New insights from low-temperature thermochronology into the tectonic and geomorphologic evolution of the south-eastern Brazilian highlands and passive margin

The South Atlantic passive margin along the south-eastern Brazilian highlands exhibits a complex landscape,including a northern inselberg area and a southern elevated plateau,separated by the Doce River valley.This landscape is set on the Proterozoic to early Paleozoic rocks of the region that once was the hot core of the Aracuai orogen,in Ediacaran to Ordovician times.Due to the break-up of Gondwana and consequently the opening of the South Atlantic during the Early Cretaceous,those rocks of the Araquai orogen became the basement of a portion of the South Atlantic passive margin and related southeastern Brazilian highlands.Our goal is to provide a new set of constraints on the thermo-tectonic history of this portion of the south-eastern Brazilian margin and related surface processes,and to provide a hypothesis on the geodynamic context since break-up.To this end,we combine the apatite fission track(AFT)and apatite(U-Th)/He(AHe)methods as input for inverse thermal history modelling.All our AFT and AHe central ages are Late Cretaceous to early Paleogene.The AFT ages vary between 62 Ma and90 Ma,with mean track lengths between 12.2μm and 13.6μm.AHe ages are found to be equivalent to AFT ages within uncertainty,albeit with the former exhibiting a lesser degree of confidence.We relate this Late Cretaceous-Paleocene basement cooling to uplift with accelerated denudation at this time.Spatial variation of the denudation time can be linked to differential reactivation of the Precambrian structural network and differential erosion due to a complex interplay with the drainage system.We argue that posterior large-scale sedimentation in the offshore basins may be a result of flexural isostasy combined with an expansion of the drainage network.We put forward the combined compression of the Mid-Atlantic ridge and the Peruvian phase of the Andean orogeny,potentially augmented through the thermal weakening of the lower crust by the Trindade thermal anomaly,as a probable cause for the uplift.

Knowledge and Practice of Breast Self-Examination among Female Undergraduates in South-Eastern Nigeria

Breast disease often presents as palpable masses (lumps), inflammatory lesions, nipple secretion, or mammography abnormalities;and this can be easily treated when discovered early. Breast Self-Examination (BSE) is the quickest and cheapest means of early breast cancer detection. The objective of this study was to determine the knowledge and practice of breast self-examination among female undergraduates in Owerri, south eastern Nigeria. A multi-stage sampling design was used to select participants. Interview using structured questionnaire was conducted on randomly selected respondents in six faculties from each tertiary institution. Questionnaire was prepared in English and was self-administered. Permission to conduct the survey was requested and obtained from the university ethical review board. Informed verbal and written consent was obtained from participants. Confidentiality of information was maintained throughout the study. Knowledge and practice of BSE was examined among 720 randomly selected female undergraduates aged 16 to 28 years. It was found that 98.9 percent have heard of BSE but only 32.5 percent of them performed this examination accurately and monthly as required. There is a statistically significant relationship between knowledge of risk factors for breast cancer and practice of BSE (χ2 = 31.17, P χ2 = 86.75, P χ2 = 75.94, P < 0.001). These female undergraduates had a poor knowledge of the right procedure and practice of BSE;therefore there is need for awareness creation on the risks of breast cancer and benefits of early detection among female undergraduates through breast self-examination.

An Assessment of Trends of Monthly Contributions to Seasonal Rainfall in South-Eastern Zimbabwe

Trends in the proportional contribution to the seasonal rainfall of each month were analyzed for the meteorological stations of Buffalo Range, Masvingo Airport and Zaka in South-Eastern Zimbabwe. Results found indicate the existence of some trends for all the stations and months. However, when subjected to a Mann-Kendel trend analysis, all the trends were found to be statistically not significant for all instances except for the month of October at the Zaka station. This month showed a significant trend of increasing proportional rainfall.

Assessment of Seed-Borne Plant Pathogenic Fungi Associated with Rice Crop in South-Eastern Nigeria

This study was conducted to assess the incidence of seed-borne fungi on rice seeds sourced from the major rice growing areas of South-Eastern Nigeria. The rice seeds were collected during the dry seasons between 2009 and 2010. Four hundred rice seeds randomly collected and surface sterilized by washing in 3% sodium hypochlorite and rinsed two times with sterile distilled water were placed in three circular rings inside the Petri dishes. The incubation was done one after the other for each variety from all the locations. Ten fungi species from eight genera were isolated from the rice seeds in all the rice growing areas of South-Eastern Nigeria. The fungi pathogens vary from one locality to another, as well as the frequency of occurrence. The pathogens isolated include： Fusarium moniliforme, F. solani, F. oxysporium, Aspergillus spp., Botridiploidia spp., Helminthosporium spp., Penicillium spp., Trichoconis padwickii, Curvularia oryzae and Phoma oryzae. Though, there was the presence of some seed-borne fungi in the rice seeds from the areas studied, most of the cultivars experienced up to 90% germination. But some cultivars had very low germination. IR 1416 from Arochukwu and GB90 from Arondiuzogu had less than 1% germination. This study shows that seed-borne organisms are major constraint in rice production in the South-Eastern states of Nigeria as a result of low seed germination stemmed from infestation of fungi organisms in the seeds.

Cardiovascular Risk Factors in South-Eastern Nigeria: A Community Based Survey

Background: Cardiovascular risk factors play a major role in cardiovascular disease burden worldwide. The prevalence is known to be in the increase especially in the developing countries. There is need for timely community based studies in order to keep tab with the current scope. It is against this background that we embarked on this cross-sectional community based study of the prevalence of selected cardiovascular risk factors in semi-urban community in Abakaliki Southeastern part of Nigeria in October 2016. Method: The consecutive consenting persons of 18 years and above were screened for selected cardiovascular risk factors in October 2016. Results: A total of 1074 adults were seen (males-567, females-507) with age range of 18 - 80 years and mean age of 35.63 ± 12.45 years. They were predominantly farmers, petty traders and artisans. The identified CVD risk factors were hypertension 285 (26.4%), alcohol abuse 131 (12.1%), obesity 122 (11.3%), diabetes 97 (9%), family history of stroke 87 (8.1%), smoking 74 (6.9%) and previous stroke 29 (2.7%). Conclusion: The cardiovascular risk factors were quite prevalent with male preponderance of alcohol abuse and smoking.

The Prevalence of Cigarette Smoking and Knowledge of Its Health Implications among Adolescents in Owerri, South-Eastern Nigeria

Despite the growing problem of global cigarette use, accurate information on the prevalence and pattern in Nigerian adolescents’ remains sparse. The aim of this study was to determine the prevalence of cigarette smoking among in-school male adolescents in Nigerian population and to assess their level of knowledge on the health effects of cigarette smoking. A descriptive cross-sectional study was carried out among 944 randomly selected in-school male adolescents in Owerri, south-east Nigeria, between September and November 2013. Information was obtained using a self-administered questionnaire. The findings indicated a prevalence of 15.3% for ever smoked adolescents and 11.2% for current smokers. The mean age at cigarette smoking initiation was 14 years. Sixty-three percent had good knowledge of health problems associated with cigarette smoking. Lung cancer was the most reported associated health problem. Fifty-two (36.1%) indicated that they were initiated by their friends who offered them their first stick of cigarette. The major reason for smoking cigarette the first time was to be like their friends/role model and out of curiosity. Poor knowledge of health effects of smoking was statistically associated with cigarette smoking (X2 = 26.82, p-value < 0.001). Knowledge of health problems associated with smoking proved to be the major reason for not smoking by never smoked adolescents, which means that awareness creation on health problems associated with cigarette smoking through health education in schools coupled with stiff legislative ban on sale of cigarette to adolescents will, to a reasonable extent, reduce the high prevalence of adolescent cigarette smoking in our society.

Micronutrient dynamics in some wetland soils of south-eastern Nigeria

The inventory of profile distribution of total iron (Fe), zinc(Zn), manganese(Mn) and copper(Cu) were determined in three different soil horizons each of the wetland soils selected form Mbiabet(MB), Nkari(NK) and Nkana(NA) in Ini Local Government Area of Akwa Ibom State. Total Fe ranged between 3 25 and 4 15 ppm. The average contents were 3 72, 3 91 and 3 62 ppm in Mbiabet(MB), Nkari(NK) and Nkana(NA) soils respectively. The total value of Zn also ranged between 2 4 and 4 9 ppm with the average content in each soil being 28.27, 17 73 and 36 53 ppm respectively. The amount of Fe and Zn in these soil profiles were strongly correlated with the clay content and high levels of organic matter of 3 70%, 2 47% and 2 5% respectively. The content clearly reflected a poor drainage conditions.In all the soil profiles Mn and Cu were detected in at least one of the soil horizons. However, Mn and Cu were not detected in the soil horizons at Nkari.Generally, the relative inventory of these micronutrients appeared to be influenced by pH, drainage pattern, organic matter and clay contents of these soils.The inventory of total values of the wetland soils considered are assessed in the light of establishing a baseline information.

南水北调东线一期工程受水区生态环境效益演变

研究南水北调东线一期工程通水以来受水区生态环境效益的演变态势,对南水北调后续工程高质量建设、加快构建国家水网以及促进工程综合效益发挥有决策参考作用。以定性定量相结合的方式分析东线一期工程在优化水资源配置、保障饮水安全、复苏河湖生态环境和畅通南北经济循环等方面的作用,进而结合层次分析法,从直接效益和间接效益2个方面,筛选构建东线一期工程受水区生态环境效益评价指标体系,主要包括工程年供水量、水质改善度、生态补水量、地下水压采量、地下水水位、水域面积、绿地面积和涵养水源等,并采用VlseKriterijumska Optimizacija I Kompromisno Resenje(VIKOR)多准则妥协解排序方法对南水北调东线一期工程通水以来即2013-2022年受水区生态环境效益演变态势进行分析。结果表明:南水北调东线一期工程通水的10年以来,受水区的生态环境整体复苏效果明显,近3年排序值保持在0.8以上;受降水偏枯进而影响地下水开采量和地下水水位等因素影响,2019年间接生态环境效益下降29.2%,之后迅速恢复并保持稳定。在分析直接效益和间接效益演变的基础上,从工程提质增效、提高工程水质状况以及完善体制机制建设等方面提出东线一期工程进一步促进受水区生态环境持续改善的策略和建议,以期为东线工程及受水区生态环境保护及高质量发展相关研究、决策制定等提供参考。

粤东连平—河源—汕尾地震测深剖面地壳速度结构及其意义

为适应防灾减灾工作的需要,广东省地震局联合中国地震局地球物理勘探中心、河南省地球物理空间信息研究院于2021年在粤东地区实施了人工地震宽角反射/折射探测,以期获得粤东地区深部地壳速度结构.本文采用地震射线走时正演对粤东地区NW向连平—河源—海丰测线数据进行了处理解释,构建了该剖面的二维壳幔速度结构模型.该模型表明,沿剖面自NW向SE,莫霍面深度由32 km缓慢抬升至29 km,广州—恩平断裂带、河源—邵武断裂带和政和—大埔断裂带的对应位置都显示莫霍面有抬升现象;研究区存在多条NE向展布深大断裂;中地壳发育低速异常区域(低速体)受断裂控制,主要分布于政和—大埔断裂带NW内陆方向,可能与中生代早期岩浆活动形成的花岗岩质岩浆相关.我们认为壳内低速区域(低速体)可能是影响研究区深部孕震环境的重要因素.

南海东部底水油藏水平井控水完井技术研究进展

南海东部底水油藏分布广泛,水平井开发方式可大幅度降低底水锥进速度,但由于水平段距离长,储层非均质性和水平井跟趾效应造成的点状见水易导致油井含水率大幅上升,降低生产效益。针对上述问题,南海东部油田采用ICD、AICD、C-AICD等控水工具,结合控水颗粒充填、智能分段分流等控水工艺,开展了底水油藏水平井控水完井技术研究与应用,取得显著效果。围绕南海东部底水油藏水平井控水完井技术研究进展,综合分析了不同控水方式的控水原理、技术特点和不同控水完井工具的特性曲线数学模型,总结了不同生产预测技术的应用规模和不同控水完井技术的应用效果。在此基础上提出了底水油藏水平井控水完井技术挑战和发展趋势,可为南海东部底水油藏水平井控水完井的进一步发展提供参考。

地层压力预测技术在南海东部高温高压井中的应用

近几年南海东部钻探高温高压井数逐渐增多,严重影响安全钻井和资料录取。文章介绍了惠州某构造A1探井因钻遇超压地层而提前完钻及高压成因分析,重新部署A2,开展钻前地层压力精细预测分析,预测目的层压力系数在1.500~1.600之间,指导A2井成功钻井,MDT实测压力系数为1.595,实现勘探目的。

南水北调东线江苏段典型泵站运行效率模拟模型

泵站机组运行受多种因素影响,导致泵站运行理论效率与实际效率误差较大。针对泵站机组运行效率精准模拟难题,运用基于高价多项式回归、回归树、多元线性回归、向量机回归、高斯过程回归、神经网络的10个回归算法,建立泵站机组效率模拟模型并开展对比分析,优选出有效的泵站运行效率模拟建模方法。讨论分析采用“上下游水位+流量”代替传统“扬程+流量”开展泵站运行模拟的效果。以南水北调东线邳州站和遂宁二站共8台机组的历史数据开展实例分析,相关实验结果表明:在所有方法中,高斯过程回归(Gaussian process regression,GPR)模型在均方根误差(ERMS)、平均绝对误差(EMA)、均方误差(EMS)、决定系数(R2)和最大个体误差(EMI)指标上综合表现最佳,R2逼近0.95;使用站上、站下水位代替传统的扬程对模型进行训练,所有模型的综合评价指标整体有所改善。综合来看,使用GPR模型并使用上游、下游水位代替扬程进行模拟效率表现最好,以邳州站4号机为例,可将模拟效率的EMA和EMI分别从16.49%和20.40%减少至0.41%和2.30%,研究成果具有一定实际意义,可为我国调水工程泵站经济运行提供有力支撑。

5月中国土壤湿度异常对7月华南-青藏高原东部偶极子型降水年际变化的影响

利用1979—2019年ERA5再分析资料和站点降水资料,研究了5月中国土壤湿度异常对7月华南和青藏高原东部偶极子型降水年际变化的影响及其可能的物理过程。结果表明,当5月青藏高原土壤湿度偏湿,华中地区土壤湿度偏干时,对应7月华南(高原东部)降水偏多(偏少),两地降水呈偶极子型分布。通过进一步的诊断分析发现,青藏高原(华中地区)土壤湿度正(负)异常可从5月持续至7月,使得7月中国北方地区地表湍流热通量正异常,进而使得对流层中低层大气增暖,中国北方与贝加尔湖之间经向温度梯度和大气斜压性增强,天气尺度的瞬变波活动增强。通过瞬变的涡度强迫有利于中国北方及蒙古地区准正压异常高压和Rossby波波源的形成,相关的Rossby波向东南方向传播至我国南方,使得华南地区出现准正压结构的异常低压,有利于西北太平洋副热带高压东移,南亚高压西移。对应中国北方及蒙古-华南地区对流层中低层为反气旋-气旋式环流异常,进而导致华南地区(高原东部)降水增多(减少)。此外,中国北方-蒙古地区的异常高压与局地偏干的土壤湿度之间的正反馈过程,有利于上述物理过程的维持和增强,进而有利于7月偶极子降水的异常,反之亦然。

南海东部E油田钙质夹层特征及影响

钙质夹层研究对储层精细研究具有重要意义。通过动静态资料分析,对南海东部E油田钙质夹层岩性、测井、分布特征及其对油田动态的影响开展了研究。结果表明,E油田分为三类钙质夹层:生物碎屑灰岩、含生屑砂岩、钙质砂岩,夹层厚度在0.2~1.5m之间,小于0.5m厚钙质夹层测井特征不明显;单砂体间钙质夹层平面展布在100m以上,且发育较连续;单砂体内部厚度小于0.5m钙质夹层平面展布范围小于100m;利用垂向0.2m网格建立地质模型,模型更符合动态特征。

南水北调东线工程江苏段泵站安全监测现状及专业化管理探讨

泵站是南水北调东线工程的主要组成部分,在运行期对泵站进行监测是保障东线工程安全运行的重要手段。为提高东线工程泵站群的安全监测专业化管理水平,通过实地考察、现场调研等手段,对东线工程江苏段宝应站、邳州站、金湖站、泗洪站、解台站等14座泵站的安全监测设施状况进行系统性的排查,并分析东线工程江苏段泵站的历年年度监测资料整编情况,结果表明:当前东线工程江苏段泵站主要存在自动化监测水平低、扬压力设施损坏严重、监测资料整编分析不规范等问题,难以全面准确地掌握泵站真实的运行状况。针对当前存在的问题,建议管理单位加强安全监测作业标准化建设并提高设施养护水平,开展安全监测系统鉴定和自动化升级改造,建立泵站工程安全监测监督平台和泵站群安全管理数字孪生体系,以实时掌握各泵站工作状态,保障泵站群安全运行。

甘肃东西区夏季不同强度降水事件天气成因分析

基于1961—2018年甘肃省逐日降水格点资料和NECP/NCAR再分析资料,依据逐年降水变化“东西反向”型分布模态,将甘肃以104°E为界分为东西两区开展不同强度的降水事件变化研究及成因分析。结果表明:中降水事件在两区夏季降水的占比均超46%,占主导作用;西区强、中降水事件发生频次呈上升趋势,东区各强度降水事件频次均呈下降趋势。天气成因分析表明,甘肃东西区降水偏强时,南亚高压异常增强,提供了较好的高空辐散条件,西太平洋副热带高压偏强、偏北或偏西,中纬度地区“+-+”的位势高度异常促使冷暖空气增强并交汇于甘肃地区,西风带波动小槽的发展,配合近地层高原东侧低涡将低纬度水汽接力向西北输送,导致降水发生;相较于东区,西区降水夏季风系统异常更强,西风带波动显著,位势高度负异常位置偏北。

南运河冬季输水冰情及对策研究

南运河的冬季输水工作开展较少,冰期输水经验不足。2022—2023年度,南水北调东线北延输水为线路启用以来首次冬季输水。输水期间,在南运河段设立安陵、北陈屯2个观测站点,对冰期输水各个阶段的冰情特点进行观测,从而了解并掌握冰情的变化规律,并提出冰期输水对策,为今后的冰期输水工作提供参考。

考虑供水均衡性的南水北调东线工程江苏段优化调度

针对南水北调东线工程江苏段向省内受水区输水时遭遇的供水时空不均衡问题,同时为了增加工程运行的综合效益,提高工程的供水均衡性,建立了以受水区综合缺水率最小、泵站总抽水量最小、缺水率时间标准差最小、缺水率空间标准差最小为目标的多目标优化调度模型,并采用NSGA-Ⅲ算法求解优化调度模型,运用基于层次分析法与TOPSIS法的组合赋权法进行方案优选。结果表明:相较于常规调度方案,优化调度方案的南水北调东线工程江苏段受水区的供水率得到明显改善,在95%、75%和50%来水频率下,综合缺水率分别下降了9.2%、8.2%和10.5%;泵站总抽水量在95%、75%来水频率下增加了21.6%、15.4%,在50%来水频率下下降了39.4%;受水区供水时空均衡性明显提高,在95%、75%和50%来水频率下缺水率时间标准差、缺水率空间标准差均显著降低,不同受水区不同时段缺水率分布范围更均匀集中。

南水北调东线工程江苏段水资源调配研究

针对南水北调东线工程江苏段受水区的水资源调度与配置问题,以受水区总缺水量最小和泵站总能耗最小为目标,建立南水北调东线工程江苏段水资源优化调度模型。将南水北调工程调水与本地水资源进行联合配置,并以经济效益、社会效益、环境效益最大为目标,构建南水北调东线工程江苏段水资源配置模型。采用基本方案和节水方案进行了模型模拟,结果表明,在降水保证率分别为50%、75%和95%3种情况下,受水区节水方案缺水率比基本方案分别下降了2.91%、3.61%和3.83%;受水区节水方案下各工程基本完成了受水区的供水任务,且优先利用了泵站单位能耗较小的运西线进行调水,说明优化调度配置方式在保障受水区用水的基础上,能够以更为经济节能的方式运行。

南水北调东线梁济运河段输水流量损失的经验估算方法

传统Kostiakov经验公式计算结果为一定值,在未衬砌的沿程地质变化较大的河段应用时不能充分体现输水损失沿程变化的动态特点。为克服原公式局限性,采用积分学方法及广义简约梯度法对Kostiakov经验公式进行改进,形成改进Kostiakov经验公式法,并以南水北调东线梁济运河段为例,利用2013—2019年实测数据,对改进Kostiakov经验公式中的参数进行率定。考虑梁济运河段运行期间易受春灌影响,分别利用受春灌影响显著的2019—2020年和影响一般的2020—2021年实测数据对改进Kostiakov经验公式进行验证。结果表明:改进Kostiakov经验公式法可克服原公式应用时的局限性,有效提升输水损失计算精度,扩大原公式的应用范围;改进后计算结果与两个时段实测数据的平均相对误差分别由原来的27.26%和11.72%降低为7.9%和6.84%,对调水工程运行调度具有重要意义。