Search

The minimum value of the geomagnetic aa index has served as a remarkably successful predictor of solar cycle amplitude. This value is reached near or just after sunspot minimum, when both the near-Earth solar wind speed and interplanetary magnetic field (IMF) strength fall to their lowest values. At this time, the heliospheric current sheet is flattened toward the heliographic equator and the dominant source of the IMF is the Sun’s axial dipole moment, which, in turn, has its source in the polar fields. As recognized previously, the success of ${{aa}}_{\min }$ as solar cycle precursor provides support for dynamo models in which the sunspots of a given cycle are produced by winding up the poloidal field built up during the previous cycle. Because they are highly concentrated toward the poles by the surface meridional flow, the polar fields are difficult to measure reliably. Here we point out that the observed value of the radial IMF strength at solar minimum can be used to constrain the polar field measurements, and that this parameter, which is directly proportional to the Sun’s axial dipole strength, may be an even better solar cycle predictor than geomagnetic activity.

Global magnetohydrodynamic (MHD) models play an important role in the infrastructure of space weather forecasting. Validating such models commonly utilizes in situ solar wind measurements made near the Earth’s orbit. The purpose of this study is to test the performance of G3DMHD (a data driven, time-dependent, 3D MHD model of the solar wind) with Parker Solar Probe (PSP) measurements. Since its launch in 2018 August, PSP has traversed the inner heliosphere at different radial distances sunward of the Earth (the closest approach ∼13.3 R _⊙ ), thus providing a good opportunity to study evolution of the solar wind and to validate heliospheric models of the solar wind. The G3DMHD model simulation is driven by a sequence of maps of the photospheric field extrapolated to the assumed source surface (2.5 R _⊙ ) using the potential field model from 2018 to 2022, which covers the first 15 PSP orbits. The Pearson correlation coefficient (cc) and the mean absolute scaled error (MASE) are used as the metrics to evaluate the model performance. It is found that the model performs better for both magnetic intensity (cc = 0.75; MASE = 0.60) and the solar wind density (cc = 0.73; MASE = 0.50) than for the solar wind speed (cc = 0.15; MASE = 1.29) and temperature (cc = 0.28; MASE = 1.14). This is due primarily to lack of accurate boundary conditions. The well-known underestimate of the magnetic field in solar minimum years is also present. Assuming that the radial magnetic field becomes uniformly distributed with latitude at or below 18 R _⊙ (the inner boundary of the computation domain), the agreement in the magnetic intensity significantly improves (cc = 0.83; MASE = 0.49).

By applying potential-field source-surface and potential-field current-sheet extrapolations to photospheric field maps from three different observatories, we predict the solar wind speed at Earth for several Carrington rotations during 2018–2021 and compare the results with in situ observations. The predicted speeds are taken to be inversely correlated with the rate of flux-tube expansion inside the source surface, located at a heliocentric distance of 2.5 R _⊙ . The results often differ markedly from one observatory to another and are very sensitive to the latitudinal position of the ecliptic relative to the narrow belt of slow wind that surrounds the source-surface neutral line. Our main conclusions are that (1) the magnetograph measurements themselves are a major source of uncertainty in solar wind predictions; (2) these uncertainties are especially large near solar minimum, when Earth is located near the rapid transition between slow and fast wind that occurs on either side of the heliospheric current sheet; (3) comparison of the derived open field regions with observed coronal holes provides a strong, underutilized constraint on wind speed predictions; and (4) the observed polarity of the interplanetary magnetic field provides another important constraint on the location of the source region.

Magnetic holes (MHs) are transient magnetic structures responsible for energy conversion in space plasma. Using single-spacecraft measurements from Mars Atmosphere and Volatile EvolutioN (MAVEN), the existence of MHs on Mars has been confirmed. However, due to the limitations of single-spacecraft observations, significant uncertainty also arises on the identification of the spatial scale and 3D geometry of MHs. In this study, we report a series of MHs successively detected by Tianwen-1 near the high-latitude magnetopause and by the MAVEN spacecraft near the subsolar magnetopause. The large separation between Tianwen-1 and MAVEN (∼4 R _M ) suggests these MHs are macroscale structures extending along the axial direction. Additionally, we observe whistler waves generated by electron perpendicular anisotropy in one of the macroscale MHs. This study is the first joint observation of Martian MHs, shedding light on the research of transient magnetic structures on Mars.

Solar wind prediction algorithms and simulations of coronal events often employ photospheric field maps that are assembled over a 27 day solar rotation. This has stimulated efforts to update and better synchronize the maps by applying flux transport and including observations of the back side of the Sun. Here, using potential-field source-surface extrapolations, we address the question of how the emergence of a large active region (AR) on the Sun’s farside affects the coronal field and configuration of coronal holes on the Earth-facing side. We find that, if the new AR is located ∼135°–180° in longitude from Earth, the effect on the coronal field and solar wind near the central meridian will be almost negligible. This is because, when sunspot activity is relatively low, the outermost AR loops will become connected to the nearby polar fields; when sunspot activity is high, the newly emerged flux will connect to neighboring ARs. However, large ARs that emerge near the solar limb may sometimes have a significant effect on the field near the central meridian. In particular, a coronal hole having opposite polarity to that of the nearest sector of the AR may partially close down, resulting in slower wind; conversely, if the coronal hole has the same polarity as the facing AR sector, it will tend to increase in areal size, resulting in faster wind. In most cases, the main effect of a new AR will be to redistribute open flux between itself and neighboring coronal holes (including the polar holes) through interchange reconnection.

To verify the adaptability of unmanned aerial vehicle (UAV) datalinks to the electromagnetic environment comprising broad-spectrum high-power microwave radiation, strong electromagnetic pulse (EMP) tests were conducted using ultra wideband (UWB) radiation source at different radiation field strengths and repetition frequencies. For UAV datalinks, interference, disturbance, degradation and other effects were found in the tests. The electromagnetic energy coupling path of the broad-spectrum high-power microwave radiation was determined by adjusting the test status of UAV datalink as well as by protecting its key parts. The radio frequency front end, power cable and terminal interfaces on the housing surface were found to be weak electromagnetic links. The methods of the protection of radio frequency front end and power cable against strong EMPs were proposed. In addition, protection effects obtained by using different protection modules of radio frequency front end as well as by applying power spike pulse suppressors were compared and validated.

Introduction Major Depressive Disorder (MDD) is one of the most common mental illnesses worldwide and is strongly associated with suicidality. Commonly used treatments for MDD with suicidality include crisis intervention, oral antidepressants (although risk of suicidal behavior is high among non-responders and during the first 10-14 days of the treatment) benzodiazepines and lithium. Although several interventions addressing suicidality exist, only few studies have characterized in detail patients with MDD and suicidality, including treatment, clinical course and outcomes. Patient Characteristics, Validity of Clinical Diagnoses and Outcomes Associated with Suicidality in Inpatients with Symptoms of Depression (OASIS-D)-study is an investigator-initiated trial funded by Janssen-Cilag GmbH. Objectives For population 1 out of 3 OASIS-D populations, to assess the sub-population of patients with suicidality and its correlates in hospitalized individuals with MDD. Methods The ongoing OASIS-D study consecutively examines hospitalized patients at 8 German psychiatric university hospitals treated as part of routine clinical care. A sub-group of patients with persistent suicidality after >48 hours post-hospitalization are assessed in detail and a sub-group of those are followed for 6 months to assess course and treatment of suicidality associated with MDD. The present analysis focuses on a preplanned interim analysis of the overall hospitalized population with MDD. Results Of 2,049 inpatients (age=42.5±15.9 years, females=53.2%), 68.0% had severe MDD without psychosis and 21.2% had moderately severe MDD, with 16.7% having treatment-resistant MDD. Most inpatients referred themselves (49.4%), followed by referrals by outpatient care providers (14.6%), inpatient care providers (9.0%), family/friends (8.5%), and ambulance (6.8%). Of these admissions, 43.1% represented a psychiatric emergency, with suicidality being the reason in 35.9%. Altogether, 72.4% had at least current passive suicidal ideation (SI, lifetime=87.2%), including passive SI (25.1%), active SI without plan (15.5%), active SI with plan (14.2%), and active SI with plan+intent (14.1%), while 11.5% had attempted suicide ≤2 weeks before admission (lifetime=28.7%). Drug-induced mental and behavioral disorders (19.6%) were the most frequent comorbid disorders, followed by personality disorders (8.2%). Upon admission, 64.5% were receiving psychiatric medications, including antidepressants (46.7%), second-generation antipsychotics (23.0%), anxiolytics (11.4%) antiepileptics (6.0%), and lithium (2.8%). Altogether, 9.8% reported nonadherence to medications within 6 months of admission. Conclusions In adults admitted for MDD, suicidality was common, representing a psychiatric emergency in 35.9% of patients. Usual-care treatments and outcomes of suicidality in hospitalized adults with MDD require further study. Disclosure of Interest None Declared

Blends from the thermoplastic elastomer (TPE) of Propylene/1-butene copolymers (PPB) and Ethylene–propylene–diene monomer (EPDM) were successfully prepared by melt-mixed in an internal mixer and crosslinking through highenergy electron beam irradiation technology. The foaming process was achieved with the assistance of eco-friendly supercritical carbon dioxide (sc-CO2). The effect of EPDM content on foaming, morphology, thermal, and mechanical properties of EPDM/PPB blends with varied irradiation dose were investigated. Microstructural analysis revealed a perfect compatibility of PPB and EPDM in TPE. The increased EPDM content caused a decrease in the mechanical properties (hardness and tensile strength) of TPE; however, it has been improved with the increased irradiation dose. The thermal analysis indicated that the addition of EPDM and high-energy electron beam crosslinking resulted in a new melting peak near 150 °C in TPE, and a new crystalline phase appears during the crystallization process. Repeated processing performance tests showed that the incorporation of higher PPB content reduces the loss of mechanical properties of the prepared blend. The micro-morphology of the cell structure in foamed TPE material was investigated, and it was found that the size of cell structure gradually decreased with the increased EPDM content; however, the cell size has a tendency to increase first and then decrease with the increase of irradiation dose. At 40 kGy irradiation dose, the cell structure size is the largest among all EPDM/PPB foams. The cyclic compression test of the TPE foamed material showed that the material’s resistance to repeated compression got promoted with the increased EPDM content.

Abstract There is increasing evidence for the vulnerability of specific retinal ganglion cell (RGC) types in those with glaucoma and in animal models. In addition, the P2X7-receptor (P2X7-R) has been suggested to contribute to RGC death following stimulation and elevated IOP, though its role in RGC dysfunction prior to death has not been examined. Therefore, we examined the effect of an acute, non-ischemic intraocular pressure (IOP) insult (50 mmHg for 30 min) on RGC function in wildtype mice and P2X7-R knockout (P2X7-KO) mice. We examined retinal function using electroretinogram recordings and individual RGC responses using multielectrode arrays, 3 days following acute IOP elevation. Immunohistochemistry was used to examine RGC cell death and P2X7-R expression in several RGC types. Acute intraocular pressure elevation produced pronounced dysfunction in RGCs; whilst other retinal neuronal responses showed lesser changes. Dysfunction at 3 days post-injury was not associated with RGC loss or changes in receptive field size. However, in wildtype animals, OFF-RGCs showed reduced spontaneous and light-elicited activity. In the P2X7-KO, both ON- and OFF-RGC light-elicited responses were reduced. Expression of P2X7-R in wildtype ON-RGC dendrites was higher than in other RGC types. In conclusion, OFF-RGCs were vulnerable to acute IOP elevation and their dysfunction was not rescued by genetic ablation of P2X7-R. Indeed, knockout of P2X7-R also caused ON-RGC dysfunction. These findings aid our understanding of how pressure affects RGC function and suggest treatments targeting the P2X7-R need to be carefully considered.

Although wanting to become an astronomer from an early age, I ended up in solar physics purely by chance, after first working in high-energy astrophysics. I’ve never regretted switching from the pulsar to the solar magnetosphere, because solar physics has a great advantage over other areas of astrophysics—in the enormous amount of high-quality data available, much of it underutilized. I’ve often wondered why theoreticians and modelers don’t spent more time looking at these data (perhaps they feel that it is cheating, like taking a peek at the answers to a difficult homework assignment?). Conversely, I wonder why observers and data analysts aren’t more skeptical of the theoretical models—especially the fashionable ones.

Shape memory polymers (SMPs) with novel functions have received increasing attention, but hyperbranched polyimide (HBPI)-based SMPs have rarely been reported. Herein, we have synthesized a series of thiol-ended hyperbranched polyimides (BTMP-n, n = 6, 9, 11) with various molecular weights using a thiol-ene click reaction, and BTMP-n was used as a crosslinking agent with 1-methacryl-allyl ethoxyethyl-diphenyl phosphate (AGDP) to prepare SMPs (BTMP-n-AGDP). The chemical structure and molecular weight of BTMP-n were characterized by Fourier transform infrared (FTIR) spectroscopy, proton nuclear magnetic resonance (1H NMR) spectroscopy, and matrix-assisted laser desorption ionization timeof-flight (MALDI-TOF) mass spectroscopy. The shape fixity ratios and shape recovery ratios of BTMP-n-AGDP were over 99% and over 90%, respectively, indicating excellent shape memory properties. The excellent cycling stability of BTMP-n-AGDP was also demonstrated using the shape recovery sharpness over consecutive cycles. A rapid transition between the temporary shape and permanent shape of the BTMP-n-AGDP was discovered using the large shape recovery sharpness and a cramped strain recovery transition breadth. The results provide a new method for obtaining high-performance SMPs.

Coronal mass ejections (CMEs) that originate from pseudostreamers, which separate coronal holes of the same magnetic polarity, are characterized by a narrow (∼5°–30°), fan-shaped appearance in white-light coronagraph images. Despite this striking morphological similarity, a wide variety of underlying eruptions are observed, including not only coronal jets, but also larger-scale filament eruptions, footpoint flares, and even extreme-ultraviolet (EUV) waves that reflect off the coronal hole boundaries. Using EUV images recorded by the Solar Dynamics Observatory during the early rising phase of cycle 25 (2020–2022), we describe examples of the different kinds of underlying eruptions and identify the corresponding fan-like ejections in Large Angle and Spectrometric Coronagraph images. We attribute the narrowness of the white-light CMEs to lateral confinement by the like-polarity open flux surrounding the pseudostreamer and point out that, although the multipolar topology facilitates the “breakout” of material through the cusp region, it also tends to inhibit the eruption of the pseudostreamer as a whole. We also note that the self-similar “continuum” formed by the pseudostreamer mass ejections does not include the larger, more space-weather-effective CMEs associated with helmet streamers, which are surrounded by open flux of opposite polarity and undergo much greater lateral expansion.

In-core or cladding structural materials exposed to heavy ion irradiation often suffer serious irradiation-induced damages. Introducing defect sinks can effectively mitigate irradiation-induced degradation in materials. Here, we investigated the radiation response of additively manufactured 316 austenitic stainless steel with high-density solidification cellular structures via in situ Kr++ irradiation at 400°C to 5 dpa. The study shows that the cellular walls with trapped dislocations can serve as effective defect sinks, thus reduce dislocation loop density compared with the conventional coarse-grained counterparts. This study provides a positive step for the potential applications of radiation-resistant, additively manufactured steels in advanced nuclear reactors.

A series of novel composite microfibers composed of β-cyclodextrin (β-CDs) functionalized POM (polyoxymethylene) were prepared using electrospining technology with a mixture of hexafluoroisopropanol (HFIP) and N,N-dimethylformamide (DMF) as solvent. The concentration of β-CDs with respect to the POM was varied from 0 to 50 wt.%. The effect of β-CDs content on the morphology of POM/β-CD composite microfiber was investigated. The results showed that the introduction of β-CDs reduced the surface roughness and porosity of the microfibers, and the morphology of the fibers was changed. The increase of β-CDs content from 10% to 50% has led to increased average diameter of POM/β-CD composite fiber from 2.1 μm to 6.4 μm. The mechanical properties of the blend fiber mats were further investigated. In addition, silver nanoparticles were introduced to the POM/β-CD composite microfiber matrices during electrospinning. The POM/β-CD composite fiber allows CDs to form host–guest complexes with various small molecules and macromolecules. The TEM, SEM, XRD, and XPS were utilized to characterize the prepared samples. The data suggest that Ag nanoparticles were homogeneously distributed within the POM/β-CD fibers, and no aggregation was observed. The catalytic activity of Ag nanoparticles was tracked by ultraviolet-visible (UV-vis) spectroscopy which showed excellent catalytic degradation performance of organic dyes in the presence of NaBH4. The Ag/POM/β-CD mats are promising for use in waste treatment, molecular recognition, catalysis, and so on.

Transcription factors are involved in lipid metabolism, and in present study, the transcription factor WRINKLED 1 (GhWRI1) was cloned from Gossypium hirsutum L. cv. Coker 201 by reverse transcription (RT)-PCR and rapid amplification of cDNA ends. The Pro35S:WRI1 vector was constructed and transformed into upland cotton cv. Sumian 20 using the pollen tube pathway method. After PCR and Southern blot verification of the positive transgenic plants, T2 transgenic lines derived from T1 individuals with the insertion gene in a single copy were chosen for further dissection. Semi-quantitative and quantitative RT-PCR analyses indicated that GhWRI1 gene expression increased in transgenic plants compared with that in the wild-type. Seed lipid content increased at most transgenic plants, and at the same time, protein content decreased. Compared to the control, major agronomical traits were not affected by overexpression of GhWRI1 in transgenic plants.

Abstract The relaxation of amorphous materials, i.e., aging, would largely endanger their performances in service. Here we report a mechanical relaxation-to-rejuvenation transition of a Zr35Ti30Be27.5Cu7.5 bulk metallic glass (BMG) in elastostatic compression at ambient temperature, thus provide an accessible way to tailor the mechanical properties of amorphous materials. To unravel the structural evolution underlying the observed transition, atomistic simulations parallel with the experimental tests on a typical model glass system Zr60Cu40 were performed, which successfully reproduced and thus upheld the experimentally observed mechanical relaxation-to-rejuvenation transition. The variations of coordination number and atomic volume during the transition are evaluated to indicate a de-mixing tendency of the constituent atoms in the rejuvenation stage. This de-mixing tendency largely explains the difference between mechanical rejuvenation and thermal rejuvenation and reveals a competitive relationship between activation enthalpy and activation entropy in the stress-driven temperature-assisted atomic dynamics of BMG, such as diffusion and plastic deformation etc.

This paper reports the rapid synthesis of a dual-responsive copolymer through reversible addition–fragmentation chain transfer (RAFT) polymerization under microwave irradiation. Through use of 2-ethoxycarbonothioylthio acetic acid (ECTA) as a RAFT agent, the microwave-assisted polymerization rate of N-isopropylacrylamide (NIPAM) was approximately 150 times faster than that observed under conventional heating conditions, and the resulting homopolymer can be reactivated as a macroinitiator to produce poly(N-isopropylacrylamide-block-methacrylic acid) (PNIPAM-b-PMAA) block copolymers through a similar method. Research into the detailed polymerization kinetics of the PNIPAM and PNIPAM-b-PMAA revealed living characteristics that included a linear relationship between Mn and conversion, controlled molecular weights, and a relatively narrow molecular weight distribution. The solution of the block copolymers in phosphate-buffered saline buffer displayed a phase transition at a lower critical solution temperature transition of 42 °C, and altering the pH from 7 to 3.5 resulted in various degrees of polymer aggregation in the solution. Cisplatin was loaded to the polymeric carrier through a ligand exchange to form a macromolecular prodrug. The observed critical micelle concentration was 0.25 mg/mL. Overall, these polymers offer considerable potential for developing a new multifunctional drug delivery system.

An in vitro experiment was conducted to evaluate the effects of Aspergillus oryzae culture (AOC) and 2-hydroxy-4-(methylthio)-butanoic acid (HMB) on rumen fermentation and microbial populations between different roughage sources. Two roughage sources (Chinese wild rye [CWR] vs corn silage [CS]) were assigned in a 2×3 factorial arrangement with HMB (0 or 15 mg) and AOC (0, 3, or 6 mg). Gas production (GP), microbial protein (MCP) and total volatile fatty acid (VFA) were increased in response to addition of HMB and AOC (p

The spatial and temporal distribution patterns of mercury (Hg) in precipitation were investigated in the core urban areas of Chongqing, China. During the period from July 2010 to June 2011, total mercury (THg) and methyl mercury (MeHg) concentrations in precipitation were analysed from three sampling sites. Our results suggested that the volume-weight mean THg and MeHg concentrations in precipitation were 30.67 ng l−1 and 0.31 ng l−1, respectively. The proportion of MeHg in THg ranged from 0.1% to 7.6% with a mean value of 1.3%. THg and MeHg concentrations showed seasonal variations, while the highest THg value was measured in winter. Contrarily, the highest MeHg concentration was observed in autumn. Additionally, a geographically gradual decline of THg concentration in precipitation was observed from the downtown to the suburb, then to the controlled site in the city. 5 mm rainfall might be a threshold for the full wash-out capability. Rainfall above 5 mm may have a diluting effect for the concentrations of THg. Moreover, the current research implies that the coal combustion and motor vehicles could be the dominant sources for Hg in the precipitation.

The objective of this study was to evaluate the antioxidant capacity of Lactobacillus plantarum ZLP001 and its effects on growth performance and antioxidant status in weaning piglets. The survival in hydrogen peroxide and free radical-scavenging activity of Lactobacillus plantarum ZLP001 were analysed in vitro. The Lactobacillus plantarum ZLP001 showed high viability in 1.0 mmol/L hydrogen peroxide and high scavenging ability against hydroxyl, superoxide anion, and DPPH (1,1-diphenyl-2-picrylhydrazyl) radicals which was dose dependent. Ninety-six weaning piglets were selected (7.45±0.79 kg) and divided into three groups comprising of negative control without any supplementation, treatment group with supplemented 6.8×107 Lactobacillus plantarum ZLP001 CFU/g of diet, and positive control with antibiotic treatment (chlorotetracycline, 80 mg/kg diet). The results showed that Lactobacillus plantarum ZLP001 supplementation enhanced feed conversion rates in piglets compared with control (p