分类： 医学、药学 >> 临床医学 提交时间： 2025-05-22 合作期刊: 《中国全科医学》
摘要： 背景 隐源性机化性肺炎（COP）是一种病理特征为肺泡内肉芽肿形成的非特异性肺损伤性疾病，对糖皮质激素治疗反应良好，但减量或停药时易复发。COP复发会导致预后不良，影响患者生活质量。因此，对COP临床特征及复发危险因素进行分析，对早期识别、减少复发尤为重要。目的 通过对COP患者临床资料的分析，筛选出可能的复发危险因素，加强临床医生对COP复发的认识和预防。方法 回顾性收集2014年1月—2023年12月在山东第一医科大学附属中心医院就诊，并经临床-影像-病理共同诊断为COP的患者95例，对患者按照出院后1个月、3个月、6个月进行随访，随访结果均由专业的呼吸内科医师和影像学医师共同判读。按照复发与否分为复发组和未复发组，对两组患者的一般临床信息、临床表现、实验室检查及影像学特点等进行分析，采用单因素及多因素Logistic回归分析探讨COP复发的独立危险因素。结果 本研究共收集95例COP患者，其中男49例，女46例，年龄18~85岁；临床表现主要为干咳、胸闷气促、呼吸困难；胸部影像学主要表现为双肺多发或大片实变影；实验室检查无明显特异性，部分患者可有炎症指标如白细胞计数、中性粒细胞计数、C反应蛋白、血沉增高。病理表现为肺泡管和肺泡腔内肉芽组织形成，同时可伴有大量泡沫细胞聚集、炎性细胞浸润、肺泡上皮增生、纤维组织增生、肺泡间隔增宽。有24例患者出现复发，单因素分析显示白细胞计数、中性粒细胞计数、C反应蛋白、谷丙转氨酶、乳酸脱氢酶、γ-谷氨酰基转移酶（γ-GT）、血沉、动脉血氧分压、诊断时间、发热与COP复发相关。多因素Logistic回归分析结果显示，乳酸脱氢酶（P=0.024，OR=1.003，95%CI=1.003~1.037）、血沉（P=0.002，OR=1.084，95%CI=1.030~1.041）、动脉血氧分压（P=0.001，OR=0.882，95%CI=0.817~0.952）、起病至就诊时间（P=0.016，OR=1.017，95%CI=1.003~1.031）为COP复发的独立危险因素。结论 乳酸脱氢酶、血沉、动脉血氧分压、诊断时间是COP复发的独立危险因素。
分类： 管理学 >> 人力资源开发与管理 提交时间： 2025-05-21
摘要： 非体面工作是指可能会给从业者造成身体、社交或道德层面的污点，令人反感或有损个人尊严的职业或工作任务。非体面工作从业者的工作意义感一直是该领域关注的重要话题。现有研究主要从个体或内群体视角出发，探讨从业者工作组文化或职业意识形态及个人正常化策略对其工作意义建构的影响。然而，关于非体面工作从业者在工作意义建构过程中所体现的共生性维度与他人维度的系统研究仍较匮乏，社会支持在其中的边界作用亦未得到充分揭示。因此，本研究拟从社会支持视角出发，基于工作意义构建四象限理论框架——“能动-共生”和“自我-他人”维度，系统探讨非体面工作从业者工作意义建构的个体与人际机制。预期成果将有助于从更全面的视角理解非体面工作从业者工作意义的构建机制，并在实践中通过管理个体或人际因素，启发员工工作意义的建构。
分类： 心理学 >> 认知心理学 提交时间： 2025-05-21
摘要： Cognitive control capacity (CCC) has been proposed as a compact index of how effectively individuals guide thought and behaviour when contingencies shift. To examine its validity, 198 adults completed a multi-component battery encompassing working-memory (N-back, AX-CPT), response inhibition (Go/No-Go, Stop-Signal), cognitive flexibility (task switching), and three attentional functions (altering, orienting and conflict). CCC was computed from entropy-time functions derived across majority function task. Higher CCC predicted greater N-back accuracy, fewer commission errors on inhibition trials, and reduced switch costs, but showed negligible ties to alerting and orienting scores. Network analysis situated the 3-back node at the graph centre with strong connections to inhibition and switching indices, whereas attentional nodes occupied peripheral positions. A least absolute shrinkage and selection operator (Lasso) regression prioritized 3-back accuracy as the significant predictor of CCC, with other subcomponent metrics (e.g., Go/No-Go errors, switching cost, and AX-CPT sensitivity) eliminated through regularization. Together, these results indicate that CCC consolidates the shared variance of updating, restraint, and flexibility without capturing stimulus-driven orienting. While the composite score proves useful for rapid screening and longitudinal tracking, the modest unique variance of each subcomponent cautions against replacing detailed process measures with a single metric. The study fills a methodological gap by integrating network topology with sparsity-based modelling and offers a framework for targeted interventions that bolster executive performance through the channels most relevant to CCC.
分类： 心理学 >> 实验心理学 提交时间： 2025-05-21
摘要： 人际情绪调节是社会互动中的一方(调节者)有目的地帮助另一方(目标者)控制情绪的过程。本研究通过两个实验考察情绪动机(包括动机强度和方向)对人际情绪调节策略选择的影响及其神经机制。结果发现在回避动机条件下，被试在调节自己情绪时倾向于选择认知重评/注意转移等调节性策略，且该倾向不受动机强度的影响；当调节他人情绪时，虽然被试也表现出调节策略使用偏好，但随着动机强度的提高，被试选择认知重评的倾向显著低于注意转移；另外，被试为他人选择重评的比例显著高于为自己选择该策略的比例，为对方选择观察的比例显著低于为自己选择的比例。在趋近动机条件下，被试并未表现出对任何调节策略的偏好。近红外成像数据显示，调节者右侧前额叶的激活能够显著正向预测他们为目标者选择调节策略的倾向；而左侧颞顶联合区(TPJ)的激活水平能显著负向预测他们为目标者选择认知重评的偏好，右侧TPJ激活则能正向预测对观察策略(不调节)的选择偏好。超扫描数据表明调节者与目标者在背外侧前额叶(dlPFC)和TPJ上的脑间同步活动水平越高，调节者越有可能使用认知重评调节目标者的回避动机情绪。上述结果为人际情绪调节策略选择的影响因素及其神经机制提供了新的理解。
分类： 计算机科学 >> 自然语言理解与机器翻译 提交时间： 2025-05-21
摘要： 【摘要】目的在构建基于人工智能生成内容（AIGC）的多模态设计生成与优化引擎，以进一步提升电子硬件定制产业的设计效率和创新能力，解决用户在设计过程中遇到的“创意不足、迭代慢、设计效果不理想”等问题。方法通过整合AIGC技术、深度学习算法与多模态数据处理能力，支持用户以自然语言、草图、3D模型等多种模态输入设计需求以算法不断提升设计方案的可行性和创新性。结果能够准确理解用户多样化的设计需求，快速生成符合行业标准的高质量设计方案。结论所构建的多模态设计生成与优化引擎，对推动电子硬件定制产业的智能化升级和可持续发展具有重要意义。
分类： 计算机科学 >> 自然语言理解与机器翻译 分类： 计算机科学 >> 计算机软件 分类： 计算机科学 >> 计算机应用技术 提交时间： 2025-05-20
摘要： Domain-specific QA systems require not just generative fluency but high factual accuracy grounded in structured expert knowledge. While recent Retrieval-Augmented Generation (RAG) frameworks improve context recall, they struggle with integrating heterogeneous data and maintaining reasoning consistency. To address these challenges, we propose DO-RAG, a scalable and customizable hybrid QA framework that integrates multi-level knowledge graph construction with semantic vector retrieval. Our system employs a novel agentic chain-of-thought architecture to extract structured relationships from unstructured, multimodal documents, constructing dynamic knowledge graphs that enhance retrieval precision. At query time, DO-RAG fuses graph and vector retrieval results to generate context-aware responses, followed by hallucination mitigation via grounded refinement. Experimental evaluations in the database and electrical domains show near-perfect recall and over 94% answer relevancy, with DO-RAG outperforming baseline frameworks by up to 33.38%. By combining traceability, adaptability, and performance efficiency, DO-RAG offers a reliable foundation for multi-domain, high-precision QA at scale.
分类： 机械工程 >> 机械设计 提交时间： 2025-05-20
摘要： This paper introduces a method for modular reconfigurable robots based on cube models to self-reconstruct and emit using the characteristics of permanent magnets in weightless environments. Although modular robots based on cubes have built various relatively mature reconstruction algorithm models, there is no relatively mature technology for implementing modular robot reconstruction due to the size, complexity, cost, etc. of modular robots. To solve this challenge, based on our existing modular robot Ubot, the permanent magnet array on the connection surface of the modular robot was transformed, so that the modular robot has three states: gravity, gravitational, and repulsive force, and can change the magnitude of the magnetic force. Based on this premise, we designed a collaboration mechanism of two modes of magnet absorption and repulsion on the module connection surface. UBot can use the electrical permanent magnet array to configure different magnetic drives to achieve flip along the edge and then absorb to adjacent positions, or use the electrical permanent magnet array to configure the same repulsive force to emit the modular robot to a predetermined working position. In addition, two-dimensional self-reconstruction experiments and emission experiments were carried out on the constructed micropore air float platform. This paper describes the design, reconstruction and emission principles and dynamic analysis of permanent magnets on the connection surface of a modular robot, as well as the reconstruction method suitable for modular robot ubot.
分类： 管理学 >> 区域经济管理 提交时间： 2025-05-20
摘要： 近年来，我国持续加大对科技型企业的金融支持力度。本文以2017-2024年A股上市公司为样本，利用科创金融改革试验区的建立这一准自然实验，采用双重差分法分析了金融创新对科技型企业股价崩盘风险的影响。实证研究结果显示，科创金融改革试验区的建立能够显署降低当地科技型企业的股价崩盘风险。进一步的机制分析发现，建立试验区对股价崩盘风险的降低效果在融资困难或者治理较为完善的企业子样本中更为显著。这一结果表明，试验区内的各项金融创新通过提升金融资源的可及性和便利性，有效缓解了科技型企业融资难、融资贵的问题。同时，金融资源也流向了公司治理良好的科技型企业，体现了精准施策的特征。此外，本文还发现地区金融发展水平也会影响政策效果。
分类： 医学、药学 >> 预防医学与公共卫生学 提交时间： 2025-05-20 合作期刊: 《中国全科医学》
摘要： 背景 心房颤动（简称房颤）的发生与心房重构、炎症、氧化应激等密切相关，其中心房重构是其主要发病机制。研究显示MOTS-c是一种新型线粒体衍生肽，具有抗炎、保护氧化应激和防止心脏重塑等作用。但MOTS-c在房颤患者中的表达及作用尚不明确。目的 探讨MOTS-c在房颤患者血清中的表达情况，其与房颤心房重构的相关性，以及MOTS-c预测房颤的价值。方法 连续选取2023年9月—2024年3月在中南大学湘雅医学院附属长沙医院心内科住院的非瓣膜性房颤患者142例（作为房颤组）。49例患者为阵发性房颤，93例患者为非阵发性房颤。并选取同期在本院行健康体检且无房颤病史的受试者48例为对照组。通过酶联免疫吸附法（ELISA法）检测不同人群血清MOTS-c水平，心脏彩色多普勒超声检查测量心脏超声指标。比较各组MOTS-c的差异；分析MOTS-c与心脏超声指标的相关性，并采用多因素Logistic回归分析探究MOTS-c是否为房颤的独立危险因素，受试者工作特征曲线（ROC曲线）分析MOTS-c对房颤的预测价值。结果 对照组、房颤组血清MOTS-c水平分别为（230.31±51.93）μg/L和（158.75±38.69）μg/L；房颤组患者血清MOTS-c水平低于对照组（t=10.111，P<0.001）。阵发性房颤患者、非阵发性房颤患者血清MOTS-c水平分别为（175.38±42.03）μg/L和（149.98±33.89）μg/L；非阵发性房颤组患者MOTS-c水平低于阵发性房颤组，差异有统计学意义（t=3.900，P<0.001）。房颤组中MOTS-c与左心房内径（LAD）呈负相关（r=-0.317，P<0.001）。多因素Logistic回归分析结果显示，LAD（OR=1.481，95%CI=1.262~1.738，P<0.001）、MOTS-c（OR=0.970，95%CI=0.958~0.982，P<0.001）是房颤的独立影响因素。血清MOTS-c预测房颤的ROC曲线下面积为0.859（95%CI=0.794~0.923），最佳截断值为188.5μg/L，灵敏度为0.88，特异度为0.73。结论 房颤患者血清MOTS-c水平显著降低，并与LAD呈负相关，提示房颤可能参与房颤患者的心房重构过程。血清MOTS-c降低可能是房颤发生的独立危险因素，并对房颤有预测诊断价值。
分类： 医学、药学 >> 预防医学与公共卫生学 提交时间： 2025-05-20 合作期刊: 《中国全科医学》
摘要： 背景 阿尔茨海默病（AD）作为认知症最常见的类型，对全球老年人群危害严重，而近年来中国饮酒量不断增加，饮酒习惯作为一种潜在的生活方式因素，其与AD疾病进展的关系尚未被充分揭示。目的 通过基于体素大脑形态学分析（VBM）技术，探究饮酒对不同AD患者大脑结构变化的影响。方法 收集2020—2023年在复旦大学附属华山医院住院的确诊为AD的患者资料，采用回顾性病历信息采集及电话回访的方式对AD者饮酒情况、颅脑结构核磁共振成像数据等信息进行收集，对数据完整的66例AD患者进行分析。根据AD严重程度（依据简易精神状态量表得分进行划分）及饮酒情况分为轻中度AD患者有无饮酒史者及重度AD患者有无饮酒史者，利用VBM方法比较不同AD患者脑灰质体积（GMV）差异。结果 66例AD患者中，轻中度AD者42例、重度AD者24例。42例轻中度AD患者中有饮酒史者16例，无饮酒史者26例。轻中度AD患者中有饮酒史者男性所占比例、吸烟史所占比例高于无饮酒史者（P<0.05）。24例重度AD患者中有饮酒史者9例，无饮酒史者15例。重度AD患者中有饮酒史者男性所占比例、吸烟史所占比例高于无饮酒史者（P<0.05）。轻中度AD患者中无饮酒史者大脑右侧角回灰质体积小于有饮酒史者（t=-3.698，P<0.05）。重度AD患者中有饮酒史者大脑左侧颞上回灰质体积小于无饮酒史者（t=5.774，P<0.05）。结论 饮酒史可显著影响AD患者大脑灰质体积的萎缩模式，轻中度患者主要表现为右侧角回萎缩减轻，而重度患者则以左侧颞上回萎缩加重为特征，即饮酒在AD进程中具有双重作用。
分类： 医学、药学 >> 预防医学与公共卫生学 提交时间： 2025-05-20 合作期刊: 《中国全科医学》
摘要： 虚拟仿真技术的快速发展给临床实践技能培训考核带来新的变革。近年来，国内外利用该技术开展了研究及实践应用。为统一、规范并推广虚拟仿真技术在临床实践技能培训考核中的应用，中国医院协会模拟医学专业委员会组织国内临床、技术、教育和管理领域等专家，在全面调研国内外医学虚拟仿真培训考核的技术标准、专家共识、系统评价、原始研究等资料及相关疾病诊疗指南、管理共识等文献的基础上，编写形成《临床实践技能虚拟仿真应用技术体系标准专家共识》（以下简称《共识》）初稿，并邀请实践技能培训考核领域的临床、技术以及管理等专家开展意见征集和专家论证，经三轮意见征集和专家论证，对初稿进行修订和完善，形成《共识》终稿，包括虚拟仿真内容设计与建模、管理平台接口设计、质量评价、数据传输与安全 4 个部分。本《共识》是在充分学习借鉴医学虚拟仿真培训相关标准、指南、共识及临床研究成果，征求和综合专家意见的基础上编制形成的，为医学院校、医疗机构或培训机构开展临床实践技能虚拟仿真培训考核工作提供参考借鉴。
分类： 图书馆学、情报学 >> 图书馆学 提交时间： 2025-05-20
摘要： The rapid growth in scientific publications has been accompanied by an increase in fake or poor-quality papers, threatening the integrity of scientific literature. To address this issue, I propose thePublication Health Index (PHI), a novel metric that evaluates the health status of a set of articles based on retraction rates. UsingNatureandScienceas benchmarks, I suggest that a healthy PHI threshold should be established at7.2, equivalent to a retraction rate of0.07%. The PHI is then applied to evaluate the publication health of journals, countries, and institutions, demonstrating its broad applicability and practical feasibility. This metric shows potential to help governments shape science policies and publishers improve the quality of scientific literature.
分类： 心理学 >> 发展心理学 提交时间： 2025-05-20
摘要： 多模态感知机制对婴儿期语言习得至关重要，其中视听整合在典型发育婴儿的语言能力发展中起着关键作用。相比之下，高风险自闭症谱系障碍（ASD）婴儿在此整合过程中常面临挑战。典型的言语感知发展轨迹强调面部特征加工的重要性——对眼部与嘴部区域的注意能促进语言学习。实证研究表明，4.5月龄的婴儿已具备视听整合能力，这种能力可有效预测后期语言发展水平。而高风险ASD婴儿则表现出社会性注意减少和视听整合功能受损，此类缺陷可能破坏常规语言习得路径。因此，早期干预策略应优先采用基于生物学的感觉引导方法，重点增强多感官整合能力，而非仅针对注意行为进行训练。理解这些机制不仅能深化对典型语言发展的认知，更能为制定早期干预方案提供实证基础，从而支持高风险ASD群体的语言习得。
分类： 心理学 >> 人格心理学 提交时间： 2025-05-19
摘要： Background:The effect of names on psychology and behavior has been widely studied,butmost studies donot distinguish between the effects of name pronunciation and semantics.Aims: This study focuseson the pronunciation of Chinese names,addressingtwo questions. First, does the pronunciation of nameendings affect individual personality and behavior? Second, what isthe underlying mechanism?Methods:Study 1 usedpeerassessmentsto examinepersonalitytraits in two college classes, and explored the relationshipbetween name pronunciation and personality. Study 2investigated whether name pronunciation correlated with the social behaviors of criminals and heroes. Study 3 tested our proposed mechanism by filming three male models pronouncing 50 names and then asked college students to rate the emotional valence of the videos.Results:Studies 1 and 2 revealed that namepronunciation isrelated to personality and behavior. We propose a novel mechanism: the degree of others’ mouth opening during namepronunciationinfluencesjudgments of others’ emotional valence, shapinganindividual’s emotional ecosystem.Study 3 supportedthis hypothesis, showing that names with open-mouth vowel endings were rated more positively than those with close-mouth vowel endings.Conclusions: The pronunciation of name endings has an effect on personality and behavior. This studyprovides evidence for “the model of the pronunciation of name endings and the establishment of individual emotional ecosystems” andreveals a pronunciation mechanism by which names influence the formation of personality and social behavior in Chinese culture.
分类： 生物学 >> 植物学 >> 植物生态学和植物地理学 提交时间： 2025-05-19 合作期刊: 《干旱区科学》
摘要： Salt-tolerant bacteria associated with halophytes enhance plant resistance and adaptation to environmental stress. The purpose of this study was to investigate the diversity and plant-beneficial traits of bacteria associated with three halophytes in an arid land, Northwest China. The bacterial strains were isolated from the roots, shoots, rhizosphere, and bulk soil of three halophytes, i.e., Salicornia europaea L., Kalidium foliatum (Pall.) Moq., and Suaeda aralocaspica (Bunge) Freitag Schütze, collected from the saline soils near to the Wujiaqu City, Xinjiang, Northwest China. A total of 567 strains were isolated and identified from these three halophytes belonging to 4 phyla, 6 classes, 25 orders, 36 families, and 66 genera, including 147 potential novel species. A total of 213 strains exhibited one or more plant growth- promoting properties, while 20 strains demonstrated multiple in vitro plant growth-promoting activities, including phosphate solubilization, nitrogen fixation, siderophore production, and production of hydrolytic enzymes such as protease and cellulase. Our findings showed that halophytes in the arid land harbor diverse bacteria with the potential to enhance plant growth and adaptability under challenging environmental conditions.
分类： 农、林、牧、渔 >> 土壤学 提交时间： 2025-05-19 合作期刊: 《干旱区科学》
摘要： The release of essential nutrients from soil minerals for plant growth in calcareous soils, facilitated by organic extractants, is critical in semi-arid areas, particularly for elements affected by high soil pH. This study aims to investigate the release of calcium (Ca), magnesium (Mg), and phosphorus (P) through the application of wood vinegar extract in surface calcareous soils in Borojerd City, Lorestan Province, Iran. The experiment was conducted using a completely randomized design with three replications. The treatments included soils from three different land uses: vineyard, wheat field, and rangeland, each treated with 1.00% wood vinegar solution. Cumulative measurements of the specified elements were recorded over 10 consecutive 0.5 h intervals. The release data were analyzed using four various kinetic models (Elovich equation, parabolic diffusion law, power function equation, and zero-order kinetics). The highest concentrations recorded were for Ca (39,500.00 mg/kg), Mg (5880.00 mg/kg), and P (5.00 mg/kg) in grape cultivation. The findings revealed a significant difference in Ca release between grape cultivation and rangeland (P<0.01), while the Mg release showed a significant difference between both grape cultivation and rangeland and wheat cultivation (P<0.01). Additionally, the cumulative release of P showed significant differences between grape cultivation and both wheat and rangeland (P<0.01). The results indicated that the zero-order kinetics provided the best fit for the data (R2=0.99). The maximum initial release amount was observed in grape cultivation when applying the zero-order kinetics, while the highest release rate was achieved using the parabolic diffusion law across three applications. Wood vinegar had the capacity to degrade various clay minerals, including vermiculite, smectite, palygorskite, and, to some extent, illite, resulting in the release of associated elements. Consequently, it can be concluded that wood vinegar can be effectively utilized in grape cultivation as an agent for reducing soil acidity, thereby enhancing the availability of soil nutrients and decreasing reliance on chemical fertilizers.
分类： 生物学 >> 植物学 >> 植物生态学和植物地理学 提交时间： 2025-05-19 合作期刊: 《干旱区科学》
摘要： Climate change and human activities have led to desertification and decreased land productivity, significantly affecting human livelihoods in desert regions. Identifying suitable areas for cultivating economic and native plants based on ecological capacity, biological restoration, and risk management can be valuable tools for combating desertification. In this study, we identified suitable areas for the growth of economic and medicinal Moringa peregrina trees in desert regions of Sistan and Baluchestan Province, southern Iran, using library research and field methods. We also assessed the economic involvement of local communities in areas under different topographic conditions (namely flat area, undulating area, rolling area, moderately sloping area, and steep area) in the study area. Financial indicators such as the net present value (NPV), benefit-cost ratio (BCR), internal rate of return (IRR), and return on investment (ROI) were calculated for areas under various topographic conditions in the study area. The rolling area with results of NPV (6142.75 USD), IRR (103.38), BCR (5.38), and ROI (in the 3rd year) was the best region for investing and cultivating M. peregrina. The minimum economic level varied from 0.80 hm2 in the flat area to 21.60 hm2 in the steep area. Also, approximately 5,314,629.51 hm2 of desert lands in the study area were deemed suitable for M. peregrina cultivation, benefiting around 1,743,246 households in the study area. Cultivating M. peregrina in southern Iran can positively affect local communities and help preserve land from erosion. Our study will provide theoretical support for planting native species in other degraded desert regions to enhance ecosystem services and the well-being of indigenous populations.
分类： 农、林、牧、渔 >> 土壤学 提交时间： 2025-05-19 合作期刊: 《干旱区科学》
摘要： Surface soil cracking in alpine meadows signifies the transition of degradation from quantitative accumulation to qualitative deterioration. Quantitative research remains insufficient regarding changes in the mechanical properties of degraded meadow soils and the mechanical thresholds for cracking initiation. This study explored the relationships between surface cracking and the physical properties, tensile strength, and matrix suction of root-soil composites in alpine meadow sites with different stages of degradation (undegraded (UD), lightly degraded (LD), moderately degraded (MD), and heavily degraded (HD)) under different water gradients (high water content (HWC), medium water content (MWC), and low water content (LWC)) corresponding to different drying durations at a constant temperature of 40.0°C. The Huangcheng Mongolian Township in Menyuan Hui Autonomous County, Qinghai Province, China was chosen as the study area. The results indicated that as the degradation degree of alpine meadow intensified, both water content of root-soil composite and the fine grain content of soil decreased. In contrast, the root-soil mass ratio and root area ratio initially increased and then decreased with progressive degradation. Under a consistent water content, the tensile strength of root-soil composite followed a pattern of MD>HD>LD>UD. The peak displacement of tensile strength also decreased as the degradation degree of alpine meadow increased. Both the tensile strength and matrix suction of root-soil composite increased as root-soil water content decreased. A root-soil water content of 30.00%–40.00% was found to be the critical threshold for soil cracking in alpine meadows. Within this range, the matrix suction of root-soil composite ranged from 50.00 to 100.00 kPa, resulting in the formation of linear cracks in the surface soil. As the root-soil water content continued to decrease, liner cracks evolved into branch-like and polygonal patterns. The findings of this study provide essential data for improving the mechanical understanding of grassland cracking and its development process.
分类： 农、林、牧、渔 >> 土壤学 提交时间： 2025-05-19 合作期刊: 《干旱区科学》
摘要： Soil moisture (SM) is a critical variable in terrestrial ecosystems, especially in arid and semi-arid areas where water sources are limited. Despite its importance, understanding the spatiotemporal variations and influencing factors of SM in these areas remains insufficient. This study investigated the spatiotemporal variations and influencing factors of SM in arid and semi-arid areas of China by utilizing the extended triple collation (ETC), Mann-Kendall test, Theil-Sen estimator, ridge regression analysis, and other relevant methods. The following findings were obtained: (1) at the pixel scale, the long-term monthly SM data from the European Space Agency Climate Change Initiative (ESA CCI) exhibited the highest correlation coefficient of 0.794 and the lowest root mean square error (RMSE) of 0.014 m3/m3; (2) from 2000 to 2022, the study area experienced significant increase in annual average SM, with a rate of 0.408×10–3 m3/(m3•a). Moreover, higher altitudes showed a notable upward trend, with SM increasing rates at 0.210×10–3 m³/(m3•a) between 1000 and 2000 m, 0.530×10–3 m3/(m3•a) between 2000 and 4000 m, and 0.760×10–3 m3/(m3•a) at altitudes above 4000 m; (3) land surface temperature (LST), root zone soil moisture (RSM) (10–40 cm depth), and normalized difference vegetation index (NDVI) were identified as the primary factors influencing annual average SM, which accounted for 34.37%, 24.16%, and 22.64% relative contributions, respectively; and (4) absolute contribution of LST was more significant in subareas at higher altitudes, with average absolute contributions of 0.800×10–3 m3/(m3•a) between 2000 and 4000 m and 0.500×10–2 m3/(m3•a) above 4000 m. This study reveals the spatiotemporal variations and main influencing factors of SM in Chinese arid and semi-arid areas, highlighting the more pronounced absolute contribution of LST to SM in high-altitude areas, providing valuable insights for ecological research and water resource management in these areas.
分类： 生物学 >> 植物学 >> 植物生态学和植物地理学 分类： 地球科学 >> 地理学 提交时间： 2025-05-19 合作期刊: 《干旱区科学》
摘要： Investigating the spatiotemporal evolution of vegetation and its response mechanisms to natural and anthropogenic elements is crucial for regional vegetation restoration and ecological preservation. The Mu Us Sandy Land (MUSL), which is situated in the semi-arid zone of northwestern China adjacent to the Loess Plateau, has been at the forefront of desertification and oasis formation over the past two millennia. This study is based on the synthesis of the Normalized Difference Vegetation Index (NDVI) data from MOD13A3 data in the MODIS (Moderate-Resolution Imaging Spectroradiometer) dataset (2002–2021) and climate data (temperature and precipitation) at annual and monthly scales from the National Earth System Science Data Center. A range of analytical methods, including univariate linear regression, Theil-Sen trend analysis and Mann-Kendall significance test, correlation analysis, residual analysis, and Hurst index, were used to explore the response mechanisms of the NDVI to climate change and human activities and to predict the future trends of the NDVI in the MUSL. The results showed that through the method of correlation analysis, in terms of both spatially averaged correlation coefficients and area proportion, the NDVI was positively correlated with temperature and precipitation in 97.59% and 96.51% of the study area, respectively, indicating that temperature has a greater impact on the NDVI than precipitation. Residual analysis quantified the contributions of climate change and human activities to the NDVI changes, revealing that climate change and human activities contribute up to 30.00% and 70.00%, respectively, suggesting that human activities predominantly affect the NDVI changes in the MUSL. The Hurst index was used to categorize the future trend of the NDVI into four main directions of development: continuous degradation (0.05% of the study area), degradation in the past but improvement in the future (54.45%), improvement in the past but degradation in the future (0.13%), and continuous improvement (45.36%). In more than 50.00% of the regions that have been degraded in the past but were expected to improve in the future, the NDVI was expected to exhibit a stable trend of anti-persistent improvement. These findings provide theoretical support for future ecological protection, planning, and the implementation of ecological engineering in the MUSL, and also offer a theoretical basis for the planning and execution of construction projects, environmental protection measures, and the sustainable development of vegetation.
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