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1. Mantle Q structure from S ,  SS ,  SSS and SSSS amplitude measurements

   https://doi.org/10.1093/gji/ggac217  

   Zhu, Min; Sun, Shuyang; Zhou, Ying; Wu, Qingju (June 2022, Geophysical Journal International)

   SUMMARY The seismic quality factor (Q) of the Earth’s mantle is of great importance for the understanding of the physical and chemical properties that control mantle anelasticity. The radial structure of the Earth’s Q is less well resolved compared to its wave speed structure, and large discrepancies exist among global 1-D Q models. In this study, we build a global data set of amplitude measurements of S, SS, SSS and SSSS waves using earthquakes that occurred between 2009 and 2017 with moment magnitudes ranging from 6.5 to 8.0. Synthetic seismograms for those events are computed in a 1-D reference model PREM, and amplitude ratios between observed and synthetic seismograms are calculated in the frequency domain by spectra division, with measurement windows determined based on visual inspection of seismograms. We simulate wave propagation in a global velocity model S40RTS based on SPECFEM3D and show that the average amplitude ratio as a function of epicentral distance is not sensitive to 3-D focusing and defocusing for the source–receiver configuration of the data set. This data set includes about 5500 S and SS measurements that are not affected by mantle transition zone triplications (multiple ray paths), and those measurements are applied in linear inversions to obtain a preliminary 1-D Q model QMSI. This model reveals a high Q region in the uppermost lower mantle. While model QMSI improves the overall datafit of the entire data set, it does not fully explain SS amplitudes at short epicentral distances or the amplitudes of the SSS and SSSS waves. Using forward modelling, we modify the 1-D model QMSI iteratively to reduce the overall amplitude misfit of the entire data set. The final Q model QMSF requires a stronger and thicker high Q region at depths between 600 and 900 km. This anelastic structure indicates possible viscosity layering in the mid mantle. 

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2. Nesting biology of Centris ( Paracentris ) burgdorfi (Apidae: Centridini)

   https://doi.org/10.1080/00218839.2020.1717760  

   Sabino, William O.; Alves-dos-Santos, Isabel; Queiroz, Elisa Pereira; de Faria, Letícia Biral; Papaj, Daniel R.; Buchmann, Stephen L.; da Silva, Cláudia Inês (January 2020, Journal of Apicultural Research)

   We describe the nesting biology of Centris (Paracentris) burgdorfi, a solitary bee that nests in sandstone in northeastern Brazil. The nest consists of a shallow tunnel with access to the brood cells. Females of C. burgdorfi made 1–7 brood cells per nest with each cell requiring 2.58 ± 0.40 (X ± SD) days to construct. The average cell-building construction time was longer when compared to other Centris species. Females were larger than males, and this difference was reflected in the size of their respective emergence cells. The temperature within C. burgdorfi nests was lower when compared to ambient temperature. Our study is the first to report the nesting biology of C. burgdorfi. The detailed behavior of the female inside the nest was also described, which is unusual in the study of solitary bee nesting biology. 

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3. a -axis YBa2Cu3O7− x /PrBa2Cu3O7− x /YBa2Cu3O7− x trilayers with subnanometer rms roughness

   https://doi.org/10.1063/5.0034648  

   Suyolcu, Y_Eren; Sun, Jiaxin; Goodge, Berit_H; Park, Jisung; Schubert, Jürgen; Kourkoutis, Lena_F; Schlom, Darrell_G (February 2021, APL Materials)

   We demonstrate a-axis YBa2Cu3O7−x/PrBa2Cu3O7−x/YBa2Cu3O7−x trilayers grown on (100) LaAlO3 substrates with improved interface smoothness. The trilayers are synthesized by ozone-assisted molecular-beam epitaxy. The thickness of the PrBa2Cu3O7−x layer is held constant at 8 nm, and the thickness of the YBa2Cu3O7−x layers is varied from 24 nm to 100 nm. X-ray diffraction measurements show all trilayers to have >97% a-axis content. The rms roughness of the thinnest trilayer is <0.7 nm, and this roughness increases with the thickness of the YBa2Cu3O7−x layers. The thickness of the YBa2Cu3O7−x layers also affects the transport properties: while all samples exhibit an onset of the superconducting transition at and above 85 K, the thinner samples show wider transition widths, ΔTc. High-resolution scanning transmission electron microscopy reveals coherent and chemically sharp interfaces and that growth begins with a cubic (Y,Ba)CuO3−x perovskite phase that transforms into a-axis oriented YBa2Cu3O7−x as the substrate temperature is ramped up. 

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4. Molecular phylogeny of Spirotrichonymphea (Parabasalia) with emphasis on Spironympha , Spirotrichonympha , and three new genera Pseudospironympha , Nanospironympha , and Brugerollina

   https://doi.org/10.1111/jeu.12967  

   Noda, Satoko; Kitade, Osamu; Jasso‐Selles, Daniel E.; Taerum, Stephen J.; Takayanagi, Miki; Radek, Renate; Lo, Nathan; Ohkuma, Moriya; Gile, Gillian H. (February 2023, Journal of Eukaryotic Microbiology)

   Abstract Spirotrichonymphea, one of the six classes of phylum Parabasalia, are characterized by bearing many flagella in spiral rows, and they occur exclusively in the guts of termites. Phylogenetic relationships among the 13 described genera are not well understood due to complex morphological evolution and a paucity of molecular data. One such understudied genus isSpironympha. It has been variously considered a valid genus, a subgenus ofSpirotrichonympha, or an “immature” life cycle stage ofSpirotrichonympha. To clarify this, we sequenced the small subunit rRNA gene sequences ofSpironymphaandSpirotrichonymphacells isolated from the hindguts ofReticulitermesspecies andHodotermopsis sjostedtiand confirmed the molecular identity ofH. sjostedtisymbionts using fluorescence in situ hybridization.Spironymphaas currently circumscribed is polyphyletic, with bothH. sjostedtisymbiont species branching separately from the “true”SpironymphafromReticulitermes. Similarly, theSpirotrichonymphasymbiont ofH. sjostedtibranches separately from the “true”Spirotrichonymphafound inReticulitermes. Our data supportSpironymphafromReticulitermesas a valid genus most closely related toSpirotrichonympha, though its monophyly and interspecific relationships are not resolved in our molecular phylogenetic analysis. We propose three new genera to accommodate theH. sjostedtisymbionts and two new species ofSpirotrichonymphafromReticulitermes. 

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5. Making K _r+1 -free graphs r -partite

   https://doi.org/10.1017/S0963548320000590  

   Balogh, József; Clemen, Felix Christian; Lavrov, Mikhail; Lidický, Bernard; Pfender, Florian (July 2021, Combinatorics, Probability and Computing)

   null (Ed.)

   Abstract The Erdős–Simonovits stability theorem states that for all ε > 0 there exists α > 0 such that if G is a K r+ 1 -free graph on n vertices with e ( G ) > ex( n , K r +1 )– α n 2 , then one can remove εn 2 edges from G to obtain an r -partite graph. Füredi gave a short proof that one can choose α = ε . We give a bound for the relationship of α and ε which is asymptotically sharp as ε → 0. 

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