Chemical characteristics and source apportionment of aerosols over Indian Ocean during INDOEX-1999

During INDOEX IFP-99, the samples of aerosols were collected onboard ORV Sagar Kanya over Indian Ocean along the cruise track, for chemical characterization and identification of dominating sources of aerosols. The concentrations of nss-SO4, nss-Ca, nss-Mg, NO3, K, NH4 and SO2 were observed to be significantly higher before ITCZ in northern hemisphere than across ITCZ in southern hemisphere. In this study, variation of concentrations of nss-SO4, nss-Ca and nss-K with respect to change in latitude, wind direction, wind speed and relative humidity have been highlighted. North of ITCZ, nss-SO4 varied from 2.20 to 18.31 μg/m3 and south of ITCZ from 0.50 to 2.79 μg/m3 while nss-Ca varied from 0.02 to 0.72 μg/m3 north of ITCZ and from 0.01 to 0.14 μg/m3 south of ITCZ. nss-K ranged 0.09-1.43 μg/m3 and 0.07-0.60 μg/m3 before ITCZ and across ITCZ respectively. nss-Ca and nss-SO4 were contributed mainly by NNW and ENE winds while nss-K was observed to be contributed mainly by SSW and ENE winds. Wind speed greater than 4.5 m/s negatively influenced the concentration of nss-Ca concentrations. Correlation coefficients of nss-SO4 with SO2 (r = 0.7) and RH (r = 0.5) suggested a significant contribution of nss-SO4 by aqueous phase oxidation of SO2. Using PCA, four major sources namely sea salt, biogenic combustion, secondary SO4 and crustal contribution were identified over Indian Ocean during INDOEX period

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Larval rearing of mud crab, Scylla tranquebarica (Fabricius, 1798) and feeding requirements of its zoea

Feeding experiments were conducted with zooplankton to find out the suitable food for zoea1 of the mud crab Scylla tranquebarica. Zoeae1 from seven berried females, three from wild and four from rematured specimens were the source material for the present study. The veliger larvae (50-55μm) of pearl oyster and two species (Pseudodiaptomus spp. and Labidocera spp.) of pelagic copepods (500-1000 μm) were tested as feed. However, the zoea1 accepted only the former. The feeding activity could be resolved into 5 stages. Significant role of the serrated caudal setae in prey abrasion into required size suitable to mandibles for mastication and the size preference of the items of diet in relation to the growth of the mandibles with the advancement of zoeal stage also have been discussed. In all the 7 feeding experiments that were conducted by providing rotifer, Brachionus rotundiformis (<100 μm), the zoea1 advanced to zoea3/zoea4 or the first crab stage. The present study is a significant development in narrating the feeding behaviour of zoea1

Prawn fauna (Crustacea: Decapoda) of India - An annotated checklist of the Penaeoid, Sergestoid, Stenopodid and Caridean prawns

Twenty four species of Pandalid shrimps reported from the Indian waters, of which six genera (Chlorotocella, Chlorotocus, Chlorocurtis, Dorodotes, Heterocarpoides and Stylopandalus) are represented by single species each. The genera, Plesionika and Heterocarpus are represented by eleven and seven species respectively. Plesionika adensameri (Balss, 1914) a deep-sea shrimp hitherto unreported from Indian waters is recorded from west coast of India. Information on some biological aspects of few Pandalid shrimps from Indian waters is also reported in the present paper

Ring Cleavages of Dimethylphenoxide Anions

The major fragmentations of isomeric dimethylphenoxide anions upon collisional activation are losses of H· and Me·. Two minor processes involve the formation of m/z 79 (C6H7-) (-C2H2O) and m/z 77 (C6H5-) [- (Me· + CHO·)]. The former is only observed when (at least) one of the ortho carbons bears a hydrogen substituent, the latter only when there is a 4-methyl substituent

Acetone chemical ionization studies VI: Hexenyl acetates

Acetone chemical ionization mass mass spectra of four isomeric hexenyl acetates were investigated. The characteristic decomposition of [M + CH3CO]+ adducts in the field-free region reveals site-specific adduct formation of acetyl ion with the double bond and the acetoxy group

Mass spectral study of substituted methyl (E)-and (Z)-cinnamates under 1,2-dibromoethane chemical ionization

Dibromoethane chemical ionization mass spectra of ten pairs of methyl (E)- and (Z)-cinnamates were studied. C2H4Br+ ion forms stable adducts with E-isomers and the adducts of Z-isomers show preferential loss of methanol. The observed results suggest that the probability of ring alkylation is greater than with the carbonyl group