981 resultados para shells of Calyptogena sp.


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In clause is given robotic a complex for drilling and milling sandwich shells from polymeric composites. The machining of polymeric composite materials has technological problems. At drilling sandwich shells there is a probability of destruction of a drill from hit of the tool in a partition. The system sensibilization robotic complex for increase of reliability of work of the cutting tool of the small size is offered.

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Recent work has provided useful Mg/Ca to water temperature calibrations for shallow-dwelling planktonic foraminifer species. Globorotalia truncatulinoides (right coiling (R)) is a deep-dwelling species that can serve as a source of information about the temporal variability in the water characteristics of the thermocline. We present a temperature calibration for the Mg/Ca in the shell of G. truncatulinoides (R) and examine some of the practical issues associated with evaluating the usefulness of the technique. The Mg/Ca in the primary and the secondary calcite of individual G. truncatulinoides (R) correlates exponentially with water column temperatures, showing a change of ~10% in the Mg/Ca per 1°C (R**2 = 0.92). A limited comparison with plankton tow samples demonstrates that the average Mg/Ca temperature was offset +1°C from the average temperature calculated using the d18O calibration of O'Neil et al. (1969, doi:10.1063/1.1671982), and the Mg/Ca temperatures have a range similar to the ?18O temperatures. Comparisons of the [Mg] in the core top samples to water depth of deposition indicates that dissolution does not alter the measured value of Mg in the primary calcite.

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Within generally calcareous sediment sequences, layers of variable thickness of the giant diatom Ethmodiscus were found in five cores recovered in the Subtropical South Atlantic between 23° and 33°S from both sides of the Mid-Atlantic Ridge. Two types of oozes occur: (almost) monospecific layers of Ethmodiscus and layers dominated by Ethmodiscus, with several accompanying tropical/subtropical, oligotrophic-water diatoms. The two thickest Ethmodiscus layers occur in GeoB3801-6 around 29°S, and accumulated during late MIS 14 and MIS 12, respectively. Downcore concentrations of Ethmodiscus valves range between 3.4 10 4 and 2.3 10 7 valves g -1. We discuss the ooze formation in the context of migration of frontal systems and changes in the thermohaline circulation. The occurrence of Ethmodiscus oozes in sediments underlying the present-day pelagic, low-nutrient waters is associated with a terminal event of the Mid-Pleistocene Transition at around 530 ka, when the ocean circulation rearranged after a period of reduced NADW production.

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Mode of access: Internet.

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Mode of access: Internet.

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Mode of access: Internet.

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The Sp/KLF transcription factors perform a variety of biological functions, but are related in that they bind GC-box and CACCC-box sequences in DNA via a highly conserved DNA-binding domain. A database homology search, using the zinc finger DNA-binding domain characteristic of the family, has identified human KLF17 as a new family member that is most closely related to KLFs 1-8 and 12. KLF17 appears to be the human orthologue of the previously reported mouse gene, zinc finger protein 393 (Zfp393), although it has diverged significantly. The DNA-binding domain is the most conserved region, suggesting that both the murine and the human forms recognize the same binding sites in DNA and may retain similar functions. We show that human KLF17 can bind G/C-rich sites via its zinc fingers and is able to activate transcription from CACCC-box elements. This is the first report of the DNA-binding characteristics and transactivation activity of human KLF17, which, together with the homology it displays to other KLF proteins, put it in the Sp/KLF family. (c) 2006 Elsevier Inc. All rights reserved.

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A novel method that relies on the decoupling of the energy production and biosynthesis processes was used to characterise the maintenance, cell lysis and growth processes of Nitrosomonas sp. A Nitrosolnonas culture was enriched in a sequencing batch reactor (SBR) with ammonium as the sole energy source. Fluorescent in situ hybridization (FISH) showed that Nitrosomonas bound to the NEU probe constituted 82% of the bacterial population, while no other known ammonium or nitrite oxidizing bacteria were detected. Batch tests were carried out under conditions that both ammonium and CO, were in excess, and in the absence of one of these two substrates. The oxygen uptake rate and nitrite production rate were measured during these batch tests. The results obtained from these batch tests, along with the SBR performance data, allowed the determination of the maintenance coefficient and the in situ cell lysis rate, as well as the maximum specific growth rate of the Nitrosomonas culture. It is shown that, during normal growth, the Nitrosomonas culture spends approximately 65% of the energy generated for maintenance. The maintenance coefficient was determined to be 0.14 - 0.16 mgN mgCOD(biomass)(-1) h(-1), and was shown to be independent of the specific growth rate. The in situ lysis rate and the maximum specific growth rate of the Nitrosomonas culture were determined to be 0.26 and 1.0 day(-1) (0.043 h(-1)), respectively, under aerobic conditions at 30 degrees C and pH7. (c) 2006 Elsevier B.V. All rights reserved.

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Investigations on growth and quantity of phycocolloids of Sargassum sp. and Gracilaria corticata was done on field and laboratorial works over one year from January 2003 to May 2004. Sargassum thalli began growth from January. The highest biomass value recorded 1611.04 gm^-2 was obtained in November. The receptacles appeared on November and released eggs. The senescence of Sargassum thalli was in December and the new thallus began to grow from January, The highest relative growth rate (6.74 percent) was in February. The relative growth rate showed significant correlation (p<0,05) with temperature. The highest value of alginate was in November (10.02 percent). Alginat content showed significant correlations (p<0.05) with Sargassum biomass. There was no significant effect of environmental factors on alginate content. The highest biomass of Graciiaria was in Match (49.88 gm^-2). Maximum relative growth rate of Gracilara (2 percent) was in December. Relative growth rate of Gracilaria (2.8 percent) was in December. Relative growth rate of Gracilaria showed significant correlations (p<0.05) with temperature. There was significant effect of ammonium (p<0.05) on growth factors of Gracilaria, maximum agar content was in August {10.005 percent). The yield of agar showed significant correlation (p<0.05) with Gracilaria biomass and ammonium in field and laboratory.

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Rutilus frisii Kutum is one of the most precious fish in the Caspian Sea. Investigation of the various aspects of its biocharactristics. Including its parasite fauna and ecological aspects are of prime importance. In this study the farmed kutum fry were on the focus of investigation in various seasons of the year and prior to their being released in the sea. This included also the study on the kutum spawners caught both from liver and the sea. The results were that 17 external and internal parasite species were distinct within different organs which were further identified down to genus and species. The single celled parasites identified included Ichthyophthirius multifilils, Chilodonella hexastica, Chilodonella pisicola, Trichodina sp Along with the monogene parasites that included Paradiplozoon chazaricum, D. rarissimus, D. turaliensis, D. nybelini, Dactylogyrus frisii. Meanwhile Diplostomum spathaceum constituted the single eyed parasites and the intestinal termatode were Aspidogaster limacoides, Asymphyoldora kubanicum as well as Bothriocephalus gowkongeniss as the sestads. The nematodes defrentiated were Raphidascaris acus, Dioctophyma renale, and Eustrongylides excisus followed by Lernaea cyprinacea as a crustacean. In this study, infestations by single celled parasites, crustaceans and sestod were found to be present only among the farmed kutum fry which varied in terms of percentage and intensity of infection as well as the parasite species and season of the year. The highest percentage of infection among kutum fry and spawners in both fresh water and in the sea during all seasons belonged to monogene parasites (33%). This was up to 100% among spawners. Infection caused by nematodes was exclusively detected among riverine spawners (7.5-5%) and the infection by Asymphyoldora kubanicum and Aspidogaster limacoides among Spawners caught at Sea and rivers varied within different seasons of the year. The infestation of Metacercer diplostomum spathaceum among kutum fry was 12% which compared to spawners was in slightly higher level. The study could identify Dioctophyma renale for the first time in the country and Eustrongylidis excisu was also detected among Rutilus frisii kutum.