Seasonal variations in phytoplankton composition and biomass in a small lowland river-lake system (Melen River, Turkey)

WOS: 000294698400012A series of studies were carried out to determine the succession and phytoplankton community of the Melen River in the Western Black Sea region of Turkey. The study was conducted at 6 stations at monthly intervals between May 2003 and April 2004. It was observed that the abundance and biovolume of phytoplankton were low in winter, though higher values were recorded in late spring and summer. Among the values noted, the spring peak was 534.38 x 10(5) ind. L-1 and 7384.8 mm(3) L-1 belonging to Peridinium sp. The most common diatom, Cyclostephanos dubius, was favoured by low discharge at stations 1 and 2 in the early summer (214.29 x 10(5) in L-1 and 9.84 x 10(5) in L-1), respectively. Chlorophyll-a concentrations were between 0.86 and 64.2 mu g L-1. A total of 135 taxa belonging to Cyanophyta, Bacillariophyta, Chlorophyta, Dinophyta, Euglenophyta, Heterokontophyta, Streptophyta, and Xanthophyta were identified. The total biomass of the stations 1 and 2 was mainly characterised by Dinophyta and at other stations by Bacillariophyta. Five major genera (Peridinium, Ceratium, Phacus, Cyclostephanos, and Melosira) accounted for over 70% of the total phytoplankton abundance. Phytoplankton abundance was significant and positively correlated with Chl-a and temperature (r = 0.57 and r = 0.78, respectively P < 0.05). Species richness and diversity indices increased gradually throughout the course of the river.Gazi University, Scientific Projects Research ManagementGazi UniversityWe would like to thank Gazi University, Scientific Projects Research Management for financing this research and also the General Directorate of State Hydraulic Works (DSI) for analysing the physical and chemical parameters of the Melen River

Open areas in a landscape enhance pollen-mediated gene flow of a tree species: evidence from northern Switzerland

Habitat fragmentation often has negative consequences for genetic diversity, and thereby for the viability of populations. However, these negative consequences might be counteracted by gene flow as the latter provides functional connectivity between apparently isolated habitat fragments. Gene flow is itself influenced by landscape structure and composition, and it is therefore important to understand the relationship between gene flow and landscape structure and composition. We used linear LAD regression models to investigate the relationship between contemporary gene flow by pollen in the rare, insect-pollinated forest tree Sorbus domestica and several landscape features. None of the landscape components—which included closed forest, deep valleys, open land and settlements—proved to be an impermeable barrier to gene flow by pollen. We found evidence that settlements, large open areas, and a pronounced topography increased long-distance gene flow in the landscape as compared to a random model including all possible gene flow trajectories. These results are encouraging from a conservation view, as gene flow in species pollinated by generalist insects seems to provide functional connectivity and may help to maintain genetic diversity in rare plant species in fragmented landscape

Atomistic modelling of large-scale metal film growth fronts

We present simulations of metallization morphologies under ionized sputter deposition conditions, obtained by a new theoretical approach. By means of molecular dynamics simulations using a carefully designed interaction potential, we analyze the surface adsorption, reflection, and etching reactions taking place during Al physical vapor deposition, and calculate their relative probability. These probabilities are then employed in a feature-scale cellular-automaton simulator, which produces calculated film morphologies in excellent agreement with scanning-electron-microscopy data on ionized sputter deposition.Comment: RevTeX 4 pages, 2 figure

Extrusion based additive manufacturing of fungal based composite materials using the tinder fungus Fomes fomentarius

Background Recent efforts in fungal biotechnology aim to develop new concepts and technologies that convert renewable plant biomass into innovative biomaterials. Hereby, plant substrates become metabolized by filamentous fungi to transform them into new fungal based materials. Current research is thus focused on both understanding and optimizing the biology and genetics underlying filamentous fungal growth and on the development of new technologies to produce customized fungal based materials. Results This manuscript reports the production of stable pastes, composed of Fomes fomentarius mycelium, alginate and water with 71 wt. mycelium in the solid content, for additive manufacturing of fungal based composite materials. After printing complex shapes, such as hollow stars with up to 39 mm in height, a combination of freeze drying and calcium crosslinking processes allowed the printed shapes to remain stable even in the presence of water. The printed objects show low bulk densities of 0.12 amp; 8201; amp; 8201;0.01 g cm3 with interconnected macropores. Conclusions This work reports for the first time the application of mycelium obtained from the tinder fungus F. fomentarius for an extrusion based additive manufacturing approach to fabricate customized light weight 3D objects. The process holds great promise for developing light weight, stable, and porous fungal based materials that could replace expanded polystyrene produced from fossil resource

Direct constraint on the distance of y2 Velorum from AMBER/VLTI observations

In this work, we present the first AMBER observations, of the Wolf-Rayet and O (WR+O) star binary system y2 Velorum. The AMBER instrument was used with the telescopes UT2, UT3, and UT4 on baselines ranging from 46m to 85m. It delivered spectrally dispersed visibilities, as well as differential and closure phases, with a resolution R = 1500 in the spectral band 1.95-2.17 micron. We interpret these data in the context of a binary system with unresolved components, neglecting in a first approximation the wind-wind collision zone flux contribution. We show that the AMBER observables result primarily from the contribution of the individual components of the WR+O binary system. We discuss several interpretations of the residuals, and speculate on the detection of an additional continuum component, originating from the free-free emission associated with the wind-wind collision zone (WWCZ), and contributing at most to the observed K-band flux at the 5% level. The expected absolute separation and position angle at the time of observations were 5.1&plusmn;0.9mas and 66&plusmn;15&deg; respectively. However, we infer a separation of 3.62+0.11-0.30 mas and a position angle of 73+9-11&deg;. Our analysis thus implies that the binary system lies at a distance of 368+38-13 pc, in agreement with recent spectrophotometric estimates, but significantly larger than the Hipparcos value of 258+41-31 pc

Near-Infrared interferometry of Eta Carinae with high spatial and spectral resolution using the VLTI and the AMBER instrument

We present the first NIR spectro-interferometry of the LBV Eta Carinae. The K band observations were performed with the AMBER instrument of the ESO Very Large Telescope Interferometer using three 8.2m Unit Telescopes with baselines from 42 to 89m. The aim of this work is to study the wavelength dependence of Eta Car's optically thick wind region with a high spatial resolution of 5 mas (11 AU) and high spectral resolution. The medium spectral resolution observations (R=1,500) were performed in the wavelength range around both the HeI 2.059 micron and the Br gamma 2.166 micron emission lines, the high spectral resolution observations (R=12,000) only in the Br gamma line region. In the K-band continuum, a diameter of 4.0 +/-0.2 mas (Gaussian FWHM, fit range 28-89m) was measured for Eta Car's optically thick wind region. If we fit Hillier et al. (2001) model visibilities to the observed AMBER visibilities, we obtain 50 % encircled-energy diameters of 4.2, 6.5 and 9.6mas in the 2.17 micron continuum, the HeI, and the Br gamma emission lines, respectively. In the continuum near the Br gamma line, an elongation along a position angle of 120+/-15 degrees was found, consistent with previous VLTI/VINCI measurements by van Boekel et al. (2003). We compare the measured visibilities with predictions of the radiative transfer model of Hillier et al. (2001), finding good agreement. Furthermore, we discuss the detectability of the hypothetical hot binary companion. For the interpretation of the non-zero differential and closure phases measured within the Br gamma line, we present a simple geometric model of an inclined, latitude-dependent wind zone. Our observations support theoretical models of anisotropic winds from fast-rotating, luminous hot stars with enhanced high-velocity mass loss near the polar regions.Comment: 22 pages, 14 figures, 2 tables; A&A in pres

GC content of early metazoan genes and its impact on gene expression levels in mammalian cell lines

With the genomes available for many animal clades, including the early-branching metazoans, one can readily study the functional conservation of genes across a diversity of animal lineages. Ectopic expression of an animal protein in, for instance, a mammalian cell line is a generally used strategy in structure–function analysis. However, this might turn out to be problematic in case of distantly related species. Here we analyzed the GC content of the coding sequences of basal animals and show its impact on gene expression levels in human cell lines, and, importantly, how this expression efficiency can be improved. Optimization of the GC3 content in the coding sequences of cadherin, alpha-catenin, and paracaspase of Trichoplax adhaerens dramatically increased the expression of these basal animal genes in human cell lines

Sustainable design of biorefinery processes: existing practices and new methodology

Nowadays, eco-designing products is increasingly practiced. The next challenge for sustain- ability is to optimize production processes. Biorefi neries are particularly concerned with this improve- ment, because they use renewable resources. To identify the contribution of transformation processes to the overall environmental impacts, Life Cycle Assessment (LCA) appears as the adequate method. A literature review highlights that LCA is mainly performed on biorefi neries to compare biomass feed- stocks between them and to a fossil reference. Another part of environmental LCA compares the impacts of different processing routes. Nevertheless, these evaluations concern already designed pro- cesses. Generally, processes are considered as a unique operation in assessments. However, some criteria like operating can notably modify environmental burdens. The eco-design of biorefi nery pro- cesses can be guided by coupling process simulation to LCA. This method has been emerging in the chemical sector in recent years. Consequently, this paper proposes a new methodological approach to assessing the complete sustainability of biorefi nery processes, since its fi rst design stages. In addi- tion to coupling process simulation and environmental LCA, the other pillars of sustainability will be assessed. Indeed, Life Cycle Costing and Social Life Cycle Assessment can be performed to obtain an integrated methodological framework. The simultaneous optimization of the environmental, economic, and social performances of the process can lead to antagonist ways of improving. Consequently, compromises should be realized. Thereby, the multi-objective optimization can be accomplished by a metaheuristic method supported by a decision-making tool. Finally, the main limits of this method and some perspectives and ways for improving are discussed

Решение оптимизационных задач для систем массового обслуживання с отказами в условиях неопределенности

Построены математические модели расчета показателей качества функционирования вычислительных сетей, которые можно представить в виде сетей массового обслуживания с отказами. Сформулированы задачи оптимизации показателей качества функционирования таких сетей при заданных ограничениях на максимальную пропускную способность каналов связи и на выделяемые для модернизации сети ресурсы. Построены алгоритмы, которые позволяют решать поставленные оптимизационные задачи в рамках оговоренных ограничений