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STUDY QUESTION Do couple's age ranges for optimal fecundability, and the associations with fecundability of couple's age combinations and age differences differ with gravidity? SUMMARY ANSWER The couple's age range of optimal fecundability and age combinations differed with gravidity, and gravidity might modify the associations of age and spousal age difference with couple's fecundability. WHAT IS KNOWN ALREADY Age is one of the strongest determinants of fecundability, but the existing studies have certain limitations in study population, couple's extreme age combinations and age differences, and have not explored whether the association between age and fecundability differs with gravidity. STUDY DESIGN, SIZE, DURATION Retrospective cohort study. 5 407 499 general reproductive-aged couples (not diagnosed with infertility) participated in the National Free Pre-conception Check-up Projects during 2015–2017. They were followed up for pregnancy outcomes through telephone interviews every 3 months until they became pregnant or were followed up for 1 year. PARTICIPANTS/MATERIALS, SETTING, METHODS The main outcome was time to pregnancy, and the fecundability odds ratios and 95% CIs were estimated using the Cox models for discrete survival time. The associations of age and spousal age difference with fecundability were evaluated by restricted cubic splines. MAIN RESULTS AND THE ROLE OF CHANCE In this large cohort of general reproductive-aged population, the age of optimal fecundability of multigravida couples was older than that of nulligravida couples, but their subsequent fecundability declined more sharply with age. The decline in female fecundability was more pronounced with age, with fecundability dropping by ∼30% in both nulligravida and multigravida couples whose female partners aged ≥35 years. In the nulligravida group, the fecundability of couples who were both ≤24 years with the same age was the highest, which decreased steadily with the increase of spousal age difference, and younger male partners did not seem to contribute to improving couple's fecundability. In the multigravida group, couples with female partners aged 25–34 years and a spousal age difference of −5 to 5 years showed higher fecundability, and the effect of spousal age difference on couple's fecundability became suddenly apparent when female partners aged around 40 years. Young male partners were unable to change the decisive effect of female partner's age over 40 years on couple's reduced fecundability, regardless of gravidity. LIMITATIONS, REASONS FOR CAUTION Lacking the time for couples to attempt pregnancy before enrollment, and some couples might suspend pregnancy plans during follow-up because of certain emergencies, which would misestimate the fecundability. Due to the lack of information on sperm quality and sexual frequency of couples, we could not adjust for these factors. Moreover, due to population characteristics, the extrapolation of our results required caution. WIDER IMPLICATIONS OF THE FINDINGS The couple's age range of optimal fecundability, age combinations, and spousal age difference on fecundability varied with gravidity. Female age-related decline in fecundability was more dominant in couple's fecundability. Targeted fertility guidance should be provided to couples with different age combinations and gravidities. STUDY FUNDING/COMPETING INTEREST(S) This research received funding from the Project of National Research Institute for Family Planning (Grant No. 2018NRIFPJ03), the National Key Research and Development Program of China (Grant No. 2016YFC1000307), and the National Human Genetic Resources Sharing Service Platform (Grant No. 2005DKA21300), People's Republic of China. The funders had no role in study design, analysis, decision to publish, or preparation of the manuscript. The authors report no conflict of interest. TRIAL REGISTRATION NUMBER N/A. [ABSTRACT FROM AUTHOR]

Compared to more developed countries, the use of land resources is less efficient in China. China's vast forest land area gives it a rich and underutilized carbon sink. This is an important way for China to achieve the goals of "carbon peaking" and "carbon neutrality", which is of great significance to China's sustainable development. In the past 20 years, China has designed a series of policies to serve the development of forestry carbon sinks, namely the forestry carbon sink mechanism (FCSM). However, the questions of which policy is the most important, and what is the socio-economic value it generates, have not been fully investigated. Accordingly, this paper studied 30 provincial-level regions in China from 2005 to 2020 using the difference-in-differences (DID) model. The conclusions show that: (1) the FCSM does increase the socio-economic value of land resources, thus improving the sustainability of land resources; (2) the FCSM helps to increase forest coverage, forest stock volume and the forest coverage rate, which increases the social value of land resources from the greening path; (3) the FCSM helps to increase the gross forestry product, which increases the economic value of land resources through the path of increasing production value. [ABSTRACT FROM AUTHOR]

[Display omitted] • Using NIRS combined with CNN-LSTM to monitor the entire process of the classic formula Zhuru Decoction. • CNN-LSTM can accurately and quickly monitor the main pharmacological components of Zhuru Decoction. • The method can provide a reference for the rapid testing of traditional Chinese medicine compound prescriptions. Traditional Chinese Medicine (TCM) is a collective term for the medicines of all ethnic groups in China, including Han Chinese and ethnic minority medicines, reflecting the Chinese people's understanding of life, health and disease, and is a system of medicine with a long historical tradition and unique theories and technical methods. Due to the nonlinearity, large hysteresis, and strong interference in the concentration process used in the production of traditional Chinese medicine, it is challenging to use just one conventional control method to achieve the desired control effect. The majority of traditional quality control methods used in processing the samples will result in the loss of the active ingredient and in the detection of impurities. Monitoring of multiple critical quality attributes (CQAs) is crucial for the overall process of the index ingredient. In this study, based on the above background, fast and nondestructive near-infrared spectroscopy (NIRS) technique incorporating convolutional neural network (CNN) and long-short-term memory network (LSTM) was utilized to construct a quantitative model based on the seven characteristic components, puerarin, 3′-hydroxy puerarin, 3′-methoxy puerarin, puerarin apigenin, daidzin, glycyrrhizin and glycyrrhizic acid, during the concentration process. The results showed that the relative mean error (MAPE) values of the different components ranged from 0.7% to 2.8% and R2 from 0.981 to 0.992 based on the proposed CNN-LSTM model. The results showed that the combined model of near-infrared spectroscopy fused with convolutional neural network (CNN) and long-short-term memory network (LSTM) was feasible for accurate and rapid monitoring of the concentration of the classic famous prescription Zhuru Decoction (ZRD) during the decoction process and that the method could provide a reference value for rapid nondestructive testing of traditional Chinese medicine compound formulas. [ABSTRACT FROM AUTHOR]

• Quantification and comparison of cloud to ground lightning characteristics in the locality of coastal wind farm in Southeast China. • Providing potential evidence of the shielding effect between wind turbines in offshore wind farm. • Pointing out the threat of spring lightning to wind turbines in Southwest China. The effects of wind turbines (WTs) on cloud-to-ground (CG) lightning activities have not been fully understood. Based on the CG lightning data obtained from lightning location system (LLS), this paper quantified and compared the characteristics of CG lightning activities, including lightning density, multiplicity, polarity, peak current, and seasonal distribution, before and after the erection of the wind farms (WFs) in China. The shielding effect of offshore WTs was also analyzed. The results showed that, since the WF located in the southeast China was constructed, the return stroke density, flash density and multiplicity within a radius of approximately 0.5 km around the WTs increased by 27.9%, 7.3% and 10.9% in terms of change rate, respectively; within the same distance, the negative median peak current was -23.9 kA, and the positive median peak current was 12.3 kA. WTs located at the edge of the offshore WF had a shielding effect on the internal WTs. The proportion of spring lightning was up to 41.4% in southwest China. Winter lightning was rare in southern China. The results suggest more detailed factors, such as the local terrain, climate and the layout of WFs, are needed when assessing the lightning risk to WTs. [ABSTRACT FROM AUTHOR]