黄土高原降水的季节性指标及其与作物水分亏缺的关系

黄土高原位于我国东部季风区与西部非季风区之过渡地区,属弱季风区,降水相对较集中。为分析本区降水的时空分布,文中采用矢量合成方法计算了黄土高原296个站的降水季节性指标值及降水季节,前者变化于0.44—0.64 之间,后者集中于7月中、下旬至8月上旬,自东南向西北推迟。降水的季节性指标与降水季节直接影响到作物水分的亏缺量,全区小麦严重缺水100—200mm 不等,玉米缺水30—50mm,而谷子生育期中水分需求基本可以得到满足。最后,讨论了本区降水与土壤水分含量的关系,指出本区水分不足,认为有的作者提出的该区尚有80％的水分潜力没有得到发挥的见解是错误的。     

Prenatal diagnosis of glutaryl-CoA dehydrogenase deficiency: Experience using first-trimester chorionic villus sampling

We have performed prenatal diagnosis for glutaryl-CoA dehydrogenase (GDH) deficiency in 16 pregnancies at risk by measuring the enzyme activity in chorionic villus samples. In most cases, GDH activity was measured both in uncultured chorionic villus samples and in cultured chorionic cells. In 4 of the 16 cases, an affected fetus was predicted, while the remaining cases were found to be normal. In three of the four affected cases, GDH activity was measured in both uncultured and cultured chorionic cells and the correct diagnosis established by both measurements. In the fourth case, only cultured cells were investigated because the chorionic villus sample was too small for the direct assay. All four pregnancies predicted to be affected were interrupted and the diagnoses confirmed on the aborted material in three of the cases. In the fourth case, no material was available for investigation. Of the 12 pregnancies predicted to be unaffected, ten cases resulted in the birth of healthy unaffected babies while two pregnancies are still in progress.     

论高职院校的市场定位

现代职业教育迅速发展,要想职业教育在这种形式下良好发展,就需要把他自身的特色发挥出来,作好高职教育特色化,首当其冲的就是做好高职院校的市场定位.     

缺磷及高光照条件下紊动对铜绿微囊藻生长的影响

通过试制隔栅搅拌模拟紊动装置,设置格栅转动频率为0,500,1000,1500Hz（对应紊流能量耗散率范围0～8.93×10^-3m²/s³）,研究高光照与缺P的不利环境条件下紊动对铜绿微囊藻生长的影响.结果发现,在高光照（8000lx）下,微囊藻生长明显受到抑制,静止条件下藻浓度仅为正常光照的47.7%,但紊动可一定程度上减缓高光环境的影响,其中高光照下1000Hz组藻浓度最高,相对静止提高了1.8倍.高光照试验组的叶绿素a含量是正常光照条件1.52~1.78倍,因此高光照并未促进藻细胞的生长分裂,而叶绿素a的大量累积可能是铜绿微囊藻应对高光照不利条件作出的抵御反应.在缺P条件下,藻生物量仅为正常营养条件1/6~1/4,但随紊动强度增加,藻生物量略有增加,而叶绿素较初始浓度增加明显,其中1000Hz组生长情况最好.水体紊动可缓解高光照、缺P等恶劣环境条件对铜绿微囊藻生长的抑制,叶绿素a的累积可能是藻细胞对不利环境条件的响应.     

果树缺铁失绿症矫治方法简述

本文简单评述了果树缺铁失绿症的多种矫治方法及其效果,以供各地在矫治果树失绿症时参考。     

Medical geology in tropical countries with special reference to Sri Lanka

Sri Lanka provides an ideal opportunity for the study of the effect of geology on human health. The vast majority of the people of Sri Lanka still live in rural areas within areas termed geochemical provinces. Very broadly, one could say that a geochemical province has characteristic chemical composition in soil, water stream sediments and rocks, enabling their delineation from others. The chemical composition is presumed to be have an impact on the health of the inhabitants of the particular geochemical province, particularly because of the fact that their food and water are obtained mostly from the terrain itself. This leads to the concept of “diseases of geochemical origin”. Among these are dental fluorosis, iodine deficiency disorders (IDDs) and selenium-based diseases. The Dry Zone of Sri Lanka has several areas rich in groundwater fluoride, the ingestion of which leads to dental fluorosis. Iodine deficiency diseases are more common in the Wet Zone, though their aetiologies are more complicated. Interestingly, it has also been observed that significant proportions of the female population of Sri Lanka are selenium-deficient, which could well be related to the geological environment. Chronic renal failure (CRF) has been observed in some areas of the Dry Zone of Sri Lanka, where there is a relationship of CRF with the mineral content of drinking water. This subject matter falls under the auspices of Medical Geology, a scientific discipline still in its infancy, and much more concerted studies are needed to attract the attention of medical research.     

贵州地氟病与碘缺乏病区环境中氟和碘的研究

为查清贵州地氟病与碘缺乏病病源,对这两种地方病区地质环境及食物中氟与碘的含量进行研究.结果表明:高氟燃煤、磷块岩及富氟岩石是产生地氟病的氟源,其致病途径主要是高氟燃煤对室内空气与食物造成氟污染,其次是富氟岩、矿经风化形成富氟土壤,使其上种植的食物含氟高,从而产生氟中毒.碘缺乏病的病源是病区岩石中贫碘,导致土壤、水体及食物中碘低而致病.并探讨了这两种地方病在贵州呈互补性分布,是由氟与碘的地球化学性质相似性及贵州省岩石地层分布的地域性所引起的.      

贵州碘缺乏病区环境中碘的特征研究

为探讨贵州碘缺乏病与环境的关系,以及环境中岩石、土壤和水对碘缺乏病分布的影响因素,对贵州碘缺乏病的重病区、轻病区和非病区进行了一定量的岩石、土壤、水及粮食作物(大米和玉米)样品采集,测试碘背景含量,并进行对比分析。结果显示,环境中岩、土及水碘背景与贵州碘缺乏病分布有一定的关系。重病区主要属岩石、土壤和水碘背景含量低的分布区,其岩石类型主要为碳酸盐岩;非病区主要属岩石、土壤和水碘背景含量相对较高的分布区,其岩石类型主要为煤系;轻病区分布的岩石、土壤和水碘背景含量则介于重病区和非病区之间,其岩石类型主要为浅变质岩和碎屑岩。      

The fate of exogenous iodine in pot soil cultivated with vegetables

A pot experiment was conducted to explore a more effective approach to enhancing vegetable uptake of soil iodine, with the ultimate goal of using agricultural fortification as a measure to prevent iodine deficiency disorders in local communities. Two types of iodine fertilizers were added separately to pot soil samples at various dosages. The fortified soil in each of the flower pots was seeded with one of four test crops (pakchoi, celery, pepper, and radish) in an effort to examine the effect of vegetable cultivation. The fate and residual levels of the exogenous iodine in the fortified soil samples were then monitored and quantified. The data showed that the soil iodine contents decreased with time (and hence with plant growth as well). At the second cutting, iodine from the inorganic form (KI) as the exogenous source was reduced to approximately 50% (41.6–61.0%) of the applied dose, whereas that in soil fortified with the seaweed fertilizer was down to approximately 60% (53.9–71.5%). The abilities of the edible portion of the four vegetables in accumulating the soil iodine were as follows: pakchoi > celery > radish > pepper. On the whole, iodine residues were found less in soil cultivated with vegetables. Vegetable cultivation appeared to have enhanced the soil content of the water-soluble form of iodine somewhat, especially in soil fortified with the inorganic forms. There also appeared to be a significant negative correlation between the residual iodine and its dissolution rate in soil. Overall, the results of the present study pointed toward the direction that the seaweed fertilizer tends to be a (more) preferred source of agricultural fortification in promoting human iodine nutrition.     

Highlights of some environmental problems of geomedical significance in Nigeria

This paper attempts to discuss the links between the geochemical composition of rocks and minerals and the geographical distribution of diseases in human beings in Nigeria. We know that the natural composition of elements in our environment (in the bedrock, soils, water, and vegetation) may be the major cause of enrichment or depletion in these elements and may become a direct risk to human health. Similarly, anthropogenic activities such as mining and mineral processes, industrial waste disposal, agriculture, etc., could distort the natural geochemical equilibrium of the environment. Thus, the enrichment or depletion of geochemical elements in the environment are controlled either by natural and/or anthropogenic processes. The increased ingestion of toxic trace elements such as As, Cd, Hg, Pb, and F, whether directly or indirectly, adversely affects human health. Of these, Cd has most dangerous long-term effect on human health. Environmental exposure to As and Hg is a causal factor in human carcinogenesis and numerous cancer health disorders. Available information on iodine deficiency disorder (IDD) in Nigeria indicates goiter prevalence rates of between 15% and 59% in several affected areas. There have been reported cases of dental fluorosis resulting from intake of water with fluoride content >1.5 ppm. Dental caries among children shows an overall prevalence rate of 39.9%. Within the Younger Granite province in central Nigeria, cases of cancer and miscarriages in pregnant women have been linked to natural radiation These examples and a number of others from the existing literature underscore the pressing need for the development of collaborative research to increase our understanding of the relationship between the geographical distribution of human and animal diseases in Nigeria and environmental factors. We submit that such knowledge is essential for the control and management of these diseases.