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The sonic scattering layer (SSL) or deep scattering layer (DSL) of the eastern Arabian Sea of India is found in depths between surfaces to 750 m with varying thicknesses and in multiple layers. There is a distinct resident community of pelagic shrimps that is widely distributed in the DSL biocomposition. Pelagic shrimps formed 19% of the total biomass and 47% of the micronekton biomass of the DSL. Many of them serve as important food resources to several pelagic/mesopelagic organisms. Pelagic shrimps concentrate in the deep scattering layer and diurnally migrate in the water column. The estimated average abundance pelagic shrimps ranged between 0.04-106 /1000m³. Shrimp catches were higher during night at 50-200 m depth than day. The dominant families encountered in the catches were Thalassocarididae, Pasiphaeidae, Sergestidae and Oplophoridae. Dominant genera of pelagic shrimps present were Gennadas, Sergestes, Sergia, Lucifer, Oplophorus, Acanthephyra, Nematocarcinus, Leptochela, and Thalassocaris. Species Sergestes seminuds, Thallassocaris crinata and Leptochela robusta were present in swarms [ABSTRACT FROM AUTHOR]

Abstract.: Over the past decade and a half there have been a number of numerical studies of the reflection of oblique axisymmetric shock waves from the axis of symmetry. Many of these have shown a complex Mach reflection pattern together with a strong toroidal vortex which significantly distorts the Mach disk. This geometry has never been captured experimentally. This note describes a special rig for the generation of strong imploding conical shocks, and presents photographs of the predicted reflection pattern.

We have measured the shear modulus and viscosity of two supercooled liquids:  tricresyl phosphate and squalane. In both cases we find that the width of the peak in the imaginary part of the shear modulus narrows as the temperature is lowered toward the glass transition temperature. For tricresyl phosphate, we find no evidence for a decoupling of the viscosity and shear modulus relaxation times from the relaxation times determined by dielectric spectroscopy.

Kurzfassung Die Kolonien des MoostierchensFlustra foliacea treten bei Helgoland in großer Abundanz, und zwar vorwiegend in Wassertiefen von 1–20 m, auf. Das Wachstum der Art zeigt einen exponentiellen Verlauf, wobei in aufeinanderfolgenden Jahren unterschiedliche Wachstumsintensitäten, deren Ursachen jedoch noch unklar sind, verzeichnet worden sind. Quantitative Angaben über den Wachstumsverlauf bei verschiedenen Altersklassen, die einen Bereich von 8 Jahren umfassen, werden mitgeteilt.

SummaryWe studied 19 infants with a mean age of 3.8 months who presented with features consistent with acute lead encephalopathy following the use of traditional medicines. All presented with convulsions; CT scans of the brain on admission showed brain oedema in four, atrophy in four and normal findings in 11. Cerebrospinal fluid analysis in nine patients showed pleocytosis in six and a high protein content in eight. The median lead level in these 19 infants with encephalopathy was 3.6 μmol/l (74.5 μg/dl). Seven had a mean lead level of only 2.7 μmol/l (56.9 μg/dl) which is much below 70 μg/dl, the level usually proposed as the threshold for encephalopathy. Thirteen infants developed brain damage during follow-up; statistical analysis correlated the lead level at 2 months post chelation with an abnormal neurological outcome. Our findings indicate that in very young infants acute lead encephalopathy may occur at lead levels lower than previously reported.

The effects of lysolecithin (lysophosphatidylcholine) derived from egg yolk as well as of synthetic lysolecithins with different aliphatic chain lengths on tension development of rabbit aortic strips were investigated. Lysolecithins caused slowly progressing, dose-dependent relaxation that was inhibited by hemoglobin, methylene blue, and nordihydroguiaretic acid. Indomethacin caused no inhibition of relaxation. The degree of relaxation was endothelium-dependent and appeared to be related to the activation of guanylate cyclase [GTP pyrophosphate-lyase (cyclizing), EC 4.6.1.2]. Superoxide dismutase failed to influence relaxation. Lysolecithins with the longest aliphatic chain were the most potent relaxants of aortic strips. The experiments suggest a role of lysolecithins through their weak detergent action on membrane dynamics of endothelial cells, resulting in the production of cyclic GMP and the relaxation of arterial smooth muscle. Lysolecithins differ in several respects from endothelium-derived relaxing factor. Endothelium-derived relaxing factor is an unstable humoral substance released from endothelium and is identical to nitric oxide, itself a labile substance causing vascular relaxation and cyclic GMP accumulation. Lysolecithins may represent a different type of endothelium-dependent muscle relaxant.

Summary Schistosoma mansoni infection is not known to produce radiologically visible calcification. In this report, we describe extensive hepatosplenic and intestinal calcification due toS. mansoni infection, demonstrated by abdominal plain x-ray and CT scan with histopathological confirmation.

Deletion mutants of Escherichia coli specific for hydrogenase isoenzyme 1 (HYD1) have been constructed and characterized. The hya operon, which contains genes for the two HYD1 structural subunits and four additional genes, was mapped at 22 min on the E. coli chromosome. The total hydrogenase activities of the HYD1-negative mutant and wild-type strains were similar. However, the formate dehydrogenase activity associated with the formate hydrogen lyase pathway was lower in the mutant. The hya mutant (strain AP1), complemented with only the hydrogenase structural genes (hyaAB), produced antigenically identifiable but inactive HYD1 protein. The first five genes of hya (hyaA to hyaE) were required for the synthesis of active HYD1, but wild-type levels of HYD1 activity were restored only when mutant cells were transformed with all six genes of the operon. When AP1 was complemented with hya carried on a high-copy-number plasmid, the HYD1 structural subunits were overexpressed, but the excess protein was unprocessed and localized in the soluble fraction of the cell. The products of hyaDEF are postulated to be involved in the processing of nascent structural subunits (HYAA and HYAB). This processing takes place only after the subunits are inserted into the cell membrane. It is concluded that the biosynthesis of active HYD1 is a complex biochemical process involving the cellular localization and processing of nascent structural subunits, which are in turn dependent on the insertion of nickel into the nascent HYD1 large subunit.

Abstract: Forty-six patients were diagnosed as having schistosomal, tuberculous, or amebic colitis over a two-year period using colonoscopy and biopsy. Both schistosomal and tuberculous colitis could be diagnosed by characteristic endoscopic and histologic features in the majority of cases. Colonoscopy provided the added advantage of endoscopic polypectomy at the diagnostic session itsell. The yield of granulomas in tuberculous lesions was 100 percent, although acid-fast bacilli could not be recovered from any. The endoscopic picture of amebic colitis often resembles that of inflammatory bowel disease; hence endoscopic biopsies are of paramount importance in establishing a correct diagnosis, especially in developing countries where both diseases exist with considerable frequency.

DNA encompassing the structural genes of an Escherichia coli [NiFe] hydrogenase has been cloned and sequenced. The genes were identified as those encoding the large and small subunits of hydrogenase isozyme 1 based on NH2-terminal sequences of purified subunits (kindly provided by K. Francis and K. T. Shanmugam). The structural genes formed part of a putative operon that contained four additional open reading frames. We have designated the operon hya and the six open reading frames hyaA through F. hyaA and hyaB encode the small and large structural subunits, respectively. The nucleotide-derived amino acid sequence of hyaC has a calculated molecular mass of 27.6 kilodaltons, contains 20% aromatic residues, and has four potential membrane-spanning regions. Open reading frames hyaD through F could encode polypeptides of 21.5, 14.9, and 31.5 kilodaltons, respectively. These putative peptides have no homology to other reported protein sequences, and their functions are unknown.

The nucleotide sequences encoding the [NiFe] hydrogenase from Desulfovibrio gigas and the [NiFeSe] hydrogenase from Desulfovibrio baculatus (N.K. Menon, H.D. Peck, Jr., J. LeGall, and A.E. Przybyla, J. Bacteriol. 169:5401-5407, 1987; C. Li, H.D. Peck, Jr., J. LeGall, and A.E. Przybyla, DNA 6:539-551, 1987) were analyzed by the codon usage method of Staden and McLachlan. The reported reading frames were found to contain regions of low codon probability which are matched by more probable sequences in other frames. Renewed nucleotide sequencing showed the probable frames to be correct. The corrected sequences of the two small and large subunits share a significant degree of sequence homology. The small subunit, which contains 10 conserved cysteine residues, is likely to coordinate at least 2 iron-sulfur clusters, while the finding of a selenocysteine codon (TGA) near the 3' end of the [NiFeSe] large-subunit gene matched by a regular cysteine codon (TGC) in the [NiFe] large-subunit gene indicates the presence of some of the ligands to the active-site nickel in the large subunit.

Four neonates with congenital Factor X deficiency presented soon after birth with bleeding episodes. Two of the newborns had intracranial hemorrhages; one of them also had antenatal ventricular dilatation and postnatal hydrocephalus and died of massive intracerebral hemorrhage at four months. One patient was lost for follow up. The two surviving infants were followed up for four years and two years respectively, while on replacement therapy with three injections of 40 units/kg prothrombin complex a month. In spite of markedly elevated prothrombin time and partial thromboplastin time, these two infants remain free of major bleeding manifestations except for troublesome petechiae and ecchymoses. A schedule for substitution therapy with Factor X is proposed for infants and children to prevent bleeding in severe Factor X deficiency.

The genes coding for the large and small subunits of the periplasmic hydrogenase from Desulfovibrio baculatus have been cloned and sequenced. The genes are arranged in an operon with the small subunit gene preceding the large subunit gene. The small subunit gene codes for a 32 amino acid leader sequence supporting the periplasmic localization of the protein, however no ferredoxin-like or other characteristic iron-sulfur coordination sites were observed. The periplasmic hydrogenases from D. baculatus (an NiFeSe protein) and D. vulgaris (an Fe protein) exhibit no homology suggesting that they are structurally different, unrelated entities.

Three species of bryozoans—Membranipora membranacea (L.), Electra pilosa (L.) and Conopeum reticulum (L.) — are capable of acclimating to elevated temperatures, above the normal range experienced in nature, when exposed to a gradual increase in ambient temperature. Conspicuous differences in LD 50 values, as a consequence of acclimation, occur between representatives of the same species acclimated and grown at constant temperatures in the laboratory. The tolerance range of these species is influenced by their thermal history in the laboratory. While increased ambient temperatures accelerate growth rate, final colony size attained after prolonged exposure declines at higher temperatures. The size of zooecia attained is inversely proportional to the test temperature. Colonies of E. pilosa maintained at 22°C develop erect branches. Hence, it is probable that E. pilosa forma erecta is only a growth form of normally encrusting colonies of E. pilosa. Temperature affects rate of regeneration.

An extensive study was conducted on the settlement and seasonal succession of fouling bryozoans in and around Cochin Harbour during the period 1965 to 1966; it was the first study of its kind performed in Indian waters. A total of 14 species was recorded from localities which were ecologically dissimilar. A distinct succession of species, mainly of a seasonal character, was observed. Seasonal succession usually occurs in localities where seasons are well marked, and where different species of animals with short life spans settle during particular times of the year. The study has shown that a distinct seasonal succession of bryozoans occurs in this locality; out of the 14 species which appeared on the panels not one species settled throughout the year. This was due to seasonal differences in the ecological conditions which prevailed in the area investigated. The significant seasonal influences on the incidence of bryozoans led to a categorisation of the species into the following patterns (a) typical brackish-water forms not encountered in purely marine localities; (b) typical brackish-water forms which may occur in marine localities; (c) typical marine forms never found in localities where low salinity conditions prevail.

Nine bryozoan species have been illustrated and described for the first time from Indian waters: Parasmittina signata (Waters), P. tubula (Kirkpatrick), P. elongata (Okada and Mawatari), P. parsevalii (Audouin), P. aviculata (Mawatari), P. egyptiaca (Waters), P. tropica (Robertson), P. california (Robertson), P. projecta (Okada and Mawatari) A comparison of the important morphological characteristics with illustrations and descriptions of these species, published in previous papers, has revealed a considerable degree of variability. My findings extend the geographical distribution of 5 species to the Indian Ocean. They demonstrate that the representatives of the genus ParasmittinaOsburn in Indian waters are Indo-Pacific in character.

The filtration rate has been determined for Electra pilosa and Conopeum reticulum, acclimated at 4 constant temperatures (6°, 12°, 18°, 22°C). Cryptomonas sp. was used as the test food-organism. Temperature affects filtration rate in both bryozoans. Clearance rate, measured at hourly intervals during the course of the experiment, was never uniform. Possibly, temporary reductions in ciliary activities were induced by the artificial conditions under which the experiments were carried out. The results obtained compare well with those reported by Bullivant (1968) on Bowerbankia imbricata, a cosmopolitan ctenostome. Rate of food passage through the alimentary canal is affected by temperature. The present study is the first to demonstrate the effect of temperature on the rate of filtration in bryozoans.

Kurzfassung In Zooiden der marinen BryozoaElectra pilosa (L.) wurden zahlreiche Exemplare des freilebenden NematodenPelagonema obtusicaudaFilipjev gefunden. Die Nematoden besiedeln offensichtlich die noch jungen Kolonien, in denen sie auch zur Fortpflanzung gelangen. Die Art der Beziehung zwischen den beiden Organismen bedarf noch weiterer Klärung.

Presents a letter to the editor about local scare tactics used to compel physicians to change their computer system.

A software package has been developed that synthesizes entire energy-loss spectra for an arbitrary distribution of impurities embedded in an arbitrary matrix, for user specified sample parameters and acquisition conditions. The simulation of a complete spectrum facilitates the estimation of quantities such as the Minimum Detectable Mass (MDM) or the Minimum Detectable Number of atoms (MDN). This is addressed with particular attention to optimising the acquisition conditions to maximize the detectability and also to estimating the error in a typical EELS quantification. It is envisaged that this approach will have wide-ranging implications for the role of EELS in quantitative microanalysis.Electron Energy Loss Spectroscopy (EELS) is widely recognized as a microanalytical tool capable of characterizing the elemental composition of materials with nm-level resolution and sensitivity approaching single atoms. Extracting quantitative information from EEL spectra is complicated by the fact that both the cross-sections and the pre-edge background used for inner-shell analysis vary widely.

Electron energy loss spectroscopy (EELS) is a powerful microanalytical tool that can be used to characterize the composition and other properties of a wide range of materials. The compositional information is retrievable from the pattern of edges displayed in the energy-loss spectrum [1]. Under favorable experimental conditions, concentrations below 1000 ppm of many different elements can be detected on a nanometer scale [2].The minimum detectable mass (MDM) and the minimum detectable mass fraction (MDF) attainable in practice depend on many parameters (sample thickness, incident beam convergence / acceptance angles, primary energy, electron dose, probe size, detector efficiency, etc.), and there are no easy rules that can be used to predict them. For instance, a minority element that gives rise to an edge situated at an energy just lower than a major edge due to a principal constituent is much easier to detect than a minority element that gives rise to an edge just above the major edge.

Presents a letter to the editor regarding the inclusion of the superannuation contributions of employers in the global sum in Great Britain.

Presents a letter to the editor in response to the article which featured a primary care trust at Redbridge in London, England.