78 research outputs found

    Gravitational losses for the binary systems induced by the next-to-leading spin-orbit coupling effects

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    The orbital energy and momentum of the compact binary systems will loss due to gravitational radiation. Based on the mass and mass-current multipole moments of the binary system with the spin vector defined by Boh\'{e} et al. [Class. Quantum Grav. 30, 075017 (2013)], we calculate the loss rates of energy, angular and linear momentum induced by the next-to-leading spin-orbit effects. For the case of circular orbit, the formulations for these losses are given in terms of the orbital frequency.Comment: 18 page

    Related consistent lures increase the judgment of multiplication facts: Evidence using event-related potential technique

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    Simple multiplication errors are primarily shown in whether the lures are related to the operands (relatedness, such as 3 × 4 = 15 vs. 17) or whether the same decades are shared with the correct answers (consistency, such as 3 × 4 = 16 vs. 21). This study used a delayed verification paradigm and event-related potential technique to investigate the effects of relatedness and consistency in simple multiplication mental arithmetic for 30 college students in an experiment of presenting probes in auditory channels. We found that, compared to the related inconsistent lures, the related consistent lures showed significantly faster reaction time and induced significantly large amplitudes of N400 and late positive component. The findings suggest that related consistent lures are less affected by the activation diffusion of the arithmetic problem, and the credibility of being perceived as the correct answer is less; the lures related to operands and sharing the same decades with the accurate results can promote the judgment of multiplication mental arithmetic, and the results support the Interacting Neighbors Model

    Meta-analysis of ridge-furrow cultivation effects on maize production and water use efficiency

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    Ridge-furrow cultivation (RF) is a popular dryland agricultural technique in China, but its effects on maize yield, total water consumption during crop growing stage (ET), and water use efficiency (WUE) have not been systematically analyzed. Here we conducted a meta-analysis of the RF effects on maize yield, ET and WUE based on the data collected from peer-reviewed literature. Yield, ET and WUE varied with climate, soil and mulching management. Averaged across all the geographic locations, RF increased the yield and WUE of maize by 47 % and 39 %, respectively, but no effects on ET. An increase in the yield and WUE occurred under RF in regions regardless of the mean growing season air temperature (MT) or a mean precipitation during the growing season (MP), although there was a trend that RF is more beneficial under low MP. RF also decreased ET in regions with MT>12 °C. RF increased the yield and WUE in regions with medium or fine soil texture. RF increased the yield, ET, and WUE in regions with low soil bulk density (BD) (≤1.3 g cm−3). But in areas where BD is larger than 1.3 g cm−3, RF only increased the yield and WUE. RF increased the yield and WUE with or without mulching, but decreased ET when no mulching was used. Together, optimizing RF effects on the yield, ET and WUE in maize was largely dependent on environmental conditions and management practices

    Crop yield and soil organic carbon under ridge–furrow cultivation in China: A meta-analysis

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    Ridge–furrow cultivation (RF) is a popular emerging technique that can increase crop productivity in dry areas. However, the efficacy of RF on crop yield and soil organic carbon (SOC) remains uncertain under different climate and management conditions. Here, we compiled data from 48 publications to evaluate the response of yield and SOC to RF in China. Overall, our meta-analysis showed that RF increased yield by 30.2%, but it had no effects on SOC. When differentiated based on different categories, yield and SOC varied by crop species, climate, soil textures, mulching management, and ridge–furrow patterns. RF increased the yield of wheat, maize, soybean, rape, linseed, potato, and SOC under soybean cultivation. Yield increase with RF was also consistent across temperature and precipitation. Yield increase was observed in all the soil textures. There were no RF effects on SOC under different soil textures. RF enhanced yields under no mulching, straw mulching and plastic film mulching, but increased SOC only in combination with straw mulching. A higher yield increase was observed under alternating small and large ridges (ASLR) than alternating ridges and furrows (AR). RF decreased SOC by 11.7% under AR, but had no effects on SOC under ASLR. Together, ASLR with straw mulching could increase yield and SOC in coarse soil texture regions with annual mean temperature >10°C and annual mean precipitation > 400 mm. This study showed the importance of considering local environmental conditions with management practices in identifying appropriate RF practices for improving crop productivity and soil carbon sequestration

    Insight-HXMT observations of Swift J0243.6+6124 during its 2017-2018 outburst

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    The recently discovered neutron star transient Swift J0243.6+6124 has been monitored by {\it the Hard X-ray Modulation Telescope} ({\it Insight-\rm HXMT). Based on the obtained data, we investigate the broadband spectrum of the source throughout the outburst. We estimate the broadband flux of the source and search for possible cyclotron line in the broadband spectrum. No evidence of line-like features is, however, found up to 150 keV\rm 150~keV. In the absence of any cyclotron line in its energy spectrum, we estimate the magnetic field of the source based on the observed spin evolution of the neutron star by applying two accretion torque models. In both cases, we get consistent results with B∼1013 GB\rm \sim 10^{13}~G, D∼6 kpcD\rm \sim 6~kpc and peak luminosity of >1039 erg s−1\rm >10^{39}~erg~s^{-1} which makes the source the first Galactic ultraluminous X-ray source hosting a neutron star.Comment: publishe

    Overview to the Hard X-ray Modulation Telescope (Insight-HXMT) Satellite

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    As China's first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band (1-250 keV) slat-collimator-based X-ray astronomy satellite with the capability of all-sky monitoring in 0.2-3 MeV. It was designed to perform pointing, scanning and gamma-ray burst (GRB) observations and, based on the Direct Demodulation Method (DDM), the image of the scanned sky region can be reconstructed. Here we give an overview of the mission and its progresses, including payload, core sciences, ground calibration/facility, ground segment, data archive, software, in-orbit performance, calibration, background model, observations and some preliminary results.Comment: 29 pages, 40 figures, 6 tables, to appear in Sci. China-Phys. Mech. Astron. arXiv admin note: text overlap with arXiv:1910.0443
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