 issue is presented.

The article presents a study which evaluates the current sheet thickness of the outer boundary of the magnetosphere as observed by four CLUSTER Satellites. Results reveal that at middle and high latitudes, the magnetopause can move with a velocity of up to 180 kilometers per second. It has been found that the thickness of the current sheet of the magnetopause at middle and high latitudes varied from 50 to 6000 kilometers.

Abstract: We present three-dimensional numerical simulations of the interaction between a Hot Jupiter and the stellar wind plasma of its host star in the framework of resistive magnetohydrodynamics (MHD). In a first step, we investigate the numerical realization of the plasma flow around the planet and the planetary magnetic field using a simplified model, before we simulate more realistic scenarios on the basis of the stellar wind model by Weber and Davis. A main goal is to understand the magnetic interaction between star and planet. In analogy to the well-known Jupiter Io scenario, we study the development of a magnetic field-aligned current system in different parameter regimes. [Copyright &y& Elsevier]

−Albert Abubakirovich Galeev is a Soviet and Russian expert in plasma physics who actively contributed to fusion research. In the early 1970s, he became a head of department at the Space Research Institute of the Academy of Sciences of USSR and began devoting most of his time to the problems of the physics of space plasma and made a very important contribution to the solution of many of them, such as physics of collisionless shock waves, the phenomenon of anomalous ionization, processes in the plasma envelopes of comets, and many others. This paper is devoted to only one of the many directions of his work: studies of current sheets and the magnetic reconnection processes that occur therein. Studies of thin current structures is space plasma, whose thickness is about the proton gyroradius, began with the pioneering works of S.I. Syrovatskii, T. Speiser, and other outstanding scientists who proposed that in space plasma, thin boundary current sheets exist, which play the key role in the dynamics of Earth's magnetosphere and Sun's corona. The development of these works was dictated by the necessity to explain the solar flares and magnetospheric perturbations during which phases of evolutionary development are replaced by explosive spontaneous processes that release free energy. One of the key physical processes is the magnetic field reconnection, which is realized in nature as a part of the general problem of generation and evolution of current sheets. In a series of works that started in 1975 by the publication (together with L.M. Zelenyi) of the article entitled "Metastable states of a diffuse neutral layer" in JETP letters, A.A. Galeev studied the stability of current sheets to the tearing mode and the dynamics of magnetic reconnection at the boundary of planetary magnetospheres and explained the processes of generation of fast ion flows with energies of several MeV in Earth's magnetotail. In this paper, we discuss further development of these works that were once initiated by A.A. Galeev. A new model of embedded current sheets is presented, which consists of an internal electron sheet and two external current sheets formed by proton and oxygen ion currents. It is shown that the free energy of such embedded structure in the corresponding range of parameters substantially exceeds the free energy of the well-known Harris's configuration. This allows one to simultaneously explain their stability (up to a certain limit) and destabilization when the current sheet parameters reach certain critical values, which leads to the change of topology of magnetic field and start of magnetic reconnection. [ABSTRACT FROM AUTHOR]

Abstract: We report our recent improvement in non-force-free extrapolation of coronal magnetic field, using vector magnetograms. Based on the principle of minimum (energy) dissipation rate (MDR), a generally non-force-free magnetic field solution is expressed as the superposition of one potential field and two () linear force-free fields, with distinct parameters. With a known potential field, the system is reduced to a second-order one that can be solved using one single-layer vector magnetogram. We devise an iteration procedure to determine the potential field, by achieving satisfactory agreement between the MDR-model computed and measured transverse magnetic field vectors on the bottom boundary. We illustrate this approach by applying it to real magnetograph measurement of solar active region AR 10953. We show that the results are satisfactory as judged from the quantitative magnetic field measurement, and the behavior of the derived Lorentz force. [Copyright &y& Elsevier]

High-magnitude magnetic barriers in space and solar plasma are proposed to be attributed to the pile up of magnetic field lines and their Alfvénic collapse for MHD flows. The analysis of experimental data from both the Interball and Cluster spacecrafts shows that high-magnitude magnetic structures found in the Earth magnetosheath and near the magnetopause are supported by a nearly thermal transverse plasma flow, with the minimum barrier width being on the order of the ion gyroradius. The collapse termination at such scales can be explained by the balance between the pile up of magnetic field lines and backward finite-gyroradius diffusion. Comparison between the theoretical, modeling, and experimental data shows that the Alfvénic collapse is, in general, a promising mechanism for magnetic field generation and plasma separation. [ABSTRACT FROM AUTHOR]

Generative deep learning models enable data-driven de novo design of molecules with tailored features. Chemical language models (CLM) trained on string representations of molecules such as SMILES have been successfully employed to design new chemical entities with experimentally confirmed activity on intended targets. Here, we probe the application of CLM to generate multi-target ligands for designed polypharmacology. We capitalize on the ability of CLM to learn from small fine-tuning sets of molecules and successfully bias the model towards designing drug-like molecules with similarity to known ligands of target pairs of interest. Designs obtained from CLM after pooled fine-tuning are predicted active on both proteins of interest and comprise pharmacophore elements of ligands for both targets in one molecule. Synthesis and testing of twelve computationally favored CLM designs for six target pairs reveals modulation of at least one intended protein by all selected designs with up to double-digit nanomolar potency and confirms seven compounds as designed dual ligands. These results corroborate CLM for multi-target de novo design as source of innovation in drug discovery., (© 2024. The Author(s).)

Terminal complement blockade by humanised monoclonal antibody eculizumab has been used to treat transplantation-associated thrombotic microangiopathy (TA-TMA) in recent years. This retrospective international study conducted by the Paediatric Diseases (PDWP) and Inborn Error Working Party (IEWP) of the European Society for Blood and Marrow Transplantation (EBMT) describes outcome and response of 82 paediatric patients from 29 centres who developed TA-TMA and were treated with eculizumab between January 2014 and May 2019. The median time from hematopoietic stem cell transplantation (HSCT) to TA-TMA manifestation was 92 days (range: 7-606) and from TA-TMA diagnosis to the start of eculizumab treatment 6 days (range: 0-135). Most patients received eculizumab weekly (72%, n = 55) with a standard weight (kg)-based dose (78%, n = 64). Six months from beginning of eculizumab therapy, the cumulative incidence of TA-TMA resolution was 36.6% (95% CI: 26.2-47) and the overall survival (OS) was 47.1% (95% CI: 35.9-57.5). All 43 patients with unresolved TA-TMA died. The cause of death was HSCT-related in 41 patients. This study also documents poor outcome of patients without aGvHD and their frequent concomitant viral infections. Considering recent publications, intensified eculizumab dosing and complement monitoring could potentially improve upon outcomes observed in this study., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

Solar eruptions are well-known drivers of extreme space weather, which can greatly disturb the Earth's magnetosphere and ionosphere. The triggering process and initial dynamics of these eruptions are still an area of intense study. Here we perform a magnetohydrodynamic simulation taking into account the observed photospheric magnetic field to reveal the dynamics of a solar eruption in a real magnetic environment. In our simulation, we confirmed that tether-cutting reconnection occurring locally above the polarity inversion line creates a twisted flux tube, which is lifted into a toroidal unstable area where it loses equilibrium, destroying the force-free state, and driving the eruption. Consequently, a more highly twisted flux tube is built up during this initial phase, which can be further accelerated even when it returns to a stable area. We suggest that a nonlinear positive feedback process between the flux tube evolution and reconnection is the key to ensure this extra acceleration.