204 research outputs found
Coupled H\'enon Map, Part I: Topological Horseshoes and Uniform Hyperbolicity
We derive a sufficient condition for topological horseshoe and uniform
hyperbolicity of a 4-dimensional symplectic map, which is introduced by
coupling the two 2-dimensional H\'enon maps via linear terms. The coupled
H\'enon map thus constructed can be viewed as a simple map modeling the
horseshoe in higher dimensions. We show that there are two different types of
horseshoes, each of which is realized around different anti-integrable limits
in the parameter regime.Comment: 26 pages, 12 figure
Whole-genome analysis of recombinant inbred rice lines reveals a quantitative trait locus on chromosome 3 with genotype-by-environment interaction effects
Elucidating genotype-by-environment interactions is fundamental for understanding the interplay between genetic and environmental factors that shape complex traits in crops. Genotype-by-environment interactions are of practical importance, as they determine the performance of cultivars grown in different environments, prompting the need for an efficient approach for evaluating genotype-by-environment interactions. Here, we describe a method for genotype-by-environment detection that involves comparing linear mixed models. This method successfully detected genotype-by-environment interactions in rice (Oryza sativa) recombinant inbred lines grown at 3 locations. We identified a quantitative trait locus (QTL) on chromosome 3 that was associated with heading date, grain number, and leaf length. The effect of this QTL on plant growth–related traits varied with environmental conditions, indicating the presence of genotype-by-environment interactions. Therefore, our method enables a powerful genotype-by-environment detection pipeline that should facilitate the production of high-yielding crops in a given environment
General Survey of Tohoku Hybrid Magnet System(Part I. Establishment and Tests of Hybrid Magnet System at HFLSM)
Outline of Tohoku Hybrid Magnet system is briefly described. High Field Laboratory was established in the Research Institute for Iron, Steel and Other Metals, Tohoku University, in 1981, for accelerating research and development of high field superconducting materials. Three hybrid magnets generating magnetic fields more than 20 T have been constructed as its main apparatuses. The strongest hybrid magnet, HM-1, could produce 31.1 T in November, 1986, which was the world record as this kind of hybrid magnet. Several important features of the hybrid magnet system are introduced which will be also useful to understand the following papers
Synthesis and physical properties of Ca1-xRExFeAs2 with RE = La ~ Gd
Synthesis of a series of layered iron arsenides Ca1-xRExFeAs2 (112) was
attempted by heating at 1000 C under a high-pressure of 2 GPa. The 112 phase
successfully forms with RE = La, Ce, Nd, Sm, Eu and Gd, while Tb, Dy and Ho
substituted and RE free samples does not contain the 112 phase. The Ce, Nd, Sm,
Eu and Gd doped Ca1-xRExFeAs2 are new compounds. All of them exhibit
superconducting transition except for the Ce doped sample. The behaviour of the
critical temperature, with the RE ionic radii have been investigated
Discovery of a gene cluster for the biosynthesis of novel cyclic peptide compound, KK-1, in Curvularia clavata
KK-1, a cyclic depsipeptide with 10 residues produced by a filamentous fungus Curvularia clavata BAUA-2787, is a promising pesticide active compound with high activity against many plant pathogens, especially Botrytis cinerea. As a first step toward the future mass production of KK-1 through synthetic biological approaches, we aimed to identify the genes responsible for the KK-1 biosynthesis. To achieve this, we conducted whole genome sequencing and transcriptome analysis of C. clavata BAUA-2787 to predict the KK-1 biosynthetic gene cluster. We then generated the overexpression and deletion mutants for each cluster gene using our originally developed transformation system for this fungus, and analyzed the KK-1 production and the cluster gene expression levels to confirm their involvement in KK-1 biosynthesis. As a result of these, a region of approximately 71 kb was found, containing 10 open reading frames, which were co-induced during KK-1 production, as a biosynthetic gene cluster. These include kk1B, which encodes nonribosomal peptide synthetase with a domain structure that is consistent with the structural features of KK-1, and kk1F, which encodes a transcription factor. The overexpression of kk1F increased the expression of the entire cluster genes and, consequently, improved KK-1 production, whereas its deletion decreased the expression of the entire cluster genes and almost eliminated KK-1 production, demonstrating that the protein encoded by kk1F regulates the expressions of the other nine cluster genes cooperatively as the pathway-specific transcription factor. Furthermore, the deletion of each cluster gene caused a reduction in KK-1 productivity, indicating that each gene is involved in KK-1 production. The genes kk1A, kk1D, kk1H, and kk1I, which showed a significant decrease in KK-1 productivity due to deletion, were presumed to be directly involved in KK-1 structure formation, including the biosynthesis of the constituent residues. kk1C, kk1E, kk1G, and kk1J, which maintained a certain level of KK-1 productivity despite deletion, were possibly involved in promoting or assisting KK-1 production, such as extracellular transportation and the removal of aberrant units incorporated into the peptide chain
Magnetized Fast Isochoric Laser Heating for Efficient Creation of Ultra-High-Energy-Density States
The quest for the inertial confinement fusion (ICF) ignition is a grand
challenge, as exemplified by extraordinary large laser facilities. Fast
isochoric heating of a pre-compressed plasma core with a high-intensity
short-pulse laser is an attractive and alternative approach to create
ultra-high-energy-density states like those found in ICF ignition sparks. This
avoids the ignition quench caused by the hot spark mixing with the surrounding
cold fuel, which is the crucial problem of the currently pursued ignition
scheme. High-intensity lasers efficiently produce relativistic electron beams
(REB). A part of the REB kinetic energy is deposited in the core, and then the
heated region becomes the hot spark to trigger the ignition. However, only a
small portion of the REB collides with the core because of its large
divergence. Here we have demonstrated enhanced laser-to-core energy coupling
with the magnetized fast isochoric heating. The method employs a
kilo-tesla-level magnetic field that is applied to the transport region from
the REB generation point to the core which results in guiding the REB along the
magnetic field lines to the core. 7.7 1.3 % of the maximum coupling was
achieved even with a relatively small radial area density core (
0.1 g/cm). The guided REB transport was clearly visualized in a
pre-compressed core by using Cu- imaging technique. A simplified
model coupled with the comprehensive diagnostics yields 6.2\% of the coupling
that agrees fairly with the measured coupling. This model also reveals that an
ignition-scale areal density core ( 0.4 g/cm) leads to much
higher laser-to-core coupling ( 15%), this is much higher than that achieved
by the current scheme
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