湿地生态系统设计的一些基本问题探讨

湿地生态系统设计是恢复、调整湿地的重要手段,本文3从湿地生态系统设计概念入手,阐述了设计的基本原则。较详细地讨论了设计中的指标（水文指标、化学指标、基质指标和生物指标）要求,根据湿地生态系统设计的用途不同,探讨了3种主要的湿地生态系统设计类型,即作为废水处理湿地的设计,作为调整湿地的系统设计和作为洪水及非点源污染控制的湿地设计。     

Tranquilizing agents; some problems in evaluating them

Four new derivatives of hydrocortisone, each containing in common a methyl grouping at the 16a-carbon position of the steroid molecule, have been synthesized and are being studied in human subjects. The compounds are 16a-methyl 9a-fluoroprednisolone (MK-125: hexadecadrol), 16a-methyl 9a-fluorohydrocortisone (MK-126), 16a-methylprednisolone (MK-110), and 16a-methylhydrocortisone (MK-117). Biologic tests in animals have indicated that these analogues exhibit, in varying degrees, striking alterations of several physiologic properties, including enhanced anti-inflammatory activity unassociated with corresponding disturbance of electrolyte metabolism. In the present study preliminary observations of the effects of the four new compounds were made in patients with rheumatoid arthritis. Clinical estimates of the antirheumatic potencies of the compounds, as compared with prednisolone, were accomplished by determining the milligram dosages required to maintain similar degrees of improvement of active rheumatoid manifestations. The approximate antirheumatic potencies of the compounds, on an average, were gauged as follows: for 16a-methyl 9a-fluoroprednisolone, about seven times greater than prednisolone; for 16a-methyl 9a-fluorohydrocortisone, about three times greater; for 16a-methylprednisolone, approximately one-third greater; and for 16a-methylhydrocortisone, about 70 per cent that of prednisolone. In the dosage used, none of the compounds promoted discernible salt and water retention. These observations would indicate that 16a-methyl 9a-fluoroprednisolone (hexadecadrol) possesses greater anti-inflammatory potency per milligram than any steroid yet produced. The therapeutic efficiency of the compound on longterm administration is being studied.     

Prevalence of nosocomial infections in general surgery, orthopedic surgery and urological departments in the Czech Republic

Two prevalence studies of Nosocomial Infections carried out in 1987 (based on 4479 patients in 64 general surgery departments and 1603 patients in 29 orthopedic surgery departments) and in 1988 (based on 1263 patients in 32 urological departments) are summarized. The prevalence rate of nosocomial infections (NI) in general surgery departments was 14.0%, in orthopedic surgery departments 8.0% and in urological departments 20.9%. The highest degree of risk of acquiring NI was run by patients above 60 years of age in urological and general surgery departments. Surgical wound infections in departments of general surgery accounted for 60%, in orthopedic surgery departments for 47% and in urological departments for 37% of all NI. The prevalence of wound infections amongst general surgical patients was 8.4%, amongst orthopedic surgical patients 3.8% and in urological patients 7.7%. The prevalence of urinary tract infections in general surgery departments was 14.4%, in orthopedic surgery departments 18.6% and in urological departments 51.6%. The problems discussed include the role of intrinsic and in-hospital risk factors and the involvement of pathogens responsible for the onset of NI.     

People's concerns about biotechnology: some problems and some solutions

Pharmaceuticals and vaccines made by genetic engineering are well accepted all over the world. In contrast, there are many people, particularly in Europe, who are worried that food, made by the same new technology, may harm their health or cause damage to the environment. This is despite the growing evidence that genetically modified crops have the potential to improve world food security and the fact that there have, as yet, been no adverse results of their use in the food chain. Because of these worries and the mechanisms of politics, agricultural biotechnology has become the target of concerns about food safety (BSE, Foot & Mouth Disease), along with globalisation and the power of multinational companies. These concerns will, hopefully, be overcome by a more open and well-informed dialogue between scientists, opinion leaders, educators and the public. If judiciously applied, genetically modified crops will help increase sustainability and the fight against hunger in the world.     

微生物肥料及其生产应用中的问题

微生物肥料和微生物制剂是新世纪实行绿色农业的重要技术保障,关键是因其中含有大量的有效微生物的生命活动产生特定的肥效或其他生理功能,导致增产,微生物肥料包括根瘤菌肥,解磷菌肥、解钾菌肥、5406菌肥,植物根际促生菌,VA菌根等等,有机肥料堆制剂中含有多种降解农业有机废料的菌种,可缩短堆肥周期,提高养份利用率,由于微生物本身的特殊性,相关市场监督机制不健全,微生物肥料的生产,应用领域存在很多问题,甚至出现明显的伪科学,科研、生产、行政各有关部门应加强基础研究,提高全民科普水平,健全市场监督机制,依靠专家设计严格试验,优选可靠技术,保证良好的经济效益和社会效益。     

On some problems of random nets

The probability problems connected with random nets are restated as probabilities of drawings from an urn containing black and white balls. A partial difference equation is obtained and its solution is given. For large nets a series expression is obtained for the connectivity γ, and this is shown to be equivalent to the transcendental equation obtained by R. Solomonoff and A. Rapport (1951).     

A probabilistic approach to some problems in blood-tissue exchange

The problem of exchange of substances between circulating blood and tissue is discussed in terms of a model with continuously distributed tissue characteristics. Consideration is given to the distribution of perfusion rates, the distribution of metabolism coefficients for a substance consumed at a rate proportional to its concentration, and the distribution of permeability coefficients for a slowly penetrating inert substance. Equations are derived for obtaining crude estimates of the moments of these distributions from exchange data.