The aqueous photochemical transformation of acrylic acid

Acrylic acid in sea water is thought to occur mostly as the product of microbial cleavage of dimethylsulphoniopropionate (DMSP), but could also be a pollutant introduced by waste waters of the organic chemical industry. Solutions of acrylic acid in natural and artificial sea water, and distilled and riverine water were photolyzed using a photochemical reactor and exposure to sunlight. The transformation of acrylic acid comprises the decarboxylation of the carboxylic group and subsequent polymerization to a polyethylene type molecule. Kinetic studies showed the lowest reaction rate in distilled water and somewhat higher and very similar rates in other aqueous media. The approximately similar reaction rates in all natural waters studied suggest that inorganic ions, especially Na⁺, Mg²⁺ and halides, and dissolved organic matter (probably humics) enhance the reaction rates. On studying the influence of different concentration ranges on the reaction kinetics, an exponential increase of rates with decreasing concentration was found. The reaction rate in the sea water solution in field conditions is rather slow. In thirty days exposure about 15% of the reactant was transformed. This reaction seems to be important in the marine environment in specific conditions, especially in phycospheres and macroaggregates where higher concentrations of acrylic acid inhibit the bacterial metabolism.     

Effects of polynuclear aromatic hydrocarbons on lysosomal membranes in molluscs

Lysosomal sequestration of polynuclear aromatic hydrocarbons (PNAHs), a major class of environmental contaminant, is a well-established phenomenon;¹ considerably less is known about their pathological effects on lysosomes. Marine molluscs contain a number of lysosome-rich tissues and PNAHs are known to induce deleterious alterations in lysosomal structure and latency of lysosomal enzymes.² The latter are presumed to involve destabilisation of the lysosomal membrane, resulting in increased permeability and reduced enzyme latency. If lysosomal injury involves derangement of membrane-lipid structure due to the interaction of PNAHs then it would be expected that membrane damage would be closely linked to the structural characteristics of the intruding molecule. Our results show that the effects of the isomeric PNAHs phenanthrene and anthracene on digestive cell lysosomal stability were markedly different in the marine mussel (Mytilus edulis) over the same range of tissue concentrations. Lysosomal membrane stability was determined using a cytochemical test for enzyme latency.³     

Reproductive Cycle of the Caribbean Feather Star Nemaster rubiginosa (Echinodermata: Crinoidea)

Abstract. The reproductive cycle of the comatulid crinoid Nemaster rubiginosa from Discovery Bay, Jamaica is described histologically. The cycle is annual and may be divided into (1) a "resting" phase (summer) in which most adults possess immature, unsexable gonads, (2) a recovery phase (early fall) marked by the re-initiation of gametogenesis and rapid gonadal growth, (3) a breeding phase (late fall and winter) during which the gonads are mature and repeated spawning likely takes place, and (4) a post-spawning phase (spring) during which relict gametes are removed from the shrinking gonads. Although unsexable individuals predominate during the "resting" phase, a small proportion of the adult population is unsexable at all times of the year. The reproductive condition of animals in the same month in two successive years was very similar, suggesting that the timing of reproduction is quite predictable from year to year. The re-initiation of gametogenesis in the early fall is correlated with both rising sea temperature and shortening daylength, and the October to March breeding season corresponds to the period of short daylengths at the study site. The well-defined and synchronized annual reproductive cycle of Nemaster rubiginosa contrasts with the more prolonged and variable reproductive cycles reported for other tropical crinoids and points to a diversity of breeding patterns among tropical crinoids.     

A nomogram method for predicting the movement of oil slicks

In order to obtain quick initial guidance on a first estimation of motion of the spilled oil, a simple manual procedure incorporating advection and spreading processes has been devised. This procedure involves the utilization of a nomogram based on simplified equations. Spill displacements throughout a given forecast period can be easily read from the nomogram. The technique is demonstrated with a real spill case.     

Fine vertical structure of currents and hydrological elements in the Black Sea

Data on the fine vertical structure of currents and hydrological elements in the Black Sea, obtained through the use of a hydrophysical OLT profiler, are examined. Vertical exchange coefficients are evaluated, whose distribution is characterized by the occurrence of minima in the seasonal pycnocline and main halocline, a maximum in the core of the cold intermediate layer (CIL), and relatively steady values within the 300–500 m layer. The vertical exchange coefficient values, are consistent with the data acquired through other techniques, and the profiles of this parameter vertically are more detailed.Translated by Vladimir A. Puchkin.     

A hydrodynamic model of a submerged lenticular wave energy device

The wavemaking capability and energy absorbing characteristics of a single submerged body, constrained to move horizontally in a surge mode, are examined. The body possesses both a vertical axis of symmetry and a horizontal plane of symmetry and is ‘thin’ in the sense that the body draft is small compared to the length. The behaviour of a single body subject to a constraint being placed upon the amplitude of its displacement and the properties of an array of interacting identical devices are also discussed.     

Induction of vitellogenin in vivo and in vitro in the model teleost medaka (Oryzias latipes): comparison of gene expression and protein levels

Quantification of the egg yolk precursor vitellogenin (VTG) in fish has become a standard technique to detect estrogenic effects of known chemicals and environmental samples. In the present study, we have analysed VTG induction by estradiol, ethynylestradiol and genistein exposure in the model teleost medaka (Oryzias latipes) and demonstrate that the medaka is a suitable model system to analyse estrogenic effects. By comparing VTG gene expression and protein levels we show that in principal both techniques can be used to study VTG induction in vivo (juvenile and adult males) and in vitro (primary cultures of male liver cells). If a short term in vivo or in vitro exposure is performed, detection of mRNA might be sufficient. For long term studies with the need to detect weak estrogenic chemicals and a precise quantification, immuno-chemical detection may be favoured.     

Spectrum of the free oscillations of the moon

The determination of the internal structure of the Moon using bulk waves is largely complicated due to inhomogeneities in its uppermost layer. We investigate the possibility of studying the Moon’s interior by a sensing method using the free oscillations of the Moon. The spectrum of the free oscillations is calculated for two current models of the internal structure of the Moon derived from the analysis of the Apollo seismic network data, based on new methods: the MG (Garsia, et al., 2011) and MW (Weber, et al., 2011) models. In contrast to the MG model, the MW model includes a solid inner core. In this latter model, we estimate how the shear modulus of the inner core affects the structure of the oscillations.     

Reproduction of Pechora runoff hydrographs with the help of a model of heat and water exchange between the land surface and the atmosphere (SWAP)

The potentialities of a procedure for calculating the Pechora River runoff from the pan-Arctic river basin are studied. The procedure is based on the use of a model describing heat and water exchange between the land surface and the atmosphere and two variants of input data sets relying on global databases on meteorological characteristics and land surface parameters and data of standard measurements of meteorological characteristics in combination with parameters of the land surface of the basin, taken from global databases. In both cases, use was made of the method for optimizing part of the most important model parameters, including both land surface parameters and correction factors for some meteorological elements.     

Electromagnetic inertio-gravity waves in the Earth's ionosphere

Propagation of electromagnetic inertio-gravity (IG) waves in the partially ionized ionospheric E- and F-layers is considered in the shallow water approximation. Accounting of the field-aligned current is the main novelty of the investigation. Existence of two new eigen-frequencies for fast and slow electromagnetic waves is revealed in the ionospheric E-layer. It is shown that in F-layer slowly damping new type of inertial-fast magnetosonic waves can propagate. Slowly damping low-frequency oscillations connected with the field-aligned conductivity are found. Broad spectrum of oscillations is investigated.