More tree growth reduction due to consecutive drought and its legacy effect for a semiarid larch plantation in Northwest China

Extreme climate has increasingly led to negative impacts on forest ecosystems globally,especially in semiarid areas where forest ecosystems are more vulnerable.However,it is poorly understood how tree growth is affected by different drought events.In 2006–2009,the larch plantations in the semiarid areas of Northwest China were negatively affected by four consecutive dry years,which was a very rare phenomenon that may occur frequently under future climate warming.In this study,we analyzed the effect of these consecutive dry years on tree growth based on the data of the tree rings in the dominant layer of the forest canopy on a larch plantation.We found that the tree-ring width index(RWI)in dry years was lower than that in normal years,and it experienced a rapidly decreasing trend from 2006 to 2009(slope=-0.139 year^(-1),r=-0.94)due to water supply deficits in those dry years.Drought induced legacy effects of tree growth reduction,and consecutive dry years corresponded with greater growth reductions and legacy effects.Growth reductions and legacy effects were significantly stronger in the third and fourth consecutive dry years than that of single dry year(p<0.05),which might have been due to the cumulative stress caused by consecutive dry years.Our results showed that larch trees experienced greater tree growth reduction due to consecutive dry years and their legacy effect,and the trees had lower recovery rates after consecutive dry years.Our results highlight that consecutive dry years pose a new threat to plantations under climate warming,and thus,the effect of climate extremes on tree growth should be considered in growth models in semiarid areas.

The legacy effects of rubber defoliation period on the refoliation phenology,leaf disease,and latex yield

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.

Persistent greening against drying in northeast Asian semiarid grasslands:Asymmetrical responses of direct and legacy effects to intensified drought

Despite experiencing a decadal shift towards drought conditions at the end of the 2Oth century,semiarid grasslands in northeast Asia(NEA)exhibited an evident greening trend from 1982 to 2020.However,the mechanism behind this phenomenon remains unclear.Hence,we analysed the interdecadal changes in vegetation response to drought on the basis of the standardised precipitation evapotranspiration index(SPEI)and Global Inventory Modelling and Mapping Studies LAI4g datasets,with an emphasis on the differences between direct and legacy effects(as measured by resilience),to explore the mechanism of persistent grassland greening.Results revealed that during the post-drought shift period(2000-2020),the sudden decrease in the water content of the intermediate soil layer triggered an intensified vegetation response to drought.Specifically,although direct effects and resilience were amplified,they exhibited asymmetric changes.Resilience was stronger than direct effects,and this difference increased with increasing drought(drought recovery)levels.These combined effects may account for persistent greening against intensified drying in the semiarid grasslands in NEA.Given the projected exacerbation of future droughts,this study holds notable importance for comprehending the long-term change dynamics of dryland ecosystems.

Effect of elevation on floristic diversity,life forms and chorotypes in the AlHada mountain escarpment,Saudi Arabia

Mountains are biodiversity hotspots,and due to their unique microclimatic circumstances,they host a vast range of endemic species.There are two main hypotheses,the Rapoport and the mid-domain effect hypotheses,which explain how elevation and species richness are linked.The current study was conducted in the Al-Hada escarpment,which is a unique area in the world.It is located on the border of Eurasia and Africa,where there are a lot of plant species from both places.The study aimed to detect the effect of elevation on the floristic composition of the study area.The obtained results showed that the Al-Hada escarpment flora consists of 297 species belonging to 194 genera and fifty-seven distinct families.Only two families,Poaceae and Asteracae,had 22%of the whole recorded species.The obtained results showed that with increasing elevation,the numbers of species,genera,and families increased,in accordance with the Rapoport hypothesis.The numbers of families increased by 62%from the lowest elevation to the highest one,while the numbers of both species and genera increased by more than twofolds.Therophytes exhibited the maximum number,which was 44%,and Chamaephytes came in second with 25%.Phanerophytes and hemicryptophytes made up 13%and 11%of all life forms,respectively,while geophytes made up just 7%.Monoregional elements represented 33.2%of the total recorded species,where Saharo-Sindian species had the most monoregional species,accounting for around 13%of the total species.At the highest elevation,succulents accounted for 7.6%of the research area,whereas Nfixing plants accounted for 6.2%.At the highest elevation,they had the lowest value,and at the middle elevation,they had the highest value.With the rise in elevation,the neotropical,endemic,and Mediterranean elements rose.Succulents and Nfixing species did not show a clear relationship with the elevation but exhibited the lowest value at the highest elevation,and vice versa.Therophytes and geophytes increased while the number of hemicryptophytes decreased with elevation.Surprisingly,phanerophytes did not show any relationship with elevation,while,with the rise in elevation,the pan-tropical,endemic,and Mediterranean elements rose.Neotropical and Saharo-Sindian elements decreased with the rise in elevation.Considering our results,we can conclude that the relationship of taxa diversity with the different altitude of the arid subtropical regions’mountains,whose elevation does not exceed 2000 m(without human disturbance),confirms the Rapoport hypothesis.

Estrogen rapid effects:a window of opportunity for the aging brain?

Estrogen produces several beneficial effects in healthy neurological tissues and exhibits cardioprotective effects.Hormone therapy has been widely used to treat menopausal estrogen deficiency for more than 80 years.Despite high initial expectations of cardioprotective effects,there has been substantial distrust following important randomized clinical trials,such as the Women’s Health Initiative.Subsequently,the timing of treatment in relation to the onset of menopause came under consideration and led to the proposal of the timing hypothesis,that early initial treatment is important,and benefits are lost as the timing since menopause becomes prolonged.Subsequent analyses of the Women’s Health Initiative data,together with more recent data from randomized and observational trials,consistently show reductions in coronary heart disease and mortality in younger menopausal women.Regarding cognitive function,the timing hypothesis is consistent with observations from basic and animal studies.There is some clinical evidence to support the benefits of hormonal therapy in this context,though skepticism remains due to the paucity of clinical trials of substantial length in younger menopausal women.It is likely that the effects of estrogens on cognitive performance are due to rapid mechanisms,including mechanisms that influence Ca2+homeostasis dynamics,provide protection in a hostile environment and reduce inflammatory signals from neural tissues.In the future,inflammatory profiles accounting for early signs of pathological inflammation might help identify the‘window of opportunity’to use estrogen therapy for successful cognitive protection.

Climate Change Perceptions , Impacts and Adaptation Strategies of F arm Households in Potohar Region of Punjab, Pakistan

Climate change has become a global phenomenon and is adversely affecting agricultural development across the globe.Developing countries like Pakistan where 18.9%of the GDP(gross domestic product)came from the agriculture sector and also 42%of the labor force involved in agriculture.They are directly and indirectly affected by climate change due to an increase in the frequency and intensity of climatic extreme events such as floods,droughts and extreme weather events.In this paper,we have focused on the impact of climate change on farm households and their adaptation strategies to cope up the climatic extremes.For this purpose,we have selected farm households by using multistage stratified random sampling from four districts of the Potohar region i.e.Attock,Rawalpindi,Jhelum and Chakwal.These districts were selected by dividing the Potohar region into rain-fed areas.We have employed logistic regression to assess the determinants of adaptation to climate change and its impact.We have also calculated the marginal effect of each independent variable of the logistic regression to measure the immediate rate of change in the model.In order to check the significance of our suggested model,we have used hypothesis testing.

基于风险管控的历史遗留硫磺冶炼废渣综合治理效果

为解决赤水河源头流域(云南段)历史遗留硫磺冶炼废渣40多年无序堆积导致流域水体持续酸化的污染问题,通过对“自然衰减”“异位修复”“风险管控”等治理途径分析,提出“风险管控+生态修复”模式开展了该区域内酸性废渣和废水的示范工程治理。在查明治理区域污染因子的基础上,采取“废渣防流失、复合阻隔控制、适生植物配比、污水收集处理和运行监测管理”的集成风险管控技术,分析工程实施前、实施中和实施后的固废属性,以及地表水、地下水和废渣渗滤液中污染因子的变化。结果表明:在投加0.35%~0.65%比例生石灰条件下,固废属性从第Ⅱ类一般工业固废改性为第Ⅰ类一般工业固废;工程完工时,地下水pH即可达标,硫酸盐超标倍数从最大5.3倍削减至1.2倍;工程实施3个月后,渗滤液pH稳定达标,硫酸盐超标倍数从最大3.2倍削减至1.7倍;工程实施7个月后地表水pH达标。基于风险管控的历史遗留硫磺冶炼废渣综合治理,能够满足管控目标,并初步完成了技术推广和应用。

基于文献计量的土壤遗留效应研究现状与热点分析

土壤遗留效应是介导植物群落和土壤特性之间相互作用的重要机制,不仅影响着植物群落动态和物种共存,同时在土地利用和管理方面也发挥着重要作用。本文基于Web of Science数据库中检索到的2000~2022年发表的相关文献进行计量学分析,探讨此研究领域的研究现状以及热点问题。结果表明:土壤遗留效应的发文量总体呈现上升趋势,美国农业部是发文量最多的机构(646篇),以中国科学院为代表的国内科研机构对该领域的发展也做出了积极贡献;生态学、环境科学、土壤学和植物学是该领域的主要发文学科,这些学科的交叉合作对深入了解土壤遗留效应起着关键作用;在国际合作方面,该领域已显示出全球交流和联系日益密切的趋势,但考虑到地理位置等因素,未来各研究团队仍需保持密切合作,共同加强该领域高水平、高认可度研究成果的产出;目前,该领域的热点问题集中在土壤遗留效应对土壤微生物群落、农业土地管理和不同生态系统恢复的影响,以及气候因素在驱动遗留效应中的作用。未来的研究可以进一步探讨这些问题,并结合新兴技术手段,如遥感技术、GIS技术和模型模拟等,推动土壤遗留效应的定量评估和预测,为实现可持续土地管理和生态系统发展提供支撑。

企业规模、市场竞争与企业数字化转型——熊彼特假说的再考察

在数字技术快速发展的背景下,数字化转型成为企业提高竞争力、实现高质量发展的必然要求。本文基于熊彼特假说视角,利用2011~2022年我国沪深A股上市公司数据,分析企业规模和市场竞争对企业数字化转型的影响。研究发现:企业规模对企业数字化转型具有非线性促进作用,且边际效应递减;市场竞争和企业数字化转型之间呈“倒U型”关系,即在某一市场竞争程度下,企业数字化转型意愿达到峰值,超过这一阀值,企业的数字化转型意愿逐渐降低。异质性检验表明,若企业是国有企业或制造业企业,企业规模对数字化转型的推动效应具有稳定性。进一步分析发现,企业规模与市场竞争的交互作用会抑制企业数字化转型。据此,本文提出促进企业数字化转型的对策建议。

记忆幽默效应产生的理论假说

记忆幽默效应是指相比于非幽默材料,个体对幽默材料的记忆较好的现象,其加工过程涉及多个层面的认知加工成分。已有研究先后提出唤醒假说、失谐消解假说、幽默感知假说、选择性复述假说和背景依赖精细化假说来解释记忆幽默效应的产生机制。唤醒假说认为个体在体验幽默时会伴有生理和情绪唤醒,而这种适度的唤醒会提升个体的记忆;失谐消解假说理论则认为幽默材料的记忆优势是由于人们分配给幽默和非幽默材料的注意资源不同所导致的;幽默感知假说认为幽默本身能够促进个体对材料的记忆能力;选择性复述假说认为对幽默材料的记忆优势是由于被试对幽默材料的复述增加造成的;背景依赖精细化假说认为精细化加工带来了记忆的幽默效应。五种理论都试图从不同的角度去解释记忆幽默效应的产生机制,唤醒假说、失谐消解假说、幽默感知假说似乎关注的是幽默效应产生的不同加工阶段,而选择性复述假说和背景依赖精细化假说则关注的是幽默效应产生过程中的有效策略。今后的研究应在整合上述理论假说的基础上,对记忆幽默效应产生的内在机制进行更加规范、深入系统地研究。

Effects of combined antibiotics on nitrification, bacteria and antibiotic resistance genes in activated sludge: Insights from legacy effect of antibiotics

The effect of combined antibiotics exposure on nitrogen removal,microbial community assembly and proliferation of antibiotics resistance genes(ARGs)is a hotspot in activated sludge system.However,it is unclear that how the historical antibiotic stress affects the subsequent responses of microbes and ARGs to combined antibiotics.In this study,the effects of combined sulfamethoxazole(SMX)and trimethoprim(TMP)pollution on activated sludge under legacy of SMX or TMP stress with different doses(0.005-30 mg/L)were investigated to clarify antibiotic legacy effects.Nitrification activity was inhibited under higher level of combined exposure but a high total nitrogen removal(∼70%)occurred.Based on the full-scale classification,the legacy effect of past antibiotic stress had a marked effect on community composition of conditionally abundant taxa(CAT)and conditionally rare or abundant taxa(CRAT).Rare taxa(RT)were the keystone taxa in the microbial network,and the responses of hub genera were also affected by the legacy of antibiotic stress.Nitrifying bacteria and genes were inhibited by the antibiotics and aerobic denitrifying bacteria(Pseudomonas,Thaurea and Hydrogenophaga)were enriched under legacy of high dose,as were the key denitrifying genes(napA,nirK and norB).Furthermore,the occurrences and co-selection relationship of 94 ARGs were affected by legacy effect.While,some shared hosts(eg.,Citrobacter)and hub ARGs(eg.,mdtD,mdtE and acrD)were identified.Overall,antibiotic legacy could affect responses of activated sludge to combined antibiotic and the legacy effect was stronger at higher exposure levels.

Overstory functional groups indicate the legacy of land use in a secondary tropical forest in southwestern China

Anthropogenic disturbances are widespread in tropical forests and influence the species composition in the overstory.However,the impacts of historical disturbance on tropical forest overstory recovery are unclear due to a lack of disturbance data,and previous studies have focused on understory species.In this study,the purpose was to deter-mine the influence of historical disturbance on the diver-sity,composition and regeneration of overstory species in present forests.In the 20-ha Xishuangbanna tropical sea-sonal rainforest dynamics plot in southwestern China,the historical disturbance boundaries were delineated based on panchromatic photographs from 1965.Factors that drove species clustering in the overstory layer(DBH≥40 cm)were analyzed and the abundance,richness and composition of these species were compared among different tree groups based on multiple regression tree analysis.The coefficient of variation of the brightness value in historical panchro-matic photographs from 1965 was the primary driver of spe-cies clustering in the overstory layer.The abundance and richness of overstory species throughout the regeneration process were similar,but species composition was always different.Although the proportion of large-seeded and vigorous-sprouting species showed no significant differ-ence between disturbed and undisturbed forests in the tree-let layer(DBH<20 cm),the difference became significant when DBH increased.The findings highlight that historical disturbances have strong legacy effects on functional group composition in the overstory and the recovery of overstory species was multidimensional.Functional group composi-tion can better indicate the dynamics of overstory species replacement during secondary succession.

Maternal Environment Effects on Phenolic Defenses in <i>Abutilon theophrasti</i>Seeds

A class of phenolic compounds, ortho-dihydroxyphenols (hereafter “o-DHP”), has been implicated with seed survival. Based on expectations of the growth-differentiation balance hypothesis, we predicted that seed o-DHP concentration exhibits a curvilinear response to increasing resource availability in the maternal environment, with maximum o-DHP occurring at moderate resource levels. To test this hypothesis, Abutilon theophrasti seeds were produced under field conditions at two locations. Each location included twelve maternal environments established through factorial combinations of soil compost (+/-), species assemblage (A. theophrasti with and without maize), and soil nitrogen fertilizer (0, 0.5× or 1× local recommendations for maize). Resource availability with respect to A. theophrasti growth was summarized by above-ground biomass at seed harvest (maternal biomass). Results indicated that seed o-DHP concentrations increased then decreased in response to increasing maternal biomass. This relationship was modeled with a unimodal function specific to location (Location 1, y = 1.18 + 0.03xe-0.02x, pseudo-R2 = 0.59, p = 0.003;Location 2, y = 1.40 + 0.006xe-0.005x;pseudo-R2 = 0.34, p = 0.05). Seed protein concentrations remained constant across maternal biomass levels. Because inherent vulnerability to predation and decay is considered a consequence of chemical protection relative to nutritional offering, our results suggest that A. theophrasti seed susceptibility to lethal attack is influenced by resource levels in the maternal environment. More broadly, our results suggest that the growth-differentiation balance hypothesis can be extended to maternal effects on seed phenolics.

Confounding of Three Binary-Variable Counterfactual Model with DAG

Confounding of three binary-variable counterfactual model with directed acyclic graph (DAG) is discussed in this paper. According to the effect between the control variable and the covariate variable, we investigate three causal counterfactual models: the control variable is independent of the covariate variable, the control variable has the effect on the covariate variable and the covariate variable affects the control variable. Using the ancillary information based on conditional independence hypotheses and ignorability, the sufficient conditions to determine whether the covariate variable is an irrelevant factor or whether there is no confounding in each counterfactual model are obtained.

Henriksen and Flora （1999） Revisited A Literature Review on Third-Person Effects and Children/Adolescents＊

In this literature review on TPE （third-person effects） and the behavioral consequences on children, the research questions posed are how the body of knowledge has evolved since the first empirical evidence of TPE among children and what knowledge gaps that remain. The traceable developments are two： （1） Compared to the vast amount of articles on TPE in general, the 5 9 identified on the topic of children are few and two thirds actually focus on adolescents/young adults rather than children. The reason put forward for studying younger children is the urge to prevent risky behavior through media literacy programs or pro-social advertisements; and （2） The studies have not primarily addressed results to support occurrence of TPE among children. Rather they support parental TPE or among the adolescents that TPE and reverse TPE occur due to certain kind of media content. The discussion on knowledge gaps that remain follow three themes： （1） Differentiations between self and others are in psychological studies implied to occur among children between the ages of 3-4 years old, yet no study address how children develop TPE; （2） There is a tendency to follow the more general development within TPE research with the renewed interest in behavioral consequences. But the primary behavioral consequence studied in TPE in general and within studies of TPE and children is support for censorship. Few studies address ＂real＂ behavioral consequences like parental mediation; and （3） There is also a need for more theoretically coherent research on the importance of social distance.

The Impact of the Integration of Culture and Tourism Industry on the Upgrading of Tourism Industry Performance

Based on the provincial data of tourism and cultural industries from 2009 to 2019,this paper studies the impact of the integration of culture and tourism on the economic benefits of regional tourism in China.The results show that:①The integration level of the two industries is generally low in all provinces and regions,and the regional differences are obvious.The integration degree of the central and eastern regions is generally higher than that of the western regions.②The integration degree of culture and tourism has a significant positive impact on the economic benefits of regional tourism.The influence on the central and eastern regions is greater than that on the western regions.③The level of informatization has a positive moderating effect on the economic benefits of regional tourism caused by the integration of culture and tourism.④Government intervention has a negative moderating effect on the economic benefits of tourism.In addition,the level of regional economic development,accessibility and tourism resource endowment are also significant factors affecting the economic benefits of regional tourism.The results show that promoting the deep integration of culture and tourism,promoting the informatization of tourism and moderate government intervention in the industry are conducive to improving the economic benefits of regional tourism.

遗赠扶养协议优先效力的正当性基础与保障路径

《民法典》第1123条规定了遗赠扶养协议相对于法定继承、遗嘱继承与遗赠的优先效力,但对其正当性基础却未尽阐明。借由整体类推的法律漏洞填补,归纳预告登记中不动产买受人、商品房消费者的法律地位等规则所内含的一般性法律规范,演绎至遗赠扶养协议优先效力的类似情势中,可厘定该优先效力的正当性基础在于,立法者对特定债权人予以特殊保护,赋予特定债权一定的物权效力,以保障该债权依约实现;具体保障路径在于扶养人对遗赠财产的处分保护,即扶养人可以阻却遗赠财产在未经扶养人同意情况下的处分效力。鉴于遗赠扶养协议的双段法权构造,当遗赠扶养协议所约定的遗赠财产特定化时,扶养人自协议生效时起即可主张处分保护;遗赠财产未特定化时,扶养人仅能在继承开始后对继承人或者遗产管理人主张处分保护。

外语与外语思维

本文基于外语思维研究近两百年历程的回顾,探讨了其定义、特性和四大对立关系,并得出如下基本结论:(1)外语思维可定义为“基于客观事物本质属性和间接规律性联系的概括,外语使用者用外语构建概念、做出判断和完成推理的过程”;(2)外语思维除了语言思维应具备的“概括性”和“间接性”之外,还具备语言的主体融合性、客体依赖性和载体辅助性;(3)外语效应的应用可较好地解决外语思维研究中“母语与外语”“个性与共性”“能力与运用”和“形式与内容”等四大关系的对立。

基于断点回归法分析广东省碳交易试点政策对碳强度的影响

在“双碳”背景下,2021年全国碳市场正式启动。广东省作为首批碳交易试点城市,取得了显著的减排效果,对于全国碳市场和其他试点城市具有较好的示范效果。基于此,采用断点回归方法,基于1878个县的样本,研究了碳交易试点政策对广东省碳强度的影响以及影响机制。实证分析结果表明,碳交易试点政策实施以来,广东省的碳强度明显下降。创新性地研究并验证了碳交易试点政策降低碳强度的3个途径——提高电能消费占比、提高电能强度和降低碳排放系数。同时,研究结果并不支持波特假说。综上结果及分析,可以认为广东省碳交易试点发挥作用的基本要素是清洁能源替代、能源结构优化和转型。

Impact of trade on China's SO_2 emissions is relatively small

To better understand trades impact on the environment, we construct a four-equation simultaneous system in whichthree economic determinants define emissions: scale, composition and technique effects, all embodied directly by trade.Supposing the three economic determinants are also endogenous to trade, we check the indirect impacts of trade onthe environment in the following three functions through the intermediation of the three effects.We then estimate 29Chinese provinces’ panel data in the model on industrial SO2 emissions （1993-2001）.Our estimation results revealthat export expansion and the accumulation of manufactured goods imports had the opposite roles on industrial SO2emissions determination.The results do not support the "pollution haven" hypothesis; the reinforced competitionexporters face is a positive factor that encourages technological progress in pollution abatement.China’s actualcomparative advantage resides in labor-intensive industries; exporting to the world market actually helps to reduce thepollution increases caused by China’s heavy-industry-oriented industrialization strategy, which government-intervenedimport activities traditionally support.