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1.
建立了台阶轴“0—1”编码法,解决了N级台阶轴数学描述和其总数计算问题。应用基于基来台阶单元的优化模型和算法,有效地解决了N级台阶轴锻件形状优化问题。  相似文献   

2.
生产玉米淀粉过程中排放大量高浓度有机废水、将其进行综合利用,可以提取蛋白粉、玉米浆等多种物质,这里以年产1万t玉米淀粉为例,具体分析了玉米淀粉生产废水综合利用的经济效益与环境效益.表明:玉米淀粉生产废水综合利用前景广阔,是解决该部分废水污染,实现经济效益与环境效益相统一的重要途径.  相似文献   

3.
本文以高斯模式为核心,在现场试验的基础上,通过分析当地污染气象特征,合理选用参数,建立了适用于重庆市大渡口地区的空气质量模式。经过与实测值的比较分析,认为该模式是可行的。应用该模式预测了重庆钢铁公司“七五”改扩建工程对大气环境质量的影响。  相似文献   

4.
Both the principles of first-trimester genetic diagnosis in multiple pregnancy and the special considerations required to avoid potential diagnostic pitfalls are presented. The experience consisted of 65 cases of twins and one case of quadruplets. Dichorionic twins were recognized by sonography in 54 cases. Transabdominal aspiration was generally preferred to trans-cervical for obtaining chorionic tissue, although in two cases both approaches were used. Diagnostic error following erroneous sampling was reported in 3 out of 54 sets of dichorionic twins (5.5 per cent). When like-sex dichorionic twins cannot be differentiated by cytogenetic or DNA polymorphism studies, amniocentesis should be recommended to confirm the reliability of the result on chorionic tissue.  相似文献   

5.
城市环境质量多层次模糊综合评价法   总被引:7,自引:0,他引:7  
通过对城市环境质量的指标的综合分析,确定了多层次模糊综合评价方法。该方法通过模糊合成运算将复杂多层次评价问题转化为定量评价,从而更合理有效地分析城市的环境质量状况。  相似文献   

6.
论述了沧炼曝气池由原来的并联运行改造为串联运行的原理,特点,并经过运行证明,改造后的曝气池运行方式更加灵活,且其耐冲击能力,处理效果等有较大幅度的提高。  相似文献   

7.
Multiple sulphatase deficiency was diagnosed in the first trimester of pregnancy by demonstrating markedly reduced activities of arylsulphatases and heparin sulphamidase by direct assays on chorionic villi (CV). The diagnosis was confirmed by assays on cell cultures of villi and fetal skin fibroblasts. Two further pregnancies of this mother were monitored similarly and predicted to be unaffected; one produced a normal healthy infant, the other miscarried shortly after CV sampling.  相似文献   

8.
9.
Due to their high phenotypic plasticity, the expression of secondary sexual characteristics is particularly sensitive to stress. Here, we investigated the expression of two conspicuous visual signals in great tits (Parus major) in a metal pollution gradient. In three study sites with marked differences in metal contamination (mainly lead, cadmium, copper and zinc), we compared melanin and carotenoid colouration of great tits. While carotenoid colouration (yellow breast) was negatively related to metal pollution, the size of a melanin trait (breast stripe) was larger in the most polluted sites. Environmental pollutants not only affect the expression of conspicuous signals but may even enhance, directly or indirectly, a signal of male quality such as breast stripe. Our results also support the multiple messages hypothesis predicting that different signals highlight different aspects of geno- and phenotypic condition of the bearer.  相似文献   

10.
Three hundred and thirty-nine cases of multiple gestation underwent prenatal diagnosis by amniocentesis. The spontaneous abortion rate (to 28 weeks) in this group was 3.57 per cent compared with our singleton abortion rate of 0.60 per cent. The perinatal mortality rate (PMR) and prematurity rate were not different from the singletons, and compared favourably with the PMR reported in the literature for multiple gestations which did not undergo any intervention during pregnancy. This increased abortion rate following amniocentesis may only represent the increased natural loss rate in multiple gestations, and not indicate any increased risk added by the procedure.  相似文献   

11.
Direct preparations and long-term cultures from a chorion villus biopsy, taken because of a known maternal additional marker chromosome, showed a 48,XX,+mar,+mar karyotype in all cells examined. The same karyotype was revealed in a subsequent amniotic fluid sample and in cord blood at delivery. Detailed examination of the child at delivery and at 1 year of age showed no evidence of phenotypic abnormality or developmental problems.  相似文献   

12.
A case of multiple intestinal atresia is described. Dilatation of the bowel was observed at 17 weeks' gestation during routine ultrasound scan of a healthy Caucasian primigravida from a non-consanguineous marriage. Amniocentesis was performed. The karyotype was normal male and cystic fibrosis screening was negative. Regular scans were performed throughout the pregnancy and a simple bowel obstruction was suspected. The baby was delivered at 37 weeks' gestation in good condition. Initial clinical examination was normal but abdominal distension developed during the first day. At laparotomy, prepyloric septal atresia, a distal duodenal membrane, and multiple intestinal atresia were found. The baby died aged 4 days. Post-mortem examination of the abdomen confirmed the absence of lumen from long segments of the small intestine together with areas of colonic atresia. Histology and distribution were consistent with those reported in familial multiple intestinal atresia. The pitfalls in the interpretation of prenatal ultrasound scans and the possibility of prenatal diagnosis in future pregnancies are discussed.  相似文献   

13.
采用多管发酵法、酶底物法两种方法同时检测水中粪大肠菌群,结果表明:与传统的多管发酵法相比,两者无显著性差异,但是酶底物法具有具有操作简便,检测时间较短,特异性高,准确度高等优点,是目前比较先进的方法。  相似文献   

14.
港湾快速城市化地区河流水质主控因子识别及调控方案   总被引:1,自引:1,他引:0  
识别快速城市化地区的河流污染的主控因子,对于科学实施河流污染防治调控及实现区域经济又好又快发展具有积极意义。运用流量校准浓度分析法、多元逐步回归分析相结合的方法识别连云港港湾快速城市化地区影响水质变化的主控因子,可准确把握该类区域河流污染趋势及主导原因,进而提出相应的优选调控方案。  相似文献   

15.
Intrauterine fetal demise (IUFD) in one of twins at 12 weeks of gestation was accompanied by markedly elevated maternal serum alpha-fetoprotein (AFP) at 17 and 18 weeks. Amniotic fluid AFP from the healthy surviving twin's sac at 18·5 and 23 weeks was also greatly increased along with a positive acetylcholinesterase (AChE) band. Persistently elevated AFP and positive AChE so long after fetal demise–-6·5 and 11 weeks post IUFD–-has not, to our knowledge, been previously described. In similar cases, high level ultrasound and careful placental examination at birth should be utilized to search for fetal abnormalities or multiple pregnancy with IUFD.  相似文献   

16.
将模糊数学应用于上海指数法 ,在评价函数中引入半梯形隶属函数和倍斜率隶属函数 ,提出模糊上海指数法 ;将此法应用于延安市的大气质量评价工作 ,与欧几里德贴近度法和上海指数法的评价结果进行比较表明 ,模糊上海指数法的评价结果是科学合理的。  相似文献   

17.
Thirty-one genetic amniocenteses involving multiple gestations were performed in the genetics unit between 1976 and 1982. Three sets of triplets were included. Precise locations of the sacs were determined using real-time ultrasonography and successful sampling of all sacs was accomplished. Spontaneous abortions occurred in two normal twins and one normal triplet gestation. Two therapeutic abortions were performed for fetal abnormalities. Two cases of discordance for trisomy 21 (one twin and one triplet) were allowed to continue; the twin case terminated at 25 weeks' gestation with neonatal deaths and the triplets are alive and well.  相似文献   

18.
空间规划体系下,环境规划在空间落地性以及精细化程度上存在短板。建议环境规划进一步完善生态保护红线制度,探索环境质量底线、环保负面清单的划定技术思路与技术路线,推动环境保护系统化参与空间规划。  相似文献   

19.
20.
The designation of marine protected areas (MPAs) may have intense social and economic effects on human communities. Driven by overarching global and European policies and national legislations, current systematic conservation planning in the UK and France requires an ecosystem approach that takes into account not only nature but also the human activities that take place in an area. Here, we identified a set of 64 socioeconomic variables potentially relevant for marine and coastal stakeholders in a European context and a comprehensive set of 20 marine and coastal stakeholder categories. Ninety national organisations in the UK and France belonging to those categories and potentially affected by/interested in the designation of multiple-use MPAs were identified and surveyed. Results show that environmental NGOs, research centres, local councils, managing agencies and statutory nature conservation bodies perceived that they are positively affected by these MPAs, whereas fishers’ organisations, shipping and aggregate industrial organisations and recreational organisations perceived to be chiefly negatively affected by MPAs. On average, the ecological effects of multiple-use MPAs are perceived as ‘largely positive’, though 30% of respondents did not perceive any positive ecological effects from these MPAs. The social, economic and cultural effects of such MPAs are perceived as ‘moderately positive’. Most respondents perceived broad range (>10 km) and permanent ecological, social, economic and cultural effects from multiple-use MPA designation suggesting high societal expectations towards these areas. However, only five variables were perceived to vary in intensity after the designation of multiple-use MPAs: ‘research’, ‘environmental performance by citizens, businesses and towns’, ‘number of green businesses’, ‘tourism’ and ‘economic activities’. The most important ‘social’ variables for stakeholder organisations referred to local populations’ engagement with the MPA, tourism and research. The most important ‘economic’ variables were linked to fishing, shipping and aquaculture activities. These variables highlight relevant topics to be considered in MPA planning, designation and management processes, especially in the UK and France. There were statistically significant differences in the ratings of socioeconomic variables between many organisations belonging to the same intuitive stakeholder categories, suggesting the importance of including as wide a range of stakeholder organisations as feasible in MPA socioeconomic-related processes. Our methods and findings can help to inform and streamline ongoing and future participatory MPA planning, management and monitoring processes in Europe and in other regions with similar socioeconomic characteristics.  相似文献   

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