Search

We report the properties of more than 600 bursts (including cluster-bursts) detected from the repeating fast radio burst (FRB) source FRB 20201124A with the Five-hundred-meter Aperture Spherical radio Telescope (FAST) during an extremely active episode on UTC September 25-28, 2021, in a series of four papers. The observations were carried out in the band of 1.0 - 1.5 GHz by using the center beam of the L-band 19-beam receiver. We monitored the source in sixteen 1-hour sessions and one 3-hour session spanning 23 days. All the bursts were detected during the first four days. In this first paper of the series, we perform a detailed morphological study of 624 bursts using the 2-dimensional frequency-time ``waterfall'' plots, with a burst (or cluster-burst) defined as an emission episode during which the adjacent emission peaks have a separation shorter than 400 ms. The duration of a burst is therefore always longer than 1 ms, with the longest up to more than 120 ms. The emission spectra of the sub-bursts are typically narrow within the observing band with a characteristic width of $\sim$277 MHz. The center frequency distribution has a dominant peak at about 1091.9 MHz and a secondary weak peak around 1327.9 MHz. Most bursts show a frequency-downward-drifting pattern. Based on the drifting patterns, we classify the bursts into five main categories: downward drifting (263) bursts, upward drifting (3) bursts, complex (203), no drifting (35) bursts, and no evidence for drifting (121) bursts. Subtypes are introduced based on the emission frequency range in the band (low, middle, high and wide) as well as the number of components in one burst (1, 2, or multiple). We measured a varying scintillation bandwidth from about 0.5 MHz at 1.0 GHz to 1.4 MHz at 1.5 GHz with a spectral index of 3.0., Comment: Accepted by Research in Astronomy and Astrophysics (RAA)

In the present study, the Mg-4Zn-0.6Y-0.5Nd alloy was hot extruded and annealed at 200°C, 225°C and 250°C for different time to optimize microstructure and mechanical properties. The results exhibit that the dual-size grain structure and linearly distributed secondary phase are the main feature of the as-extruded Mg-Zn-Y-Nd alloy, which can be described as the elongated grain is surrounded by the fine equiaxed grain. Moreover, the as-extruded alloy shows strong { 01 1 ¯ 0 } fiber texture feature, especially for the large elongated grains. The annealing treatment results in static recrystallization, which increases fine equiaxed grains but decreases large elongated grains. In addition, the equiaxed grains formed during the annealing treatment demonstrate relative random orientations, which weaken the { 01 1 ¯ 0 } fiber texture of the alloy. Moreover, during the annealing at 225°C and 250°C, the extension twins begin to form in the alloy and weaken the { 01 1 ¯ 0 } fiber texture of the alloy further. The annealing treatment has little influence on the linearly distributed secondary phase but promotes the coarsening of small precipitates at 250°C. The annealing treatment could increase the yield and ultimate strength, but the elongation decreases, especially at higher temperature. Such a variation can be ascribed to the evolution of texture, grain structure, twinning and precipitation during the annealing treatment.

Background Delirium is common in elderly patients after surgery and is associated with poor outcomes. This study aimed to investigate the impact of intraoperative dexmedetomidine on the incidence of delirium in elderly patients undergoing major surgery. Methods This was a randomized double-blind placebo-controlled trial. Elderly patients (aged 60 years or more) scheduled to undergo major non-cardiac surgery were randomized into two groups. Patients in the intervention group received a loading dose of dexmedetomidine 0·6 μg/kg 10 min before induction of anaesthesia followed by a continuous infusion (0·5 μg per kg per h) until 1 h before the end of surgery. Patients in the control group received volume-matched normal saline in the same schedule. The primary outcome was the incidence of delirium during the first 5 days after surgery. Delirium was assessed with the Confusion Assessment Method (CAM) for non-ventilated patients and CAM for the Intensive Care Unit for ventilated patients. Results In total, 309 patients who received dexmedetomidine and 310 control patients were included in the intention-to-treat analysis. The incidence of delirium within 5 days of surgery was lower with dexmedetomidine treatment: 5·5 per cent (17 of 309) versus 10·3 per cent (32 of 310) in the control group (relative risk (RR) 0·53, 95 per cent c.i. 0·30 to 0·94; P = 0·026). The overall incidence of complications at 30 days was also lower after dexmedetomidine (19·4 per cent (60 of 309) versus 26·1 per cent (81 of 310) for controls; RR 0·74, 0·55 to 0·99, P = 0·047). Conclusion Intraoperative dexmedetomidine halved the risk of delirium in the elderly after major non-cardiac surgery. Registration number: ChiCTR-IPR-15007654 (www.chictr.org.cn).

This study reports a relation between electron flux modulations and chorus emissions by using correlation analysis. On April 18, 2017, Arase observed an enhancement of electron fluxes and intensification of banded chorus emissions at the same time. A result of the analysis shows that both the upper-band and lower-band chorus emissions have good correlations with field-aligned electron fluxes that satisfy their resonance conditions. This indicates simultaneous interactions with both the emission bands and electrons, resulting in electron pitch-angle scattering toward the magnetic field direction. In addition, low-energy electron fluxes in the perpendicular direction also show positive correlations with the chorus intensities, probably because the chorus emissions are modulated by a fluctuation of perpendicular low-energy electron fluxes.

Mg–Zn–Y–Nd alloy was prepared by casting and hot extrusion. The microstructure and mechanical properties of OM, SEM, XRD, TEM, and tensile tests were investigated with casting and hot extruded alloys. The results demonstrate that in a casting Mg–Y–Nd–Zr alloy, the α-Mg matrix is separated into the cell structure by a discontinuously distributed coarse Mg24Y5/α-Mg eutectic structure and fine Mg12Nd particles. TEM analysis shows that the Mg12Nd and Mg24Y5 phases have the orientation of $$ {\left[001\right]}_{{\mathrm{Mg}}_{12}\mathrm{Nd}}//{\left[0221\right]}_{\upalpha -\mathrm{Mg}} $$ , and $$ {\left[111\right]}_{{\mathrm{Mg}}_{24}{\mathrm{Y}}_5}//{\left[0001\right]}_{\upalpha -\mathrm{Mg}} $$ and $$ {\left(10\overline{1}\right)}_{{\mathrm{Mg}}_{24}{\mathrm{Y}}_5}//{\left(10\overline{1}0\right)}_{\upalpha -\mathrm{Mg}} $$ , respectively. The hot extrusion separates the Mg24Y5/α-Mg eutectic structure into fragments and aligns fragmentary Mg24Y5 particles along the extrusion direction. The interaction of hot extrusion and strengthening particles refines the α-Mg matrix greatly. Moreover, large strains result in the stacking faults of the matrix. As compared to the casting alloy, the hot-extruded one exhibits high yield strength, ultimate tensile strength, and elongation, which should be ascribed to the grain fineness, optimum distribution of strengthening particles and multiple substructures.

In this paper, combined with the wind farm blade failure cases, the blade failure reasons are analyzed from the aspects of blade design, material performance, manufacturing quality, transportation and hoisting, online monitoring, wind farm operation, and maintenance. In order to prevent blade operation failure, measures and suggestions based on blade selection, supplier selection, operation and maintenance management are proposed, which provide methods for blade design, manufacturing, and production maintenance.

Plague is a zoonotic disease caused by the bacterium Yersinia pestis. This pathogen can be transmitted by fleas and has an enzootic cycle, circulating among small mammals, and occasionally epizootic cycles, infecting other species. In China, infected wild rodents are primarily reservoirs of Y. Pestis and are related to human infection (Int. J. Infect. Dis., 33, 2015 and 67; BMC Microbiol., 9, 2009 and 205). Because shepherd dogs prey on and eat rodents (e.g. marmots and mice), they are valuable sentinel animals for plague serosurveillance in endemic disease foci, although their infections are usually asymptomatic (Vet. Microbiol., 172, 2014 and 339).

Transgenic Bacillus thuringiensis (Bt) crops are increasingly significant in pest control, but resistance development of target pests is a major issue in the sustainable deployment of Bt crops. The fitness cost of resistance in target pests is regarded as one of the main factors delaying resistance when adopting the refuge strategy. In this study, we compared the life-history traits of three independent sets of Helicoverpa armigera (Hübner, 1809) adults, of each there were a susceptible population and a Cry1Ac-resistant population derived by selection from it. Confirming to the previous studies, resistant individuals exhibited fewer progeny, less fecundity, lower egg hatching rate, and longer adult longevity. And poor fecundity in resistant strains was associated with the decline of the mature follicular amount, the ovarian weight ratio, and the length of the longest ovarian tubule. Interestingly, the juvenile hormone (JH) level appeared higher in resistant strains relative to susceptible strains. Application of methoprene (JH analogue) in vivo was effective in reducing fecundity and hatchability with the up-regulation of detected JH titer. These results suggested that resistance against Bt toxin reduced the reproductive capacity of H. armigera, and JH level is affected in the tradeoff between reproductive capacity and Bt resistance.

著者人数: 102名（所属. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS): 松岡, 彩子; 篠原, 育; 浅村, 和史), Accepted: 2018-12-29, 資料番号: SA1180350000

There are many problems in the technological development, research investment, staff ability and industrialized level of domestic wind turbine blade. This review summarizes the quality situation of wind turbine blade in the production process and proposes some advices and solutions in the further development of domestic wind turbine blade.

Correction for ‘Systematic investigation of the SERS efficiency and SERS hotspots in gas-phase deposited Ag nanoparticle assemblies’ by L. B. He et al., Phys. Chem. Chem. Phys., 2017, 19, 5091–5101.

Genetic causes account for more than half of congenital hearing loss cases. The most frequent mutations found in non-syndromic hearing loss patients occur in GJB2 and SLC26A4. Mitochondrial genome mutations are also prevalent. However, the frequency of common hearing loss mutations in the Chinese population has not yet been well estimated. Here, we implemented the SNaPshot genotyping method to investigate the carrier frequency of 15 commonly reported hearing loss mutations in GJB2, SLC26A4 and the mitochondrial genome based on a cohort of 5800 neonates in China. Up to 15.9% (923/5800) of the newborns carry at least one mutant allele. The top three were GJB2-c.109G>A, GJB2-c.235delC, and SLC26A4-c.919A>G, with notably high carrier frequencies of 1/10, 1/53 and 1/62 respectively, and mt-7444G>A with 1/141 was the most frequent allele in the mitochondrial genome. In this cohort, 0.48% (28/5800) of neonates were genetically diagnosed with hearing loss, from which seven cases failed an OAE test. This is the first epidemiological study of non-syndromic hearing loss in Chinese newborns indicating a notably high carrier frequency (1 per 6.3 newborns) among these 15 mutant alleles. Our carrier frequency data also aid in effective risk assessment and genetic counseling for hearing loss patients in the Chinese population.

Bone marrow mesenchymal stem cells (BMMSCs) have been widely applied in osteonecrosis. However, lack of biomechanical support limited application of BMMSCs. And porous tantalum (PTA) has been identified as a cell-friendly scaffold for bone regeneration. Herein, we aimed to investigate the efficacy of PTA seeded with BMMSCs in the treatment of osteonecrosis.After the production of PTA seeded with BMMSCs, MTT and GFP were performed to identify the proliferation and adhesion of BMMSCs respectively, which was further examined by scanning electron microscopy (SEM). And real-time PCR was also used to determine mRNA level of osteogenic markers, including Alp, OCN, OPN, Col I and Runx-2 in BMMSCs. Nineteen adult rabbits were applied for building steroid-associated osteonecrosis (SAON) models. Bone formation rate (BFR) and mineral apposition rate (MAR) were determined. And Goldner Trichrome Staining was used in these SAON models, which further confirmed the efficacy of PTA seeded with BMMSCs in SAON.PTA seeded with BMMSCs showed excellent biocompatibility. Additionally, SEM assay showed that BMMSCs adhered tightly and spread fully in the pores of PTA. Next, the expression of ALP and OPN mRNA in BMMSCs were significantly (p0.05) higher in the PTA-treated group compared to those in the PTA-untreated group. Furthermore, compared to those treated by only PTA, the dynamic bone formation in rabbits treated by PTA seeded with BMMSCs was significantly increased (p0.001) at both week 3rd and week 6th.The product, PTA seeded with BMMSCs, was successfully produced, and was determined as high efficacy for treatment of steroid-associated osteonecrosis. PTA seeded with BMMSCs may afford a promising option for treating osteonecrosis.

The production of Al based monotectic alloys with uniform microstructure is usually difficult due to the large density difference between the two immiscible liquid phases, which limits the application of such alloys. Here, we apply three orthogonal ultrasounds during the liquid phase separation process of ternary Al71.9Sn20.4Cu7.7 immiscible alloy. A uniform microstructure consisting of fine secondary (Sn) phase dispersed on Al-rich matrix is fabricated in the whole alloy sample with a large size of 30 × 30 × 100 mm. The numerical calculation results indicate that the coupled effect of three ultrasounds promotes the sound pressure level and consequently enlarges the cavitation zone within the alloy melt. The strong shockwaves produced by cavitation prevent the (Sn) droplets from coalescence, and keep them suspended in the parent Al-rich liquid phase. This accounts for the formation of homogeneous composite structures. Thus the introduction of three orthogonal ultrasounds is an effective way to suppress the macrosegregation caused by liquid phase separation and produce bulk immiscible alloys with uniform structures.

This study aimed to analyze the clinical efficacy of different resections in treating non-muscle-invasive bladder cancer (NMIBC), including partial cystectomy, transurethral resection of bladder tumor (TURBT) and holmium laser resection of bladder tumor. Two hundred and sixteen patients were recruited with NMIBC who were available for follow-up visits in hospital, including 62 cases treated with partial cystectomy, 90 cases treated with TURBT and 64 cases with holmium laser resection. Analysis was made on the cases with tumor relapse in the two years, on operation time, blood loss, time for indwelling urinary catheter, hospital stay and complications after operation. Results were compared to the clinical efficacy of these operation patterns. It was found that the two-year relapse rate for TURBT group, partial cystectomy group and Holmium laser resection group was 41%, 31%, and 33% respectively, and the difference had no statistical significance (p0.05). Both the TURBT group and holmium laser resection group had shorter operation time, hospital stay and time for indwelling urinary catheter as well as much less blood loss when compared with the partial cystectomy group; the difference had statistical significance (p0.001). In terms of complications, the TURBT group was likely to induce obturator nerve reflex and bladder perforation while the partial cystectomy group was likely to induce bladder spasm. Therefore, this study presumes that holmium laser resection and TURBT are much safer and quicker for recovery and obviously superior to the partial cystectomy.

This paper aims to compare the curative effects of persimmon leaf extract and ginkgo biloba extract in the treatment of headache and dizziness caused by vertebrobasilar insufficiency. Sixty patients were observed, who underwent therapy with persimmon leaf extract and ginkgo biloba extract based on the treatment of nimodipine and aspirin. After 30 days, 30 patients treated with persimmon leaf extract and 30 patients with ginkgo biloba extract were examined for changes in hemodynamic indexes and symptoms, such as headache and dizziness. The results showed statistically significant differences of 88.3% for the persimmon leaf extract and 73.1% for the ginkgo biloba extract, P0.05. Compared to the group of ginkgo biloba extract, the group of persimmon leaf extract had more apparent improvement in the whole blood viscosity, plasma viscosity, fibrinogen, hematokrit, and platelet adhesion rate, and the difference was statistically significant (P0.05 or P0.01). Based on these analyses, it can be concluded that persimmon leaf extract is better than ginkgo biloba extract in many aspects, such as cerebral circulation improvement, cerebral vascular expansion, hypercoagulable state lowering and vertebrobasilar insufficiency-induced headache and dizziness relief.

In this study, regression and cost analyses based on both mass balance and cost are applied to optimize the recycling of processing water for a 6-inch semiconductor wafer manufacturing plant. The analyses can also be applied to obtain the optimum reuse rate if the plant is expanded to produce 8-inch or 12-inch wafers. A mass balance diagram is first developed for three systems: processing system, wastewater system and recovery system. The information contained in the diagram is then modified to include the total costs of various water treatment unit processes for analyzing the costs for the above three systems. These costs are then used as the bases for optimizing the water recycling operation. Regression analyses to show the influence of various parameters e.g. the recovery rate of processing water, water usage, operation and maintenance costs and quantities of pollutants, on the operation costs of the above systems, have also been carried out using the Statistical Package for Social Science (SPSS) software. The resulting optimum recovery rates are 77% for the 6-in wafer plant, 80% for the 8-in wafer plant and 86% for the 12-in wafer plant. Thus, when the wafer size is upgraded, the water-recycling rate should also be raised for achieving the most cost-effective water reuse. The analyses also evaluate the water recycling practice for various assumed unit water costs. Using the 6-in wafer plant as an example, the optimum water-recycling rate should be raised to 74%, 77%, 78%, 81% and 84% for water costing $0.20, $0.36, $0.51, $0.71 and $1.00 per tons, respectively. Applying the cost analysis methods proposed in this study, the optimum water-recycling rate could be determined in response to variations of wafer manufacturing operations. Additionally, the regression analysis results have demonstrated that the wafer size, costs of the three aforementioned systems, and water cost significantly influence the optimized recycling rate of semiconductor processing water.

We propose a new method for the multiple attribute decision making problem. In this problem, the decision making information assembles multiple source data. Two main advantages of this proposed approach are that (i) it provides a data fusion technique, which can efficiently deal with the multisource decision making information; (ii) it can produce the degree of credibility of the entire decision making. The proposed method performs very well especially for the scenario that there exists conflict among the multiple source information. Finally, a traffic engineering example is given to illustrate the effect of our method.

A structured thermocline model is employed to elucidate the role of environmental factors in the characteristics of internal solitary waves, including the related implications for wave-induced resuspension and the formation of thin layers with enhanced concentration of passive particles. The model considers varying relative strengths between a thin seasonal thermocline and a broad permanent thermocline together with a sheared current in the upper mixed layer. The influence of these environmental factors on the stimulus of the benthic boundary layer under the footprint of solitary waves is assessed, particularly the potential for inducing boundary layer separation and lowering the near-bottom Richardson number. Also, the flow field associated with an internal solitary wave is shown not only to transport particles horizontally, but to create a tendency for passive particles located in the mixed layer to migrate vertically and concentrate in a thin layer. This latter effect is especially pronounced for particles that are heavier than the host fluid and have particle Reynolds numbers of order unity or greater. Although specific calculations for bubbles have not been included here, the net vertical displacement for light particles following the passage of a solitary wave may be quite large.

Genetic causes account for more than half of congenital hearing loss cases. The most frequent mutations found in non-syndromic hearing loss patients occur in GJB2 and SLC26A4. Mitochondrial genome mutations are also prevalent. However, the frequency of common hearing loss mutations in the Chinese population has not yet been well estimated. Here, we implemented the SNaPshot genotyping method to investigate the carrier frequency of 15 commonly reported hearing loss mutations in GJB2, SLC26A4 and the mitochondrial genome based on a cohort of 5800 neonates in China. Up to 15.9% (923/5800) of the newborns carry at least one mutant allele. The top three were GJB2-c.109GA, GJB2-c.235delC, and SLC26A4-c.919AG, with notably high carrier frequencies of 1/10, 1/53 and 1/62 respectively, and mt-7444GA with 1/141 was the most frequent allele in the mitochondrial genome. In this cohort, 0.48% (28/5800) of neonates were genetically diagnosed with hearing loss, from which seven cases failed an OAE test. This is the first epidemiological study of non-syndromic hearing loss in Chinese newborns indicating a notably high carrier frequency (1 per 6.3 newborns) among these 15 mutant alleles. Our carrier frequency data also aid in effective risk assessment and genetic counseling for hearing loss patients in the Chinese population.

OBJECTIVES--To determine the prevalence, clinical features, and patterns of hand dermatosis in hairdressers in Tainan, Taiwan, and to examine the associations between patterns of dermatosis and risk factors such as job description, work exposure, and sensitisation to common allergens. METHODS--Interviews, examinations, and patch tests of the hairdressers from nine hairdressing stores randomly selected from Tainan City. Patch test agents included 41 substances with common allergens, shampoo preservatives, hair dyes, permanent waving and bleaching agents. RESULTS--98 hairdressers finished the examination, 83% of them had occupational dermatosis and 32% had scissor induced scars or wounds. Most of the dermatoses belonged to either dry metacarpophalangeal dermatitis or eczema of the fingers. 44% of the hairdressers showed positive skin reaction to one or more patch test agents. The patch test results were different from previous reports in that the most common allergens were nickel, thimerosal, Captan, Kathon CG, and fragrance mix, and that the sensitivity to hair dye and permanent wave ingredients were low. The dry metacarpophalangeal dermatitis was associated with exposure to shampoo, and the eczema of the fingers with skin sensitivity to patch test agents. CONCLUSION--Hairdressers in Tainan City had a high prevalence of dermatoses including traumatic wounds, and allergic and irritant contact dermatitis. The rates of sensitivity to some of the common sensitising agents were different from previous reports.

Meiotic chromosome pairing in three Hordeum x Elymus hybrids was analyzed. Hybrid plants of H. jubatum (HHHH) x E. canadensis (SSHH) showed a low level of chromosome pairing, but the observation of trivalents indicated the presence of three H genomes as expected. In the hybrid plants of H. parodii (HHHHHH) x E. canadensis (SSHH), the level of chromosome pairing was rather low, but up to three trivalents per pollen mother cell could be detected rather infrequently. In the progeny of H. parodii (HHHHHH) x E. scabriglumis (SSHH??), chromosome pairing was quite frequent with the occasional occurrence of quadrivalents and pentavalents. This can be explained if the genomic constitution of E. scabriglumis is assumed to be SSHHHH.

Temperature or pressure anisotropies are characteristic of space plasmas, standard magnetohydrodynamic (MHD) model for describing large-scale plasma phenomena however usually assumes isotropic pressure. In this paper we examine the characteristics of MHD waves, fire-hose and mirror instabilities in anisotropic homogeneous magnetized plasmas. The model equations are a set of gyrotropic MHD equations closed by the generalized Chew-Goldberger-Low (CGL) laws with two polytropic exponents representing various thermodynamic conditions. Both ions and electrons are allowed to have separate plasma beta, pressure anisotropy and energy equations. The properties of linear MHD waves and instability criteria are examined and numerical examples for the nonlinear evolutions of slow waves, fire-hose and mirror instabilities are shown. One significant result is that slow waves may develop not only mirror instability but also a new type of compressible fire-hose instability. Their corresponding nonlinear structures thus may exhibit anticorrelated density and magnetic field perturbations, a property used for identifying slow and mirror mode structures in the space plasma environment. The conditions for nonlinear saturation of both fire-hose and mirror instabilities are examined.

A general formulation is proposed for electrostatic solitons in multicomponent plasmas consisting of one cold species described by the fluid model and multiple hot components described by the kinetic equation. For hot species two types of generalized velocity distributions are adopted: the kappa function and the highly nonthermal distribution with two free parameters which incorporate the widely used nonthermal distribution proposed by Cairns et al (1995 Geophys. Res. Lett. 22 2709) as a special limit. The general expressions for the KdV equations and the Sagdeev potential, as well as the conditions for electrostatic solitons with positive or negative polarity, are derived, which may give rise to various solutions for acoustic solitons in multicomponent plasmas with generalized nonthermal velocity distributions.

[1] In a homogeneous anisotropic plasma the magnetohydrodynamic (MHD) shear Alfven wave may become unstable for p∥ > p⟂ + B2/μo. Recently, a new type of fire-hose instability was found by Hellinger and Matsumoto [2000] that has maximum growth rate occurring for oblique propagation and may grow faster than the Alfven mode. This new mode is compressional and may be more efficient at destroying pressure anisotropy than the standard fire hose. This paper examines the fire-hose type (p∥ > p⟂) instabilities based on the linear and nonlinear double-polytropic MHD theory. It is shown that there exist two types of MHD fire-hose instabilities, and with suitable choice of polytropic exponents the linear instability criteria become the same as those based on the Vlasov theory in the hydromagnetic limit. Moreover, the properties of the nonlinear MHD fire-hose instabilities are found to have great similarities with those obtained from the kinetic theory and hybrid simulations. In particular, the classical fire-hose instability evolves toward the linear fire-hose stability threshold, while the nonlinear marginal stability associated with the new fire hose is well below the condition of β∥ − β⟂ = 2 but complies with less stringent linear stability threshold for compressible Alfven waves.