Co-limitation towards lower latitudes shapes global forest diversity gradients

The latitudinal diversity gradient (LDG) is one of the most recognized global patterns of species richness exhibited across a wide range of taxa. Numerous hypotheses have been proposed in the past two centuries to explain LDG, but rigorous tests of the drivers of LDGs have been limited by a lack of high-quality global species richness data. Here we produce a high-resolution (0.025° × 0.025°) map of local tree species richness using a global forest inventory database with individual tree information and local biophysical characteristics from ~1.3 million sample plots. We then quantify drivers of local tree species richness patterns across latitudes. Generally, annual mean temperature was a dominant predictor of tree species richness, which is most consistent with the metabolic theory of biodiversity (MTB). However, MTB underestimated LDG in the tropics, where high species richness was also moderated by topographic, soil and anthropogenic factors operating at local scales. Given that local landscape variables operate synergistically with bioclimatic factors in shaping the global LDG pattern, we suggest that MTB be extended to account for co-limitation by subordinate drivers

Effect of composition and sintering temperature on mechanical properties of ZrO2 particulate-reinforced titanium-matrix composite

The titanium-based composites were synthesized by powder metallurgy method. The effects of composition and sintering temperature on the microstructure and properties of the titanium-based composites were investigated by X-ray diffraction, optical microscopy, scanning electron microscopy and mechanical properties tests. The results demonstrate that adding ZrO 2 particles can improve the mechanical properties of powder metallurgy (P/M) titanium-based composites. The Ti composite with 4% (mole fraction) ZrO 2 sintered at 1100 °C for 4 h shows an appropriate mechanical property with a relative density of 93.9%, a compressive strength of 1380 MPa (570 MPa higher than pure Ti) and good plasticity (an ultimate strain above 24%)

A longitudinal study of airway responsiveness, lung function and respiratory symptoms from early infancy to eleven years of age

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Diagram of the structural elements of Tube and Pelle homologs.

<p><i>D. melanogaster</i> Tube and <i>N. vitripennis</i> Tube-like proteins lack their individual kinase domains. Repeat motifs are observed in both insect Tube and Tube-like proteins and <i>Sp</i>Pelle.</p

Phylogenetic analysis of the retrieved Tube and Pelle homologs from insects, crustaceans, and humans.

<p>NJ trees were generated using the MEGA 4.0 software. The corresponding GenBank accession numbers are listed in this figure. <i>Sp</i>Tube and <i>Sp</i>Pelle are marked with red and blue frames, respectively. <i>Dm, Drosophila melanogaster; Cp, Culex pipiens; Aa, Aedes aegypti; Ag, Anopheles gambiae; Nv, Nasonia vitripennis; Dp, Daphnia pulex; Am, Apis mellifera; Cf, Camponotus floridanus; Tc, Tribolium castaneum; Lv, Litopenaeus vannamei; Hs, Homo sapiens; Sp, Scylla paramamosain</i>.</p

Full-length cDNA and translated amino acid sequences of <i>Sp</i>Tube.

<p>The death domain (the first domain) and kinase domain (the second domain) are shadowed. The stop codon is indicated by an asterisk (*). The initiation codon and the polyadenylation signal are shown in bold and red letters, respectively. The RD dipeptide existing only in Tube-like kinases but not in Pelle or Pelle-like protein sequences is marked with red box.</p

Comparisons of the predicted 3D structure of the <i>Sp</i>Tube death domain (DD).

<p>(14 aa to 144 aa, yellow) and the crystal structure of DmTube DD (PDB ID: 1d2z, chain B) (red) (A); the predicted 3D structure of <i>Sp</i>Pelle DD (13 aa to 109 aa, yellow) and the solution structure of DmPelle DD (PDB ID: 1d2z, chain A) (red) (B); the predicted 3D structure of <i>Sp</i>Tube kinase domain (251 aa to 488 aa, yellow) and the crystal structure of human IRAK4 kinase domain (PDB ID: 2nru, chain B) (red) (C); and the predicted 3D structure of <i>Sp</i>Pelle kinase domain (540 aa to 825 aa, yellow) and the crystal structure of human IRAK4 kinase domain (PDB ID: 2nru, chain B) (red) (D). Residues required for binding to MyD88 (blue) and Pelle (red) are indicated (A). The position of R (ARG) residue in RD dipeptide, which is the hallmark of Tube-like kinases, is also shown (C). These four predicted structures merge well with their corresponding templates.</p

Pull-down assays to test the binding activity of <i>Sp</i>Tube death domain (TubeDD) with <i>Sp</i>MyD88 death domain (MyDD).

<p>(A) Recombinant MyDD was bound to His Bind resin, to which purified GST-TubeDD protein was added. MyDD and TubeDD were eluted simultaneously with elution buffer but not with wash buffer. (B) Recombinant MyDD was added to His Bind resin, to which GST alone was added as a control. Only MyDD was eluted by elution buffer. M, protein markers; Lane 1, recombinant MyDD; Lane 2, GST-TubeDD; Lane 3, collection of wash buffer; Lane 4, collection of elution buffer; Lane 5, recombinant MyDD; Lane 6, GST; Lane 7, collection of wash buffer; Lane 8, collection of elution buffer.</p