A new interstellar polyatomic molecule: detection of propynal in the cold cloud TMC-1

We report the detection of the acetylene derivative propynal (HC triple bond CCHO) in the cold cloud TMC-1, with an abundance that is very close to that for the related species tricarbon monoxide (C3O). Propadienone, an isomer of propynal with the formula H2C=C=C=O, was not detected and is hence less abundant than either C3O or HC2CHO.     

Temporal variations in dimethylsulphoniopropionate and dimethyl sulphide in the Zuari estuary,Goa (India)

Despite tropical estuarine systems representing important sites for active biogeochemical processes, studies on dimethyl sulphide (DMS) in these systems are sparse. Here we report on DMS and dimethylsulphoniopropionate (DMSP) variability in relation to physicochemical and biological parameters for a period of 14 months in a tropical estuarine environment. DMS and DMSP showed high temporal variations with maximal concentrations during the southwest monsoon coinciding with a dinoflagellate bloom. Dinoflagellates appear to be the major contributors to the DMSP pool. Average DMS and DMSP concentrations (surface and bottom) suggested that much of the DMSP produced is converted to forms other than DMS. Surface DMS varied between 0.3 and 15.4 nmol dm(-3) while DMSP ranged from 0.8 to 419.5 nmol dm(-3). The DMS flux was 0.03-1.9 microM m(-2) d(-1) (average=0.6 microM m(-2) d(-1)) during the study period, that concurs well with the values reported for temperate estuaries.     

勘查研究沉积岩和火山岩型贵金属矿床的遥感特征及图像处理方法

贵金属矿床的类型一般是由几种亚类组成的,其产出型式是按物理化学地质特征进行分类的,并受热液成因系统控制,它适合于遥感探测。矿床类型之间的变化情况,就遥感数据选择,应用及解释研究方面来说,是种重要的考虑问题。本文将讨论及对比重要的经济型沉积岩型、火山岩型矿床的物理地质特征及遥感特点。阐述了原生与次生蚀变,围岩,线性和环状构造和植被异常等有意义的矿床特征,以及表现的特征光谱,空间分辨率的条件要求。勘查     

Pre-census mapping in Lesotho

Lesotho may be taken as a classic case of how African countries have attempted to cope with the demands of census operations. This paper discusses in respect of Lesotho the existing cartographic base for census mapping; census organization; methodology of census taking in Lesotho; geographical planning and specific strategies evolved in census mapping for the recent 1986 population census; some of the basic problems encountered in enumeration area mapping during the 1986 census; and also the use of census enumeration areas as a frame for national household survey capability programme and post-census cartographic activities.     

Isotopic and microbial indicators of sewage pollution from Stone Town, Zanzibar, Tanzania

In Stone Town, Zanzibar, sewage treatment is minimal, with a biological oxygen demand reduction to 60% and no removal of bacteria or nutrients. Here, Stone Town's sewage pollution was studied by measuring Enterococci and NH(4)(+) concentrations in seawater and δ(15)N of benthic organisms; samples were collected along the Stone Town shoreline and from offshore coral reefs. Public perceptions of sewage pollution were investigated via interviews. Enterococci from the Stone Town shoreline exceeded USEPA guidelines for recreational use. Benthic organisms from two of the four reefs were relatively enriched (δ(15)N>10 ‰), indicative of sewage derived N. δ(15)N values of organisms from Stone Town exceeded 16 ‰. A strong correlation was found between Enterococci and δ(15)N across sites, while step-wise regression indicated rainfall and tidal stage as important predictors for bacterial concentrations. These data provide an important impact assessment from which the efficacy of future policy and management change can be assessed.