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We discuss applications of the study of the new and barely explored class of changing-look (CL) narrow-line Seyfert 1 (NLS1) galaxies and comment on their detection with the space mission SVOM (Space Variable Objects Monitor). We highlight the case of NGC 1566, which is outstanding in many respects, for instance as one of the nearest known CL AGN undergoing exceptional outbursts. Its NLS1 nature is discussed, and we take it as a nearby prototype for systems that could be discovered and studied in the near future, including with SVOM. Finally, we briefly examine the broader implications and applications of CL events in NLS1 galaxies and show that such systems, once discovered in larger numbers, will greatly advance our understanding of the physics of the environment of rapidly growing supermassive black holes. This White Paper is part of a sequence of publications which explore aspects of our understanding of (CL) NLS1 galaxy physics with future missions. [ABSTRACT FROM AUTHOR]

It is well known that ordinary supernovae (SNe) are powered by 56Ni cascade decay. Broad-lined type Ic SNe (SNe Ic-BL) are a subclass of SNe that are not all exclusively powered by 56Ni decay. It was suggested that some SNe Ic-BL are powered by magnetar spin-down. iPTF16asu is a peculiar broad-lined type Ic supernova discovered by the intermediate Palomar Transient Factory. With a rest-frame rise time of only 4 d, iPTF16asu challenges the existing popular models, for example, the radioactive heating (56Ni-only) and the magnetar +56Ni models. Here we show that this rapid rise could be attributed to interaction between the SN ejecta and a pre-existing circumstellar medium ejected by the progenitor during its final stages of evolution, while the late-time light curve can be better explained by energy input from a rapidly spinning magnetar. This model is a natural extension to the previous magnetar model. The mass-loss rate of the progenitor and ejecta mass are consistent with a progenitor that experienced a common envelope evolution in a binary. An alternative model for the early rapid rise of the light curve is the cooling of a shock propagating into an extended envelope of the progenitor. It is difficult at this stage to tell which model (interaction+magnetar + 56Ni or cooling+magnetar + 56Ni) is better for iPTF16asu. However, it is worth noting that the inferred envelope mass in the cooling+magnetar + 56Ni is very high. [ABSTRACT FROM AUTHOR]

The flow control of a circular cylinder by using a flexible filament has been numerically investigated in this work. The cylinder is either fixed or elastically mounted, and the filament is attached to the base of the cylinder. Its leading end is fixed and its trailing end is free to flap. To execute the numerical simulation and deal with the fluid-structure interaction (FSI) of the filament as well, an improved immersed boundary-lattice Boltzmann method (IB-LBM) is presented. As compared to the conventional IB-LBM for handling the FSI of a filament, the current method can incorporate the mass effect of the filament and no user-defined spring parameter is needed to calculate the interaction force on the filament. After validating the employed method, the effects of the filament on the flow control of the cylinder are systematically examined by varying the bending coefficient (Kb) and length (L) of the filament. The laminar flow with a Reynolds number of 150 is considered in this study. Based on the numerical results obtained, it is found that the fluctuation of lift force and vortex shedding of a fixed cylinder and the vortex-induced vibration of an elastically mounted cylinder can be suppressed efficiently. [ABSTRACT FROM AUTHOR]

A numerical investigation on the power extraction of a pitching-motion-activated flapping foil near solid walls is performed by using an immersed boundary-lattice Boltzmann method in this study. The flapping motions of the foil include a forced pitching component and an induced plunging component. The foil is placed either near a solid wall or between two parallel plane walls. Compared to previous work on the flapping foil for power extraction, the effect of the walls is first considered in this work. At a Reynolds number of 1100 and with the position of the foil pitching axis at third chord, the influences of the mechanical parameters (such as damping coefficient and spring constant) of the foil, the amplitude and frequency of the pitching motion and the clearance between the foil pitching axis and the wall on the power extraction performance of the flapping foil are systematically evaluated. Compared to the situation of free stream, the power extraction performance of the foil near the wall is improved. For given amplitude and frequency, as the clearance decreases the net power extraction efficiency improves. Moreover, as the foil is placed near one wall, there is a transverse shift to the plunging motion that consequently weakens the improvement of net power extraction efficiency. In contrast, the shift can be significantly eliminated as the foil is placed between two walls, which can further improve the net power extraction efficiency. In addition, it is found that the efficiency improvement is essentially from the increased power extraction, which is due to the generation of high lift force. [ABSTRACT FROM AUTHOR]

We present our optical observations of the GRB 070518 afterglow obtained at the 0.8-m Tsinghua University–National Astronomical Observatory of China Telescope (TNT) at Xinglong Observatory. Our follow-up observations were performed from 512 s after the burst trigger. With the upper limit of redshift ∼0.7, GRB 070518 is found to be an optically dim burst. The spectra indices of optical to X-ray are slightly larger than 0.5, which implies that the burst might be a dark burst. The extinction of the host galaxy is 3.2 mag, inferred from the X-ray hydrogen column density with Galactic extinction law, and 0.3 mag with the Small Magellanic Cloud extinction law. Also, it is similar to three other low-redshift optically dim bursts, which belong to X-ray rich gamma-ray bursts or X-ray flashes and have mid-term duration ( , except for GRB 070419A, s). Moreover, its R-band afterglow flux is well fitted by a single power law with an index of 0.87. The optical afterglow and the X-ray afterglow in the normal segment might have the same mechanism, as they are consistent with the prediction of the classical external shock model. Besides, GRB 070518 agrees with the Amati relation under reasonable assumptions. The Ghirlanda relation is also tested with the burst. [ABSTRACT FROM AUTHOR]

Prior research has indicated that the two sperm cells of Nicotiana tabacum are dimorphic, suggesting that they may participate in preferential fertilization during in vivo fusion with the egg and central cells. To probe the mechanism of potential preferential fertilization in this plant, it will be necessary to use modern sensitive molecular techniques. For this purpose, two individual populations of two sperm cells, constituting the Svn (associated with the vegetative nucleus) and Sua (unassociated with the vegetative nucleus), were isolated in the thousands from tobacco pollen tubes with a micromanipulator as a preliminary step toward research on gametic recognition using molecular techniques. Microelectrophoresis of paired sperm cells from a single pollen tube was conducted at different developmental stages. Sperm cells isolated from 1-, 2-, 3- and 4-cm stylar lengths migrated to the negative pole, with the Sua displaying significantly greater electrophoretic mobility than the Svn, reflecting a more positively charged cell surface on the Sua. The sperm cells isolated from 1-cm style are very sensitive to electron potential in an electrophoretic field, presumably reflecting that they are still in a young state. Differences in cell surface charge between the Sua and Svn may be related with cell fate during fertilization. [ABSTRACT FROM AUTHOR]

A genic male sterile Chinese cabbage, Brassica campestris L. ssp. chinensis Makino, was examined using cytological and cytochemical methods to characterize the process of pollen abortion in this plant. Thick sections of both fertile and sterile anthers at different developmental stages were stained using Toluidine Blue O, Periodic Acid-Schiff’s (PAS) reaction and Sudan Black B to detect cytochemical changes that may occur in the distribution of insoluble polysaccharide and lipid storage bodies. Pollen abortion in sterile anthers occurs at an early stage of microspore development. During early microspore development, reductions in the number of starch grains in the connective tissue of fertile anthers coincide with the accumulation of starch grains in cells of the anther wall. In the late microspore stage, a large vacuole forms in the microspore, and tapetal cells synthesize and accumulate lipid droplets. The cellular organization of tapetal cells in sterile anthers appears similar to that in fertile anthers, except for the absence of lipid droplets in cells of sterile anthers and diffusely labeled tapetal polysaccharides, suggesting defects in nutrient storage. [ABSTRACT FROM AUTHOR]

To optimize the efficiency of bioremediation, treatability studies are needed to understand the fate of pollutants and environmental conditions under which microorganism growth is promoted and efficient degradation of these pollutants result. This article presents a recommended procedure which may achieve these goals. Results and treatability comparisons for candidate compounds including carbon tetrachloride (CT), methyl-tert-butyl-ether (MTBE) and hexachloro-butadiene (HCBD) are presented and discussed. Culture redox potential (ORP) which is an indicator or free electron activity of a system appeared to have a significant impact on CT biodegradation. Optimum biodegradation of CT by Pseudomonas cepacia was observed between 3100 and 3200 mv. Under the optimum environmental conditions established during the batch-scale biotransformation study, 98 to 99.9% of CT and 70% of MTBE introduced into the continuous fixed-biofilm reactor were degraded. The biphasic model simulating biodegradation of CT and MTBE provided an excellent correlation in the fixed-biofilm study and was simple to apply as compared with other models. [ABSTRACT FROM AUTHOR]

VT (Visible Telescope) is an instrument onboard SVOM (Space-based multi-band astronomical Variable Objects Monitor) satellite working in the visible band, which will play an important role in follow-up of two categories of GRBs: very distant events at higher redshift and faint/soft nearby events in SVOM mission. To fulfill these primary science requirements, decent sensitivity and wavelength coverage are fundamental for VT design. VT performance and data process strategy were successfully studied on its feasibility in Phase A, which is presented in this poster. Additionally, preliminary VT image simulator is also introduced here. [ABSTRACT FROM PUBLISHER]

Objectives: Home-based self-screening and monitoring for obesity is particularly valuable for the prevention and control of chronic diseases. This study aimed to identify an anthropometric index suitable for home-based obesity screening in children and adolescents., Study Design: The design of this study is a cross-sectional study., Methods: A total of 14,042 students (6-17 years) from the Qibao Community, Minhang District, Shanghai, were studied in 2018. The percentage body fat (PBF), height, weight, waist circumference (WC) and hip circumference were measured. Body mass index (BMI), triponderal mass index (TMI), body adiposity index (BAI), waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR) were calculated. Partial correlation analysis was used to evaluate the relationships between these indices and PBF, and receiver operating characteristic (ROC) curves were used to evaluate their performance for obesity screening., Results: BMI, TMI, WC and WHtR were found to strongly correlate with PBF (r ≥ 0.830, all P < 0.001). The optimal index for obesity screening in children (6-11 years) was BMI (area under the ROC curve [AUC] = 0.980 for boys and 0.981 for girls) and in adolescents (12-17 years) was TIM (AUC = 0.976 for boys and 0.945 for girls); however, the optimal cut-off values for BMI and TMI differed among the subgroups. The ROC curve analysis showed that WHtR had similar cut-off values in each subgroup (0.45 for boys of 6-11 years and 0.43 for the other subgroups), excellent performance in children (AUC>0.90) and good performance in adolescents (AUC = 0.960 for girls and 0.878 for boys)., Conclusions: Owing to its accuracy and stable cut-off value for defining obesity, WHtR should be recommended for home-based obesity screening in children and adolescents., (Copyright © 2020 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.)

A series of Co nanocluster-assembled films with cluster sizes ranging from 4.5 nm to 14.7 nm were prepared by the plasma-gas-condensation method. The size-dependent electrical transport properties were systematically investigated. Both of the longitudinal resistivity ([Formula: see text]) and saturated anomalous Hall resistivity ([Formula: see text]) continuously increased with the decrease of the cluster sizes (d). The [Formula: see text] firstly increased and then decreased with increasing the temperature for all samples, which could be well described by involving the thermally fluctuation-induced tunneling (FIT) process and scattering. The tunneling effect was verified to result in the invalidation of classical anomalous Hall effect (AHE) scaling relation. After deducting the contribution from tunneling effect to [Formula: see text], the AHE scaling relation between [Formula: see text] and the scattering resistivity ([Formula: see text]) by varying the temperature was reconstructed. The value of scaling exponent γ increased with increasing Co cluster sizes. The size dependence of γ might be qualitatively interpreted by the interface and surface-induced spin flip scattering. We also determined the scaling relation between [Formula: see text] and [Formula: see text] at 5 K by changing the Co cluster sizes, and a large value of γ = 3.6 was obtained which might be ascribed to the surface and interfacial scattering.

Coke-plant wastewater was treated by an anaerobic-anoxic-aerobic (A(1)-A(2)-O) biofilm system and an anoxic-aerobic (A/O) biofilm system, respectively. At same or similar levels of hydraulic retention time (HRT), the two systems had almost identical chemical oxygen demand (COD) and NH(3) removals, but a different organic-N removal. Set-up of an acidogenic stage benefited for the removal of organic-N and the A(1)-A(2)-O system was more useful for total nitrogen removal than the A-O system. HRT did not have a substantial effect on the COD and NH(3)-N removal efficiencies, but considerably influenced the organic-N removal and distribution of oxidized nitrogen in the final effluent. The GC/MS analysis demonstrated that some refractory compounds were decomposed at the acidogenic stage and resulted in the production of some intermediates, which were more readily degraded in the subsequent aerobic stage. Hence, the A(1)-A(2)-O system had better effluent quality than the A-O system in terms of effluent composition.