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1.
本文以云南保山地区中上志留统栗柴坝组海相碳酸盐岩作为研究载体,运用锶同位素比值方法,结合岩石学、古生物学等,对该区志留系中晚期的海平面变化情况及其影响因素进行了研究。其中锶同位素比值数据为该区首次获得,其所反映的海平面变化趋势与同时期美国中西部的海平面演化曲线具有良好的耦合性。研究结果表明;剖面第一段至第二段,~(87)Sr/~(86)Sr值逐渐减小,表明此时海平面相对逐渐升高;第二段~(87)Sr/~(86)Sr值整体处于相对低的水平,总体呈现出逐渐减小趋势,且在21号样品处达到最低值(0.710 5),说明此阶段海侵作用明显;第三段,在较短的地质时期内,~(87)Sr/~(86)Sr值表现出相对强烈的正偏移,达到极值0.728 49,说明海平面相对下降明显。总之,志留系中晚期海平面表现为先升后降的过程。锶同位素的强烈偏移以及岩石内较高的~(87)Sr/~(86)Sr值,正是同时期造山运动和海平面下降事件的反映。  相似文献   

2.
Integral quantities, wind run, S, and recirculation factor, R, useful for describing air flow, are calculated and combined with CO2 mixing ratios. Meteorological observations were obtained from a RASS sodar and CO2 mixing ratios from a continuous analyzer installed at a rural site in the upper Spanish plateau. The measuring campaign spread over 3 years and two approaches were followed. The first approach considered integral quantities on a daily basis and two classifications of air flow, to date scarcely used. The first classification distinguished among stagnation, recirculation, and ventilation, the second considering synoptic, meso-, and local scales. Moreover, 52.94% of daily values handled in this paper corresponded to ventilation and 49.70% to synoptic scale. The main goal of this approach is the subsequent link between the two classifications: the synoptic scale was associated with ventilation, mesoscale with recirculation and local scale partially with recirculation. CO2 observations were distributed in air flow groups following these classifications and mesoscale processes were satisfactorily described since noticeable evidence of transport from nearby cities was observed. In the second approach, S and R pairs were used and CO2 mixing ratios were distributed following percent intervals of ventilation, calculated by binning these pairs. The main goal of the second approach is to consider only three groups of mixing ratios. In the first group, with high ventilation, mixing ratios were low. With intermediate ventilation, mixing ratios were medium, and with low ventilation mixing ratios were high. A contrast of 21 ppm between the third and first groups was obtained at the 95th percentile. Finally, the second group provided a contrast of 3 ppm between north and south directions and also between east and west attributed to transport from nearby cities.  相似文献   

3.
生态承载力是生态学研究的难点之一,是较资源承载力、环境承载力等更为复杂和综合的概念.论文在分析当前生态承载力研究进展的基础上提出以"生态系统—生态系统服务—人口和经济(承载力)"为研究主线的基于生态系统服务的生态承载力(Ecosystem-Servicesbased Ecological Carrying Capacity,ESECC)的定义,即某个区域生态系统的结构、过程及其空间格局决定的生态系统服务所能支撑的具有一定发展水平的人口和经济规模,并构建ESECC评估模型:将所有与人类密切相关的生态系统服务纳入评估模型,把生态系统和人类活动看作"黑箱",针对每种生态系统服务分别评估其承载力,并根据"短板效应"取最小值作为区域生态承载力.最后以全球重要农业文化遗产"云南红河哈尼稻作梯田系统"核心保护区之一云南省红河县为例对ESECC评估模型进行案例研究.  相似文献   

4.
This article opens briefly with the recent discussions about the effectiveness of pollution prevention. As pollution prevention and cleaner production are important elements of industrial ecology, the different definitions and approaches of industrial ecology as a term also need clarity. The major part of this article reflects the first results of the cleaner production and industrial ecology concepts, applied in an industrial ecosystem project (INES) in the Rotterdam harbour area. In this industrial area with many refineries and (petro)chemical facilities, the possibilities for companies to reuse waste streams, by-products and energy from each other was researched. The project was initiated by an industrial association. Sixty-nine members of the industrial association joined the INES project and provided confidential information about their resources, products and waste streams to the research team. Based on this information, 15 projects were designed. The selected three projects for further feasibility studies showed the potency to reduce the use of energy, water and bio sludge significantly.  相似文献   

5.
Congenital diaphragmatic hernia (CDH) is a developmental defect of as yet unknown aetiology which accounts for 8 per cent of all major congenital anomalies and is associated with up to 80 per cent mortality despite optimal postnatal treatment. The risk of recurrence of CDH for future sibs after one affected infant is about 2 per cent. A multifactorial/threshold inheritance pattern with an observed high male:female sex ratio is currently favoured for the rare occurrence of familial CDH, although other modes of inheritance have also been described. We report three cases of familial CDH, two of whom were brother and sister sibs and the third was a first cousin, born within 18 months of each other. The diagnosis was by ultrasound and there were several factors predicting a poor outcome. The mortality in this group was 100 per cent. The prenatal diagnosis, treatment options, the unusual genetic aspects, outcome, and the pathology involved are discussed.  相似文献   

6.
本文阐述了用微波消解——原子吸收分光光度法测定土壤中的铜锌镍铬锰铅镉。通过硝酸-盐酸-氢氟酸-高氯酸体系消解液对土壤样品进行消解,选择出微波消解的最佳消解条件。通过对微波消解体系和传统电热板硝酸-氢氟酸-高氯酸消解体系进行对比实验,前者不仅操作简便快捷赶酸时间短,而且准确度高、精密度好,提高了工作效率,是一种值得推广的土壤消解方法。  相似文献   

7.
The polymorphic information content (PIC) and the degree of heterozygosity of several polymorphic systems within the phenylalanine hydroxylase (PAH) gene were determined in 85 European Caucasian and 19 Chinese phenylketonuria (PKU) kindreds. The first system examined, a short tandem repeat (STR), had a PIC of 80 and 73 per cent in these Caucasian and Chinese samples, respectively. The degree of heterozygosity actually observed for this system was 81 and 64 per cent in the Caucasian and Chinese PKU families, respectively. Through the addition of a second polymorphism based on a variable number of tandem repeats (VNTR), the PIC was increased to 90 per cent in Caucasians, but only to 75 per cent in Chinese. The degree of heterozygosity observed for this combination was 94 per cent in European PKU families and 67 per cent in Chinese PKU families. The further addition of an Xmnl RFLP increased both the PIC and the level of heterozygosity in Caucasians to 95 per cent, but did not change either of these measures in Chinese. The combined use of these three polymorphisms significantly increases the informativity of prenatal diagnostic and carrier screening procedures in both Caucasian and Chinese PKU kindreds. Furthermore, since each of these polymorphisms can be studied by PCR-based methods, these new tests can be performed more quickly and easily than previous Southern-based procedures.  相似文献   

8.
Chorionic villus sampling (CVS) was performed on a 40-year-old woman at 9 1/2 menstrual weeks because of advanced maternal age. The direct preparation showed 46,XY,dup(10)(q11.2q23.2). CVS long-term culture and fetal tissue revealed a rare additional abnormality: 48,XXXY,dup(10)(q11.2q23.2). This abnormality represented the major cell line (>85 per cent in 691 cells) in an (XY)/XXY/XXXY/(XXXXY) mosaic (all cell lines presumably bearing the dup(10q); the presence of XY and XXXXY cell lines is uncertain). To our knowledge, this is the first report of trisomy 10q11-q23 and of prenatally detected 48,XXXY in chorionic villi. The mosaic could have resulted from early post-zygotic non-disjunctions in a 46,XY,dup(10q) or 47,XXY,dup(10q) zygote. The results from DNA studies of four polymorphisms, mapped to Xp and Xq, support this theory. The literature on prenatally detected cases with sex chromosome tetrasomy and pentasomy and those with additional autosomal abnormalities is reviewed. The reported case underlines the problem of false-negative findings when only direct CVS preparations are karyotyped.  相似文献   

9.
This editorial introduces and provides an overview of this Special Issue dedicated to papers from the 7th conference Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction – PRES 2004. It contains 10 selected papers. The first three papers address important features of cleaner production – renewable resources, CO2 emissions and Life Cycle Assessment. The second group of papers addresses cleaner production approaches to batch processed. The third set of papers studies reduction of emissions from industrial production including SOx and NOx. The last paper focuses upon minimisation of wastewater from industrial production.  相似文献   

10.
The first prenatally diagnosed case of 49,XXXYY is reported. The pathological findings of the fetus included bilateral clinodactyly, decreased carrying angles (OO), and hypertelorism, slightly low set ears and mildly prominent forehead. A minimum of two independent non- disjunctional events are postulated for this polysomy to arise.  相似文献   

11.
A new deep core drilling operation started in 1990 central Greenland and in 1992 reached the bottom at a depth of 3028 m.b. surface. Taking advantage of recent developments in the analytical technique of chemical trace species, continuous high resolution measurements of H2O2, HCHO, NH4+ and Ca2+ concentrations were performed directly on the ice core in the field. During the 1991 season all four components were measured simultaneously between 1300 m.b. surface and 2300 m.b. surface, corresponding to the time interval between 8000 and 38,000 years B.P. In this paper an overview of the results and our first interpretations in terms of climatic changes are given.  相似文献   

12.
分离到1株能降解噻嗪酮的细菌BF3,通过生理生化试验和16S rRNA基因同源性序列分析,初步鉴定其属于副球菌属(Paracoccus sp.).该菌在接种量为2%的条件下,7d内对50mg/L噻嗪酮的降解率为68.2%.其最适降解pH值为7.0,降解最适温度为30℃.BF3对低浓度(1,10,30,50mg/L)的噻嗪酮有较好的降解效果,但对高浓度(100,200mg/L)的噻嗪酮降解效果一般,降解速率与起始接种量呈正相关.需氧量试验表明,BF3在通气良好的状况下降解速率较高.  相似文献   

13.
Cytogenetic study of chorionic villi sampled because of advanced maternal age revealed, after overnight culture, an apparently non-mosaic trisomy 7. Amniocentesis showed exclusively normal mitoses, and the pregnancy continued normally. One hundred mitoses from cord blood of the normal newborn revealed a non-mosaic 46,XX complement. No cells with a proven trisomy 7 were found in cultures from either of two biopsies of the morphologically normal placenta, but the peripheral biopsy showed in multiple cultures an abnormal clone: 47,XX, + 20,-2,-21, + t(2;21)(p13;q22). To our knowledge, this is the first case of non-mosaic trisomy 7 detected on CVS which has had follow-up studies of amniotic fluid, cord blood, and term placenta.  相似文献   

14.
The complexities inherent in land use, land-use change and forestry (LULUCF) activities have led to contentious and prolonged debates about the merits of their inclusion in the 2008–2012 first commitment period of the Kyoto Protocol. Yet the inclusion of these activities played a key role in agreement on the general framework of the Kyoto Protocol, and LULUCF will likely continue to play a substantial part in negotiations on national commitments post-2012. The Marrakech Accords dictate which LULUCF activities are to be included under the Kyoto Protocol and provide rules on how they are to be accounted in the first commitment period. However, these rules have limitations and drawbacks that may be avoided in the structure of future commitments beyond 2012. Through adherence to the objectives of the United Nations Framework Convention on Climate Change (UNFCCC), and the incorporation of several critical features, a future framework can more effectively address the mitigation challenges and opportunities of this sector.  相似文献   

15.

Objective

Omphalocele is known to be associated with genetic anomalies like trisomy 13, 18 and Beckwith–Wiedemann syndrome, but not with Turner syndrome (TS). Our aim was to assess the incidence of omphalocele in fetuses with TS, the phenotype of this association with other anomalies, their karyotype, and the fetal outcomes.

Method

Retrospective multicenter study of fetuses with confirmed diagnosis of TS. Data were extracted from a detailed questionnaire sent to specialists in prenatal ultrasound.

Results

680 fetuses with TS were included in this analysis. Incidence of small omphalocele in fetuses diagnosed ≥12 weeks was 3.1%. Including fetuses diagnosed before 12 weeks, it was 5.1%. 97.1% (34/35) of the affected fetuses had one or more associated anomalies including increased nuchal translucency (≥3 mm) and/or cystic hygroma (94.3%), hydrops/skin edema (71.1%), and cardiac anomalies (40%). The karyotype was 45,X in all fetuses. Fetal outcomes were poor with only 1 fetus born alive.

Conclusion

TS with 45,X karyotype but not with X chromosome variants is associated with small omphalocele. Most of these fetuses have associated anomalies and a poor prognosis. Our data suggest an association of TS with omphalocele, which is evident from the first trimester.  相似文献   

16.
立式宽极距多电场组合管同心圆静电收尘器在辽阳小屯水泥厂煤烘干机上首次应用 ,取得了非常理想的效果。在此对该组合管同心圆静电收尘器的原理、设计新特点等方面作出了理论论述  相似文献   

17.
山东沂南金矿床流体包裹体特征及地质意义   总被引:3,自引:0,他引:3  
本文从流体包裹体出发,讨论了沂南金矿床的成矿物质来源和成矿机制。各成矿阶段的矽卡岩矿物、石英和方解石中流体包裹体岩相学和显微测温研究结果表明,包裹体主要类型有气液水包裹体、含子矿物多相包裹体、CO2-H2O包裹体和晶质熔体包裹体,其中熔体包裹体在较早期的石榴石、绿帘石和石英中发育。Ⅰ、Ⅱ成矿阶段的成矿流体具有高温和高盐度的特征,均一温度分别为430~520℃、340~430℃,盐度分别为56.7 wt%NaCl2、2.2~53.5 wt%NaCl,代表铁矿化时的流体特征;Ⅲ成矿阶段流体具有中低温(190~250℃)、盐度范围变化较大(6.45~53.5 wt%NaCl)的特征,代表了Cu,Au矿化时的流体活动情况;Ⅳ成矿阶段包裹体均一温度100~190℃,盐度为2.07~15.76 wt%NaCl。根据不同类型包裹体共生组合及流体演化特征,认为流体的不混溶性是导致大量金属沉淀的主要原因,岩浆热液在成矿流体中占主导地位。  相似文献   

18.
Cystic hygromas have historically been associated with a grim prognosis when discovered during prenatal sonographic study of the fetus. This same grim prognosis is not observed by the paediatric surgeon who evaluates the neonate or paediatric patient. We present a fetal patient with a massive anterior cystic hygroma discovered in the third trimester prior to 30 weeks. This case and a review of the literature suggest tailoring the prognosis by category when counselling patients: (1) first trimester, normal karyotype-good; (2) first trimester, abnormal karyotype-poor; (3) second trimester and early third-poor to guarded; and (4) mid to late third trimester-good.  相似文献   

19.
A 70,XXX, +18 karyotype was found by chorionic villus sampling, while the fetal fibroblast culture of the affected fetus revealed a 47,XX,+ 18 karyotype. From several possible mechanisms, we assume that a second gamete fusion occurred after the first cell division of the zygote. According to this interpretation, the mosaicism arose in very early pregnancy (at the two-cell stage). This discrepancy can therefore be explained by selection pressure, due to the differentiation processes in the embryonic tissues.  相似文献   

20.
溶藻细菌DC21的分离、鉴定及其溶藻特性   总被引:4,自引:0,他引:4       下载免费PDF全文
从云南滇池中分离得到一株溶藻细菌DC21,经鉴定为葡萄球菌属的1种(Staphylococcussp.),可溶解铜绿微囊等9种藻.试验表明,经过滤、离心沉降及高温灭菌处理的滤液,均能强烈抑制铜绿微囊藻的生长,说明其溶藻作用的因子之一为该菌的胞外分泌物,且这种物质具有热稳定性.细菌DC21使藻的光合作用受到抑制;在试验的第1d,受试藻的超氧物歧化酶及过氧化氢酶活性显著增高,但在第7d,这两种抗氧化保护酶的活性显著下降;受试藻的丙二醛含量明显增高,说明该菌促使其发生了膜脂过氧化.  相似文献   

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