328 research outputs found

    Biodiversity in drinking water distribution systems:a brief review

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    In drinking water distribution systems, three groups of living organisms are usually found in the biofilm and circulating water: heterotrophic bacteria, free-living protozoa, and macro-invertebrates. Indirect evidence suggests that protozoa grazing in distribution systems can partially eliminate biomass production and accidental microbiological pollution. This paper examines the biodiversit in drinking water distribution systems

    Sustaining family forests in rural landscapes: Rationale, challenges, and an illustration from Oregon, USA

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    Family forests are critical components of rural landscapes, societies and economies. In Oregon, where nonindustrial private forests comprise only 16% of the forestland base, the ecological, social and economic impact of this ownership category is disproportionately large. This is due to the landscape position these lands occupy, the diversification they contribute to forest cover and local economies, and the political and cultural connections they provide to urban populations. The significance of this ownership category is even greater in the United States as a whole, where nonindustrial private forests comprise nearly two-thirds of the commercial forestland base, dominating rural landscapes in many regions of the country. Despite the important role family forests play, their ability to contribute to the wellbeing of rural areas is challenged by several dynamic factors, including industrial consolidation in global wood markets, loss of family forestland to corporate ownership, and parcelization and fragmentation of family forestland at the urban fringe. Moreover, family forestry does not enjoy a strong social contract with the American public, which is largely ignorant of the existence of this ownership class. A foundation of broad social approval and appreciation for family forestry is a prerequisite to development of policies which can sustain family forestland ownerships and the contributions they make. This paper draws from recent research in Oregon to argue that, whereas most research on nonindustrial private forests has focused on economics and management at the individual producer level, these challenges demand greater attention to the role of family forests in the wider context of landscape, culture and rural economy

    A versatile reactor for continuous monitoring of biofilm properties in laboratory and industrial conditions

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    Aims: The understanding of the dynamics of surface microbial colonization with concomitant monitoring of biofilm formation requires the development of biofilm reactors that enable direct and real-time evaluation under different hydrodynamic conditions. Methods and Results: This work proposes and discusses a simple flow cell reactor that provides a means to monitoring biofilm growth by periodical removing biofilm-attached slides for off-line, both non-destructive and destructive biofilm analyses. This is managed without the stoppage of the flow, thus reducing the contamination and the disturbance of the biofilm development. With this flow cell, biofilm growth and respiratory activity can be easily followed, either in well-defined laboratory conditions or in an industrial environment. Conclusions, Significance and Impact of the Study: The reproducible and typical biofilm development curves obtained, validated this flow cell and confirmed its potential for different biofilm-related studies, which can include biocidal treatment.Instituto de Biotecnologia e Química Fina(IBQF)

    Efficiency of the dynamical mechanism

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    The most extreme starbursts occur in galaxy mergers, and it is now acknowledged that dynamical triggering has a primary importance in star formation. This triggering is due partly to the enhanced velocity dispersion provided by gravitational instabilities, such as density waves and bars, but mainly to the radial gas flows they drive, allowing large amounts of gas to condense towards nuclear regions in a small time scale. Numerical simulations with several gas phases, taking into account the feedback to regulate star formation, have explored the various processes, using recipes like the Schmidt law, moderated by the gas instability criterion. May be the most fundamental parameter in starbursts is the availability of gas: this sheds light on the amount of external gas accretion in galaxy evolution. The detailed mechanisms governing gas infall in the inner parts of galaxy disks are discussed.Comment: 6 pages, 3 figures, to be published in "Starbursts - From 30 Doradus to Lyman break galaxies", ed. R. de Grijs and R. Gonzalez-Delgad

    Total photoproduction cross-section at very high energy

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    In this paper we apply to photoproduction total cross-section a model we have proposed for purely hadronic processes and which is based on QCD mini-jets and soft gluon re-summation. We compare the predictions of our model with the HERA data as well as with other models. For cosmic rays, our model predicts substantially higher cross-sections at TeV energies than models based on factorization but lower than models based on mini-jets alone, without soft gluons. We discuss the origin of this difference.Comment: 13 pages, 9 figures. Accepted for publication in EPJC. Changes concern added references, clarifications of the Soft Gluon Resummation method used in the paper, and other changes requested by the Journal referee which do not change the results of the original versio

    Composition Of ω-3 And ω-6 Fatty Acids In Freeze-dried Chicken Embryo Eggs With Different Days Of Development

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    Fatty acids ω-3 and ω-6 composition and specially DHA were determined in freeze-dried chicken embryo eggs with pre-determined incubation periods. Fertile and embryo eggs presented palmitic (23.18 ± 0.54%), stearic (7.70 ± 0.28%), palmitoleic (3.00 ± 0.19%), oleic (36.28 ± 0.58%), linoleic (22.18 ± 0.34%), linolenic (1.08 ± 0.04%), arachidonic (2.04 ± 0.03%), docosahexaenoic (0.91 ± 0.03%), total ω-3 acids (2.26 ± 0.10%) and total ω-6 acids (24.62 ± 0.33%). There were no significant differences in total contents of ω-3 fatty acids (p=0.1226) between freeze-dried chicken embryo eggs with different incubation periods (3, 5, 7, 9, and 11 days) and fertile freeze-dried chicken eggs (day 0). However, there were significant differences in total medium contents of ω-6 fatty acids (P=0.001). There was also a strong statistical evidence that quadratic model was related with expected values of DHA content (p= 0.0013).472219224Abril, R., Barclay, B., Fatty acid analysis of poultry eggs as methyl esters (1999) Método OT-GCPE, Rev. 3.1, , OmegaTech. Bolder, Co. 24/03/99(1996) Official Methods and Recommended Practices of de American Oil Chemists' Society. 4th Ed., , American Oil Chemists' Society, Champaign IIBragagnolo, N., Turatti, J.M., Evaluation of "light" eggs in Brazil (1999) Associazione Italiana di Avicoltura Scientifica, Instituto di Zootecnia, 2, pp. 177-181. , Paper presented at VIII European Symposium on the Quality of Eggs and Eggs Products, Bologna, ItáliaBeig, D., Garcia, F.C.M., (1986) O Embrião de Galinha, , Campo Grande : UFMS/ Imprensa UniversitáriaCherian, G., Sim, J.S., Net transfer and incorporation of yolk n-3 fatty acids into developing chick embryos (1993) Poultry Science, 72, pp. 98-105Cherian, G., Gopalakrishnan, N., Akiba, Y., Sim, J.S., Effect of maternal dietary n-3 fatty acids on the accretion of long-chain polyunsaturated fatty acids in the tissues of developing chick embryo (1997) Biology of Neonate, 72, pp. 165-174Connor, W.E., Importance of n-3 fatty acids in health and disease (2000) American Journal of Clinical Nutritional, 71 (SUPPL.), pp. 171S-175SFarkas, K., Noble, R.C., Speake, B.K., Development changes in the levels of molecular species of triacylglicerol that contain docosahexaenoic acid in adipose tissue of chick embryo (1996) Comparative Biochemistry and Physiology B-Biochemistry and Molecular Biology, 115, pp. 1-6Ferrier, L.K., Gaston, L.J., Leeson, S., Squires, J., Weaver, B.J., Holub, B.J., α-linolenic acid - and docosahexaenoic acid - enriched eggs from hens fed flaxseed: Influence on blood lipids and platelet phospholipid fatty acids in human (1995) The American Journal of Clinical Nutrition, 62, pp. 81-86Lin, D.S., Connor, W.E., Anderson, G.J., The incorporation of n-3 and n-6 essential fatty acids into chicken embryo from eggs yolks having vastly different fatty acid compositions (1991) Pediatric Research, 29, pp. 601-605Maldjian, A., Falkas, K., Noble, R.C., Cocchi, M., Speake, B.K., The transfer of docosahexaenoic acid from the yolk to the tissues of chicken embryo (1995) Biochimica et Biophysica Acta, 1258, pp. 81-99Nettleton, J.A., (1995) Omega-3 Fatty Acids and Health, , Chapman and Hall, New YorkNoble, R.C., Cocchi, M., Lipid metabolism and the neonatal chicken (1990) Prog. Lipid Res., 29, pp. 107-140Park, Y.K., Koo, M.H., Carvalho, P.O., Recentes Progresses dos Alimentos Funcionais (1997) Bol. SBCTA, 31Salatin, J., Pastured poultry profits (1993) Polyface Swoope, , VirginiaSpeake, B.K., Murray, A.M.B., Noble, R.C., Transport and transformations of yolk lipids during development of avian embryo (1998) Prog. Lipid Res., 37, pp. 1-32Stadelman, W.J., Pratt, D.E., Factors influencing composition the hen's egg (1989) World's Poultry Science Journal, 45, pp. 247-261Thapon, J.L., Bourgeois, C.M., L'oeuf et les ovoproduits (1994) Lavoisier -Technique et Documentation, , ParisVieira, S., Hoffmann, R., Estatísitica experimental (1989) Atlas, , São Paul

    Next-to-Leading Order Cross Sections for Tagged Reactions

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    We extend the phase space slicing method of Giele, Glover and Kosower for performing next-to-leading order jet cross section calculations in two important ways: we show how to include fragmentation functions and how to include massive particles. These extensions allow the application of this method to not just jet cross sections but also to cross sections in which a particular final state particle, including a DD or BB-meson, is tagged.Comment: 36 pages, Latex Small corrections to text. To appear in Phys. Rev.

    Electroactive biofilms: new means for electrochemistry

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    This work demonstrates that electrochemical reactions can be catalysed by the natural biofilms that form on electrode surfaces dipping into drinking water or compost. In drinking water, oxygen reduction was monitored with stainless steel ultra-microelectrodes under constant potential electrolysis at )0.30 V/SCE for 13 days. 16 independent experiments were conducted in drinking water, either pure or with the addition of acetate or dextrose. In most cases, the current increased and reached 1.5–9.5 times the initial current. The current increase was attributed to biofilm forming on the electrode in a similar way to that has been observed in seawater. Epifluorescence microscopy showed that the bacteria size and the biofilm morphology depended on the nutrients added, but no quantitative correlation between biofilm morphology and current was established. In compost, the oxidation process was investigated using a titanium based electrode under constant polarisation in the range 0.10–0.70 V/SCE. It was demonstrated that the indigenous micro-organisms were responsible for the current increase observed after a few days, up to 60 mA m)2. Adding 10 mM acetate to the compost amplified the current density to 145 mA m)2 at 0.50 V/SCE. The study suggests that many natural environments, other than marine sediments, waste waters and seawaters that have been predominantly investigated until now, may be able to produce electrochemically active biofilm

    Rings and bars: unmasking secular evolution of galaxies

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    Secular evolution gradually shapes galaxies by internal processes, in contrast to early cosmological evolution which is more rapid. An important driver of secular evolution is the flow of gas from the disk into the central regions, often under the influence of a bar. In this paper, we review several new observational results on bars and nuclear rings in galaxies. They show that these components are intimately linked to each other, and to the properties of their host galaxy. We briefly discuss how upcoming observations, e.g., imaging from the Spitzer Survey of Stellar Structure in Galaxies (S4G), will lead to significant further advances in this area of research.Comment: Invited review at "Galaxies and their Masks", celebrating Ken Freeman's 70-th birthday, Sossusvlei, Namibia, April 2010. To be published by Springer, New York, editors D.L. Block, K.C. Freeman, & I. Puerari; minor change

    Study of the decay mode D^0 -> K-K-K+pi+

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    Using data from the FOCUS (E831) experiment at Fermilab, we present a new measurement of the branching ratio for the Cabibbo-favored decay mode D0KKK+π+D^0 \to K^-K^-K^+\pi^+. From a sample of 143±19143 \pm 19 fully reconstructed D0KKK+π+D^0 \to K^-K^-K^+\pi^+ events, we measure Γ(D0KKK+π+)/Γ(D0Kππ+π+)=0.00257±0.00034(stat.)±0.00024(syst.)\Gamma(D^0 \to K^-K^-K^+\pi^+)/\Gamma(D^0 \to K^-\pi^-\pi^+\pi^+) = 0.00257 \pm 0.00034(stat.) \pm 0.00024(syst.). A coherent amplitude analysis has been performed to determine the resonant substructure of this decay mode. This analysis reveals a dominant contribution from ϕ\phi and Kˉ0(890)\bar K^{*0}(890) states.Comment: 15 pages, 4 figures, to be submitted to Physics Letters
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