legacy effect

遗留效果
  • 文章类型: Journal Article
    观察到一种称为遗留效应的现象,即新诊断的2型糖尿病(T2D)患者早期血糖控制不良会增加随后发生心血管疾病(CVD)的风险。早期使用一些新型的抗高血糖药物,如钠-葡萄糖转运蛋白2抑制剂(SGLT-2i),可能会减弱这种影响,但证据有限.
    使用鄞州地区卫生保健数据库(YRHCD)收集了2010-2023年新诊断的T2D患者的两个回顾性队列,对早期暴露期进行了不同的定义-1年暴露队列和2年暴露队列,其中包括在T2D诊断后1年内和2年内有HbA1c测量数据的受试者,分别。使用Cox比例风险模型,我们研究了暴露早期高HbA1c水平(HbA1c>7%)与随后的CVD风险之间的关系.这项分析是在整个队列和三个亚群不同的治疗在早期暴露期,包括启动SGLT-2i或胰高血糖素样肽-1受体激动剂(GLP-1RA)的患者,使用二肽基肽酶-4抑制剂(DPP-4i)的患者,和没有使用SGLT-2i的患者,GLP-1RA,和DPP-4i。此外,通过将患者分为年龄<55岁和≥55岁进行亚组分析.
    共有21,477和22,493例新诊断的T2D患者被纳入两个最终队列。与暴露早期平均HbA1c≤7%的患者相比,HbA1c>7%的患者发生CVD的风险更高,在1年和2年暴露期队列中,HR分别为1.165(95CI,1.056-1.285)和1.143(95CI,1.044-1.252)。与非用户相比,在T2D诊断后1或2年内开始SGLT-2i/GLP-1RA的患者,在两个队列中,基线时更高的HbA1c水平与CVD无关.在亚组分析中,结果与主要分析基本一致。
    T2D早期血糖控制不良会增加新诊断T2D的中国成年人的后期CVD风险。与非用户相比,在T2D早期接受SGLT-2i/GLP-1RA的患者中,这种关联较小且无意义,提示早期使用这些药物可能有可能减轻高血糖的遗留影响.
    UNASSIGNED: A phenomenon known as legacy effect was observed that poor glycemic control at early stage of patients with newly-diagnosed type 2 diabetes (T2D) increases the risk of subsequent cardiovascular diseases (CVD). Early use of some novel anti-hyperglycemic agents, such as sodium-glucose transport protein 2 inhibitors (SGLT-2i), may attenuate this effect, but the evidence is limited.
    UNASSIGNED: Two retrospective cohorts of newly diagnosed T2D patients from 2010-2023 were assembled using the Yinzhou Regional Health Care Database (YRHCD) with different definitions of the early exposure period - the 1-year exposure cohort and 2-year exposure cohort, which were comprised of subjects who had HbA1c measurement data within 1 year and 2 years after their T2D diagnosis, respectively. Using Cox proportional hazards models, we examined the association between high HbA1c level (HbA1c>7%) during the early exposure period and the risk of subsequent CVD. This analysis was performed in the overall cohort and three subpopulations with different treatments during the early exposure period, including patients initiating SGLT-2i or glucagon-like peptide-1 receptor agonists (GLP-1RA), patients using dipeptidyl peptidase-4 inhibitors (DPP-4i), and patients without using SGLT-2i, GLP-1RA, and DPP-4i. Besides, subgroup analyses were performed by stratifying patients into age <55 and ≥55 years.
    UNASSIGNED: A total of 21,477 and 22,493 patients with newly diagnosed T2D were included in the two final cohorts. Compared with patients with mean HbA1c ≤ 7% during the early exposure period, those with HbA1c>7% had higher risks of incident CVD, with a HR of 1.165 (95%CI, 1.056-1.285) and 1.143 (95%CI, 1.044-1.252) in 1-year and 2-year exposure period cohort. Compared to non-users, in patients initiating SGLT-2i/GLP-1RA within 1 or 2 years after T2D diagnosis, higher HbA1c level at baseline was not associated with CVD in both two cohorts. In subgroup analyses, results were generally consistent with the main analysis.
    UNASSIGNED: Poor glycemic control in the early stage of T2D increased later CVD risk in Chinese adults with newly diagnosed T2D. Compared to non-users, this association was smaller and non-significant in patients receiving SGLT-2i/GLP-1RA during the early stage of T2D, indicating early use of these drugs may have the potential to mitigate legacy effects of hyperglycemia.
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  • 文章类型: Journal Article
    持续的全球变暖轨迹对植物生态系统提出了广泛的挑战,橡胶种植园特别脆弱,因为它们不仅影响生长周期的寿命和橡胶产量,还有碳的复杂相互作用,水,森林冠层和大气之间的能量交换。然而,橡胶园物候对气候变化的响应机制尚不清楚。本研究集中在云南省环境次优的橡胶种植园,中国西南地区。利用GoogleEarthEngine(GEE)云平台,以8天的间隔合成多源遥感图像,空间分辨率为30米。使用Savitzky-Golay(S-G)滤波器重建了归一化植被指数(NDVI)时间序列,结合季节振幅法提取三个关键物候指标,即生长季节的开始(SOS),生长季节结束(EOS),和生长季节的长度(LOS)。线性回归法,皮尔逊相关系数,采用多元逐步回归分析提取物候趋势,发现SOS,EOS和气候因素。研究结果表明,1)在过去的二十年中,橡胶种植园的物候发生了动态变化。具体来说,SOS每十年提前9.4天(R2=0.42,p<0.01),而EOS每十年延迟3.8天(R2=0.35,p<0.01)。此外,LOS每十年延长13.2天(R2=0.55,p<0.01);2)橡胶物候表现出对旱季温度波动和雨季降水模式的显着敏感性。在凉爽干燥的季节,SOS每升高1°C,SOS提前2.0天(r=-0.19,p<0.01),EOS提前2.8天(r=-0.35,p<0.01)。而雨季降水增加100毫米导致SOS延迟2.0天(r=0.24,p<0.01),干热季节降水增加100毫米,导致EOS提前7.0天(r=-0.28,p<0.01);3)橡胶物候表现出季前气候变化的遗留影响。第四个季前赛月的温度变化以及第四个和第十一个季前赛月的降水是SOS变化的主要原因。同时,温度变化在第二,第四,和第九个季前赛月是EOS变化的主要原因。该研究旨在增强我们对橡胶种植园如何在次优环境中应对气候变化的理解,并为面对不断变化的环境条件下的可持续橡胶生产管理提供有价值的见解。
    The ongoing global warming trajectory poses extensive challenges to plant ecosystems, with rubber plantations particularly vulnerable due to their influence on not only the longevity of the growth cycle and rubber yield, but also the complex interplay of carbon, water, and energy exchanges between the forest canopy and atmosphere. However, the response mechanism of phenology in rubber plantations to climate change remains unclear. This study concentrates on sub-optimal environment rubber plantations in Yunnan province, Southwest China. Utilizing the Google Earth Engine (GEE) cloud platform, multi-source remote sensing images were synthesized at 8-day intervals with a spatial resolution of 30-meters. The Normalized Difference Vegetation Index (NDVI) time series was reconstructed using the Savitzky-Golay (S-G) filter, coupled with the application of the seasonal amplitude method to extract three crucial phenological indicators, namely the start of the growing season (SOS), the end of the growing season (EOS), and the length of the growing season (LOS). Linear regression method, Pearson correlation coefficient, multiple stepwise regression analysis were used to extract of the phenology trend and find the relationship between SOS, EOS and climate factors. The findings demonstrated that 1) the phenology of rubber plantations has undergone dynamic changes over the past two decades. Specifically, the SOS advanced by 9.4 days per decade (R2 = 0.42, p< 0.01), whereas the EOS was delayed by 3.8 days per decade (R2 = 0.35, p< 0.01). Additionally, the LOS was extended by 13.2 days per decade (R2 = 0.55, p< 0.01); 2) rubber phenology demonstrated a notable sensitivity to temperature fluctuations during the dry season and precipitation patterns during the rainy season. The SOS advanced 2.0 days (r =-0.19, p< 0.01) and the EOS advanced 2.8 days (r =-0.35, p< 0.01) for every 1°C increase in the cool-dry season. Whereas a 100 mm increase in rainy season precipitation caused the SOS to be delayed by 2.0 days (r = 0.24, p< 0.01), a 100 mm increase in hot-dry season precipitation caused the EOS to be advanced by 7.0 days (r =-0.28, p< 0.01); 3) rubber phenology displayed a legacy effect of preseason climate variations. Changes in temperature during the fourth preseason month and precipitation during the fourth and eleventh preseason months are predominantly responsible for the variation in SOS. Meanwhile, temperature changes during the second, fourth, and ninth preseason months are primarily responsible for the variation in EOS. The study aims to enhance our understanding of how rubber plantations respond to climate change in sub-optimal environments and provide valuable insights for sustainable rubber production management in the face of changing environmental conditions.
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  • 文章类型: Journal Article
    与具有不同植物(远离)的土壤相比,家庭土壤中植物残留物的分解速度更快,并在森林和草原生态系统中得到了证明。目前尚不清楚这种遗留效应是否适用于耕地作物轮作中的作物残留物分解。这些知识可以提高我们对耕地土壤分解动力学的理解,并可以通过巧妙地将作物-残留物轮换与作物轮换结合起来,以增加土壤中残留的C含量,从而优化耕地系统中的作物残留物改良剂。
    我们在短轮作系统的三个阶段的土壤中使用含有小麦和油菜残留的网袋进行了相互移植实验,测试了HFA假设。每月检索网袋的子集,为期六个月,以确定残留物分解率,同时测量土壤有效氮,微生物群落结构(磷脂脂肪酸分析),和微生物活性(茶袋指数协议),以评估植物如何通过改变土壤生化特性和微生物群落来影响凋落物分解率。
    残留物在所有旋转阶段都以相似的速率分解。使用几种统计方法进行的全面数据调查显示,作物轮作中没有HFA。土壤微生物群落结构在所有轮作阶段都相似。
    我们将缺乏HFA归因于集约化农业实践中涉及的轮作和土壤扰动的短促。因此,通过引入作物-残留物轮作,在短期常规管理的耕地轮作中不可能获得明显的好处。
    在线版本包含补充材料,可在10.1007/s11104-022-05419-z获得。
    UNASSIGNED: The home-field advantage (HFA) hypothesis predicts faster decomposition of plant residues in home soil compared to soils with different plants (away), and has been demonstrated in forest and grassland ecosystems. It remains unclear if this legacy effect applies to crop residue decomposition in arable crop rotations. Such knowledge could improve our understanding of decomposition dynamics in arable soils and may allow optimisation of crop residue amendments in arable systems by cleverly combining crop-residue rotations with crop rotations to increase the amount of residue-derived C persisting in soil.
    UNASSIGNED: We tested the HFA hypothesis in a reciprocal transplant experiment with mesh bags containing wheat and oilseed rape residues in soils at three stages of a short-rotation cropping system. Subsets of mesh bags were retrieved monthly for six months to determine residue decomposition rates, concomitantly measuring soil available N, microbial community structure (phospholipid fatty acid analysis), and microbial activity (Tea Bag Index protocol) to assess how plants may influence litter decomposition rates via alterations to soil biochemical properties and microbial communities.
    UNASSIGNED: The residues decomposed at similar rates at all rotational stages. Thorough data investigation using several statistical approaches revealed no HFA within the crop rotation. Soil microbial community structures were similar at all rotational stages.
    UNASSIGNED: We attribute the absence of an HFA to the shortness of the rotation and soil disturbance involved in intensive agricultural practices. It is therefore unlikely that appreciable benefits could be obtained in short conventionally managed arable rotations by introducing a crop-residue rotation.
    UNASSIGNED: The online version contains supplementary material available at 10.1007/s11104-022-05419-z.
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  • 文章类型: Journal Article
    新诊断的2型糖尿病(T2D)患者达到HbA1c目标的延迟与发生心血管疾病(CVD)的长期风险增加有关。一种被称为遗产效应的现象。早期引入对CVD有明显益处的降糖药物是否可以减弱这种现象尚不清楚。
    使用来自大型意大利临床注册的数据,即AMD年鉴,我们确定了251,339名新诊断为T2D且基线无CVD的受试者.通过Cox回归对多个风险因素进行调整,我们检查了平均HbA1c在7.1和8%之间或>8%之间的相关性,与≤7%相比,对于早期暴露的各个时期(0-1,0-2,0-3年)和晚期(平均后续随访4.6±2.9年)CVD的发展,评估为心肌梗塞的复合物,中风,冠状动脉或外周血管重建术,和冠状动脉或外周搭桥。我们在整个队列中进行了此分析,然后将人群分为两组患者:在暴露阶段引入钠-葡萄糖转运蛋白2抑制剂(SGLT-2i)的患者和未使用这些药物治疗的患者。
    考虑到整个队列,受试者的平均HbA1c在7.1和8%之间,>8%,与平均HbA1c≤7%的患者相比,在评估的所有三个早期暴露期中,显示出发展结果的风险增加,在3年暴露期平均HbA1c>8%的患者中观察到最高风险(风险比[HR]1.33;95%置信区间[CI]1.063-1.365).在0-1和0-2年的暴露期引入SGLT-2i消除了不良血糖控制与结果之间的关联(p分别为0.006和0.003,vs.血糖控制程度相同但未使用这些药物治疗的患者)。
    在基线时新诊断为T2D且无CVD的患者中,诊断后前3年血糖控制不佳与随后的CVD风险增加相关.当SGLT-2i在头两年推出时,这种关联不再明显,这表明这些药物减弱了遗留效应的现象。因此,这些药物的早期治疗可能会促进T2D诊断后未达到适当血糖控制的患者的长期益处。
    这项工作得到了支持,在某种程度上,由意大利卫生部(RicercaCorrente)到IRCCSMultiMedica。
    UNASSIGNED: A delay in reaching HbA1c targets in patients with newly-diagnosed type 2 diabetes (T2D) is associated with an increased long-term risk of developing cardiovascular diseases (CVD), a phenomenon referred to as legacy effect. Whether an early introduction of glucose-lowering drugs with proven benefit on CVD can attenuate this phenomenon is unknown.
    UNASSIGNED: Using data derived from a large Italian clinical registry, i.e. the AMD Annals, we identified 251,339 subjects with newly-diagnosed T2D and without CVD at baseline. Through Cox regressions adjusted for multiple risk factors, we examined the association between having a mean HbA1c between 7.1 and 8% or >8%, compared with ≤7%, for various periods of early exposure (0-1, 0-2, 0-3 years) and the development of later (mean subsequent follow-up 4.6 ± 2.9 years) CVD, evaluated as a composite of myocardial infarction, stroke, coronary or peripheral revascularization, and coronary or peripheral bypass. We performed this analysis in the overall cohort and then splitting the population in two groups of patients: those that introduced sodium-glucose transport protein 2 inhibitors (SGLT-2i) during the exposure phase and those not treated with these drugs.
    UNASSIGNED: Considering the whole cohort, subjects with both a mean HbA1c between 7.1 and 8% and >8%, compared with patients attaining a mean HbA1c ≤ 7%, showed an increased risk of developing the outcome in all the three early exposure periods assessed, with the highest risk observed in patients with mean HbA1c > 8% in the 3 years exposure period (hazard ratio [HR]1.33; 95% confidence interval [CI] 1.063-1.365). The introduction of SGLT-2i during the exposure periods of 0-1 and 0-2 years eliminated the association between poor glycemic control and the outcome (p for interaction 0.006 and 0.003, respectively, vs. patients with the same degree of glycemic control but not treated with these drugs).
    UNASSIGNED: Among patients with newly diagnosed T2D and free of CVD at baseline, a poor glycemic control in the first three years after diagnosis is associated with an increased subsequent risk of CVD. This association is no longer evident when SGLT-2i are introduced in the first two years, suggesting that these drugs attenuate the phenomenon of legacy effect. An early treatment with these drugs might thus promote a long-lasting benefit in patients not attaining proper glycemic control after T2D diagnosis.
    UNASSIGNED: This work was supported, in part, by the Italian Ministry of Health (Ricerca Corrente) to IRCCS MultiMedica.
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  • 文章类型: Journal Article
    豆类作物轮作有利于提高土壤多功能性,但是,以前的豆科植物的遗留作用如何影响以下作物的根际微生物群落以及生长阶段仍不清楚。这里,在变绿和灌浆阶段,用四个先前的豆类(绿豆,小豆,大豆,和花生),以及谷物玉米作为对照。细菌和真菌群落的组成和结构在两个生长阶段之间变化很大。在绿化和灌浆阶段都观察到轮作系统之间真菌群落结构的差异。仅在填充阶段观察到旋转系统之间细菌群落结构的差异。微生物网络的复杂性和中心性随着作物生长阶段而降低。在灌浆阶段,基于豆类的轮作系统的物种关联比基于谷物的轮作系统的物种关联得到了加强。与碳相关的KEGG直向同源物(KOs)的丰度,氮,磷,细菌群落的硫代谢从变绿阶段到灌浆阶段降低。然而,轮换系统中KO的丰度没有差异。一起,我们的结果表明,植物生长阶段对塑造小麦根际微生物群落的影响比轮作系统的遗留效应更强,轮作系统之间的差异在生长后期更为明显。这样的组成,结构,和功能的变化可能提供作物生长和土壤养分循环的可预测的后果。
    Legume-based crop rotation is conducive to improve soil multifunctionality, but how the legacy effect of previous legumes influenced the rhizosphere  microbial community of the following crops along with growth stages remains unclear. Here, the wheat rhizosphere microbial community was assessed at the regreening and filling stages with four previous legumes (mungbean, adzuki bean, soybean, and peanut), as well as cereal maize as a control. The composition and structure of both bacterial and fungal communities varied dramatically between two growth stages. The differences in fungal community structure among rotation systems were observed at both the regreening and filling stages, while the difference in bacterial community structure among rotation systems was observed only at the filling stage. The complexity and centrality of the microbial network decreased along with crop growth stages. The species associations were strengthened in legume-based rotation systems than in cereal-based rotation system at the filling stage. The abundance of KEGG orthologs (KOs) associated with carbon, nitrogen, phosphorus, and sulfur metabolism of bacterial community decreased from the regreening stage to the filling stage. However, there was no difference in the abundance of KOs among rotation systems. Together, our results showed that plant growth stages had a stronger impact than the legacy effect of rotation systems in shaping the wheat rhizosphere microbial community, and the differences among rotation systems were more obvious at the late growth stage. Such compositional, structural, and functional changes may provide predictable consequences of crop growth and soil nutrient cycling.
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  • 文章类型: Journal Article
    树木的叶片物候因其在全球水和碳平衡中的关键作用而受到特别关注,生态系统,和物种分布。然而,目前对叶片物候的研究主要集中在温带树木上,而包括热带树木在内的研究很少。对全球范围内广泛的工业种植园的关注很少。橡胶种植园对当地和全球经济都很重要。在这项研究中,我们调查了落叶物候对次年叶片冲洗的遗留影响,叶病,还有橡胶树的乳胶产量,对当地人民和世界经济上重要的树。结果表明,延长落叶持续时间增加了随后的落叶持续时间和白粉病感染率,但导致3月份乳胶产量下降。橡胶落叶的这种传统效果可能与树木中保留的碳水化合物有关。更长的落叶时间会消耗更多的储备碳水化合物,减少疾病防御和乳胶生产的可用储备。脱叶期的持续时间延长与10月至11月停止乳胶敲击之前的较低温度和/或12月至1月停止乳胶敲击之后的较高温度有关。落叶标志着落叶树光合活动的结束。因此,落叶物候将影响涉及橡胶树的生态过程。我们的研究结果表明,在未来的橡胶树研究中包括落叶期,将对我们进一步了解叶子冲洗至关重要,白粉病,和乳胶产量。
    The leaf phenology of trees has received particular attention for its crucial role in the global water and carbon balances, ecosystem, and species distribution. However, current studies on leaf phenology have mainly focused on temperate trees, while few studies including tropical trees. Little attention has been paid to globally extensive industrial plantations. Rubber plantations are important to both the local and global economies. In this study, we investigated the legacy effects of defoliation phenology on the following year\'s leaf flushing, leaf disease, and also latex yield of rubber trees, an economically important tree to local people and the world. Results show that extended duration of defoliation increased the subsequent duration of refoliation and rates of infection by powdery mildew disease, but led to reduced latex yield in March. This legacy effect of rubber defoliation may relate to the carbohydrate reserved in the trees. A longer duration of defoliation would consume more reserved carbohydrates, reducing available reserves for disease defense and latex production. Extended duration of defoliation period was associated with either a lower temperature before the cessation of latex tapping in October-November and/or a higher temperature after the cessation of latex tapping in December-January. Leaf falling signals the end of photosynthetic activities in deciduous trees. Thus, the leaf falling phenology will impact ecological processes involving rubber trees. Our findings indicated that the inclusion of defoliation periods in future rubber trees\' research, will be crucial to furthering our understanding of leaf flushing, powdery mildew disease, and latex yield.
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  • 文章类型: Journal Article
    BACKGROUND: Fish gut microbial colonisation starts during larval stage and plays an important role in host\'s growth and health. To what extent first colonisation could influence the gut microbiome succession and growth in later life remains unknown. In this study, Nile tilapia embryos were incubated in two different environments, a flow-through system (FTS) and a biofloc system (BFS); hatched larvae were subsequently cultured in the systems for 14 days of feeding (dof). Fish were then transferred to one common recirculating aquaculture system (RAS1, common garden, 15-62 dof), followed by a growth trial in another RAS (RAS2, growth trial, 63-105 dof). In RAS2, fish were fed with two types of diet, differing in non-starch polysaccharide content. Our aim was to test the effect of rearing environment on the gut microbiome development, nutrient digestibility and growth performance of Nile tilapia during post-larvae stages.
    RESULTS: Larvae cultured in the BFS showed better growth and different gut microbiome, compared to FTS. After the common garden, the gut microbiome still showed differences in species composition, while body weight was similar. Long-term effects of early life rearing history on fish gut microbiome composition, nutrient digestibility, nitrogen and energy balances were not observed. Still, BFS-reared fish had more gut microbial interactions than FTS-reared fish. A temporal effect was observed in gut microbiome succession during fish development, although a distinct number of core microbiome remained present throughout the experimental period.
    CONCLUSIONS: Our results indicated that the legacy effect of first microbial colonisation of the fish gut gradually disappeared during host development, with no differences in gut microbiome composition and growth performance observed in later life after culture in a common environment. However, early life exposure of larvae to biofloc consistently increased the microbial interactions in the gut of juvenile Nile tilapia and might possibly benefit gut health.
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  • 文章类型: Journal Article
    在医学上,传统效应定义为给定治疗对疾病结果的持续有益效果,即使在停止干预之后。最初在糖尿病的优化控制中描述,在探索其他心血管危险因素的强化策略的临床试验中也观察到了这一点,如高血压或高胆固醇血症。遗留机制在糖尿病中尤其被破译,导致了代谢记忆的概念。以更谨慎的方式,在临床前研究中还描述了其他记忆现象,这些研究表明脂质或血管紧张素II对血管壁成分具有持久的有害作用.有趣的是,表观遗传变化和活性氧(ROS)似乎是血管壁“记忆”的共同特征。
    In medicine, a legacy effect is defined as the sustained beneficial effect of a given treatment on disease outcomes, even after cessation of the intervention. Initially described in optimized control of diabetes, it was also observed in clinical trials exploring intensification strategies for other cardiovascular risk factors, such as hypertension or hypercholesterolemia. Mechanisms of legacy were particularly deciphered in diabetes, leading to the concept of metabolic memory. In a more discreet manner, other memory phenomena were also described in preclinical studies that demonstrated long-lasting deleterious effects of lipids or angiotensin II on vascular wall components. Interestingly, epigenetic changes and reactive oxygen species (ROS) appear to be common features of \"memory\" of the vascular wall.
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  • 文章类型: Journal Article
    Landscape composition and configuration determine the exchange of matter and energy among different landscape patches and may affect riverine phosphorus (P) exports derived from watershed legacy sources. However, a lack of understanding of landscape pattern effects on legacy P releases has yielded large uncertainties in mitigating watershed water quality using management practices or landscape planning. This study revealed the significance of legacy effect in the headwater catchments through the time-lag response of the long-term trend of river P exports to the change of net anthropogenic P input (NAPI). By constructing empirical statistical models that incorporated NAPI, hydroclimatic, terrain factors, soil chemical properties, and land use variables, the sources of annual riverine total phosphorus (TP) and dissolved inorganic phosphorus (DIP) exports were divided into current annual NAPI input and legacy sources inputs. The model estimations indicated that the contribution of legacy sources to riverine TP exports was 0.33-1.12 kg ha-1 yr-1 (50.7-82.8%), which was significantly higher than the contribution to DIP exports (0.18-0.49 kg ha-1 yr-1, 42.4-81.4%) in 2012-2017. Redundancy analysis (RDA) and variance partitioning analysis (VPA) methods were used to quantify the relative contribution of landscape patterns, soil P content, and terrain factors to legacy P releases. Results revealed that the relative contribution of the landscape composition and configuration to the total variations of legacy P releases was greater than that of the soil P and terrain factors. For different land use patches, a large area of woodland with a high aggregation degree and a large area of ponds with multiple net structures may significantly alleviate legacy P releases. In contrast, the legacy P releases were significantly positively associated with highly aggregated agricultural, tea plantation, and residential patches. This study provides theoretical support for strategies aiming to control legacy P from the perspective of landscape planning.
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  • 文章类型: Journal Article
    Dendroclic研究提供了对树木生长-气候响应的见解,以解决前向问题,并提供了气候变量的重建作为反向问题的产物。树状气候学的方法学发展导致该领域包括了各种树木生长参数。在生长季节的短时间间隔内形成的树木年轮性状可能会为两种树状气候应用提供更精细的时间尺度,并更好地了解树木生长对气候变化的反应机制。此外,从基于单个积分变量(树木年轮宽度)的经典树状气候研究过渡到现代众多定量变量(例如,木材解剖结构)增加了很多复杂性,这主要来自木材性状之间的内在反馈和注册气候信号的混乱季节性。这项研究利用了在西伯利亚南部(俄罗斯)森林草原的湿度敏感栖息地中生长的150至280岁的樟子松树的终身木材解剖学测量,以调查和消除细胞生产中的遗留影响草管性状。计算解剖学参数以描述针叶树木质部管胞发育的三个主要后续阶段的结果,即,环中每个径向文件的单元格编号,平均和最大细胞径向直径,以及平均和最大细胞壁厚度。尽管树环宽度几乎与细胞数成正比,在气管测量中揭示了与细胞数量的非线性关系。它们在窄环区域表现出更强的关系,在较宽的环中表现出稳定的解剖结构。本研究中提出的指数模型以具有形态计量学意义的数字术语证明了这些关系。解剖测量值与其建模值的比率用于开发长期解剖年表,事实证明,它保留了与年轮宽度(细胞数)无关的气候波动信息,尽管共同信号下降。
    Dendroclimatic research offers insight into tree growth-climate response as a solution to the forward problem and provides reconstructions of climatic variables as products of the reverse problem. Methodological developments in dendroclimatology have led to the inclusion of a variety of tree growth parameters in this field. Tree-ring traits developed during short time intervals of a growing season can potentially provide a finer temporal scale of both dendroclimatic applications and offer a better understanding of the mechanisms of tree growth reaction to climatic variations. Furthermore, the transition from classical dendroclimatic studies based on a single integral variable (tree-ring width) to the modern multitude of quantitative variables (e.g., wood anatomical structure) adds a lot of complexity, which mainly arises from intrinsic feedbacks between wood traits and muddles seasonality of registered climatic signal. This study utilized life-long wood anatomical measurements of 150- to 280-year-old trees of Pinus sylvestris L. growing in a moisture-sensitive habitat of the forest-steppe of Southern Siberia (Russia) to investigate and eliminate legacy effect from cell production in tracheid traits. Anatomical parameters were calculated to describe the results of the three main subsequent stages of conifer xylem tracheid development, namely, cell number per radial file in the ring, mean and maximum cell radial diameter, and mean and maximum cell-wall thickness. Although tree-ring width was almost directly proportional to cell number, non-linear relationships with cell number were revealed in tracheid measurements. They exhibited a stronger relationship in the areas of narrow rings and stable anatomical structure in wider rings. The exponential models proposed in this study demonstrated these relationships in numerical terms with morphometric meaning. The ratio of anatomical measurements to their modeled values was used to develop long-term anatomical chronologies, which proved to retain information about climatic fluctuations independent of tree-ring width (cell number), despite decreased common signal.
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