缺水环境下造林苗木生根萌芽机理与造林关键技术研究

该研究针对黄土高原人工造林成活率低问题中的关键技术，系统研究了苗木定植后生根萌芽、展叶过程中内源激素与水分变化特征及其对生根萌芽的调控规律；缺水环境下内源激素变化规律和不同苗木在大气干旱和土壤水分亏缺下自身水分平衡的维持能力，水分平衡、激素消长与生根萌芽的关系等取得了以下研究成果：1、首次证明沙棘具有节水型御旱特性和典型的耐旱特性。双重作用使沙棘成为强抗旱性植物。 2、造林苗木成活过程中的水分平衡与致死机理研究提示了顺序性变化在4个树种（沙棘、杨树、刺槐、油松）中具有普遍性。系统研究了不同土壤水分含量对黄土高原4个树种的耗水特性、生长及干物质积累的过程以及水分利用效率（WUE）的影响。3、幼林生长特性研究表明干旱下树种生长受干旱影响程度不同，沙棘在干旱条件下生长受影响程度小于杨树、刺槐、油松等。 4、苗木水分平衡的抗旱造林技术措施，主要是减少蒸腾失水，促进根系吸水，保证苗体水分平衡，调控内源激素比例，达到提高造林成活率目的。可利用黄土透气性好推广截杆、埋苗等措施 5、不同立地条件下的林木生产力与水分关系研究和沙棘杨树混交林研究不仅提示了沙棘杨树混交林促进杨树生长机理，而且对黄土高原大面积人工林的利用和生态建设具有重要的指导意义。6、针对黄土高原4个乡土树种水分生理生态特征和不同立地条件水分特征研究，为黄土高原人工造林提供了科学依据。并对取得的单项和综合性技术成果通过示范推广，已在不同类型区建立了人工林，获得了社会生态经济效益，可在我国西部同类型区进行推广应用

气候变化国家评估报告(Ⅱ):气候变化的影响与适应

已经观测到的气候变化影响是显著的、多方面的。各个领域和地区都存在有利和不利影响,但以不利影响为主,未来的气候变暖将会对中国的生态系统、农业以及水资源等部门和沿海地区产生重大的不利影响。采取适应措施可以减轻气候变化的不利影响,应将适应气候变化的行动逐步纳入国民经济和社会发展的中长期规划中。由于我国科学研究的相对不足和科学认识能力的局限,目前的气候变化影响评估方法和结果还存在很大的不确定性。应当加强区域适应气候变化的案例研究、扩大研究领域、加强极端天气、气候事件影响的研究,以降低影响评估的不确定性,并提出切实可行的适应对策

Determination of the number of ψ(3686) events taken at BESIII

The number of ψ(3686) events collected by the BESIII detector during the 2021 run period is determined to be (2259.3±11.1)×106 by counting inclusive ψ(3686) hadronic events. The uncertainty is systematic and the statistical uncertainty is negligible. Meanwhile, the numbers of ψ(3686) events collected during the 2009 and 2012 run periods are updated to be (107.7±0.6)×106 and (345.4±2.6)×106, respectively. Both numbers are consistent with the previous measurements within one standard deviation. The total number of ψ(3686) events in the three data samples is (2712.4±14.3)×10^

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

Prediction of Energy Resolution in the JUNO Experiment

International audienceThis paper presents the energy resolution study in the JUNO experiment, incorporating the latest knowledge acquired during the detector construction phase. The determination of neutrino mass ordering in JUNO requires an exceptional energy resolution better than 3% at 1 MeV. To achieve this ambitious goal, significant efforts have been undertaken in the design and production of the key components of the JUNO detector. Various factors affecting the detection of inverse beta decay signals have an impact on the energy resolution, extending beyond the statistical fluctuations of the detected number of photons, such as the properties of liquid scintillator, performance of photomultiplier tubes, and the energy reconstruction algorithm. To account for these effects, a full JUNO simulation and reconstruction approach is employed. This enables the modeling of all relevant effects and the evaluation of associated inputs to accurately estimate the energy resolution. The study reveals an energy resolution of 2.95% at 1 MeV. Furthermore, the study assesses the contribution of major effects to the overall energy resolution budget. This analysis serves as a reference for interpreting future measurements of energy resolution during JUNO data taking. Moreover, it provides a guideline in comprehending the energy resolution characteristics of liquid scintillator-based detectors

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies