Optical Photometric Observations of 7-Ray Loud Blazars

We report results of our optical photometric observations of ten gamma-ray loud blazers, namely: 0219+428 (3C66A), PKS 0420-014 (OA 129), S5 0716+714, 0754+100 (OI 090.4), 0827+243 (OJ248), 1652+398 (Mrk 501), 2200+420 (BL Lacertae), 2230+114 (CTA 102), 2251+158 (3C 454.3) and 2344+514. The observations were carried out in September-October, 2000 using the 70 cm optical telescope at Abstumani Observatory, Georgia. We found intra-day variations in 0420-014, S5 0716+714, BL Lacertae and CTA 102. A variation of 0.3 magnitude over a time scale of about 3 hours was observed in the R passband in BL Lacertae on JD 2451827. We did not detect any variation in 3C 66A, Mrk 501, or 3C 454.3 during our observations. Nor did we detect any clear evidence of variation in 1ES 2344+514 during our two weeks' observing run of the TeV gamma-ray source.     

世界石油的总贮量

现在世界石油的日产量约为5,700万桶,将来即使没有什么新发现,日产量也可增长到6,600万桶。如加上新发现的部分,则可增长到9,000万桶。     

隐伏矿床普查中如何确定钻进深度

为了确定矿田的剥蚀切割深度,必须掌握两个数值:一是被剥蚀的岩石距离成矿时期存在的地表的厚度,二是矿化区间的深度.例如,假定剥蚀切割为500米,这个数值对矿化区间为300～1000米的矿床来说,相当于中等深度的切割值;而对生成深度为1500～3000米的矿床则相当于矿体上部的浅部切割深度.任何一个区域范围内,同类成因的矿床在围岩地质纵剖面上的分布受正态法则支配,并且具有矿化的固定最大值和矿化边缘     

欧洲绝对重力仪比对观测(ECGS'07)

介绍了2007年11月在欧洲卢森堡Walferdange举办的第二次绝对重力比对观测的概况及结果.有20台绝对重力仪参加了比对观测,在ECGS共15个测点上的比测结果标准偏差小于2.1×10~(-8)m·s~(-2).文章简述了数据处理方法以及结果分析,中国地震局地震研究所引进的FG5/232绝对重力仪参加了本次比对,为在中国大陆建立绝对重力基准提供了重要经验.     

Metal contamination in southern Brazil vineyard soils

The viticulture is a rapidly developing agricultural branch in the Rio Grande do Sul State (southern Brazil). Situated in a region with a humid temperate climate, Brazilian vine-growing areas are dampest in the world (annual precipitation close to 2000 mm…     

Discussion on “Hydraulic parameters in channels with wall vegetation and gravel bed” by Hossein Afzalimehr, Jueyi Sui and Razieh Moghbel [Int. J. Sed. Res., 25 (2010) 81–90]

We discussants appreciate the authors’ investigation on the impacts of the vegetated channel walls and aspect ratio on flow velocity profiles,shear stress distribution and roughness coefficient of channel.The primary aim of this comment is to emphasize some of the points which were not considered by the authors during their study.The discussers would like to mention the following points regarding the paper. The expression of "wall vegetation" is a new term for the current literature.However the researchers have not given enough explanation about wall-vegetation.What is "wall vegetation"?Where can we observe wall-vegetation in nature?What are the characteristic species as "wall-vegetation"?We think that the clarification of this point will significantly improve the benefit of this study.     

Climate Change and Pastoral Economy in Kenya:A Blinking Future

Abstract: The present paper examines the changing climatic scenarios and associated effects on livestock farming (pastoralism) in the arid and semi arid lands (ASAL) of Kenya, which cover over 80% of the country. The study was carried out in the semi arid Mukogodo Division of Laikipia District in Kenya. This division received a mean annual rainfall of approximately 507.8?mm and the main source of livelihood was pastoralism. Questionnaire, structured interview, observation and literature review were the main methods of data collection. Rainfall was used in delineating changes in climate. Standardized precipitation index (SPI) and Markov process were used in analyzing drought severity and persistence, respectively. Approximately 38% of all droughts between 1975 and 2005 were prolonged and extremely severe, with cumulative severity indices ranging between ?2.54 and ?6.49. The probability that normal climatic conditions persisted for two or more consecutive years in Mukogodo Division remained constant at approximately 52%. However, the probability of wet years persisting for two or more years showed a declining trend, while persistence of dry years increased with duration. A drying climatic trend was established. This drying trend in the area led to increased land degradation and encroachment of invasive nonpalatable bushes. The net effect on pastoralism was large-scale livestock loss through starvation, disease and cattle rustling. Proper drought monitoring and accurate forecasts, community participation in all government interventions, infrastructural development in the ASAL and allocation of adequate resources for livestock development are some of the measures necessary for mitigating the dwindling pastoral economy in Kenya and other parts of the world.     

国外政府加强矿产勘查的主要措施

在市场经济条件下,政府对商业性矿产勘查工作起着关键性的作用。但由于各国国情不同,在矿业发展周期的不同阶段,政府加强矿产勘查所采取的措施也不尽相同。国家矿业发展的兴盛期,政府加强基础性、战略性、前瞻性的地质调查工作,实施一系列大型公益性地质调查计划或矿产勘查促进计划,获得大量新的基础地质信息和勘查信息,有效地促进矿产勘查工作,提高提供信息服务的能力。而国家矿业不景气时,则采取国家投资（基金）、补贴或减税等过渡措施,促进筹资和引资,保持稳定的矿产勘查投入,创造良好的矿产勘查发展环境,从而推动国家经济社会的发展。详尽分析了国外政府在加强矿产勘查中所采取的有力措施,从中总结经验,为中国矿产勘查工作提供参考与借鉴。     

金融危机对矿业的影响及分析预测

席卷全球的金融危机正在疯狂肆虐,矿业也难以独善其身。金融危机导致矿产品价格全线跳水、矿业公司股价大幅下跌、矿产品需求下降。矿产品价格大幅下跌是矿产品价格在挤出泡沫之后的一种理性回归。矿业发展自身的规律与百年不遇的金融危机的相互叠加、相互影响,加速了此轮矿业繁荣周期的终结并开始了走向下行期的步伐。金融危机给矿业带来了挑战与机遇,但机遇远大于挑战。对此提出如下建议：改善中国矿业投资环境,调整矿产品进出口政策;培育大型跨国矿业公司,提高竞争力;建立国外资源储备基地,吸引海外地质勘查人才;重新审视和再认识地勘基金的定位;抓住有利时机整合资源,促进矿业结构调整。