Self-consistent Calculation of Real Space Renormalization Group Flows and Effective Potentials

We show how to compute real space renormalization group flows in lattice field theory by a self-consistent method. In each step, the integration over the fluctuation field (high frequency components of the field) is performed by a saddle point method. The saddle point depends on the block-spin. Higher powers of derivatives of the field are neglected in the actions, but no polynomial approximation in the field is made. The flow preserves a simple parameterization of the action. In this paper we treat scalar field theories as an example.Comment: 52 pages, uses pstricks macro, three ps-figure

Phylogeographic Analysis Elucidates the Influence of the Ice Ages on the Disjunct Distribution of Relict Dragonflies in Asia

Unusual biogeographic patterns of closely related groups reflect events in the past, and molecular analyses can help to elucidate these events. While ample research on the origin of disjunct distributions of different organism groups in the Western Paleartic has been conducted, such studies are rare for Eastern Palearctic organisms. In this paper we present a phylogeographic analysis of the disjunct distribution pattern of the extant species of the strongly cool-adapted Epiophlebia dragonflies from Asia. We investigated sequences of the usually more conserved 18 S rDNA and 28 S rDNA genes and the more variable sequences of ITS1, ITS2 and CO2 of all three currently recognised Epiophlebia species and of a sample of other odonatan species. In all genes investigated the degrees of similarity between species of Epiophlebia are very high and resemble those otherwise found between different populations of the same species in Odonata. This indicates that substantial gene transfer between these populations occurred in the comparatively recent past. Our analyses imply a wide distribution of the ancestor of extant Epiophlebia in Southeast Asia during the last ice age, when suitable habitats were more common. During the following warming phase, its range contracted, resulting in the current disjunct distribution. Given the strong sensitivity of these species to climatic parameters, the current trend to increasing global temperatures will further reduce acceptable habitats and seriously threaten the existences of these last representatives of an ancient group of Odonata

Chemical Defence in a Millipede: Evaluation and Characterization of Antimicrobial Activity of the Defensive Secretion from Pachyiulus hungaricus (Karsch, 1881) (Diplopoda, Julida, Julidae)

The chemical defence of the millipede Pachyiulus hungaricus is reported in the present paper, in which a chemical characterization is given and antimicrobial activity is determined. In total, independently of sex, 44 compounds were identified. All compounds belong to two groups: quinones and pentyl and hexyl esters of long-chain fatty acids. The relative abundances of quinones and non-quinones were 94.7% vs. 5.3% (males) and 87.3% vs. 12.7% (females), respectively. The two dominant quinones in both sexes were 2-methyl-1,4,-benzoquinone and 2-methoxy-3-methyl-1,4-benzoquinone. Antibacterial and antifungal activity of the defensive secretion was evaluated in vitro against seven bacterial strains and eight fungal species. With the aid of a dilution technique, the antimicrobial potential of the secretion and high sensitivity of all tested strains were confirmed. The lowest minimum concentrations of these compounds (0.20-0.25 mg/mL) were sufficient for inhibition of Aeromonas hydrophila, Listeria monocytogenes and Methicillin resistant Staphylococcus aureus (MRSA). The growth of eight tested fungal species was inhibited by slightly lower concentrations of the secretion, with Fusarium equisetias the most sensitive fungus and Aspergillus flavus as the most resistant. Values of MIC and MFC in the employed microdilution assay ranged from 0.10 to above 0.35 mg/m L. The given extract contains antimicrobial components potentially useful as therapeutic agents in the pharmaceutical and agricultural industries

Effect of cultivation parameters on growth and pigment biosynthesis in flagellated cells of Haematococcus pluvialis

The volvocalean microalga Haematococcus pluvialis is used as a source of the ketocarotenoid astaxanthin for applications in aquaculture and the pharmaceutical and cosmetic industries. This green alga accumulates astaxanthin, mostly esterified, canthaxanthin and echinenone in lipid vesicles outside the chloroplast. This accumulation process normally but not exclusively accompanies formation of the resting state in the developmental cycle. With regard to increased bioavailability of the accumulated secondary carotenoids, the fragility of the extracellular matrix makes the flagellated state of H. pluvialis an interesting alternative to the thick-walled aplanospore state. A two-step batch cultivation scheme was developed that leads to accumulation of secondary carotenoids in flagellated cells of H. pluvialis (strain 192.80, Göttingen, Germany). Germination of green aplanospores during the first step of cultivation proceeded optimally under 30 μmol photon m-2 S-1 of white fluorescent light 20°C. For optimal induction and enhancement of carotenoid biosynthesis, the flagellated cells formed were then exposed to a decreased level of nitrate (0.4 mM KNO3) and to enhanced irradiance (150 μmol photon m-2 s-1). Under these conditions, which still permitted cell division and chlorophyll synthesis during the first two days of exposure, carotenoid accumulation in the flagellated cells reached 2% of dry mass at the fourth day of exposure. As a mixotrophic carbon source, addition of acetate at a concentration not higher than 10 mM increased carotenoid synthesis only slightly whereas partial or complete phosphate deficiency or salt stress (40 mM NaCl) did not

Effect of cultivation parameters on growth and pigment biosynthesis in flagellated cells of Haematococcus pluvialis

The volvocalean microalga Haematococcus pluvialis is used as a source of the ketocarotenoid astaxanthin for applications in aquaculture and the pharmaceutical and cosmetic industries. This green alga accumulates astaxanthin, mostly esterified, canthaxanthin and echinenone in lipid vesicles outside the chloroplast. This accumulation process normally but not exclusively accompanies formation of the resting state in the developmental cycle. With regard to increased bioavailability of the accumulated secondary carotenoids, the fragility of the extracellular matrix makes the flagellated state of H. pluvialis an interesting alternative to the thick-walled aplanospore state. A two-step batch cultivation scheme was developed that leads to accumulation of secondary carotenoids in flagellated cells of H. pluvialis (strain 192.80, Göttingen, Germany). Germination of green aplanospores during the first step of cultivation proceeded optimally under 30 μmol photon m-2 S-1 of white fluorescent light 20°C. For optimal induction and enhancement of carotenoid biosynthesis, the flagellated cells formed were then exposed to a decreased level of nitrate (0.4 mM KNO3) and to enhanced irradiance (150 μmol photon m-2 s-1). Under these conditions, which still permitted cell division and chlorophyll synthesis during the first two days of exposure, carotenoid accumulation in the flagellated cells reached 2% of dry mass at the fourth day of exposure. As a mixotrophic carbon source, addition of acetate at a concentration not higher than 10 mM increased carotenoid synthesis only slightly whereas partial or complete phosphate deficiency or salt stress (40 mM NaCl) did not

Structure of the central nervous system of a juvenile acoel, Symsagittifera roscoffensis

The neuroarchitecture of Acoela has been at the center of morphological debates. Some authors, using immunochemical tools, suggest that the nervous system in Acoela is organized as a commissural brain that bears little resemblance to the central, ganglionic type brain of other flatworms, and bilaterians in general. Others, who used histological staining on paraffin sections, conclude that it is a compact structure (an endonal brain; e.g., Raikova 2004; von Graff 1891; Delage Arch Zool Exp Gén 4:109-144, 1886). To address this question with modern tools, we have obtained images from serial transmission electron microscopic sections of the entire hatchling of Symsagittifera roscoffensis. In addition, we obtained data from wholemounts of hatchlings labeled with markers for serotonin and tyrosinated tubulin. Our data show that the central nervous system of a juvenile S. roscoffensis consists of an anterior compact brain, formed by a dense, bilobed mass of neuronal cell bodies surrounding a central neuropile. The neuropile flanks the median statocyst and contains several types of neurites, classified according to their types of synaptic vesicles. The neuropile issues three pairs of nerve cords that run at different dorso-ventral positions along the whole length of the body. Neuronal cell bodies flank the cords, and neuromuscular synapses are abundant. The TEM analysis also reveals different classes of peripheral sensory neurons and provides valuable information about the spatial relationships between neurites and other cell types within the brain and nerve cords. We conclude that the acoel S. roscoffensis has a central brain that is comparable in size and architecture to the brain of other (rhabditophoran) flatworms