水库调水调沙回顾与展望--兼论小浪底水库运用方式研究

作者简要回顾了三门峡、恒山水库调度方式和小浪底工程设计、“八五”攻关和专题研究之运用方式以及碛口、三门峡、小浪底水库联合调度方式等。提出小浪底水库调度应坚持“多年调节泥沙 ,相机排沙”运用方式 ;调控库容应大一些 ,同时要有灵活性 ;充分利用天然大水过程排沙 ,必要时也可相机造峰 ;注重水库联合调水调沙运用及有关技术问题研究     

2座烟囱定向爆破拆除

介绍了2座分别高37m、45m砖砌烟囱定向爆破拆除的情况,给出了爆破方案,爆破参数和安全防护措施,爆破效果良好.     

Detection of ultrasonic tones and simulated dolphin echolocation clicks by a teleost fish, the American shad (Alosa sapidissima)

The authors previously reported that American shad (Alosa sapidissima) can detect sounds from 100 Hz to 180 kHz, with two regions of best sensitivity, one from 200 to 800 Hz and the other from 25 to 150 kHz [Mann et al., Nature 389, 341 (1997)]. These results demonstrated ultrasonic hearing by shad, but thresholds at lower frequencies were potentially masked by background noise in the experimental room. In this study, the thresholds of the American shad in a quieter and smaller tank, as well as thresholds for detecting stimulated echolocation sounds of bottlenosed dolphins was determined. Shad had lower thresholds for detection (from 0.2 to 0.8 kHz) in the quieter and smaller tank compared with the previous experiment, with low-frequency background noise but similar thresholds at ultrasonic frequencies. Shad were also able to detect echolocation clicks with a threshold of 171 dB re: 1 microPa peak to peak. If spherical spreading and an absorption coefficient of 0.02 dB/m of dolphin echolocation clicks are assumed, shad should be able to detect echolocating Tursiops truncatus at ranges up to 187 m. The authors propose that ultrasonic hearing evolved in shad in response to selection pressures from echolocating odontocete cetaceans.     

Planned condom use among women undergoing tubal sterilization

BACKGROUND AND OBJECTIVES: Women who are undergoing tubal sterilization are at risk for various sexually transmitted diseases (STDs) if they do not use a barrier method of contraception. There is a paucity of data concerning dual use of condoms among sterilized women. GOAL: Planned use of condoms for protection against STDs was examined among 2,782 women undergoing surgical sterilization from 1991 to 1996. STUDY DESIGN: Cross-sectional survey. RESULTS: Planned condom use increased significantly over the 6-year study period. Of women who were using condoms before sterilization (n = 646), nearly half indicated no plans to do so after becoming sterilized. Thus, 11% of the total sample experienced an increased risk for exposure to human immunodeficiency virus or other STDs. Condom abandonment was significantly higher among Hispanic and married women. Multiple regression analysis was used to examine the association between condom use and various characteristics. Factors associated with future condom use were younger age, black ethnicity, being unmarried, previous STD, not having a steady partner, higher number of previous sexual partners, having used condoms for disease prevention in the past, and lack of partner involvement in the decision to undergo sterilization. CONCLUSIONS: Use of condoms among sterilized women appears to be on the rise, women at higher risk for disease are more likely than others to be using condoms, and only a small group of women experience an increased risk for exposure to disease as a result of selecting this permanent method of contraception.     

Rapid, sensitive procedure to determine buspirone levels in rat brains using gas chromatography with nitrogen-phosphorus detection

Reported here is a rapid, sensitive and relatively inexpensive procedure using gas chromatography with nitrogen-phosphorus detection (GC-NPD) to quantify buspirone levels in brains of rats. The analyte was directly extracted from brain homogenate with toluene after basification and then subjected to GC-NPD analysis using a capillary column. The calibration curves were linear over the range of 10 to 320 ng per 2 ml of brain homogenate, with typical r2 values >0.99. The assay was highly reproducible and gave peaks with excellent chromatographic properties.     

Patients with rheumatoid arthritis: study of the correlation between density of glucocorticoid receptors in synovial cells and clinical response to steroidal treatment

BACKGROUND: The target cellular response to glucocorticoids is proportional to the concentrations or affinity of specific receptors to these substances. AIM: To look for a correlation between glucocorticoid receptor concentrations in synovial wall cells and the clinical response to steroidal treatment in patients with rheumatoid arthritis. PATIENTS AND METHODS: Twenty eight patients with rheumatoid arthritis were studied. Each subject was subjected to a synovial biopsy, in which a dry radioautographic technique for diffusible compounds was used. Patients were treated afterwards with three 500 mg intravenous pulses of methilprednisolone. RESULTS: A mean of 44.8% of synovial cells (range 30.1-62.8%) had binding sites for 3H dexamethasone. All patients had a significant clinical improvement after methylprednisolone. Multiple regression analysis did not show a correlation between clinical response and glucocorticoid receptor concentration. CONCLUSIONS: The lack of association between glucocorticoid receptor concentrations and clinical response could be due to the large steroid dose used, that saturated all available receptors.     

Physiologo-biochemical characteristics if Gluconobacter oxydans and prospects for its use in biotechnology and biosensor systems (review)

Gluconobacter oxydans possesses a unique organization of metabolic systems, which are characterized by reduction of major dissimilation pathways, surface localization of main oxidative enzymes responsible for partial oxidation of carbon substrates, high performance of electron-transport chains, and accumulation of partially oxidized metabolites in the medium. These features allow us to use the cells of these microorganisms in biotechnology for production of several food products and medicines. The use of G. oxydans in biosensors for estimation of concentrations of sugars, aldoses and polyalcohols is promising. Physiological and biochemical features of these microorganisms enabling their use in biotechnology and receptor elements of biosensors are reviewed.     

基于受控时间Petri网的车辆检测过程模型

针对汽车检测线运行效率评估及确保给定数量车辆检测时间最短的问题,通过分析检测过程中的驱动事件和状态演变,给出了车辆调度的约束条件,在此基础上把模型中的时间约束与受控Petri网相结合,提出了受控时间Petri网（Controlled Time Petri Nets）模型,采用该模型对检测线调度过程中的节拍控制与车辆调度进行可视化的建模与分析。实践表明对于多批次车辆检测任务采用该过程模型可明显缩短检测时间。