10,084 research outputs found
Mussel larval responses to turbulence are unaltered by larvalage or light condition
No full textLarval responses to hydromechanical cues potentially have important effects on larval dispersal and settlement. This study examined the behavior of mussel larvae (Mytilus edulis) in laboratory-generated turbulence representative of nearshore currents. We video recorded the behavior of early- and late-stage veligers in a grid-stirred tank at five turbulence levels under light and dark conditions. Water velocities and kinetic energy dissipation rates were measured using particle image velocimetry and acoustic Doppler velocimetry. We characterized the vertical velocity distributions for sinking, hovering, and swimming modes in still water and calculated the average larval behavioral velocity in turbulence. In still water, young larvae had more positive (upward) velocities than old larvae, and both stages had more positive velocities in light than in dark. In turbulence, the mean larval vertical velocity varied from positive at low dissipation rates to negative at dissipation rates above a threshold of 8.3 £ 1022 cm2 s23. At this threshold, the Kolmogorov length scale (h ¼ 590mm) was two to three times the mean larval shell lengths (171–256mm), implying that turbulence is detectable even by larvae that are smaller than the smallest eddies. Responses to turbulence were unaffected by larval age or light conditions and contributed substantial behavioral variation. By sinking in strong turbulence, mussel larvae could increase their flux to the bed in energetic coastal flows, particularly over rough substrates like mussel beds. The response to turbulence by early-stage larvae will also affect their dispersal and may help larvae remain near coastal populations.Peer reviewedOriginally published in Limnology and Oceanography: Fluids & Environments (2011) and available via this link: http://lofe.dukejournals.org/content/1/120.full.pdfCopyright 2011 by the Association for the Sciences of Limnology and Oceanography, Inc
Ideal chain two dimensional critical percolation cluster
No full textThe authors study the statistics of the ideal chain (or equally weighted trajectories) for the first time on a two-dimensional critical percolation cluster. They discuss the asymptotic behaviour of the mean end-to-end distance and the number of chains for the long chain limit by exact enumeration. The results strongly suggest that this problem does not belong to the same universality class as the random walk (or kinetically weighted trajectories) on the same fractal cluster
O. Fuchs, N. Greinacher, L. Karrer, N. Mette et H. Steinkamp, Der Pastorale Notstand. Notwendige Reformen für eine zukunftsfähige Kirche. 1992
No full textWeber Philippe. O. Fuchs, N. Greinacher, L. Karrer, N. Mette et H. Steinkamp, Der Pastorale Notstand. Notwendige Reformen für eine zukunftsfähige Kirche. 1992. In: Revue théologique de Louvain, 26ᵉ année, fasc. 3, 1995. p. 388
Tangible strategies for pro-environmental behaviours through monitoring park visitors’ activities and perceived values
No full textO. Fuchs, N. Greinacher, L. Karrer, N. Mette et H. Steinkamp, Der Pastorale Notstand. Notwendige Reformen für eine zukunftsfähige Kirche. 1992
No full textWeber Philippe. O. Fuchs, N. Greinacher, L. Karrer, N. Mette et H. Steinkamp, Der Pastorale Notstand. Notwendige Reformen für eine zukunftsfähige Kirche. 1992. In: Revue théologique de Louvain, 26ᵉ année, fasc. 3, 1995. p. 388
Combining satellite imagery (QuickBird, ASTER) and field inventory data with a non parametric approach
No full textCombining satellite imagery (QuickBird, ASTER) and field inventory data with a non parametric approach
No full textA new gene locus of Bordetella pertussis defines a novel family of prokaryotic transcriptional accessory proteins
No full textRecently, a novel type of regulatory mutation causing differential effects on the expression of virulence genes due to a slight overexpression of the RNA polymerase α subunit (RpoA) was found in Bordetella pertussis (N. H. Carbonetti, T. M. Fuchs, A. A. Patamawenu, T. J. Irish, H. Deppisch, and R. Gross, J. Bacteriol. 176:7267-7273, 1994). To gather information on the molecular events behind this phenomenon, we isolated suppressor mutants of the RpoA-overexpressing strains after random mutagenesis. Genetic characterization of these suppressor strains revealed the existence of at least three distinct groups of dominant alleles. Mutations occurred either in the rpoA locus itself, in the bvg locus, or in unknown gene loci. One mutant of the latter group was further characterized. By the introduction of a cosmid library containing genomic B. pertussis DNA into this suppressor strain, we isolated a cosmid which suppressed the phenotype of the suppressor strain, thus restoring the negative effect on transcription of the ptx and cya toxin genes. Mutagenesis of the cosmid with Tn5 led to the identification of the gene locus responsible for this phenomenon. Its DNA sequence revealed the presence of an open reading frame (ORF) consisting of 2,373 bp coding for a hypothetical 86-kDa protein with extensive sequence similarities to ORFs with not yet identified functions of Escherichia coli, Haemophilus influenzae, and Neisseria meningitidis. The new gene, termed tex, for toxin expression, seems to be an essential factor for B. pertussis, as it cannot be deleted from the bacterial chromosome. All members of this new protein family show significant sequence similarities with the mannitol repressor protein MtIR and with the presumptive RNA-binding domains of the Pnp and ribosomal S1 proteins of E. coli in their N- and C- terminal parts, respectively. These sequence similarities and the fact that the tex gene was isolated by virtue of its effects on gene expression in B. pertussis indicate that the members of this new protein family may play an important role in the transcription machinery of prokaryotic organisms
Epstein Cynthia Fuchs — Woman's Place Options and Limits in Professional Careers
No full textP. H. Epstein Cynthia Fuchs — Woman's Place Options and Limits in Professional Careers. In: Population, 26ᵉ année, n°6, 1971. pp. 1177-1178
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