Abstract
In this study, we report on a detailed single-pulse analysis of the radio emission from a rotating radio transient (RRAT) J1918−0449, which is discovered with the Five-hundred-meter Aperture ...Spherical radio Telescope (FAST). The sensitive observations were carried out on 2021 April 30 using the FAST with a central frequency of 1250 MHz and a short time resolution of 49.152
μ
s, which forms a reliable basis to probe single-pulse emission properties in detail. The source was successively observed for around 2 hr. A total of 83 dispersed bursts with significance above 6
σ
are detected over 1.8 hr. The source’s dispersion measure (DM) and rotational period are determined to be 116.1 ± 0.4 pc cm
−3
and 2479.21 ± 0.03 ms, respectively. The share of registered pulses from the total number of observed periods is 3.12%. No underlying emission is detected in the averaged off-pulse profile. For bursts with fluence larger than 10 Jy ms, the pulse energy follows a power-law distribution with an index of −3.1 ± 0.4, suggesting the existence of bright pulse emission. We find that the distribution of time between subsequent pulses is consistent with a stationary Poisson process and find no evidence of clustering over the 1.8 hr observations, giving a mean burst rate of one burst every 66 s. Close inspection of the detected bright pulses reveals that 21 pulses exhibit well-defined quasiperiodicities. The subpulse drifting is present in nonsuccessive rotations with periodicity of 2.51 ± 0.06 periods. Finally, possible physical mechanisms are discussed.
As the rapid development of 5G and Internet of Things (IoT) techniques, more and more mobile devices with specific sensing capabilities access to the network and large amounts of data. The ...traditional architecture of the cloud computing cannot satisfy the requirements, such as low latency, fast data access for IoT applications. Mobile edge computing (MEC) can solve these problems, and improve the execution efficiency of the system. In this paper, we propose a privacy preserving data aggregation scheme for MEC assisted IoT applications. In our model, there are three participants, i.e., terminal device (TD), edge server (ES), and public cloud center (PCC). The data generated by the TDs is encrypted and transmitted to the ES, then the ES aggregates the data of the TDs and submits the aggregated data to the PCC. At last, the aggregated plaintext data can be recovered by PCC through its private key. Our scheme not only guarantees data privacy of the TDs but also provides source authentication and integrity. Compared with traditional model, our scheme can save half of communication cost, and is very suitable for MEC assisted IoT applications.
We present the discovery of a planet on a very wide orbit in the microlensing event OGLE-2012-BLG-0838. The signal of the planet is well separated from the main peak of the event and the planet-star ...projected separation is found to be twice the Einstein ring radius, which corresponds to a projected separation of 4 au. Similar planets around low-mass stars are very hard to find using any technique other than microlensing. We discuss microlensing model fitting in detail and discuss the prospects for measuring the mass and distance of the lens system directly.
This review article provides an overview of a range of recent technical developments in advanced arterial spin labeling (ASL) methods that have been developed or adopted by the community since the ...publication of a previous ASL consensus paper by Alsop et al. It is part of a series of review/recommendation papers from the International Society for Magnetic Resonance in Medicine Perfusion Study Group. Here, we focus on advancements in readouts and trajectories, image reconstruction, noise reduction, partial volume correction, quantification of nonperfusion parameters, fMRI, fingerprinting, vessel selective ASL, angiography, deep learning, and ultrahigh field ASL. We aim to provide a high level of understanding of these new approaches and some guidance for their implementation, with the goal of facilitating the adoption of such advances by research groups and by MRI vendors. Topics outside the scope of this article that are reviewed at length in separate articles include velocity selective ASL, multiple-timepoint ASL, body ASL, and clinical ASL recommendations.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
High salt concentration is a major abiotic stress limiting plant growth and productivity in many areas of the world.
Elaeagnus angustifolia
L. adapts to adverse environments and is widely planted in ...the western region of China as a windbreaker and for landscape and soil stabilization. High salt concentrations inhibited photosynthesis of
E. angustifolia
, but the mechanism is not known. In this paper, RNA-sequencing was used to investigate effects of salt stress on the photosynthetic characteristics of the species. In total, 584 genes were identified and involved in photosynthetic pathways. The downregulation of genes that encode key enzymes involved in photosynthesis and genes correlated to important structures in photosystem and light-harvesting complexes might be the main reason, particularly, the downregulation of the gene that encodes magnesium chelatase. This would decrease the activity of enzymes involved in chlorophyll synthesis and the downregulation of the key gene that encodes Rubisco, and thereby decreases enzyme activity and the protein content of Rubisco.
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FZAB, GEOZS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The photo-induced dynamics of
-nitrophenol, particularly its photolysis, has garnered significant scientific interest as a potential source of nitrous acid in the atmosphere. Although the photolysis ...products and preceding photo-induced electronic structure dynamics have been investigated extensively, the nuclear dynamics accompanying the non-radiative relaxation of
-nitrophenol on the ultrafast timescale, which include an intramolecular proton transfer step, have not been experimentally resolved. Herein, we present a direct observation of the ultrafast nuclear motions mediating photo-relaxation using ultrafast electron diffraction. This work spatiotemporally resolves the loss of planarity which enables access to a conical intersection between the first excited state and the ground state after the proton transfer step, on the femtosecond timescale and with sub-Angstrom resolution. Our observations, supported by
multiple spawning simulations, provide new insights into the proton transfer mediated relaxation mechanism in
-nitrophenol.
We present the detection and analysis of molecular hydrogen emission towards ten interstellar regions in the Large Magellanic Cloud. We examined low-resolution infrared spectral maps of 12 regions ...obtained with the Spitzer infrared spectrograph (IRS). The pure rotational 0-0 transitions of H... at 28.2 and 17.1 mu m are detected in the IRS spectra for 10 regions. The higher level transitions are mostly upper limit measurements except for three regions, where a 3... detection threshold is achieved for lines at 12.2 and 8.6 mu m. The excitation diagrams of the detected H... transitions are used to determine the warm H... gas column density and temperature. The single-temperature fits through the lower transition lines give temperatures in the range 86-137 K. The bulk of the excited H... gas is found at these temperatures and contributes ~5-17 per cent to the total gas mass. We find a tight correlation of the H... surface brightness with polycyclic aromatic hydrocarbon and total infrared emission, which is a clear indication of photoelectric heating in photodissociation regions. We find the excitation of H... by this process is equally efficient in both atomic- and molecular-dominated regions. We also present the correlation of the warm H... physical conditions with dust properties. The warm H... mass fraction and excitation temperature show positive correlations with the average starlight intensity, again supporting H... excitation in photodissociation regions. (ProQuest: ... denotes formulae/symbols omitted.)
Abstract
In order to improve the seismic performance of railway simply supported beam bridges, the seismic design schemes in different seismic intensity areas are compared and analyzed in this paper. ...The results show that the relative displacement of beam piers is too large when the simply supported beam bridge (≥ 0.3g) in high intensity earthquake area only adopts damping and isolation bearings. In order to reduce the displacement after earthquake, it is necessary to increase damping energy dissipation devices. Simply supported beam bridge in low intensity earthquake area (≤ 0.2g) adopt shock-absorbing isolation bearing. The cost of bearing will not increase, and the safety of bridge under earthquake will be greatly improved. It is recommended to adopt isolation design in low intensity seismic area.
Abstract
This paper introduces the research on guide band welding in China and other countries, analyzes the characteristics of guide bands produced by remelt deposit welding and the application of ...the welding process to the joining between thin-walled submunition-based projectiles with a large caliber and launched by a howitzer. In addition, this paper raises the performance testing requirements for the grooveless remelt deposit welding process.
To investigate the prevalence of, and risk factors for, cervical infection with human papillomavirus (HPV) in Shenyang City, People's Republic of China, we interviewed and obtained cervical cell ...samples from 685 women aged 15-59 years enumerated from local population lists. Human papillomavirus DNA was detected in cervical cell samples using a GP5+/6+-based PCR assay for 44 HPV types. Human papillomavirus prevalence was 16.8% overall and 13.6% among women without cervical abnormalities (16.6% and 12.4%, respectively, age-standardised to the world standard population), with no significant trends in HPV prevalence by age group. Of the 32 types identified, high-risk HPV types predominated in all age groups, HPV16 being the most common (3.4% of all women), followed by HPV52 (2.5%) and 58 (1.9%). Multiple-type infections accounted for 31.3% of all infected women. Not being married, reporting multiple sexual partners and husband's extramarital sexual relationships were all significantly associated with being HPV-positive. The disclosure of a relatively high HPV prevalence in Shenyang, in comparison with other worldwide populations, raises important questions concerning the prevention of cervical cancer in China, especially given the promising efficacy of prophylactic HPV vaccines.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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