Polarization phenomena in hyperon-nucleon scattering

We investigate polarization observables in hyperon-nucleon scattering by decomposing scattering amplitudes into spin-space tensors, where each component describes scattering by corresponding spin-dependent interactions, so that contributions of the interactions in the observables are individually identified. In this way, for elastic scattering we find some linear combinations of the observables sensitive to particular spin-dependent interactions such as symmetric spin-orbit (LS) interactions and antisymmetric LS ones. These will be useful to criticize theoretical predictions of the interactions when the relevant observables are measured. We treat vector analyzing powers, depolarizations, and coefficients of polarization transfers and spin correlations, a part of which is numerically examined in $\Sigma^{+} p$ scattering as an example. Total cross sections are studied for polarized beams and targets as well as for unpolarized ones to investigate spin dependence of imaginary parts of forward scattering amplitudes.Comment: 15 pages, 8 figure

Central and tensor components of three-nucleon forces in low-energy proton-deuteron scattering

Contributions of three-nucleon forces (3NF) to proton-deuteron scattering observables at energies below the deuteron breakup threshold are studied by solving the Faddeev equation that includes the Coulomb interaction. At E_p=3.0 MeV, we find that the central part of a two-pion exchange 3NF removes the discrepancy between measured cross sections and the calculated ones by two-nucleon forces, and improves the agreement with T_{22} experimental data. However, the tensor part of the 3NF fails in reproducing data of the analyzing power T_{21} by giving worse agreement between the measured and the calculated. Detailed examinations of scattering amplitudes suggest that a P-wave contribution in spin quartet tensor amplitudes has unsuitable sign for reproducing the T_{21} data.Comment: 6 pages, 6 figure

Identity and function of an essential nitrogen ligand of the nitrogenase cofactor biosynthesis protein NifB.

NifB is a radical S-adenosyl-L-methionine (SAM) enzyme that is essential for nitrogenase cofactor assembly. Previously, a nitrogen ligand was shown to be involved in coupling a pair of [Fe4S4] clusters (designated K1 and K2) concomitant with carbide insertion into an [Fe8S9C] cofactor core (designated L) on NifB. However, the identity and function of this ligand remain elusive. Here, we use combined mutagenesis and pulse electron paramagnetic resonance analyses to establish histidine-43 of Methanosarcina acetivorans NifB (MaNifB) as the nitrogen ligand for K1. Biochemical and continuous wave electron paramagnetic resonance data demonstrate the inability of MaNifB to serve as a source for cofactor maturation upon substitution of histidine-43 with alanine; whereas x-ray absorption spectroscopy/extended x-ray fine structure experiments further suggest formation of an intermediate that lacks the cofactor core arrangement in this MaNifB variant. These results point to dual functions of histidine-43 in structurally assisting the proper coupling between K1 and K2 and concurrently facilitating carbide formation via deprotonation of the initial carbon radical

Fine-Scale Spatial Organization of Face and Object Selectivity in the Temporal Lobe: Do Functional Magnetic Resonance Imaging, Optical Imaging, and Electrophysiology Agree?

The spatial organization of the brain's object and face representations in the temporal lobe is critical for understanding high-level vision and cognition but is poorly understood. Recently, exciting progress has been made using advanced imaging and physiology methods in humans and nonhuman primates, and the combination of such methods may be particularly powerful. Studies applying these methods help us to understand how neuronal activity, optical imaging, and functional magnetic resonance imaging signals are related within the temporal lobe, and to uncover the fine-grained and large-scale spatial organization of object and face representations in the primate brain

Identifying Key Points to Consider in the Implementation of Programming Education for Students with Intellectual Disabilities

知的障害のある児童生徒に対する指導内容としての妥当性の検証と実施上の留意点を得ることを目的として，知的障害特別支援学校において６名を対象にプログラミングロボットを使用し，「進む方向や進む距離を正しく表現できる」をねらいとして授業実践を行った。アンプラグド学習を組み合わせた指導を実施し，その結果，個人差はあるものの全員前後左右の理解が促進された。また，プログラミング的思考の評価は，小学校や保育等の評価基準に関する先行研究を参考にして作成した「プログラミング的思考段階表（試案）」から目標を設定し，評価を行った。評価の結果，プログラミング的思考の育成にも実践の効果が示唆された。以上のことから，知的障害教育における実施上の留意点として「目標設定」「指導計画の作成」「指導・支援」「評価」の４つに整理することができた。今後は段階表や留意点の内容や活用方法，有用性についてさらに検証が必要である

Plastid Genome-Based Phylogeny Pinpointed the Origin of the Green-Colored Plastid in the Dinoflagellate Lepidodinium chlorophorum

Unlike many other photosynthetic dinoflagellates, whose plastids contain a characteristic carotenoid peridinin, members of the genus Lepidodinium are the only known dinoflagellate species possessing green alga-derived plastids. However, the precise origin of Lepidodinium plastids has hitherto remained uncertain. In this study, we completely sequenced the plastid genome of Lepidodinium chlorophorum NIES-1868. Our phylogenetic analyses of 52 plastid-encoded proteins unite L. chlorophorum exclusively with a pedinophyte, Pedinomonas minor, indicating that the green-colored plastids in Lepidodinium spp. were derived from an endosymbiotic pedinophyte or a green alga closely related to pedinophytes. Our genome comparison incorporating the origin of the Lepidodinium plastids strongly suggests that the endosymbiont plastid genome acquired by the ancestral Lepidodinium species has lost genes encoding proteins involved in metabolism and biosynthesis, protein/metabolite transport, and plastid division during the endosymbiosis. We further discuss the commonalities and idiosyncrasies in genome evolution between the L. chlorophorum plastid and other plastids acquired through endosymbiosis of eukaryotic photoautotrophs

CO Binding onto Heterometals of [Mo₃S₄M] (M = Fe, Co, Ni) Cubes

We have previously shown that cyclopentadienyl (Cp[R])-supported [Mo₃S₄] platforms capture and stabilize halides of hetero-metals (M) under reducing conditions to give [Mo₃S₄M] cubes. Here we report Co and Ni variants with Cp[XL] ligands (Cp[XL] = C₅Me₄SiEt₃) and CO binding to the [Mo₃S₄M] clusters (M = Fe, Co, Ni). Properties of the isolated CO-bound [Mo₃S₄M] cubes were investigated by X-ray diffraction, IR, and electrochemical analyses. Density functional theory (DFT) calculations were performed for the isolated CO-bound clusters to evaluate M-CO interactions. These analyses constitute foundations to develop bio-mimetic molecular catalysts for the direct conversion of CO and/or CO₂ into hydrocarbons, which can contribute to the reduction of carbon emissions

Spin observables in nucleon-deuteron scattering and three-nucleon forces

Three-nucleon forces, which compose an up-to-date subject in few-nucleon systems, provide a good account of the triton binding energy and the cross section minimum in proton-deuteron elastic scattering. However, three-nucleon forces do not explain spin observables such as the nucleon and deuteron analyzing powers, suggesting serious defects in their spin dependence. We study the spin structure of nucleon-deuteron elastic amplitudes by decomposing them into spin-space tensors and examine effects of three-nucleon forces to each component of the amplitudes obtained by solving the Faddeev equation. Assuming that the spin-scalar amplitudes dominate the others, we derive simple expressions for spin observables in the nucleon-deuteron elastic scattering. The expressions suggest that a particular combination of spin observables in the scattering provides direct information on scalar, vector, or tensor component of the three-nucleon forces. These effects are numerically investigated by the Faddeev calculation