Reconstruction of sediment-transport pathways on a modern microtidal coast by a new grain-size trend analysis method

A new method for granulometric-parameter-based reconstruction of sediment-transport pathways is proposed and is termed P-GSTA (grain-size trend analysis using principal component analysis) herein. The main advantage of this method is its applicability to depositional environments involving mixed transport processes, for instance, fluvial, tidal, and wave-influenced environments. In the P-GSTA method, a linear function with all significant granulometric parameters that are summed with different weighting factors was used to infer sediment-transport direction (sediment flux pattern); the previous grain-size trend analysis (GSTA) methods considered only three parameters (mean grain size, sorting, and skewness) with equal weighting. This study chose six parameters (namely, median grain size, coefficient of variation, skewness, kurtosis, and mud and gravel log-ratios) for calculation. First, the zero values of mud and gravel fractions are replaced, and their log-ratios are defined. Then, all values are standardized. Thereafter, principal component analysis (PCA) is conducted to determine the weighting factor of each granulometric parameter. Each principal component is then interpreted, and the function best representing a sediment flux pattern is chosen from these components. Trend vectors are calculated, solely on the basis of a map interpolated from the scores of the chosen principal component, as the two-dimensional gradient of this value. The P-GSTA method proposed in this study was applied to a modern microtidal coast (tidal sand flat along the Kushida River Delta, central Japan). Sediment-transport pathways reconstructed by this method were consistent with observed sediment-transport patterns determined by field experiments using tracer sediments and geomorphologic observation; the results of the previous GSTA method were inconsistent with the observations. The proposed method also revealed additional minor depositional processes on the sand flat, namely, the deposition of fluvial-channel lags and muddy particles. Thus, this study demonstrates that the proposed P-GSTA method is a potentially powerful tool to reconstruct sediment-transport patterns even under mixed transport processes, where the estimation of the sediment-transport function is difficult

Structure of corrosion product formed on carbon steel covered with NiSO4-Added resin coating under sulfuric acid mist environment containing chloride

Corrosion resistance of carbon steel covered with resin coating containing nickel sulfate has been evaluated under chloride and sulfuric acid mist environment. The structure of corrosion products formed on steel surface was investigated by XRD and XAFS analyses using synchrotron radiation. Nickel sulfate promoted the formation of goethite and akaganeite. It was considered that this akaganeite was not tetragonal β-FeOOH but monoclinic akaganeite containing nickel.Shota Hayashida, Masamitsu Takahashi, Hiroshi Deguchi, Hiroaki Tsuchiya, Koushu Hanaki, Masato Yamashita, Shinji Fujimoto, Structure of Corrosion Product Formed on Carbon Steel Covered with NiSO4-Added Resin Coating under Sulfuric Acid Mist Environment Containing Chloride, Materials Transactions, 2021, Volume 62, Issue 6, Pages 781-787, Released on J-STAGE May 25, 2021, Advance online publication May 14, 2021, Online ISSN 1347-5320, Print ISSN 1345-9678, https://doi.org/10.2320/matertrans.C-M2021819

Morphology, taxonomy and mating‑type loci in natural populations of Volvox carteri in Taiwan

Background: Volvox carteri f. nagariensis is a model taxon that has been studied extensively at the cellular and molecular level. The most distinctive morphological attribute of V. carteri f. nagariensis within V. carteri is the production of sexual male spheroids with only a 1:1 ratio of somatic cells to sperm packets or androgonidia (sperm packet initials). However, the morphology of male spheroids of V. carteri f. nagariensis has been examined only in Japanese strains. In addition, V. carteri f. nagariensis has heterothallic sexuality; male and female sexes are determined by the sex-determining chromosomal region or mating-type locus composed of a \u3e 1 Mbp linear chromosome. Fifteen sexspecific genes and many sex-based divergent shared genes (gametologs) are present within this region. Thus far, such genes have not been identified in natural populations of this species. Results: During a recent fieldwork in Taiwan, we encountered natural populations of V. carteri that had not previously been recorded from Taiwan. In total, 33 strains of this species were established from water samples collected in Northern Taiwan. Based on sequences of the internal transcribed spacer 2 region of nuclear ribosomal DNA and the presence of asexual spheroids with up to 16 gonidia, the species was clearly identified as V. carteri f. nagariensis. However, the sexual male spheroids of the Taiwanese strains generally exhibited a 1:1 to \u3e 50:1 ratio of somatic cells to androgonidia. We also investigated the presence or absence of several sex-specific genes and the sex-based divergent genes MAT3m, MAT3f and LEU1Sm. We did not identify recombination or deletion of such genes between the male and female mating-type locus haplotypes in 32 of the 33 strains. In one putative female strain, the female-specific gene HMG1f was not amplified by genomic polymerase chain reaction. When sexually induced, apparently normal female sexual spheroids developed in this strain. Conclusions: Male spheroids are actually variable within V. carteri f. nagariensis. Therefore, the minimum ratio of somatic cells to androgonidia in male spheroids and the maximum number of gonidia in asexual spheroids may be diagnostic for V. carteri f. nagariensis. HMG1f may not be directly related to the formation of female spheroids in this taxon

Retinoic acid controls vascular formation by activating transcription of aryl hydrocarbon receptor gene in medakafish Oryzias latipes

Retinoic acid (RA) has been shown to have a role in vascular formation, but how it affects is not fully understood. Previously, we reported that RA and its nuclear receptor (RAR) is required for transcription of ahr1 encoding an aryl hydrocarbon receptor (AHR), and that pharmacological modulation of RA, RAR, and AHR impairs the formation of common cardinal veins (CCVs) on the yolk of medakafish embryos. Here, to delineate a role for ahr1 in the vascular formation, we used an antisense-ahr1 mRNA to suppress ahr1. Following the development of vegfr1-expressing angioblast cells, we show that the antisense-ahr1 greatly inhibited the accumulation of angioblasts at the prospective branchial arch (PBA) where CCVs begin to develop on the yolk and the following CCV formation, demonstrating for the first time the essential role of ahr1 in the embryonic vascular formation of vertebrates. We also show that rarα and ahr1 mRNAs are co-expressed at PBA, suggesting a possible role of the specific expression.This work was supported in part by a grant from the Ministry of Education, Science, Sports and Culture of Japan

Dwarf Novae in the Shortest Orbital Period Regime: I. A New Short Period Dwarf Nova, OT J055717+683226

We report the observation of a new dwarf nova, OT J055717+683226, during its first-ever recorded superoutburst in December 2006. Our observation shows that this object is an SU UMa-type dwarf nova having a very short superhump period of 76.67+/- 0.03 min (0.05324+/-0.00002 d). The next superoutburst was observed in March 2008. The recurrence time of superoutbursts (supercycle) is, hence, estimated to be ~480 d. The supercycle is much shorter than those of WZ Sge-type dwarf novae having supercycles of >~ 10 yr, which are a major population of dwarf novae in the shortest orbital period regime (<~85 min). Using a hierarchical cluster analysis, we identified seven groups of dwarf novae in the shortest orbital period regime. We identified a small group of objects that have short supercycles, small outburst amplitudes, and large superhump period excesses, compared with those of WZ Sge stars. OT J055717+683226 probably belongs to this group.Comment: 14 pages, 11 figures, accepted for publication in PAS

Complete genome sequence of Nitratireductor sp. strain OM-1:A lipid-producing bacterium with potential use in wastewater treatment

Reducing CO 2 emissions is necessary to alleviate rising global temperature. Renewable sources of energy are becoming an increasingly important substitute for fossil fuels. An important step in this direction is the isolation of novel, technologically relevant microorganisms. Nitratireductor sp. strain OM-1 can convert volatile short-chain fatty acids in wastewater into 2-butenoic acid and its ester and can accumulate intracellularly esterified compounds up to 50% of its dried cell weight under nitrogen- depleted conditions. It is believed that a novel fatty acid biosynthesis pathway including an esterifying enzyme is encoded in its genome. In this study, we report the whole-genome sequence (4.8 Mb) of OM-1, which comprises a chromosome (3,977,827 bp) and a megaplasmid (857,937 bp). This sequence information provides insight into the genome organization and biochemical pathways of OM-1. In addition, we identified lipid biosynthesis pathways in OM-1, paving the way to a better understanding of its biochemical characterization

〈研究論文〉新たな学校ガバナンスにおける「教育の専門性」の再定位（2）: 小学校教員の専門性認識に関する分析を中心に

Since the 1990s, the concept of “Governance” has become widely known and has been often discussed in many fields including public education. Contemporary public education reform policies basically include the restructuring of relationships between teaching professionals and other stakeholders. It should be noted that, in fact, some education policies do not take into account the “professionality of teaching” very much; thus, there is a possibility that teaching professionals will be seen as comparatively inferior to other actors. It is therefore important to consider the position of teaching professionals within the new school governance structure and replace it, taking into account the concept of “professionality of education.”..

Free-Floating planet Mass Function from MOA-II 9-year survey towards the Galactic Bulge

We present the first measurement of the mass function of free-floating planets (FFP) or very wide orbit planets down to an Earth mass, from the MOA-II microlensing survey in 2006-2014. Six events are likely to be due to planets with Einstein radius crossing times, $t_{\rm E}<0.5$days, and the shortest has $t_{\rm E} = 0.057\pm 0.016$days and an angular Einstein radius of $\theta_{\rm E} = 0.90\pm 0.14\mu$as. We measure the detection efficiency depending on both $t_{\rm E}$ and $\theta_{\rm E}$ with image level simulations for the first time. These short events are well modeled by a power-law mass function, $dN_4/d\log M = (2.18^{+0.52}_{-1.40})\times (M/8\,M_\oplus)^{-\alpha_4}$ dex$^{-1}$star$^{-1}$ with $\alpha_4 = 0.96^{+0.47}_{-0.27}$ for $M/M_\odot < 0.02$. This implies a total of $f= 21^{+23}_{-13}$ FFP or very wide orbit planets of mass $0.33<M/M_\oplus < 6660$ per star, with a total mass of $80^{+73}_{-47} M_\oplus$ per star. The number of FFPs is $19_{-13}^{+23}$ times the number of planets in wide orbits (beyond the snow line), while the total masses are of the same order. This suggests that the FFPs have been ejected from bound planetary systems that may have had an initial mass function with a power-law index of $\alpha\sim 0.9$, which would imply a total mass of $171_{-52}^{+80} M_\oplus$ star$^{-1}$. This model predicts that Roman Space Telescope will detect $988^{+1848}_{-566}$ FFPs with masses down to that of Mars (including $575^{+1733}_{ -424}$ with $0.1 \le M/M_\oplus \le 1$). The Sumi(2011) large Jupiter-mass FFP population is excluded.Comment: 17 pages, 7 figures, accepted for publication in A