821 research outputs found

    Different environmental variables predict distribution and cover of the introduced red seaweed Eucheuma denticulatum in two geographical locations

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    In this study we examined abiotic and biotic factors that could potentially influence the presence of a non-indigenous seaweed, Eucheuma denticulatum, in two locations, one outside (Kane'ohe Bay, Hawai'i, USA) and one within (Mafia Island, Tanzania) its natural geographical range. We hypothesized that the availability of hard substrate and the amount of wave exposure would explain distribution patterns, and that higher abundance of herbivorous fishes in Tanzania would exert stronger top-down control than in Hawai'i. To address these hypotheses, we surveyed E. denticulatum in sites subjected to different environmental conditions and used generalized linear mixed models (GLMM) to identify predictors of E. denticulatum presence. We also estimated grazing intensity on E. denticulatum by surveying the type and the amount of grazing scars. Finally, we used molecular tools to distinguish between indigenous and non-indigenous strains of E. denticulatum on Mafia Island. In Kane'ohe Bay, the likelihood of finding E. denticulatum increased with wave exposure, whereas on Mafia Island, the likelihood increased with cover of coral rubble, and decreased with distance from areas of introduction (AOI), but this decrease was less pronounced in the presence of coral rubble. Grazing intensity was higher in Kane'ohe Bay than on Mafia Island. However, we still suggest that efforts to reduce non-indigenous E. denticulatum should include protection of important herbivores in both sites because of the high levels of grazing close to AOI. Moreover, we recommend that areas with hard substrate and high structural complexity should be avoided when farming non-indigenous strains of E. denticulatum

    Identification of Long stress-induced non-coding transcripts that have altered expression in cancer

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    AbstractIt has recently become clear that the transcriptional output of the human genome is far more abundant than previously anticipated, with the vast majority of transcripts not coding for protein. Utilizing whole-genome tiling arrays, we analyzed the transcription across the entire genome in both normal human bronchial epithelial cells (NHBE) and NHBE cells exposed to the tobacco carcinogen NNK. Our efforts focused on the characterization of non-coding transcripts that were greater than 300 nucleotides in length and whose expression was increased in response to NNK. We identified 12 Long Stress-Induced Non-coding Transcripts that we term LSINCTs. Northern blot analysis revealed that these transcripts were larger than predicted from the tiling array data. Quantitative real-time RT-PCR performed across a panel of normal cell lines indicates that these transcripts are more abundantly expressed in rapidly growing tissues or in tissues that are more prone to cellular stress. These transcripts that have increased expression after exposure to NNK also had increased expression in a number of lung cancer cell lines and also in many breast cancer cell lines. Collectively, our results identified a new class of long stress responsive non-coding transcripts, LSINCTs, which have increased expression in response to DNA damage induced by NNK. LSINCTs interestingly also have increased expression in a number of cancer-derived cell lines, indicating that the expression is increased in both, correlating cellular stress and cancer

    Six simple guidelines for introducing new genera of fungi

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    We formulate five guidelines for introducing new genera, plus one recommendation how to publish the results of scientific research. We recommend that reviewers and editors adhere to these guidelines. We propose that the underlying research is solid, and that the results and the final solutions are properly discussed. The six criteria are: (1) all genera that are recognized should be monophyletic; (2) the coverage of the phylogenetic tree should be wide in number of species, geographic coverage, and type species of the genera under study; (3) the branching of the phylogenetic trees has to have sufficient statistical support; (4) different options for the translation of the phylogenetic tree into a formal classification should be discussed and the final decision justified; (5) the phylogenetic evidence should be based on more than one gene; and (6) all supporting evidence and background information should be included in the publication in which the new taxa are proposed, and this publication should be peer-reviewed

    Fermilab E791

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    Fermilab E791, a very high statistics charm particle experiment, recently completed its data taking at Fermilab's Tagged Photon Laboratory. Over 20 billion events were recorded through a loose transverse energy trigger and written to 8mm tape in the the 1991-92 fixed target run at Fermilab. This unprecedented data sample containing charm is being analysed on many-thousand MIP RISC computing farms set up at sites in the collaboration. A glimpse of the data taking and analysis effort is presented. We also show some preliminary results for common charm decay modes. Our present analysis indicates a very rich yield of over 200K reconstructed charm decays.Comment: 4 pages, 1 figure, LaTe

    Measurement of the Ds Lifetime

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    We report the results of a precise measurement of the Ds meson lifetime based on 1662 +/- 56 fully reconstructed Ds -> phi pi decays, from the charm hadroproduction experiment E791 at Fermilab. Using an unbinned maximum likelihood fit, we measure the Ds lifetime to be 0.518 +/- 0.014 +/- 0.007 ps. The ratio of the measured Ds lifetime to the world average D0 lifetime is 1.25 +/- 0.04. This result differs from unity by six standard deviations, indicating significantly different lifetimes for the Ds and the D0.Comment: 12 pages, 3 figures, 2 table. LaTe

    Experimental evidence for a light and broad scalar resonance in D+→π−π+π+D^+\to \pi^-\pi^+\pi^+ decay

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    From a sample of 1172±611172 \pm 61 D+→π−π+π+D^+ \to \pi^- \pi^+ \pi^+ decay, we find Γ(D+→π−π+π+)/Γ(D+→K−π+π+)=0.0311±0.0018−0.0026+0.0016\Gamma (D^+ \to \pi^- \pi^+ \pi^+) / \Gamma (D^+ \to K^- \pi^+ \pi^+) = 0.0311 \pm 0.0018 ^{+0.0016}_{-0.0026}. Using a coherent amplitude analysis to fit the Dalitz plot of this decays, we find strong evidence that a scalar resonance of mass 478−23+24±17478^{+24}_{-23} \pm 17 MeV/c2c^2 and width 324−40+42±21324^{+42}_{-40} \pm 21 MeV/c2c^2 accounts for approximately half of all decays.Comment: 10 pages, 3 eps figure
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