Deep electrical structure over the igneous arc of the Indo Burman Orogen in Sagaing province,Myanmar from magnetotelluric studies

Magnetotelluric studies over the igneous arc of the Indo Burman range in the Sagaing province of Myanmar have delineated the high resistivity Indian plate subducting westwards beneath the Burmese block to depths of 30 km and beyond. The thick moderately resistive (20–100 Ω m) layer overlying the subducting Indian plate may be due to the low resistivity sediments. The entire region is covered with prominent sedimentary layer with a conductance varying between 20 and 3000 S showing a general increase from the east to west, suggesting that their thickness increases toward the west. The large unsystematic variations in the conductance are indicative of the widely varying depositional environments and also possible vertical block movements during the course of their deposition. A west dipping low resistivity zone to the east of Burmese block seems to demarcate its eastern limit, suggesting the possibility of a hitherto unknown deep seated fault, which is also supported by the several earthquake foci located over this zone. The nature of the crustal movements over this fault is not immediately apparent. Possibility exists that the Sagaing fault is an en echelon fault and the present feature observed here is a part of this en echelon fault. The possibility of channel flows of the weakened rocks in the deep crust observed in the vicinity of the eastern Himalayan syntaxis may also cause such low resistivity zones.     

4种再分析资料在中国区域的适用性研究进展

根据NCEP/NCAR、NCEP/DOE、ERA-40和JRA-25共4种比较常用的再分析资料在中国区域的适用性研究作了概述。结果表明：发现4种资料既呈现出一定的共性,又在不同区域、不同时间尺度上差异显著。再分析资料的可信度普遍表现为在东部地区好于西部地区,低纬地区好于高纬地区,这可能与中国地面气象站点“东密西疏”有关;1979年前的再分析资料存在较大的不确定性,因此应用该时段NCEP/NCAR资料研究长期气候变化研究时需要谨慎;再分析资料的不同要素在不同时间、不同地域的适用性不同,因此应分区域、分要素、分季节选择合适的资料。从不同角度研讨了再分析资料的优缺点及在中国区域的适用性,旨在为中国区域气候变化研究选用再分析资料提供借鉴和参考。     

4种再分析资料在中国区域的适用性研究进展

根据NCEP/NCAR、NCEP/DOE、ERA-40和JRA-25共4种比较常用的再分析资料在中国区域的适用性研究作了概述。结果表明：4种资料既呈现出一定的共性,又在不同区域、不同时间尺度上差异显著;再分析资料的可信度普遍表现为在东部地区好于西部地区,低纬地区好于高纬地区,这可能与中国地面气象站点＂东密西疏＂有关;1979年前的再分析资料存在较大的不确定性,因此在应用该时段NCEP/NCAR资料研究长期气候变化研究时需要谨慎;再分析资料的不同要素在不同时间、不同地域的适用性不同,因此应分区域、分要素和分季节选择合适的资料。从不同角度探讨了再分析资料的优缺点及在中国区域的适用性,旨在为中国区域气候变化研究选用再分析资料提供借鉴和参考。     

Optimization of Minimal Salt Medium for Efficient Phenanthrene Biodegradation by Mycoplana sp. MVMB2 Isolated from Petroleum Contaminated Soil Using Factorial Design Experiments

This study presents the degradation of phenanthrene by Mycoplana sp. MVMB2 isolated from petroleum contaminated soil and the media optimization by factorial design experiments. The Plackett–Burman design was used to evaluate the effects of eight variables (potassium dihydrogen phosphate, disodium hydrogen phosphate, magnesium sulfate, calcium chloride, ferrous sulfate, glucose, inoculum concentration, and phenanthrene concentration) on phenanthrene degradation. Based on the results, the critical medium components having significant influence on the degradation were found to be disodium hydrogen phosphate, magnesium sulfate, ferrous sulfate, and phenanthrene. Furthermore, these four variables were used as central composite design parameters. The optimum minimal salt medium composition obtained by conventional and factorial design experiments for the degradation of phenanthrene by Mycoplana sp. MVMB2 at pH 6.5 and 30°C were found to be, potassium 2.5 g/L dihydrogen phosphate, 0.3505 g/L disodium hydrogen phosphate, 0.5501 g/L magnesium sulfate, 0.02 g/L calcium chloride, 0.0261 g/L ferrous sulfate, 0.6756 g/L phenanthrene, 0.5 g/L glucose, 0.5 g/L ammonium sulfate, and inoculum 5% v/v. The phenanthrene degradation was confirmed by analyzing the metabolites formed.     

Pesticide Health Risk Mapping and Sensitivity Analysis of Parameters in Groundwater Vulnerability Assessment

The extensive use of pesticides for increasing the agricultural production is affecting the quality of groundwater. The objectives of this article are to (i) develop pesticide relative leaching ranks for well sites, (ii) develop maps for human health risks due to pesticide applications, and (iii) identify the most significant parameters in pesticide simulations for groundwater vulnerability assessment. The methods include (i) development of acifluorfen relative leaching ranks for 25 well sites using ArcPRZM‐3, (ii) development of health risk maps using model simulated maximum dissolved bentazon concentrations on the basis of USA drinking water quality guidelines, (iii) sensitivity analysis for 14 ArcPRZM‐3 input parameters using the Plackett–Burman method. ArcPRZM‐3 is a user‐friendly system for spatial modeling of pesticide leaching from surface to groundwater. Thirteen acifluorfen relative leaching potential ranks were developed in which the pesticide leaching decrease from 1 to 13. The model predicted ranks for well 34 and well 9 were 2nd and 3rd, respectively, and acifluorfen was detected in both wells during the physical monitoring. The percentages of high health risks in the agricultural areas were 48.38 and 72.72% for Randolph and Independence Counties, respectively. The most significant parameters were thickness of horizon compartment, runoff curve number of antecedent moisture condition II for cropping, soil bulk density, and total application of pesticide. The irrigation, soil permeability, and numerical dispersion could impact the pesticide leaching in soils toward groundwater. The ArcPRZM‐3 system could be efficiently applied for spatial modeling and mapping of pesticide concentrations for groundwater vulnerability assessment on a large scale.     

Statistical Optimization of Anaerobic Biological Processes for Dye Treatment

In the present study both the synthetic media composition as well as some process parameters in the anaerobic decolorization of Reactive Black 5 (RB5) by activated sludge were studied and optimized using statistical design of experiments (DOEs). Statistical analysis of the results of Plackett–Burman DOE showed that the addition of Mn or Fe, or increase in concentration of Mg, had a positive effect on the anaerobic decolorization efficiency whereas the effect of increase in concentration of glucose, ammonium chloride, and calcium chloride was negative. The effect of change in the concentration of glucose, mixed liquor suspended solid (MLSS), and RB5 on the anaerobic decolorization efficiency and rate and chemical oxygen demand (COD) removal was studied using central composite design methodology. Statistical analysis of the data showed that all the factors had significant effect on both the dye decolorization efficiency and rate. The interaction of glucose with MLSS and with dye and the interaction of MLSS with glucose and with dye were significant when the response was decolorization efficiency and rate, respectively. When COD removal was the response, the effect of change in glucose and MLSS concentration and the interaction between these two factors had statistically significant effect on the response.     

PALEOCENE—MIDDLE EOCENE DEXTRAL STRIKE-SLIP DEFORMATION AND ITS TECTONIC IMPLICATION IN THE WESTERN YUNNAN, CHINA

PALEOCENE—MIDDLE EOCENE DEXTRAL STRIKE-SLIP DEFORMATION AND ITS TECTONIC IMPLICATION IN THE WESTERN YUNNAN, CHINA     

Evolution of Late Oligocene - Early Miocene attached and isolated carbonate platforms in a volcanic ridge context (Maldives type), Yadana field,offshore Myanmar

This study investigates the stratigraphic evolution of the Late Oligocene - Early Miocene carbonate platforms of the Yadana area (offshore Myanmar). Well data, regional 2D and local 3D seismic surveys allow the identification of three shallow-water carbonate platforms (Yadana, 3DF and 3DE) showing various morphologic and stratigraphic patterns influenced by the presence of a paleohigh. The identification of seven seismic sequences in the Yadana area constrains the stratigraphic evolution in three stages: (1) development of aggrading attached and isolated platforms during the Chattian; (2) a period of platform emersion during the Oligocene - Miocene transition; (3) drowning of the smaller buildup (3DE) associated with km-scale backstepping on the large platforms (3DF and Yadana) during the Aquitanian. The Aquitanian marks the onset of renewed volcanic activity associated with the development of fringing carbonate reefs during the Burdigalian. The rapid (∼6 My) development of these wide (∼5–70 km) and thick (∼300–850 m) carbonate platforms has been mainly controlled by the subsidence. However, the results highlight a strong overprint of eustatic fluctuations on the rates of change in accommodation, and hence on the stratigraphic architecture of the carbonate platforms. Based on an alternative model for the Cenozoic geodynamic evolution of the Yadana area, our results suggest that the platforms developed on a volcanic ridge of hotspot origin located in the Indian Ocean and not on a volcanic arc. Subduction jump processes are interpreted to have played a key role in the demise of all platforms by drastically changing the paleoenvironmental conditions during the Early Miocene, and led to the present-day location of the Yadana Ridge in a back-arc setting. The carbonate platforms from the Yadana area are thus a representative example of the interplay between global mechanisms and local paleoenvironmental parameters on carbonate platform initiation, growth and demise.     

青藏高原地区NCEP新再分析地面通量资料的检验

利用1979—1998年地面气象站温度观测资料和1982年8月-1983年7月高原热源观测资料,检验了NCEP／DOE新再分析地面气温和地面辐射收支在青藏高原地区的偏差。比较表明,气温和地面辐射量新再分析值能反映实际年变化特征,但其温度值系统性偏低,偏低幅度随地区和季节而变化。由于其气温和地表温度偏低造成地表长波辐射和大气逆辐射系统性偏低;冬季积雪地区的地表吸收太阳辐射和净辐射新再分析值偏小;地面净长波、净短波和总的净辐射与实测的偏差比较小。分析发现,同化模式地形高度与地面气象站海拔高度的差异是造成气温新再分析与实测偏差的主要原因,冬季积雪区地表反照率新再分析值偏大是造成冬季地面净辐射偏小的因素,并加剧了冬季气温新再分析的偏差。其研究对改进气候模拟结果分析有一定的启发。