18 research outputs found
Slopes of smooth curves on Fano manifolds
Ross and Thomas introduced the concept of slope stability to study
K-stability, which has conjectural relation with the existence of constant
scalar curvature K\"ahler metric. This paper presents a study of slope
stability of Fano manifolds of dimension with respect to smooth
curves. The question turns out to be easy for curves of genus and the
interest lies in the case of smooth rational curves. Our main result classifies
completely the cases when a polarized Fano manifold is not slope
stable with respect to a smooth curve. Our result also states that a Fano
threefold with Picard number 1 is slope stable with respect to every smooth
curve unless is the projective space.Comment: 13 pages, Theorems in the original version were modified. This paper
will be published in the Bulletin of the London Mathematical Societ
Benthic invertebrate fauna in the islets of Namuseom and Bukhyeongjeseom off Busan
AbstractThis study was conducted to examine the benthic invertebrate fauna inhabiting in the subtidal zone in and around the islets of Namuseom and Bukhyeongjeseom off the coast of Busan by SCUBA diving in September 2013. As a consequence, it was confirmed that a total of 6 phyla, 14 classes, 20 orders, 46 families, and 73 species of zoobenthos inhabit in and around those islets. The total number of species surveyed by taxon during the study is 22 species of Arthropoda (30%), 20 species of Mollusca (27%), 15 species of Cnidaria (21%), 10 species of Echinodermata (14%), four species of Poridera (5%), and two species of Chordata
The ENIGMA Stroke Recovery Working Group: Big data neuroimaging to study brainābehavior relationships after stroke
The goal of the Enhancing Neuroimaging Genetics through MetaāAnalysis (ENIGMA) Stroke Recovery working group is to understand brain and behavior relationships using wellāpowered metaā and megaāanalytic approaches. ENIGMA Stroke Recovery has data from over 2,100 stroke patients collected across 39 research studies and 10 countries around the world, comprising the largest multisite retrospective stroke data collaboration to date. This article outlines the efforts taken by the ENIGMA Stroke Recovery working group to develop neuroinformatics protocols and methods to manage multisite stroke brain magnetic resonance imaging, behavioral and demographics data. Specifically, the processes for scalable data intake and preprocessing, multisite data harmonization, and largeāscale stroke lesion analysis are described, and challenges unique to this type of big data collaboration in stroke research are discussed. Finally, future directions and limitations, as well as recommendations for improved data harmonization through prospective data collection and data management, are provided
A modeling process of equivalent terrains for reduced simulation complexity in radar scene matching applications
This study proposes a modeling process of equivalent terrains to reduce the computational load and time of a full-wave electromagnetic (EM) simulation. To verify the suitability of the proposed process, an original terrain model with a size of 3 m ?? 3 m is equivalently quantized based on the minimum range resolution of a radar, and the radar image of the quantized model is compared with that of the original model. The results confirm that the simulation time can be reduced from 407 hours to 162 hours without a significant distortion of the radar images, and an average estimation error of the quantized model (20.4 mm) is similar to that of the original model (20.3 mm)
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Room temperature multiferroic properties of single-phase (Biā.āLaā.ā)FeOā-Ba(Feā.ā Nbā.ā )Oā solid solution ceramics
The crystal structure and multiferroic properties of single-phase (Biā.āLaā.ā)FeOāāBa(Feā.ā
Nbā.ā
)Oā ceramics were investigated. The rhombohedral-type structure of 1.0(Biā.āLaā.ā)FeOā) was transformed to a monoclinic-type structure for the 0.5(Biā.āLaā.ā)FeOāā0.5Ba(Feā.ā
Nbā.ā
)Oā) composition. It shows the coexistence of ferroelectricity and magnetism at room temperature, represented by a high dielectric constant with ferroelectric hysteresis and clear magnetic hysteresis behavior. The authors propose that the solid solution of A and B site cations according to their ionic radii and valence state stabilized the spontaneous polarization and magnetization at room temperature.Keywords: valency, bismuth compounds, dielectric polarisation, permittivity, ferromagnetic materials, magnetic hysteresis, ferroelectricity, ferroelectric ceramics, multiferroics, barium compounds, crystal structure, lanthanum compounds, dielectric hysteresi
A study on the biodiversity of benthic invertebrates in the waters of Seogwipo, Jeju Island, Korea
The biodiversity of benthic invertebrates in the intertidal and subtidal regions of Gapado, Beomseom, and Munseom islets was surveyed twice in May and September 2013 to study the state of biodiversity in Seogwipo, Jeju Island. As a result, a total of 77 species, 46 families, 25 orders, 14 classes, and nine phyla of benthic invertebrates were found. The species which were found, by taxon, consisted of the following: 26 species of Cnidaria (34%), 24 species of Mollusca (31%), seven species of Chordata (9%), six species of Arthropoda (8%), six species of Porifera (8%), five species of Echinodermata (7%), one species of Bryozoa (1%), one species of Annelida (1%), and one species of Ctenophora (1%)
Invertebrates fauna in the intertidal regions of Yubudo Island, SouthĀ Korea
Yubudo Island, which is located at the estuary of the Geumgang River, is known to have high biodiversity level. This study investigated the invertebrates fauna in the intertidal regions of Yubudo Island during May 2014 to December 2014. A total of 49 species from 32 families were observed. Among them, arthropods were the most abundant, accounting for 48% of the total with 24 species. A large number of Uca (Austruca) lactea, Endangered Wild Species Class II of Korea, were found on the mud flats in December 2014
Tie2 activation promotes choriocapillary regeneration for alleviating neovascular age-related macular degeneration
Choriocapillary loss is a major cause of neovascular age-related macular degeneration (NV-AMD). Although vascular endothelial growth factor (VEGF) blockade for NV-AMD has shown beneficial outcomes, unmet medical needs for patients refractory or tachyphylactic to anti-VEGF therapy exist. In addition, the treatment could exacerbate choriocapillary rarefaction, necessitating advanced treatment for fundamental recovery from NV-AMD. In this study, Tie2 activation by angiopoietin-2ābinding and Tie2-activating antibody (ABTAA) presents a therapeutic strategy for NV-AMD. Conditional Tie2 deletion impeded choriocapillary maintenance, rendering eyes susceptible to NV-AMD development. Moreover, in a NV-AMD mouse model, ABTAA not only suppressed choroidal neovascularization (CNV) and vascular leakage but also regenerated the choriocapillaris and relieved hypoxia. Conversely, VEGF blockade degenerated the choriocapillaris and exacerbated hypoxia, although it suppressed CNV and vascular leakage. Together, we establish that angiopoietin-Tie2 signaling is critical for choriocapillary maintenance and that ABTAA represents an alternative, combinative therapeutic strategy for NV-AMD by alleviating anti-VEGF adverse effects. Copyright Ā© 2019 The Author
Phase transitions via selective elemental vacancy engineering in complex oxide thin films
Defect engineering has brought about a unique level of control for Si-based semiconductors, leading to the optimization of various opto-electronic properties and devices. With regard to perovskite transition metal oxides, O vacancies have been a key ingredient in defect engineering, as they play a central role in determining the crystal field and consequent electronic structure, leading to important electronic and magnetic phase transitions. Therefore, experimental approaches toward understanding the role of defects in complex oxides have been largely limited to controlling O vacancies. In this study, we report on the selective formation of different types of elemental vacancies and their individual roles in determining the atomic and electronic structures of perovskite SrTiO3 (STO) homoepitaxial thin films fabricated by pulsed laser epitaxy. Structural and electronic transitions have been achieved via selective control of the Sr and O vacancy concentrations, respectively, indicating a decoupling between the two phase transitions. In particular, O vacancies were responsible for metal-insulator transitions, but did not influence the Sr vacancy induced cubic-to-tetragonal structural transition in epitaxial STO thin film. The independent control of multiple phase transitions in complex oxides by exploiting selective vacancy engineering opens up an unprecedented opportunity toward understanding and customizing complex oxide thin films.11Nsciescopu