Effect of dietary docosahexaenoic acid on lipogenesis and lipolysis in black sea bream, Acanthopagrus schlegeli

1 IntroductionIt is well known that varying dietary fatty acidprofile affects the tissue fatty acid composition and e-ven the growth performance in fish ( Bell et al.,2002; Figueiredo -Silva et al., 2005; Harel andPlace, 2003; Schulz et al., 2005; Tocher et al.,2003). Docosahexaenoic acid (DHA), an importantessential fatty acid for marine species, has the effectnot only on the fatty acid profile of fish body tissue,but also on biological and physiological conditions(Ishizaki et al., 2000; …     

Chloride retention in forest soil by microbial uptake and by natural chlorination of organic matter

Inorganic chlorine (i.e. chloride; Cl_in) is generally considered inert in soil and is often used as a tracer of soil and ground water movements. However, recent studies indicate that substantial retention or release of Cl_in can occur in soil, but the rates and processes responsible under different environmental conditions are largely unknown. We performed ³⁶Cl tracer experiments which indicated that short-term microbial uptake and release of Cl_in, in combination with more long-term natural formation of chlorinated organic matter (Cl_org), caused Cl_in imbalances in coniferous forest soil. Extensive microbial uptake and release of Cl_in occurred over short time scales, and were probably associated with changes in environmental conditions. Up to 24% of the initially available Cl_in within pore water was retained by microbial uptake within a week in our experiments, but most of this Cl_in was released to the pore water again within a month, probably associated with decreasing microbial populations. The natural formation of Cl_org resulted in a net immobilization of 4% of the initial pore water Cl_in over four months. If this rate is representative for the area where soil was collected, Cl_org formation would correspond to a conversion of 25% of the yearly wet deposition of Cl_in. The study illustrates the potential of two Cl_in retaining processes in addition to those previously addressed elsewhere (e.g. uptake of chloride by vegetation). Hence, several processes operating at different time scales and with different regulation mechanisms can cause Cl_in imbalances in soil. Altogether, the results of the present study (1) provide evidence that Cl_in cannot be assumed to be inert in soil, (2) show that microbial exchange can regulate pore water Cl_in concentrations and (3) confirm the controversial idea of substantial natural chlorination of soil organic matter.     

Influence of land use on the abundance of wildlife and livestock in the Kalahari,Botswana

Human land use such as pastoralism may be a key determinant of wildlife populations. We studied the influence of land use on wildlife and livestock in south-western Kalahari, Botswana, during the wet and dry seasons. We included two types of livestock areas and two types of wildlife protection areas. Wild and domestic mammals >0.2 kg were sampled by distance technique. Small mammals <0.2 kg were trapped and a vegetation survey was performed. Livestock and some medium-sized wildlife species were most abundant in livestock areas, while large-sized wildlife species were mainly restricted to wildlife areas. Most red-listed species were confined to the national park. The influence of land use on abundances changed moderately between seasons. However, cattle moved into wildlife areas during the wet season. Differences in species richness and diversity were most pronounced during the dry season. The trapping frequency of small mammals was highest in the national park. Differences in vegetation structure included sparser field layer and higher cover of an invasive shrub in livestock areas. Our study shows the importance of protected areas for many wildlife species in the Kalahari. It also shows the value of a multi-species approach for investigating the effects of land use on wildlife communities.     

P/2004 A1 (Loneos) – a comet under transition from Saturn to Jupiter

The newly discovered periodic comet P/2004 A1 (LONEOS) is found to have experienced a recent capture into its present orbit, following a close approach to Saturn in 1992 to within 0.032 AU. This induced orbital change transfered the comet into an orbit tangent to that of Jupiter, which will, after a close passage in 2026, gain control by further decoupling it from the influence of Saturn. A long‐term orbital investigation yields support that the comet is on its first sojourn into the inner solar system. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Globalising Swedish countrysides? A relational approach to rural immigrant restaurateurs with refugee backgrounds

The main purpose of the article is to connect rural immigrants’ business ventures and development in Sweden to relational perspectives on their proximate and distant family and co-ethnic networks at structural and individual levels. Accordingly, the authors employ a relational approach and draw on in-depth interviews. In the context of urban–rural relationships’ meanings for the restaurateurs’ business benefits and constraints, they address two questions: (1) What does embeddedness in proximate and distant family and co-ethnic networks mean for the interviewed restaurateurs and for their businesses? and (2) How do previous and anticipated transitions in the restaurateurs’ families influence their business decisions and migration trajectories? The results suggest that the interviewees employed transnational dimensions in their social embeddedness and that they maintained material and emotional relationships with their countries of origin. This relational approach thus contributes to a better understanding of what the studied businesses mean for the entrepreneurs and the selected localities. The restaurateurs contribute to a globalisation of Swedish countrysides, but their socio-economic potential for countering rural depopulation in Sweden is not fully realised. Additionally, the study illuminates how individuals influence, and are influenced by, place-to-place mobilities on a daily basis and during their life course.     

Surface Charge Concentrations on Silica in Different 1.0 M Metal-Chloride Background Electrolytes and Implications for Dissolution Rates

The empirical rate laws formulated to describe the dissolution rates of oxide minerals include the surface charge concentration that results from the protonation and deprotonation of surface functional groups. Previous experiments on quartz and silica have shown that dissolution rates vary as a function of different background electrolyte solutions, however, such experiments are often conducted at elevated temperatures where it is difficult to estimate surface charge along with the dissolution rates. In the present study we measuresurface charge concentrations for silica in different electrolyte solutions at 298 K in order to quantify the extent to which the different counterions could affect the dissolution rates through their influence on the surface charge concentrations. The experimental solutions in the electrolyte series: LiCl, NaCl, KCl, RbCl, CaCl₂, SrCl₂ and BaCl₂ were prepared to maintain a constant metal concentration of 1.0 M. For the alkali-metal chlorides, the surface charge concentrations correlate with the size of the hydrated alkali metal, consistent with the idea that these counterions affect charge via outer-sphere coordination that shield proton surface complexes from one another. The reactivity trend for alkaline-earth cations is less clear, but the data demonstrate distinct differences in the acid-base propertiesof the silica surface in these different electrolytes. We then discuss how these trends are manifested in the rate equations used to interpret dissolution experiments.     

New Reference Materials,Analytical Procedures and Data Reduction Strategies for Sr Isotope Measurements in Geological Materials by LA-MC-ICP-MS

Laser ablation multi-collector mass spectrometry (LA-MC-ICP-MS) has emerged as the technique of choice for in situ measurements of Sr isotopes in geological minerals. However, the method poses analytical challenges and there is no widely adopted standardised approach to collecting these data or correcting the numerous potential isobaric inferences. Here, we outline practical analytical procedures and data reduction strategies to help establish a consistent framework for collecting and correcting Sr isotope measurements in geological materials by LA-MC-ICP-MS. We characterise a new set of plagioclase reference materials, which are available for distribution to the community, and present a new data reduction scheme for the Iolite software package to correct isobaric interferences for different materials and analytical conditions. Our tests show that a combination of Kr-baseline subtraction, Rb-peak-stripping using βRb derived from a bracketing glass reference material, and a CaCa or CaAr correction for plagioclase and CaCa or CaAr + REE²⁺ correction for rock glasses, yields the most accurate and precise ⁸⁷Sr/⁸⁶Sr measurements for these materials. Using the analytical and correction procedures outlined herein, spot analyses using a beam diameter of 100 μm or rastering with a 50–65 μm diameter beam can readily achieve < 100 ppm 2SE repeatability ("internal") precision for ⁸⁷Sr/⁸⁶Sr measurements for materials with < 1000 μg g^-1 Sr.