6,020 research outputs found
Railroad Car - Export
No full textThe ""St. Paul"". Number M.28, manufactured for Saint Paul & Pacific Railroad. Exterior view. passenger ca
Codon usage bias in Archaea
No full textSynonymous codon usage bias has been extensively studied in Bacteria and Eukaryotes and
yet there has been little investigation in the third domain of life, the Archaea. In this thesis I
therefore examine the coding sequences of nearly 70 species of Archaea to explore patterns
of codon bias. Heterogeneity in codon usage among genes was initially explored for a single
species, Methanococcus maripaludis, where patterns were explained by a single major trend
associated with expression level and attributed to natural selection. Unlike the bacterium
Escherichia coli, selection was largely restricted to two-fold degenerate sites.
Analyses of patterns of codon usage bias within genomes were extended to the other species
of Archaea, where variation was more commonly explained by heterogeneity in G+C content
and asymmetric base composition. By comparison with bacterial genomes, far fewer trends
were found to be associated with expression level, implying a reduced prevalence of
translational selection among Archaea. The strength of selected codon usage bias (S) was
estimated for 67 species of Archaea, and revealed that natural selection has had less impact
in shaping patterns of codon usage across Archaea than across many species of Bacteria.
Variation in S was explained by the combined effects of growth rate and optimal growth
temperature, with species growing at high temperatures exhibiting weaker than expected
selection given growth rate. Such a relationship is expected if temperature kinetically
modulates growth rate via its impact upon translation elongation, since rapid elongation
rates at high temperatures reduce the selective benefit of optimal codon usage for the
efficiency of translation. Consistent with this, growth temperature is negatively correlated
with minimal generation time, and numbers of rRNA operons and tRNA genes are reduced
at high growth temperatures. The large fraction of thermophilic Archaea relative to Bacteria
account for the lower values of S observed.
Two major trends were found to describe variation in codon usage among archaeal
genomes; the first was attributed to GC3s and the second was associated with arginine
codon usage and was linked both with growth temperature and the genome-wide excess of
G over C content. The latter is unlikely to reflect thermophilic adaptation since the codon
primarily underlying the trend appears to be selectively disfavoured. No correlations were
observed with genome wide GC3s and optimal growth temperature and neither was GC3s
associated with aerobiosis. The identities of optimal codons were explored and found to be invariant across U and C-ending
two-fold degenerate amino acid groups. The identity of optimal codons and
anticodons across four and six-fold degenerate amino acid groups was found to vary with
mutational bias. As was first observed in M. maripaludis, selected codon usage bias was
consistently greater across two-fold relative to four-fold degenerate amino acid groups
across Archaea. This broad pattern could reflect ancestral patterns of optimal codon
divergence, prevalent among four-fold but not two-fold degenerate amino acid groups.
Consistent with this, the strength of selected codon usage bias was found to be reduced
following the divergence of optimal codons, and implies that optimal codon divergence
typically proceeds following the relaxation of selection.
Finally, a method was developed to partition the strength of selection (S) into separate
components reflecting selection for translational efficiency (Seff) and selection for
translational accuracy (Sacc) by comparing the codon usage across conserved and nonconserved
amino acid residues. While estimates of Sacc are somewhat sensitive to the
designation of conserved sites, a general pattern emerged whereby accuracy-selected codon
usage bias was consistently strongest across a subset of the most highly conserved sites.
Several estimates of Sacc were consistently higher than the 95% range of null values
regardless of the dataset, providing evidence for accuracy-selected codon usage bias in these
species
The SAGE Handbook of Diplomacy
No full textThe SAGE Handbook of Diplomacy provides a major thematic overview of Diplomacy and its study that is theoretically and historically informed and in sync with the current and future needs of diplomatic practice . Original contributions from a brilliant team of global experts are organised into four thematic sections: Section One: Diplomatic Concepts & Theories Section Two: Diplomatic Institutions Section Three: Diplomatic Relations Section Four: Types of Diplomatic Engagemen
Visualization and characterization of dynamic patterns of flow, growth and activity of Vibrio fischeri biofilms growing in porous media
No full textUsing a mesoscale porous media flat plate reactor we utilized a naturally bioluminescent biofilm (V. fischeri) and dye studies to obtain valuable information on the interactions between biofilms and reactive flow in porous media. The growth and development of the V. fischeri biofilm in a porous media geometry was studied using digital time lapse images of the bioluminescent signal given off by the developing biofilm. The effect of biofilm development on porous media hydrodynamics was examined using dye tracer studies and image analysis. The natural bioluminescence of the V. fischeri allowed real-time, in-situ study of biofilm development in porous media, without destruction of the biofilm. Dye studies and image analysis enabled the study of effects of biofilm accumulation on porous media hydraulics, with comparisons to plug flow and completely mixed systems with varying degrees of biofilm accumulation. The real-time nature of the study permitted us to visualize dynamic flow channel formation within the biofilm/porous media system. In addition, the sensitivity of the V. fischeri biofilm to dissolved oxygen allowed us to capture real-time images of reactive transport within the system. This work is the first meso-scale visualization of the interactions between biofilm and flow in porous media
Cavonus Sharp, 1875 (Coleoptera: Scarabaeidae: Dynastinae: Pentodontini Pseudoryctina) in Western Australia with description of a new species and the female of Cavonus sculpturatus Blackburn, 1888
No full textHutchinson, Paul M., Allsopp, Peter G. (2020): Cavonus Sharp, 1875 (Coleoptera: Scarabaeidae: Dynastinae: Pentodontini Pseudoryctina) in Western Australia with description of a new species and the female of Cavonus sculpturatus Blackburn, 1888. Zootaxa 4852 (4): 449-460, DOI: 10.11646/zootaxa.4852.4.
Cavonus Sharp, 1875 (Coleoptera: Scarabaeidae: Dynastinae: Pentodontini Pseudoryctina) in Western Australia with description of a new species and the female of Cavonus sculpturatus Blackburn, 1888
No full textHutchinson, Paul M., Allsopp, Peter G. (2020): Cavonus Sharp, 1875 (Coleoptera: Scarabaeidae: Dynastinae: Pentodontini Pseudoryctina) in Western Australia with description of a new species and the female of Cavonus sculpturatus Blackburn, 1888. Zootaxa 4852 (4): 449-460, DOI: https://doi.org/10.11646/zootaxa.4852.4.
Cavonus Sharp 1875
No full textKey to Cavonus females (modified from Carne 1957) Females of C. leai and C. fovealacus are unknown. 1. Clypeus with sides sinuate.............................................................................. 2 - Clypeus evenly rounded................................................................................ 4 2. Clypeal apex bisinuate; dorsal elytral striae heavily impressed and continuous over apical calli...... C. acutifrons Lea, 1917 - Clypeal apex truncate; dorsal elytral striae obsolete posterior to apical calli....................................... 3 3. Posteromedian area of pronotum finely micropunctate, surface microreticulate; frons with a transverse groove behind clypeofrontal ridge (Carne 1957, Fig. 337)................................................... C. sharpi Blackburn, 1888 - Posteromedian area of pronotum with coarse punctation, surface shiny; frons lacking, or with only a trace of a transverse groove............................................................................ C. armatus Sharp, 1875 4. Coxal vestiture brownish black; metatibia with smaller spur straight, blunt; scutellum punctate at base but without submarginal sculpturing..................................................................... C. niger (Blackburn, 1888) - Coxal vestiture dark brown or brownish yellow; metatibia with smaller spur strongly curved, subacute; scutellum with welldefined submarginal groove or punctures.................................................................. 5 5. Coxal vestiture brownish yellow; pronotum lacking anteromedial swelling, surface strongly convex; pygidium contracted either side of apex, disc with impunctate median stripe................................... C. bidens (Blackburn, 1896) - Coxal vestiture dark brown (Fig. 12); pronotum (Figs. 11, 14) with anteromedial swelling, surface slightly flattened behind swelling; pygidium (Fig. 16) not contracted on either side of apex, disc lacking impunctate median stripe.......................................................................................... C. sculpturatus Blackburn, 1888Published as part of Hutchinson, Paul M. & Allsopp, Peter G., 2020, Cavonus Sharp, 1875 (Coleoptera: Scarabaeidae: Dynastinae: Pentodontini Pseudoryctina) in Western Australia with description of a new species and the female of Cavonus sculpturatus Blackburn, 1888, pp. 449-460 in Zootaxa 4852 (4) on page 459, DOI: 10.11646/zootaxa.4852.4.3, http://zenodo.org/record/441007
Highly-conformal sputtered through-silicon vias with sharp superconducting transition
No full textThis paper describes the microfabrication and electrical characterization of aluminum-coated superconducting through-silicon vias (TSVs) with sharp superconducting transition above 1 K. The sharp superconducting transition was achieved by means of fully conformal and void-free DC-sputtering of the TSVs with Al, and is here demonstrated in up to 500μ m-deep vias. Full conformality of Al sputtering was made possible by shaping the vias with a tailored hourglass profile, which allowed a metallic layer as thick as 430 nm to be deposited in the center of the vias. Single-via electric resistance as low as 160 mΩ at room temperature and superconductivity at 1.27 K were measured by a three-dimensional (3D) cross-bridge Kelvin resistor structure. This work establishes a CMOS-compatible fabrication process suitable for arrays of superconducting TSVs and 3D integration of superconducting silicon-based devices. [2020-0354].Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.EKL ProcessingElectronic Components, Technology and MaterialsTera-Hertz SensingElectronic
FIGURES 3–10. Cavonus sculpturatus Blackburn, 1888, holotype male. 3 in Cavonus Sharp, 1875 (Coleoptera: Scarabaeidae: Dynastinae: Pentodontini Pseudoryctina) in Western Australia with description of a new species and the female of Cavonus sculpturatus Blackburn, 1888
No full textFIGURES 3–10. Cavonus sculpturatus Blackburn, 1888, holotype male. 3, Dorsum; 4, venter; 5, lateral; 6, head, lateral; 7, head, dorsal; 8, pygidium; 9, parameres, apices missing; 10, aedeagus, lateral.Published as part of Hutchinson, Paul M. & Allsopp, Peter G., 2020, Cavonus Sharp, 1875 (Coleoptera: Scarabaeidae: Dynastinae: Pentodontini Pseudoryctina) in Western Australia with description of a new species and the female of Cavonus sculpturatus Blackburn, 1888, pp. 449-460 in Zootaxa 4852 (4) on page 453, DOI: 10.11646/zootaxa.4852.4.3, http://zenodo.org/record/441007
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