86 research outputs found
New Covariant Gauges in String Field Theory
A single-parameter family of covariant gauge fixing conditions in bosonic
string field theory is proposed. It is a natural string field counterpart of
the covariant gauge in the conventional gauge theory, which includes the Landau
gauge as well as the Feynman (Siegel) gauge as special cases. The action in the
Landau gauge is largely simplified in such a way that numerous component fields
have no derivatives in their kinetic terms and appear in at most quadratic in
the vertex.Comment: 24 page
Supersymmetric extended string field theory in NS^n sector and NS^{n-1}-R sector
We construct a class of quadratic gauge invariant actions for extended string
fields defined on the tensor product of open superstring state space for
multiple open string Neveu-Schwarz (NS) sectors with or without one Ramond (R)
sector. The basic idea is the same as for the bosonic extended string field
theory developed by the authors [arXiv:1309.3850]. The theory for NS^n sector
and NS^{n-1}-R sector contains general n-th rank tensor fields and (n-1)-th
rank spinor-tensor fields in the massless spectrum respectively. In principle,
consistent gauge invariant actions for any generic type of 10-dimensional
massive or massless tensor or spinor-tensor fields can be extracted from the
theory. We discuss some simple examples of bosonic and fermionic massless
actions.Comment: 25 page
Physical state representations and gauge fixing in string theory
We re-examine physical state representations in the covariant quantization of
bosonic string. We especially consider one parameter family of gauge fixing
conditions for the residual gauge symmetry due to null states (or BRST exact
states), and obtain explicit representations of observable Hilbert space which
include those of the DDF states. This analysis is aimed at giving a necessary
ingredient for the complete gauge fixing procedures of covariant string field
theory such as temporal or light-cone gauge.Comment: 16 page
Probing Rotation of Core-collapse Supernova with Concurrent Analysis of Gravitational Waves and Neutrinos
The next time a core-collapse supernova (SN) explodes in our galaxy, vari-
ous detectors will be ready and waiting to detect its emissions of
gravitational waves (GWs) and neutrinos. Current numerical simulations have
successfully introduced multi-dimensional effects to produce exploding SN
models, but thus far the explosion mechanism is not well understood. In this
paper, we focus on an investigation of progenitor core rotation via comparison
of the start time of GW emission and that of the neutronization burst. The GW
and neutrino de- tectors are assumed to be, respectively, the KAGRA detector
and a co-located gadolinium-loaded water Cherenkov detector, either EGADS or
GADZOOKS!. Our detection simulation studies show that for a nearby supernova
(0.2 kpc) we can confirm the lack of core rotation close to 100% of the time,
and the presence of core rotation about 90% of the time. Using this approach
there is also po- tential to confirm rotation for considerably more distant
Milky Way supernova explosions.Comment: 31pages, 15figures, submit to Ap
Level Truncated Tachyon Potential in Various Gauges
New gauge fixing condition with single gauge parameter proposed by the
authors is applied to the level truncated analysis of tachyon condensation in
cubic open string field theory. It is found that the only one real non-trivial
extremum persists to appear in the well-defined region of the gauge parameter,
while the other solutions are turned out to be gauge-artifacts. Contrary to the
previously known pathology in the Feynman-Siegel gauge, tachyon potential is
remarkably smooth enough around Landau-type gauge.Comment: 13 pages, 5 figures. For associated movie files, see
http://hep1.c.u-tokyo.ac.jp/~kato/sft
Diagnosis of osteoporosis from dental panoramic radiographs using the support vector machine method in a computer-aided system
<p>Abstract</p> <p>Background</p> <p>Early diagnosis of osteoporosis can potentially decrease the risk of fractures and improve the quality of life. Detection of thin inferior cortices of the mandible on dental panoramic radiographs could be useful for identifying postmenopausal women with low bone mineral density (BMD) or osteoporosis. The aim of our study was to assess the diagnostic efficacy of using kernel-based support vector machine (SVM) learning regarding the cortical width of the mandible on dental panoramic radiographs to identify postmenopausal women with low BMD.</p> <p>Methods</p> <p>We employed our newly adopted SVM method for continuous measurement of the cortical width of the mandible on dental panoramic radiographs to identify women with low BMD or osteoporosis. The original X-ray image was enhanced, cortical boundaries were determined, distances among the upper and lower boundaries were evaluated and discrimination was performed by a radial basis function. We evaluated the diagnostic efficacy of this newly developed method for identifying women with low BMD (BMD T-score of -1.0 or less) at the lumbar spine and femoral neck in 100 postmenopausal women (≥50 years old) with no previous diagnosis of osteoporosis. Sixty women were used for system training, and 40 were used in testing.</p> <p>Results</p> <p>The sensitivity and specificity using RBF kernel-SVM method for identifying women with low BMD were 90.9% [95% confidence interval (CI), 85.3-96.5] and 83.8% (95% CI, 76.6-91.0), respectively at the lumbar spine and 90.0% (95% CI, 84.1-95.9) and 69.1% (95% CI, 60.1-78.6), respectively at the femoral neck. The sensitivity and specificity for identifying women with low BMD at either the lumbar spine or femoral neck were 90.6% (95% CI, 92.0-100) and 80.9% (95% CI, 71.0-86.9), respectively.</p> <p>Conclusion</p> <p>Our results suggest that the newly developed system with the SVM method would be useful for identifying postmenopausal women with low skeletal BMD.</p
The whole blood transcriptional regulation landscape in 465 COVID-19 infected samples from Japan COVID-19 Task Force
「コロナ制圧タスクフォース」COVID-19患者由来の血液細胞における遺伝子発現の網羅的解析 --重症度に応じた遺伝子発現の変化には、ヒトゲノム配列の個人差が影響する--. 京都大学プレスリリース. 2022-08-23.Coronavirus disease 2019 (COVID-19) is a recently-emerged infectious disease that has caused millions of deaths, where comprehensive understanding of disease mechanisms is still unestablished. In particular, studies of gene expression dynamics and regulation landscape in COVID-19 infected individuals are limited. Here, we report on a thorough analysis of whole blood RNA-seq data from 465 genotyped samples from the Japan COVID-19 Task Force, including 359 severe and 106 non-severe COVID-19 cases. We discover 1169 putative causal expression quantitative trait loci (eQTLs) including 34 possible colocalizations with biobank fine-mapping results of hematopoietic traits in a Japanese population, 1549 putative causal splice QTLs (sQTLs; e.g. two independent sQTLs at TOR1AIP1), as well as biologically interpretable trans-eQTL examples (e.g., REST and STING1), all fine-mapped at single variant resolution. We perform differential gene expression analysis to elucidate 198 genes with increased expression in severe COVID-19 cases and enriched for innate immune-related functions. Finally, we evaluate the limited but non-zero effect of COVID-19 phenotype on eQTL discovery, and highlight the presence of COVID-19 severity-interaction eQTLs (ieQTLs; e.g., CLEC4C and MYBL2). Our study provides a comprehensive catalog of whole blood regulatory variants in Japanese, as well as a reference for transcriptional landscapes in response to COVID-19 infection
DOCK2 is involved in the host genetics and biology of severe COVID-19
「コロナ制圧タスクフォース」COVID-19疾患感受性遺伝子DOCK2の重症化機序を解明 --アジア最大のバイオレポジトリーでCOVID-19の治療標的を発見--. 京都大学プレスリリース. 2022-08-10.Identifying the host genetic factors underlying severe COVID-19 is an emerging challenge. Here we conducted a genome-wide association study (GWAS) involving 2, 393 cases of COVID-19 in a cohort of Japanese individuals collected during the initial waves of the pandemic, with 3, 289 unaffected controls. We identified a variant on chromosome 5 at 5q35 (rs60200309-A), close to the dedicator of cytokinesis 2 gene (DOCK2), which was associated with severe COVID-19 in patients less than 65 years of age. This risk allele was prevalent in East Asian individuals but rare in Europeans, highlighting the value of genome-wide association studies in non-European populations. RNA-sequencing analysis of 473 bulk peripheral blood samples identified decreased expression of DOCK2 associated with the risk allele in these younger patients. DOCK2 expression was suppressed in patients with severe cases of COVID-19. Single-cell RNA-sequencing analysis (n = 61 individuals) identified cell-type-specific downregulation of DOCK2 and a COVID-19-specific decreasing effect of the risk allele on DOCK2 expression in non-classical monocytes. Immunohistochemistry of lung specimens from patients with severe COVID-19 pneumonia showed suppressed DOCK2 expression. Moreover, inhibition of DOCK2 function with CPYPP increased the severity of pneumonia in a Syrian hamster model of SARS-CoV-2 infection, characterized by weight loss, lung oedema, enhanced viral loads, impaired macrophage recruitment and dysregulated type I interferon responses. We conclude that DOCK2 has an important role in the host immune response to SARS-CoV-2 infection and the development of severe COVID-19, and could be further explored as a potential biomarker and/or therapeutic target
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