CO2倍增和施氮对水稻不同生长期土壤反硝化细菌丰度的影响

随着全球气候变化的不断加剧,大气CO₂浓度呈明显增加趋势,这将间接影响土壤-植物-微生物系统的氮循环过程.为研究典型水稻土壤反硝化细菌对CO₂浓度升高的响应规律和机制,借助水稻密闭培养箱,运用实时荧光定量聚合酶链式反应（Real-Time qPCR）分子技术,设置不施氮（0 mg/kg）和常规施氮（100 mg/kg）2个处理,研究CO₂倍增对水稻不同生长期土壤关键反硝化功能细菌（narG、nirK和nirS型）丰度的影响.结果表明:①在2种施氮水平,CO₂倍增显著促进了水稻分蘖期、孕穗期、扬花期和成熟期水稻根系生长（增幅为2.96%~28.4%）、地上部生物量增加（增幅为7.1%~107.3%）以及成熟期籽粒干质量的增加（增幅为19.5%和38.0%）,具有显著的增产效应.②反硝化细菌丰度对CO₂倍增的响应与生育期及施氮水平有关,CO₂倍增在2个施氮水平均抑制分蘖期反硝化细菌的繁殖,显著增加孕穗期反硝化细菌数量;在水稻扬花期,CO₂倍增促进了施氮处理narG和nirS型反硝化细菌数量的增加,在成熟期抑制未施氮处理下narG、nirK和nirS型反硝化细菌的生长.另外,narG、nirK、nirS型反硝化细菌丰度整体表现为narG > nirS > nirK,且随水稻的生长,其在成熟期的丰度均呈降低趋势.nirK和nirS基因同属亚硝酸还原酶,但nirS基因丰度高于nirK,且对CO₂倍增和施氮的响应有所差异.研究显示,CO₂倍增可显著增加水稻生长和产量,不同施氮水平对稻田土壤反硝化细菌丰度的影响存在差异.      

国土空间规划“三条控制线”划定的沈阳实践与优化探索

国务院机构改革前,生态保护红线、永久基本农田、城镇开发边界三条控制线分别由国家不同部委主导划定,存在划定过程统筹协同不够、划定结果交叉重叠、实施管理困难等问题。国务院机构改革后,自然资源部负责建立国土空间规划体系,要求在资源环境城镇能力和国土空间开发适宜性评价基础上,自上而下逐级统筹划定落实三条控制线。本文总结了沈阳作为试点城市,在三条控制线划定中的矛盾冲突表现与成因,构建三条控制线与生态、农业、城镇三大空间关系,建立管控体系与调整规则,并阐释在市级权限范围内的调整优化做法。研究发现：三条控制线存在空间交叉重叠、功能难以区分的现象,主要是因为基本农田承担了限制城市空间蔓延的使命,指标不允许跨行政区调整导致部分基本农田不得不安排到城镇内部;由于概念界定不同导致部分城市公园被划入生态保护红线;生态保护红线内的部分耕地被先期划为永久基本农田。提出国土空间规划背景下三条控制线优化建议：一是突出既是政策线又是技术线的特征,自上而下和自下而上相结合划定;二是国家自上而下对基本农田调整政策和制度进行创新;三是建立事权分级管理机制,合理预留地方事权弹性。     

天津市郊夏季VOCs化学特征及其时间精细化的来源解析

夏季为环境空气中臭氧污染事件的频发时期,针对挥发性有机化合物(VOCs)及其臭氧生成潜势(OFP)的时间精细化的来源解析研究,对有效地进行臭氧污染防控具有非常重要的作用.利用2019年夏季(6～8月)天津市郊区点位监测的小时分辨率VOCs在线数据,分析臭氧污染事件和非臭氧污染时期环境受体中VOCs及其OFP的变化特征,并利用正定矩阵因子分解(PMF)模型进行精细化的来源解析研究.结果表明,夏季环境受体中VOCs平均体积分数为24.42×10-9,臭氧污染事件中的VOCs平均体积分数为27.72×10-9,较非臭氧污染时期增加15.69％.夏季总VOCs(TVOCs)的OFP为87.92×10-9,其中烯烃的OFP最高,对TVOCs的OFP的贡献达58.28％.臭氧污染事件中TVOCs的OFP为102.68×10-9,较非臭氧污染时期增加19.59％.臭氧污染事件中VOCs的来源分别为石化工业及汽油挥发(29.44％)、柴油车尾气(23.52％)、液化石油气及汽油车尾气(22.00％)、天然气及燃烧(13.41％)、溶剂使用(6.14％)和植物排放(5.49％).相比于非臭氧污染时期,液化石油气及汽油车尾气和柴油车尾气分别增长4.84％和5.29％.石化工业及汽油挥发和植物排放的贡献均表现为08:00开始上升,11:00达到最高,这与太阳辐射增强和温度不断上升密切相关.液化石油气及汽油车尾气和柴油车尾气均具有明显的早晚高峰特征,并在夜间(00:00～06:00)保持较高贡献水平.根据PMF结果并结合OFP的计算方法,解析了不同源类对臭氧生成潜势的 贡献.石化工业及汽油挥发(31.01％)和柴油车尾气(36.64％)是较高贡献源类,相比非臭氧污染时期分别增加了 1.74％和8.27％;并且石化工业及汽油挥发贡献率在臭氧污染事件发生过程的上升阶段显著增加,而在下降阶段明显下降.     

Deletion 15q24-26 in prenatally detected diaphragmatic hernia: increasing evidence of a candidate region for diaphragmatic development

Survival of children with congenital diaphragmatic hernia (CDH) is mainly dependent on the extent of lung hypoplasia and the presence of additional congenital anomalies or chromosomal aberrations. A chromosomal deletion 15q25-q26.2 in a fetus with prenatally diagnosed CDH and growth retardation is reported. Despite optimal pre- and neonatal management the baby died shortly after birth. There is increasing evidence that the long arm of chromosome 15, and especially the region 15q24 to 15q26, plays a crucial role in the development of the diaphragm. The finding of a deletion within 15q24-26 in a fetus with CDH has to be considered a predictor of poor prognosis. It is of utmost interest for proper parental counselling to search in fetuses with CDH for subtle chromosomal lesions paying special attention to chromosome 15q. Copyright © 2001 John Wiley & Sons, Ltd.     

First trimester maternal serum placenta growth factor (PIGF)concentrations in pregnancies with fetal trisomy 21 or trisomy 18

Placenta growth factor (PIGF), an angiogenic factor belonging to the vascular endothelial growth factor family, pregnancy-associated plasma protein A (PAPP-A) and free β-human chorionic gonadotrophin (β-hCG) were measured in maternal serum from 45 pregnancies with trisomy 21, 45 with trisomy 18 and 493 normal controls at 10–13 completed weeks of gestation. In the normal pregnancies maternal serum PIGF levels increased exponentially with gestation. The median multiple of the median (MoM) PIGF concentration in the trisomy 21 group (1.26 MoM) was significantly higher (p<0.0001) than in the control group (1.00 MoM). In the trisomy 18 group the median PIGF was lower (0.889 MoM) but this did not quite reach significance (p=0.064). The corresponding median MoM values for PAPP-A were 1.00 MoM for the controls, 0.49 MoM for trisomy 21 and 0.16 MoM for trisomy 18. The median MoM values for free β-hCG were 1.00 MoM for the controls, 2.05 MoM for trisomy 21 and 0.38 MoM for trisomy 18. In the control group there was a small but significant correlation of PIGF with free β-hCG (r=+0.1024) and PAPP-A (r=+0.2288). In the trisomy 18 group there was a significant association between PIGF and free β-hCG (r=+0.2629) but not with PAPP-A (r=+0.0038). In the trisomy 21 group there was a small but significant association with PAPP-A (r=+0.1028) but not with free β-hCG (r=+0.0339). The separation of affected and unaffected pregnancies in maternal serum PIGF is small, and therefore it is unlikely that measurement of PIGF would improve screening for these abnormalities provided by the combination of fetal nuchal translucency and maternal serum PAPP-A and free β-hCG. Copyright © 2001 John Wiley & Sons, Ltd.     

历史时期长江中游水灾与厄尔尼诺事件的遥相关

长江中游历来是长江流域水灾最严重的地区，研究历史时期这一地区水灾发生的变化波动并找出其与厄尔尼诺事件的遥相关，将有助于对长江中游水灾发生的预测。对这二个时间序列自1525年以来的数据进行了统计学分析。结果表明，水灾发生的主要周期比厄尔尼诺事件发生的周期要长：后者主要表现为2年和3~4年的振动，而前者的主要周期为2年、8年和40年，其显著性也没有后者明显（但都超过了0.03的置信度）。通过进一步分析历史时期长江中游水灾与厄尔尼诺事件的耦合振动，发现它们之间存在显著的遥相关。结果表明，长江中游水灾对厄尔尼诺现象的响应不仅存在着如许多中国学者相信的短期滞后（如：1年），而且还存在着比较长时间的滞后（最长可达8年）。研究结果同时表明，如果厄尔尼诺事件发生的相距时间愈短，这一时期长江中游水灾响应的滞后时间也愈短，反之亦然。     

科技资源开发与区域经济增长研究--以河南为例

本文以河南为例，对科技资源的存量动态变化、配置效率及其对区域经济增长的推动作用进行了定量分析。结果表明。1991．2002年。河南科技资源存在总体上呈持续上升趋势。但是。科技资源的配置效率却呈现出下降趋势。在这个期间。科技资源开发对河南区域经济增长的贡献率为42．1％，达到了全国的平均水平。为了进一步发挥科技资源开发对河南经济增长的推动作用，建议河南继续加快科技资源的积累；重点提高科技资源配置的效率；特别重视大幅度提高对R＆D的投入。     

Studies On the Effect of Hexachlorocyclohexane On the Growth and Silk Qualities of Silkworm, Bombyx Mori L

Toxicity of an organochloride insecticide, hexachlorocyclohexane (HCH) on the alterations in the growth and silk qualities of silkworm, Bombyx mori L were investigated. HCH yielded higher growth constants (K), indicating impairment of growth of silkworms and silk gland. the decrement in fibroin content is significant. HCH treatment also resulted in considerable reduction in the cocoon, pupal and shell weights, survival and emergence of pupae and number of eggs laid and deterioration in quality and quantity of silk thread.     

Confined placental mosaicism for trisomy 14 and maternal uniparental disomy in association with elevated second trimester maternal serum human chorionic gonadotrophin and third trimester fetal growth restriction

A case of confined placental mosaicism (CPM) and maternal uniparental isodisomy 14 identified after placental karyotype revealed trisomy 14 in a newborn with intrauterine growth restriction (IUGR) and minor dysmorphic features is reported. During the second trimester of the pregnancy, multiple marker screening revealed an increased risk for Down syndrome of >1 in 10. The maternal serum human chorionic gonadotrophin (MShCG) was markedly elevated at 4.19 MoM. Amniocentesis revealed a normal 46,XX karyotype. Fetal growth restriction has been associated with elevated MShCG and placental aneuploidy with CPM for chromosomes 2, 7, 9 and 16. The present case of CPM for chromosome 14 was also associated with fetal growth restriction and elevated second trimester MShCG, suggesting a common link. Further studies need to be done to determine if indeed elevation of second trimester MShCG is associated with increased risk of CPM. The present case again demonstrates the need to perform placental karyotype in unexplained fetal growth restriction. Copyright © 2001 John Wiley & Sons, Ltd.     

Sustaining Economic Welfare: Estimating Changes in Total and Per Capita Wealth

Genuine saving measures the real change in0 total wealth, factoring in the depreciation of produced assets, depletion of natural resources, pollution damages, and expenditures on education. This paper presents a theoretical framework for measuring changes in wealth in total and per capita terms, establishes the link between savings measures and prospects for social welfare, and provides summary empirical estimates of the savings measures. China excepted, the majority of countries below median income are distinguished by apparent declines in total wealth per capita.