Forest characteristics,population structure and growth trends of threatened relict Pseudotsuga forrestii in China

Pseudotsuga forrestii is a relict evergreen coniferous tree species in Pinaceae endemic to China.P.forrestii tree numbers have greatly decreased due to deforestation,over-utilization and habitat degradation.Here we clarify P.forrestii community types,structure,species diversity,seedling recruitments and growth trends.We identified four P.forrestii community types:(1)Pseudotsuga forrestii-Quercus guyavifolia-Acer davidii evergreen coniferous and broad-leaved mixed forest;(2)Pseudotsuga forrestii-Pinus yunnanensis-Quercus guyavifolia evergreen coniferous and broad-leaved mixed forest;(3)Pseudotsuga forrestii evergreen coniferous forest;(4)Pseudotsuga forrestii-Abies georgei var.smithii evergreen coniferous forest.P.forrestii forests are characterized by both warm temperate and temperate affinities.Simpson diversity,Pielou evenness,Shannon-Wiener diversity indices ranged from 0.75 to 0.76,0.74-0.81,and 1.62-1.93,respectively,with no significant differences among the four forest types.The forest stratification was multilayered.The canopy layer was generally 10-25 m tall,with the emergent layer reached 25-42 m.DBH and age structures of P.forrestii showed multimodal distributions.Its maximum age P.forrestii was 570 years with a DBH of 143 cm.The growth of annual ring width of P.forrestii was slow,and generally decreased with age,whereas the basal area at the breast height increased with age.Established seedlings/saplings were mainly found in unstable micro-habitats.Regeneration of P.forrestii depends on moderate natural disturbances.Finally,we provide recommendations for P.forrestii conservation.

THE ANALYSIS OF CHILD′S GROWTH TREND DURING 1958～1995 IN XI′AN CITY

The paper analyzed the growth level and velocity to find the growth trend with the data collected in 8 investigations on growth of children aged 7～17 years in 1958～1995 in Xi′an. The results showed that child′s growth level was elevated with the passage of years and was the lowest in 1962, the highest in 1995 during the 38 years. The height of boy of the same age in 1995 has average increased by 9 59 cm over 1958 and girl 8 38 cm. The weight of boy of the same age in 1995 has averagely increased by 8 35 kg over 1958 and girl 5 90 kg. The chest girth of boy of the same age in 1995 has average increased by 5 69 cm over 1958 and girl 4 66 cm. The growth level of children aged 9～15 years had greater increase than others in 7～17 years of age. The average increment per 10 years of boy's height was 2 57 cm and girl's 2 26 cm. The average increment of per 10 years of boy's weight was 2 17 kg and girl's 1 56 kg. The average increment of per 10 years of boy's chest girth was 1 50 cm and girl's 1 23 cm. The analysis of the growth velocity in different period during 38 years showed the velocity in 1958～1962 was a negative value and indicated a growth retard, but the velocity in 1962～1964 was the fastest and indicated a catch up growth. And then, growth velocities of height, weight and chest girth were different in different period. The analysis of the growth curves of height, weight and chest girth showed that the 2 cross ages were 1～3 years of age ahead of time and menarche and emission also were ahead of time that during the 38 years indicated there is a child's growth acceleration in Xi′an and the trend of child's growth acceleration could continue if there are more and better nourishment, sports requisites, health care and housing conditions.

Divergent growth trends and climatic response of Picea obovata along elevational gradient in Western Sayan mountains, Siberia

In mountain ecosystems,plants are sensitive to climate changes,and an entire range of species distribution can be observed in a small area.Therefore,mountains are of great interest for climate–growth relationship analysis.In this study,the Siberian spruce’s(Picea obovata Ledeb.)radial growth and its climatic response were investigated in the Western Sayan Mountains,near the SayanoShushenskoe Reservoir.Sampling was performed at three sites along an elevational gradient:at the lower border of the species range,in the middle,and at the treeline.Divergence of growth trends between individual trees was observed at each site,with microsite landscape-soil conditions as the most probable driver of this phenomenon.Cluster analysis of individual tree-ring width series based on inter-serial correlation was carried out,resulting in two sub-set chronologies being developed for each site.These chronologies appear to have substantial differences in their climatic responses,mainly during the cold season.This response was not constant due to regional climatic change and the local influence of the nearby Sayano-Shushenskoe Reservoir.The main response of spruce to growing season conditions has a typical elevational pattern expected in mountains:impact of temperature shifts with elevation from positive to negative,and impact of precipitation shifts in the opposite direction.Chronologies of trees,growing under more severe micro-conditions,are very sensitive to temperature during September–April and to precipitation during October–December,and they record both inter-annual and long-term climatic variation.Consequently,it would be interesting to test if they indicate the Siberian High anticyclone,which is the main driver of these climatic factors.

An Analysis of China’s Economic Growth Trend(1998-2002)

The growth of the world economy in 2001 featured significant slowdowns, with various developed countries plunging into economic recessions or economic downturns synchronously. Against this context, China was able to maintain a 7.3 percent growth. A simple direct comparison of economic growth of all countries shows that China outshone all the others.

Age trends and correlations of growth and wood properties in clone of Eucalyptus urophylla × E. grandis in Guangdong, China

We assessed growth traits and wood properties ofDH32-29, a clone of Eucalyptus urophylla x E. grandis, at age of two to six years in Guangdong in China. Analysis of variance of studied traits showed that there were significant differences （1% level） on all studied traits among ages except for wood basic density. Analysis of age trends of growth traits and wood properties revealed that rotation length of DH32-29 should be more than six years or longer. Phenotypic correlations among traits at individual ages indicated that correlations between growth traits were strongly positive. There was significant change in relationship between growth and wood basic density with increasing age, ranging from -0.03 to -0.54 at 2 and 5 year and 0.003 to 0.3 at 3, 4 and 6 year. Correlations between Pilodyn pin penetration and basic density measured on increment cores showed that Pilodyn could rank or group genotypes or sites into density classes, but failure to predict individual tree and individual clone.

Trends of Population Growth in China:Maximum Number Will Exceed 1.5 Billion

ＴｒｅｎｄｓｏｆＰｏｐｕｌａｔｉｏｎＧｒｏｗｔｈｉｎＣｈｉｎａ：ＭａｘｉｍｕｍＮｕｍｂｅｒＷｉｌｌＥｘｃｅｅｄ１．５ＢｉｌｌｉｏｎⅠ．ＴｈｅＴｒｅｎｄｏｆＣｈｉｎａ＇ｓＰｏｐｕｌａｔｉｏｎＧｒｏｗｔｈａｔａＬｏｗＦｅｒｔｉｌｉｔｙＲａｔｅＴｈｅｍｏｓ...

矿产勘查市场周期性波动与我国矿产勘查趋势分析

在社会经济发展的驱动下,矿产勘查市场具有明显的周期性波动,包括长周期变化、中短周期变化和随机性变化。澳大利亚50年矿产勘查市场变化表明,经济发展的长周期变化决定了矿产资源供需关系基本面,矿产资源供需关系基本面决定了矿产勘查投入的长周期变化;经济发展中短周期变化决定了矿产品价格周期性变化,矿产品价格周期性变化决定了矿产勘查投入的中短周期变化。在国家新一轮找矿突破战略行动驱动下,我国矿产勘查活动进入新一轮增长周期,并呈现出与全球不同的变化特征。2020年以来,我国矿产勘查投入连续4年实现增长,且增速逐年扩大,2023年同比增长25.4%,矿产勘查市场内生回升动力不断增强。2016年之后,主要受国内政策环境的影响,我国矿产勘查投入变化偏离了全球勘查市场走势。综合判断,我国矿产勘查市场正处在长中短周期叠加、政策环境发生明显改善的特殊阶段。经济发展长周期变化和中短周期变化对矿产勘查投入形成较大的下行压力,而政策环境改善对市场形成了较强的上行拉力,未来2~3 a将是政策红利集中释放的时间,本轮矿产勘查增长周期可能将延续2~3 a时间。

1985—2019年中国18个少数民族17岁学生身高长期趋势分析

目的:分析1985—2019年我国18个少数民族17岁学生身高生长长期变化趋势。方法:提取7次中国学生体质与健康调研报告(除1991年)中蒙古族、回族、维吾尔族、壮族、朝鲜族、藏族、苗族、布依族、侗族、白族、土家族、哈尼族、傣族、傈僳族、佤族、纳西族、土族、羌族等18个少数民族学生身高均值进行研究。结果:34年间各少数民族男生17岁身高均值显著增长(P<0.05)。2019年18个少数民族17岁男学生中,回族男生身高均值最高(173.09 cm),苗族男生身高均值最低(162.66 cm),每10年身高增长>1 cm的民族有侗族(1.96 cm/10年)、白族(1.96 cm/10年)、土家族(1.95 cm/10年)、羌族(1.80 cm/10年)、回族(1.80 cm/10年)、蒙古族(1.79 cm/10年)、土族(1.72 cm/10年)、维吾尔族(1.63 cm/10年)、藏族(1.61 cm/10年)、布依族(1.55 cm/10年)、纳西族(1.52 cm/10年)、傣族(1.35 cm/10年)、傈僳族(1.29 cm/10年)、哈尼族(1.25 cm/10年)、壮族(1.16 cm/10年)、佤族(1.06 cm/10年);每10年身高增长<1 cm的民族是苗族(0.95 cm/10年)。2019年,18个少数民族17岁女学生中,回族女生身高均值最高(161.71 cm),布依族女生身高均值最低(151.63 cm),每10年身高增长>1 cm的民族分别是土家族(1.80 cm/10年)、回族(1.52 cm/10年)、土族(1.25 cm/10年)、白族(1.23 cm/10年)、侗族(1.18 cm/10年)、朝鲜族(1.12 cm/10年)、羌族(1.04 cm/10年);34年间除维吾尔族、苗族女生外,其余少数民族女生身高增长显著(P<0.05)。结论:我国少数民族男生均出现了较为明显的生长长期趋势,大部分少数民族女生出现了较为明显的生长长期趋势,各民族男女生身高增长不平衡,证明我国不同地区、不同少数民族学生生长潜力得以发挥,对于身高增长较慢的民族需要给予更高的关注,而对于那些身高增长较快的民族也要预防其带来的负面效应。

1990-2020年植物生长调节剂用量分析

植物生长调节剂作为一种外源激素,在植物整个生长过程中发挥着重要的作用,被广泛应用于农林业。为满足现代农药的发展需求,植物生长调节剂在未来农林业发展中的作用越来越重要。随着农业科技的不断进步,植物生长调节剂总量、各国使用量及其在整个农药市场中所占份额也出现不同程度的变化。本文从植物生长调节剂的用量、在农药中的占比及其变化趋势等不同角度分析了1990-2020年植物生长调节剂的使用情况,并提出了相关展望,以期为植物生长调节剂的应用提供参考。

Effects of Climate and the Urban Heat Island Effect on Urban Tree Growth in Houston

The growing conditions of urban trees differ substantially from forest sites and are mainly characterized by small planting pits with less water, nutrient and aeration availability, high temperatures and radiation inputs as well as pollution and soil compaction. Especially, global warming can amplify the negative effects of urban microclimates on tree growth, health and well-being of citizens. To quantify the growth of urban trees influenced by the urban climate, ten urban tree species in four climate zones were assessed in an overarching worldwide dendrochronological study. The focus of this analysis was the species water oak (Quercus nigra L.) in Houston, Texas, USA. Similar to the overall growth trend, we found in urban trees, water oaks displayed an accelerated growth during the last decades. Moreover, water oaks in the city center grew better than the water oaks growing in the rural surroundings of Houston, though this trend was reversed with high age. Growth habitat (urban, suburban, rural and forest) significantly affected tree growth (p < 0.001) with urban trees growing faster than rural growing trees and forest trees, though a younger age of urban trees might influence the found growth patterns. Growing site in terms of cardinal direction did not markedly influence tree growth, which was more influenced by the prevalent climatic conditions of Houston and the urban climate. Higher temperatures, an extended growing season and eutrophication can cause an accelerated growth of trees in urban regions across, across all climatic zones. However, an accelerated growth rate can have negative consequences like quicker ageing and tree death resulting in higher costs for new plantings and tree management as well as the decrease in ecosystem services due to a lack of old trees providing greatest benefits for mitigating the negative effects of the urban climate.

海南省国内旅游经济的潜在增长与周期特征

以内生增长理论为指导,采用Census X-13季节调整和High-Pass滤波结合的方法,对2002—2019年海南省国内旅游经济的潜在增长趋势与周期特征进行研究。结果表明:研究期内,海南省国内旅游经济发展的潜在趋势表现为持续性增长,但增速存在“小降—稳升—放缓”的阶段性特征,周期波动效应显著,呈现出与宏观经济环境的阶段性特征高度耦合的非平稳特征。周期内部存在着显著不对等现象,但经济运行整体均衡。研究认为,旅游收入数据的复杂波形掩盖了省域旅游经济持续性稳定增长的真实特征。旅游产业本身具有内生修复能力,以旅游业作为核心产业具有一定的必然性和合理性。旅游产业整体仍处于不断转型和完善过程中,产业发展需要以政策调控的规则性帮助旅游业适应环境变化的不规律性。

Analysis on Change Tendency of the Precipitation Resource during Growth Period of the Conventional Crops in Plain Area before Taihang Mountains

[Objective] The aim was to study change tendency of the precipitation resource during growth period of the conventional crops in plain area before Taihang Mountains. [ Method] Based on daily precipitation data at Shijiazhuang meteorological station in recent 51 years, average rainfall dudng growth periods of the 9 kinds of conventional crops was obtained. Precipitation tendency dudng growth periods of the 9 kinds of conventional crops in plain area before Taihang Mountains was analyzed by Mann-Kendall nonparametric test. [ Result] Seen from rainfall during growth pedods of the different crops, rainfall was the least during the growth period of winter wheat, followed by summer corn. Rainfall during growth peri- ods of the cotton, oil plant, vegetable, fruit tree, potato, rice and legumes was more. Under different guaranteed rates, precipitation change also had difference. Rainfall change during growth periods of the wheat and corn was bigger, and rainfall change during growth period of the rice was smaller. Change degree of the precipitation during growth periods of the cotton, oil plant, vegetable, fruit tree and legumes was equivalent, while precipitation change during growth period of the potato was the biggest. Seen from change tendency of the precipitation during growth periods of the different crops, precipitation in the growth period of winter wheat was increasing at a speed of 0.62 mm/a. However, precipitation in growth periods of the other crops had a decreasing tendency. Precipitation in the growth periods of summer corn and legumes decreased at the same speed which was 2.11 mm/a, while precipitation in growth periods of the cotton, oil plant, vegetable, fruit tree, potato and rice decreased insignificantly. [ Con dusion] The study laid foundation for determination of the agricultural irrigation water and provided theoretical reference for regional agricultural water-saving.

一种基于随机森林算法的探明储量预测新方法

传统的哈伯特模型、翁氏模型等预测方法主要采用一元多项式拟合储量增长趋势,无法解决多变量对储量预测的影响,使得预测结果与客观实际存在较大差距。文章基于随机森林机器学习模型,建立了一种预测累计探明储量增长趋势的新方法。该方法通过相关性分析找出影响探明储量增长的可量化指标,从而确定模型训练中的输入属性,以同类盆地油田年度累计探明储量为评价单元,建立随机森林机器学习样本数据集,通过调整决策树个数和单个决策树的最大特征数,对模型进行优化训练,从而建立累计探明储量预测模型,成功解决了多因素叠加下储量非线性增长预测的难题。该方法在东部断陷盆地油田年度累计探明储量预测中应用成效显著,预测模型拟合的准确率达到88.19%,具有巨大的推广应用价值。

中国东北植被生长峰值时空变化及可持续性分析

植被生长峰值不仅是典型的物候节点,也是植被最大生长能力的重要指示参数。本文以中国东北地区为研究区域,基于长时序遥感NDVI数据,采用Mann-Kendall检验法探索植被生长峰值的变化趋势,利用Hurst指数对植被生长峰值进行可持续性分析。结果表明:1)我国东北地区植被生长峰值时间点(POP)和最大生长幅度(PEAK)整体上呈现出波动上升的趋势。植被峰值时间点在东部以及北部阔叶林和草原区域表现为延迟趋势;植被最大生长幅度在中部、北部以及西南部表现为增强趋势,在森林区峰值时间点表现为延迟趋势,生长峰值表现为增强趋势;2)东北地区整体上植被返青开始期(SOS)和生长峰值时间主要以延迟为主,峰值幅度有所升高;3)Hurst指数结果表明,东北地区植被PEAK呈持续增强趋势,仅6.38%的区域与过去呈现相反的变化趋势,植被增强区域主要集中在中部地区。东北地区植被生长峰值变化可持续性研究,可以为评价东北地区植被固碳能力和生态系统功能提供参考。

A Review of Trends in Import of Some Selected Foods in Nigeria (1981-2010): Matters Arising

This research assessed empirically the quantitative analysis of some selected food imports of Nigeria (rice, wheat and sugar). Time series data were used to examine the determinant of total food imports and the trend in the quantity of the food imported. The secondary data were obtained from institutional and national database over 1981-2010. Descriptive statistics, regression and correlation analysis were used as analytical tools. Statistical analysis shows that food deficit began in the 1970’s, when Nigeria started the importation of food to feed the country. The result of the correlation analysis shows that the postulated determinants of food imports were positively correlated with the quantity of food import. The test for the individual variables shows that;national income explains 40%, external reserves explains 38%, food production index explains 46%, population explains 58% and exchange rate explains 74% of the total variation in the quantity of food import. The over-all goodness of fit of the regression analysis result shows that, the postulated regressors namely, relative price, national income, external reserves, lagged index of domestic food production, population estimate and exchange rate explained approximately 70% of the variability in the quantity of the selected food imports for the period of study. Consequently, there is the need for Nigeria to shift base from the ideology of nationalist orientation, as well as afro centric point of view and move towards unrestrained export-led growth that seeks to develop that market as the first option with corresponding development in international trade. This is however possible by limiting the importation of foods/raw materials that can be sourced for locally, increasing the domestic production of food generally and maintaining a healthy foreign investment with developed countries as a short term measure while in the long run, diversification of the economy, massive investment in agriculture and introduction of population control measures could serve as saviours to lower the rate of increase in food import demand.

创伤后成长的研究热点和主题趋势:基于关键词的共词分析

目的 采用基于关键词的共词分析方法,分析、总结近15年创伤后成长(post-traumatic growth,PTG)的研究热点和进展趋势,为PTG的相关研究和临床干预提供参考依据.方法 在PubMed和Web of Science数据库中检索于2013年1月至2022年7月发表的与PTG相关的研究文献.采用共11个医学主题词(Medical Subject Headings,MeSH)和关键词来检索、选择研究文献.使用书目共现分析系统(Bibliographic Item Co-occurrence Matrix Builder,BICOMB 2.0)提取高频主题词并生成词篇矩阵,使用图形聚类工具包(Graphical Clustering Toolkit,gCLUTO 1.0)进行聚类分析,使用SPSS 25.0进行战略图分析.结果 共筛选出2 370篇文献,提取38个高频主题词.研究结果揭示了 2013-2022年关于PTG的6个研究热点:遭遇负性生活事件后的情绪反应研究,癌症患者的PTG研究,经历创伤后的反刍和韧性研究,儿童和青少年的PTG研究,社会支持和应对策略在PTG中的作用研究,以及PTG与生活质量之间的关系研究.结论 采用共词分析方法,有效揭示了近15年PTG相关研究的概况.本研究中揭示的6个研究类别既反映了PTG研究领域的多样性,也说明部分研究主题尚未成熟.本研究结果对未来开展与PTG相关的研究具有重要参考价值.

气候变化对拉萨河谷冬小麦主要生育期的影响分析

了解气候变化对冬小麦生育期的影响,可为农业应对气候变化、调整农作物种植结构提供科学依据。本文利用1996—2022年近26 a拉萨冬小麦生育期以及逐日平均气温(T_(m))、最高气温(T_(max))、最低气温(T_(min))、气温日较差(DTR)、相对湿度(RH)、降水量(Pr)、日照时数(S)和≥0℃积温(ΣT_(0))等资料,采用线性倾向估计、Pearson相关系数和优势分析方法等,分析了拉萨河谷冬小麦生育期变化特征以及影响的主导气象因子。结果表明:(1)近26 a拉萨河谷冬小麦营养生长期(Vegetative Growth Period,VGP)、生殖生长期(Reproductive Growth Period,RGP)和全生育期(Whole Growth Period,WGP)的T_(m)均呈上升趋势,T_(min)升温率大于T_(max)的升温率,DTR、RH呈减小趋势,ΣT_(0)、Pr和S趋于增加。(2)冬小麦拔节前各生育期提早,提早率为0.47~6.75 d/10 a;拔节后各生育期推迟,推迟率为3.17~7.03 d/10 a;VGP、WGP延长,RGP缩短。(3)拉萨河谷10月、1月T_(min)和2月T_(m)的升高,是冬小麦出苗、分蘖和返青期提前的主要因素,导致冬小麦拔节后生育期推迟的重要因素则是4—5月S增加及6月RH减少。