Orbital Evolution of Close-in Super-Earths Driven by Atmospheric Escape

The increasing number of super-Earths close to their host stars have revealed a scarcity of close-in small planets with 1.5–2.0 R⊕ in the radius distribution of Kepler planets. The atmospheric escape of super-Earths by photoevaporation can explain the origin of the observed “radius gap.” Many theoretical studies have considered the in situ mass loss of a close-in planet. Planets that undergo atmospheric escape, however, move outward due to the change in the orbital angular momentum of their star–planet systems. In this study, we calculate the orbital evolution of an evaporating super-Earth with a H₂/He atmosphere around FGKM-type stars under stellar X-ray and extreme-UV irradiation (XUV). The rate of increase in the orbital radius of an evaporating planet is approximately proportional to that of the atmospheric mass loss during a high stellar XUV phase. We show that super-Earths with a rocky core of ≲10 M⊕ and a H₂/He atmosphere at ≲0.03–0.1 au (≲0.01–0.03 au) around G-type stars (M-type stars) are prone to outward migration driven by photoevaporation. Although the changes in the orbits of the planets would be small, they would rearrange the orbital configurations of compact, multiplanet systems, such as the TRAPPIST-1 system. We also find that the radius gap and the so-called “Neptune desert” in the observed population of close-in planets around FGK-type stars still appear in our simulations. On the other hand, the observed planet population around M-type stars can be reproduced only by a high stellar XUV luminosity model

Molecular regulation of starch metabolism

Starch is the second most abundant biomass next to cellulose and composed of amylopectin, a highly branched glucan, and amylose, an essentially linear glucan. The former and the latter glucans usually account for approximately 65–85% and 15–35% of the total starch, respectively. During the last three decades the basic scheme of starch biosynthesis has been established based on numerous biochemical, genetic, and molecular biological approaches worldwide using a variety of higher plants and algae. It is well known that after the synthesis of ADPglucose by ADPglucose pyrophosphorylase (AGPase), amylopectin’s fne structure is formed by concerted actions of multiple isozymes from three classes of enzymes, starch synthase (SS), starch branching enzyme (BE), and starch debranching enzyme (DBE), and that amylose is synthesized by mainly granule-bound SS (GBSS). In addition to the roles of starch biosynthetic isozymes, the contributions of α-glucan phosphorylase, α-glucan, water dikinase, phosphoglucan, water dikinase, pyruvate, phosphate dikinase, α-amylase, and carbohydrate-binding modules have been documented. Information on the whole genome sequence and omics analyses are available in main plant species. All these results revealed the roles of key biosynthetic isozymes of SS, GBSS, BE, and DBE and subunits of AGPase to starch biosynthesis, and presently we know to what extent the fne structure of starch molecules and the internal structure and physicochemical properties of starch granules as well as starch amounts can be modifed in accord with the activity levels of these isozymes and subunits. However, in spite of numerous past investigations, the regulation of the network of enzymatic reactions has not been fully understood. To resolve the complex mechanisms, we need to examine several topics such as redundancy and supplementary functions of multiple isozymes, enzymeenzyme interaction(s), and regulatory factors controlling catalytic and specific activities of individual isozymes, temporal and spatial co-expression of multiple isozymes, post-translational modifcation of enzymatic capacities such as phosphorylation, glycosylation, and redox state. There are still lots of uncertainties in the understanding of the initiation of starch biosynthesis.Fil: Nakamura, Yasunori. Akita Prefectural University; JapónFil: Steup, Martin. Universitat Potsdam; AlemaniaFil: Colleoni, Christophe. Université de Lille; FranciaFil: Iglesias, Alberto Alvaro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; ArgentinaFil: Bao, Jinsong. Zhejiang University; ChinaFil: Fujita, Naoko. University of Guelph; CanadáFil: Tetlow, Ian. University of Guelph; Canad

New 3-D flow interpolation method on moving ADCP data

A simple but accurate interpolation procedure for obtaining the three-dimensional distribution of three-component velocity data, from moving acoustic doppler current profiler (ADCP) observation data, is proposed. For understanding actual flow structure within a river with complex bathymetry, the three-dimensional mean velocity field provides a basic picture of the flow. For obtaining the three-dimensional distribution of three-component velocity data, in this work, anisotropic gridding was introduced in order to remove the random component of measured velocity data caused by the turbulence of the flow and measurement error. A continuity correction based on the pressure equation was used to reduce both random and systematic errors. The accuracy of the developed method was evaluated using three-dimensional flow simulation data from a detached-eddy simulation (DES). By using the procedure developed, the complex flow structure surrounding the spur dikes section in the Uji River was successfully visualized and explored. The proposed method shows superiorities in both accuracy and consistency for the interpolated velocity field, as compared to the kriging and inverse-distance weighted (IDW) methods

Velocity measurements around non-submerged and submerged spur dykes by means of Large-Scale image velocimetry

Field observations on the surface flow were carried out in a straight reach of the Uji River, Kyoto, Japan. Velocity distributions on the water surface were obtained based on the captured video images by means of the Large-Scale Particle Image Velocimetry (LSPIV) developed by Fujita et al. (3). Flow structures around spur dykes are studied for both non-submerged and submerged cases. It is clearly seen that, for both cases, the dykes work as an additional roughness. Their effect on channel conveyance capacity is estimated in terms of the effective channel width calculated from the velocity distributions. For the non-submerged case the area enclosed by the spur dykes has little contribution to the channel conveyance capacity. Whereas for the submerged case the streamwise velocity is fairly decelerated on the dykes' side due to the drag effect of the dykes themselves. It is also of interest that the maximum velocity filament appears at a different position as the water depth varies in case of the channel with single-side dykes such as studied here. In addition, large-scale boils shedding from the submerged dykes are clearly observed. Their origin and advection mechanisms are also evaluated from the video image. The time period of boils appearing on the water surface is well related with the time calculated by the mean upward velocity and the water depth on the dyke

Fan-shaped aurora as seen from Japan during a great magnetic storm on February 11, 1958

During a great magnetic storm on Feb 11, 1958, a fan-shaped aurora was photographed at Memambetsu, Hokkaido, Japan – the first and oldest photograph record of auroras observed in Japan, accompanied by many hand-made drawings, thus, portraying a rare opportunity of coexistence between photograph images and hand-made drawings. In fact, the same portrayal reminds us of the great red aurora with fan-shaped white pillars observed during the 1872 and 1770 great magnetic storms. The hand-made sketches, photographs, and the spectral data revealed that the white pillars and red glow of the fan-shaped aurora were dominated by auroral green and red lines, respectively. From the analysis of newly digitized microfilm data and hand-made drawings, we found that the fan-shaped aurora appeared during the peak activity of magnetic storm and moved westward at 0.4 km/s at 400-km altitude at 38°–40° magnetic latitudes, which is consistent with the enhanced convection pattern in the middle latitude at storm time. Such a fan-shaped aurora can fundamentally characterize the middle-latitude evening-to-midnight auroras during great magnetic storms, which show the most destabilized transient appearance of the inner magnetosphere

Expression of ADAM15 in rheumatoid synovium: up-regulation by vascular endothelial growth factor and possible implications for angiogenesis

ADAMs (a disintegrin and metalloproteinases) comprise a new gene family of metalloproteinases, and may play roles in cell-cell interaction, cell migration, signal transduction, shedding of membrane-anchored proteins and degradation of extracellular matrix. We screened the mRNA expression of 10 different ADAMs with a putative metalloproteinase motif in synovial tissues from patients with rheumatoid arthritis (RA) or osteoarthritis (OA). Reverse transcription PCR and real-time quantitative PCR analyses indicated that among the ADAMs, ADAM15 mRNA was more frequently expressed in the RA samples and its expression level was significantly 3.8-fold higher in RA than in OA (p < 0.01). In situ hybridization, immunohistochemistry and immunoblotting demonstrated that ADAM15 is expressed in active and precursor forms in the synovial lining cells, endothelial cells of blood vessels and macrophage-like cells in the sublining layer of RA synovium. There was a direct correlation between ADAM15 mRNA expression levels and vascular density in the synovial tissues (r = 0.907, p < 0.001; n = 20). ADAM15 was constitutively expressed in RA synovial fibroblasts and human umbilical vein endothelial cells (HUVECs), and the expression level was increased in HUVECs by treatment with vascular endothelial growth factor (VEGF)(165). On the other hand, ADAM15 expression in RA synovial fibroblasts was enhanced with VEGF(165 )only if vascular endothelial growth factor receptor (VEGFR)-2 expression was induced by treatment with tumor necrosis factor-α, and the expression was blocked with SU1498, a specific inhibitor of VEGFR-2. These data demonstrate that ADAM15 is overexpressed in RA synovium and its expression is up-regulated by the action of VEGF(165 )through VEGFR-2, and suggest the possibility that ADAM15 is involved in angiogenesis in RA synovium

Starch biosynthesis in rice endosperm requires the presence of either starch synthase I or IIIa

Starch synthase (SS) I and IIIa are the first and second largest components of total soluble SS activity, respectively, in developing japonica rice (Oryza sativa L.) endosperm. To elucidate the distinct and overlapping functions of these enzymes, double mutants were created by crossing the ss1 null mutant with the ss3a null mutant. In the F2 generation, two opaque seed types were found to have either the ss1ss1/SS3ass3a or the SS1ss1/ss3ass3a genotype. Phenotypic analyses revealed lower SS activity in the endosperm of these lines than in those of the parent mutant lines since these seeds had different copies of SSI and SSIIIa genes in a heterozygous state. The endosperm of the two types of opaque seeds contained the unique starch with modified fine structure, round-shaped starch granules, high amylose content, and specific physicochemical properties. The seed weight was ∼90% of that of the wild type. The amount of granule-bound starch synthase I (GBSSI) and the activity of ADP-glucose pyrophosphorylase (AGPase) were higher than in the wild type and parent mutant lines. The double-recessive homozygous mutant prepared from both ss1 and ss3a null mutants was considered sterile, while the mutant produced by the leaky ss1 mutant×ss3a null mutant cross was fertile. This present study strongly suggests that at least SSI or SSIIIa is required for starch biosynthesis in rice endosperm

Molecular contribution to cleft palate production in cleft lip mice

Cleft palate following cleft lip may include a developmental disorder during palatogenesis. CL/Fr mice fetuses, which develop cleft lip and palate spontaneously, have less capability for in vivo cell proliferation in palatal mesenchyme compared with CL/Fr normal fetuses. In order to know the changes of signaling molecules contributing to cleft palate morphogenesis following cleft lip, the mRNA expression profiles were compared in palatal shelves oriented vertically (before elevation) in CL/Fr fetuses with or without cleft lip. The changes in mRNA profile of cleft palate morphogenesis were presented in a microarray analysis, and genes were restricted to lists contributing to cleft palate development in CL/Fr fetuses with cleft lip. Four candidate genes (Ywhab, Nek2, Tacc1 and Frk) were linked in a gene network that associates with cell proliferation (cell cycle, MAPK, Wnt and Tgf beta pathways). Quantitative real-time RT-PCR highlighted the candidate genes that significantly changed in CL/Fr fetuses with cleft lip (Ywhab, Nek2 and Tacc1). The results of these molecular contributions will provide useful information for a better understanding of palatogenesis in cleft palate following cleft lip. Our data indicated the genetic contribution to cleft palate morphogenesis following cleft lip

Explicit Supersymmetry Breaking on Boundaries of Warped Extra Dimensions

Explicit supersymmetry breaking is studied in higher dimensional theories by having boundaries respect only a subgroup of the bulk symmetry. If the boundary symmetry is the maximal subgroup allowed by the boundary conditions imposed on the fields, then the symmetry can be consistently gauged; otherwise gauging leads to an inconsistent theory. In a warped fifth dimension, an explicit breaking of all bulk supersymmetries by the boundaries is found to be inconsistent with gauging; unlike the case of flat 5D, complete supersymmetry breaking by boundary conditions is not consistent with supergravity. Despite this result, the low energy effective theory resulting from boundary supersymmetry breaking becomes consistent in the limit where gravity decouples, and such models are explored in the hope that some way of successfully incorporating gravity can be found. A warped constrained standard model leads to a theory with one Higgs boson with mass expected close to the experimental limit. A unified theory in a warped fifth dimension is studied with boundary breaking of both SU(5) gauge symmetry and supersymmetry. The usual supersymmetric prediction for gauge coupling unification holds even though the TeV spectrum is quite unlike the MSSM. Such a theory may unify matter and Higgs in the same SU(5) hypermultiplet.Comment: 30 pages, version to appear in Nucl. Phys.