The classification of chemical reactions

The classification and shorthand designation of chemical reactions are considered. It is concluded that single-step reactions can be divided into a finite number of types, each of which could be represented by an unambiguous symbol. The various types are listed and illustrated. Multi-step reactions, however, cannot be classified (in any detail) in a limited number of ways and for such reactions the use of symbols to represent each step unambiguously results in unwieldy designations.     

Bioaccumulation of lead and the influence of chelating agents in Catla catla fingerlings

Lead is a widespread element and one of the persistent and cumulative pollutants of the environment. The present study deals with the bioaccumulation of lead and the influence of chelating agents, meso 2,3-dimercaptosuccinic acid (DMSA), D-Penicillamine and CaNa₂EDTA in reducing the concentration of lead on the selected organs of Catla catla fingerlings for both acute and chronic exposures by using ICP-AES. It is inferred from the present findings that there was a correlation between environmental conditions and the heavy metal contents of the fish. The highest concentration of lead is found in kidney tissues and the lowest in muscle tissues. The accumulation pattern of lead in the selected organs of Catla catla is: kidney > liver > gill > brain > muscle. Also, it has been found that the treatment of chelating agents, DMSA, D-Penicillamine and CaNa₂EDTA reduces the concentration of lead significantly for both acute and chronic exposures. The results also show that DMSA is the most effective chelator of lead in reducing the body burden of C. catla fingerlings. The observed data further indicate that C. catla could be suitable for monitoring organisms to study the bioavailability of water-bound metals in freshwater habitats.     

The occurrence of Oratosquilla investigatoris (Crustacea: Stomatopoda) in the pelagic zone of the Gulf of Aden and the equatorial western Indian Ocean

Surface swarms of the stomatopod Oratosquilla investigatoris (Lloyd, 1907) were observed in the Gulf of Aden and the equatorial western Indian Ocean during 1967. Collections from inshore and offshore swarms were made in both areas, and from demersal trawl catches in the equatorial area. O. investigatoris was also collected from the stomachs of several species of oceanic pelagic and inshore fish from 1965 to 1967, and was also reported in the stomach contents of the lesser frigate bird. Further collections were made from strandings on two oceanic islands in the equatorial area. Indirect observations on the occurrence of the species resulted from increased predation on pelagic longline baits during seasos of apparent abundance of O. investigatoris in the equatorial region. At the surface, predation by the species was observed on fast-swiming fish, and the swimming behaviour was noted. A size range of 6 to 37 mm carapace length (CL) was recorded for the 4000 specimens collected, and there was no size difference between the sexes. Length-frequency analysis of the samples indicated a major mode at 19 to 21 mm CL and an increase in length of 3 mm over 3 months. The sex ratio was weighted in favour of females in the majority of collections. It was concluded that the pelagic swarming of O. investigatoris is an important ecological phenomenon, but not regular in the area, and the factors affecting it could not be deduced from the available data.     

2015年10月南京霾污染过程分析

为探讨南京秋季霾污染过程发生的主要影响因素,利用南京信息工程大学太阳光度计观测霾污染发生天气下AOD（aerosol optical depth,气溶胶光学厚度）数据,计算AE_440-1020（?ngstr?m Exponent,波长指数）以及a₂（光谱曲率）,结合CALIPSO（Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations）卫星气溶胶组分分析以及MODIS（Moderate Resolution Imaging Spectroradiometer）火点数据,对2015年10月南京霾污染过程进行分析.结果表明:2015年10月出现的两次霾污染过程期间南京地区AE_440-1020均高于1.0并且a₂呈负值,其中10月16日AQI达到峰值（201）,AOD₅₀₀达1.51,AE_440-1020达1.37,a₂达-0.77;这两次较为严重的霾污染过程均主要由人为因素（工业污染、城市建设、生物质燃烧、汽车尾气排放等）产生的细粒子所致.后向轨迹分析发现,2015年10月16日南京地区霾污染天气发生的主要原因是区域型污染,同时受长距离输送影响,大量携带人为因素产生的细粒子以及少量沙尘等污染物的空气团途经内蒙古、山东等地到达南京,加剧了当日的污染程度;2015年10月23日南京地区霾污染天气的发生则主要受长距离输送影响,同时也受到区域型污染影响,加剧了当日的污染程度.研究显示,在稳定的气象条件下,较高的相对湿度、较低的地表风速、低混合层高度以及贴地逆温的出现是诱发霾污染天气产生的有利气象条件.      

Deposition and Storage of Spheroidal Carbonaceous Fly-Ash Particles in European Mountain Lake Sediments and Catchment Soils

Spheroidal carbonaceous particles(SCPs) are produced only from high temperaturecombustion of fossil-fuels. In mountain lakesystems, they provide an unambiguous indicator ofatmospheric deposition. In order to comparedepositional fluxes of SCPs between mountainareas experiencing various pollutant regimes,intensive bulk deposition sampling was undertakenat five sites across Europe. Catchment soil coresand lake sediment cores were also taken at eachsite to compare SCP storage over the post-industrial period. Atmospheric, sediment and soilSCP data showed similar patterns. Highestcontamination was found in Scotland, Slovakia andSpain with the Austrian site intermediate and themid-Norwegian site least contaminated. A highproportion of accumulated SCPs were found to bestored in catchment soils at each site.Therefore, a significant increase in soilerosion, possibly as a result of future climatechange, could lead to the input of largequantities of catchment stored SCPs and, byimplication, other atmospherically depositedcontaminants to the lake ecosystem.     

Characteristics of the contact zone of three chromosome races of the common shrew <Emphasis Type="Italic">Sorex araneus</Emphasis> L. (Mammalia) as indices of interpopulation competition

The distribution of three chromosome races (Moscow, Western Dvina, and Seliger) of the common shrew Sorex araneus L. in the zone of contact between their ranges in the Valdai Heights (32°00′ E, 57°00′ N) is discussed. The area co-inhabited by all the three races is extremely small. Representatives of all the three races have been captured on only one trap line, although there are no obstacles to the expansion of shrews. The extremely small area co-inhabited by the three races, as well as the strictly parapatric distribution of the Moscow and Western Dvina races, may be related with competition forms such as avoidance of contacts and separation of ecological niches.     

The Synthesis and FTIR, Kinetics and TG/DTG/DTA Study of Inter Penetrating Polymer Networks (IPNs) Derived from Polyurethanes of Glycerol Modified Castor Oil and Cardanol Based Dyes

Interpenetrating polymer networks from agricultural products such as glycerol modified castor oil polyurethanes and cardanol based dyes have not been extensively studied so far. Such polymers were synthesized using benzoyl peroxide as initiator and ethylene glycol dimethacrylate as cross-linker. Characterizations of these polymers were performed by Fourier Transform infra red spectra and thermal analysis techniques such as thermogravimetric analysis, derivative thermogravimetry and differential thermal analysis. The kinetic parameters such as activation energies and orders of reaction were estimated by using Freeman?CAnderson??s method. The effects of changes in polyurethane to dye monomer weight ratio and NCO/OH molar ratio of polyurethanes on the properties of such polymers were studied.     

Radium-226 in water, sediments, and fish from lakes near the city of Elliot Lake, Ontario, Canada

Ra-226 was measured by alpha-emission spectroscopy in water, sediments, and fish (tissues and gut contents), from five lakes in a watershed containing U mining and milling operations at Elliot Lake, Ontario, and from control lakes in an adjacent non-industrialized watershed. Ra-226 transfer parameters from lake water and sediments to fish tissues, and annual intakes by humans consuming fish, were estimated. Mean dissolved 226Ra levels ranged from approximately 76 mBq litre(-1) in water of the most affected lake, to < 10 mBq litre(-1) in control lakes. Levels in summer were consistently higher than in fall or winter; no consistent variation with depth was noted. Sediment levels ranged from approximately 3000 mBq g(-1) dry wt in one study lake to < 100 mBq g(-1) dry wt of sediment in control lakes. Bone 226Ra concentrations were higher than in muscle. The lake trout (Salvelinus namaycush), a predatory secondary consumer, had bone 226Ra levels (< 20 mBq g(-1) dry wt) that did not show significant site variation. In contrast, bottom feeding whitefish had significantly more 226Ra in bone tissue (to 38 mBq g(-1) dry wt in the lake whitefish, Coregonus clupeaformis, and 76 mBq g(-1) in round whitefish, Prosopium cylindraceum) in study lakes than in controls (< 20 mBq g(-1) dry wt). Ra-226 levels in lake trout muscle were low and showed erratic variation among lakes whereas levels in whitefish muscle did not vary significantly among study and control sites. Lake herring (= cisco, Coregonus artedii), a planktivorous fish taken only from Quirke Lake, had mean 226Ra levels of 18 and 1.4 mBq g(-1) dry wt in bone and muscle, respectively. Gut 226Ra levels, highest in lake trout from McCabe and Quirke Lakes (126 +/- 53, 64 +/- 44 mBq g(-1) dry wt, respectively), and just detectable in McCabe and Elliot Lake whitefish (24 +/- 2, 36 +/- 14 mBq g(-1) dry wt, respectively), were below detection in lake trout and whitefish from other lakes. Concentration ratios (CRs) of 226Ra from water to muscle ranged from 8 to 14 in lake trout, 7 to 14 in whitefish, and 4 to 6 in lake herring. The water to bone CRs varied from 81 to 142, 314 to 548, and 126 to 272 in the same species. CRs were always < 1 between sediments and fish tissues. Annual intake of 226Ra by human consumers of these fish was estimated to provide an effective dose of 0.003 mSv year(-1). This represents a small fraction of both natural background (> 2 mSv year(-1)) and the public dose limit (5 mSv year(-1)).