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Biochar is becoming an environmentally friendly material for remediation of heavy metal contaminated soils and improving food safety. A field trial over four rice seasons was conducted to investigate the use of biochar and low Cd accumulating cultivars on Cd uptake in a heavy metal contaminated soil. Wheat straw derived biochar was applied at 0, 20 and 40 t ha − 1 . Two rice cultivars with differing Cd accumulation abilities were selected in each season. The results showed that both biochar and low Cd affinity cultivars significantly reduced rice grain Cd accumulation. Biochar had no significant effect the first season but thereafter consistently reduced rice grain Cd by a maximum of 61, 86 and 57% over the next three seasons. Zn accumulation in the rice grains was not decreased by biochar application, although available soil Zn was sharply reduced (35–91%). Indica conventional rice cultivars had much lower Cd, but higher Zn and lower Cd/Zn ratios in the grain than indica hybrid cultivars. Biochar was more effective for mitigating grain Cd accumulation in low Cd affinity cultivars than in high affinity cultivars. Soil pH was sustainably increased (up to nearly 1 unit) while available Cd significantly decreased by a maximum of 85% after biochar addition. The translocation of Cd from rice roots to shoots was reduced from 20 to 80% by biochar. Low uptake affinity cultivars combined with biochar reduced late rice grain Cd concentration and Cd/Zn ratios by 69–80% and 72–80%, respectively. It indicated that the management of combining biochar and low Cd affinity cultivars should be an efficient way to remediate Cd contaminated rice paddies and reduce health risk associated with consuming rice from these soils. [ABSTRACT FROM AUTHOR]

Background: Induced abortion can seriously harm the physical and mental health of adolescent women. Long-acting reversible contraception (LARC) can effectively reduce unplanned pregnancies and prevent repeated abortions among adolescents. This study aimed to analyse the factors affecting the choice of LARC among adolescents in Chongqing of China., Methods: A total of 555 adolescents who underwent induced abortions for unplanned pregnancies between January 2019 and October 2021 were selected as study subjects. Logistic regression analysis was used to determine the factors affecting adolescent LARC choices following induced abortions., Results: The factors that affected adolescent LARC choices included an average monthly income ≥ ¥3000 (OR = 3.432, 95% CI: 1.429∼8.244), history of previous abortions (OR = 3.141, 95% CI: 1.632∼6.045), worrying about unplanned pregnancy (OR = 0.365, 95% CI: 0.180∼0.740), parental support for using LARC (OR = 3.549, 95% CI: 1.607∼7.839), sexual partners' support for using LARC (OR = 2.349, 95% CI: 1.068∼5.167), concerns about using LARC (OR = 0.362, 95% CI: 0.176∼0.745), and willingness to use free IUDs (OR = 13.582, 95% CI: 7.173∼25.717)., Conclusion: Cost is one of the factors affecting LARC choices. Parents and sexual partners may play important role in the choice of LARC.

Optical serial coherent analyzer of radio-frequency is a novel scheme that enables fast-scanning microwave signal measurements in a large bandwidth. The measurements are performed based on serial channelization realized by using a fast scanning laser source as the local oscillator to down-convert the to-be-measured radio-frequency (RF) signals. Optical coherent detection effectively removes interferences induced by RF's self-beating and guarantees the accuracy of measurements. In the experimental demonstration, instantaneous multi-frequency measurements and vector information acquisition of RF signals can be achieved by this scheme within 2.8 μs over 14 GHz bandwidth.

A serial photonic channelized radio frequency (RF) measurement scheme is proposed and experimentally demonstrated. This scheme can be used for instantaneous multiple-frequency measurement and capturing key parameters of linear frequency modulation signals. Based on high-speed wavelength scanning, this photonic RF channelizer works serially in time domain, and each wavelength labels a certain RF channel. With only one low-bandwidth photodetector (PD), we can implement multiple channel RF frequency measurements, which have a much simpler structure compared with parallel channelized schemes using broadband filter-bank and multiple PDs.