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Search Results: 1 - 10 of 1305 matches for " Yutaka Hiroe "
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Twisted Euler transform of differential equations with an irregular singular point
Kazuki Hiroe
Mathematics , 2009,
Abstract: N. Katz introduced the notion of the middle convolution on local systems. This can be seen as a generalization of the Euler transform of Fuchsian differential equations. In this paper, we consider the generalization of the Euler transform, the twisted Euler transform, and apply this to differential equations with irregular singular points. In particular, for differential equations with an irregular singular point of irregular rank 2 at $x=\infty$, we describe explicitly changes of local datum caused by twisted Euler transforms. Also we attach these differential equations to Kac-Moody Lie algebras and show that twisted Euler transforms correspond to the action of Weyl groups of these Lie algebras.
Linear differential equations on $\mathbb{P}^{1}$ and root systems
Kazuki Hiroe
Mathematics , 2010,
Abstract: In this paper, we study the Euler transform on linear ordinary differential operators on $\mathbb{P}^{1}$. The spectral type is the tuple of integers which count the multiplicities of local formal solutions with the same leading terms. We compute the changes of spectral types under the action of the Euler transform and show that the changes of spectral types generate a transformation group of a $\mathbb{Z}$-lattice which is isomorphic to a quotient lattice of a Kac-Moody root lattice with the Weyl group as the transformation group.
Generalized Whittaker functions for degenerate principal series of $GL(4,\R)$
Kazuki Hiroe
Mathematics , 2008,
Abstract: We give a characterization of a generalized Whittaker model of a degenerate principal series representation of $GL(n,\R)$ as the kernel of some differential operators. By this characterization, we investigate some examples on $GL(4,\R)$. We obtain the dimensions of the generalized Whittaker models and give their basis in terms of hypergeometric functions of one and two variables. We show the multiplicity one of the generalized Whittaker models by using the theory of hypergeometric functions.
Linear differential equations on the Riemann sphere and representations of quivers
Kazuki Hiroe
Mathematics , 2013,
Abstract: Our interest in this paper is a generalization of the additive Deligne-Simpson problem which is originally defined for Fuchsian differential equations on the Riemann sphere. We shall extend this problem to differential equations having an arbitrary number of unramified irregular singular points and determine the existence of solutions of the generalized additive Deligne-Simpson problems. Moreover we apply this result to the geometry of the moduli spaces of stable meromorphic connections of trivial bundles on the Riemann sphere. Namely, open embedding of the moduli spaces into quiver varieties is given and the non-emptiness condition of the moduli spaces is determined.
Local Fourier transform and blowing up
Kazuki Hiroe
Mathematics , 2014,
Abstract: We consider a resolution of ramified irregular singularities of meromorphic connections on a formal disk via local Fourier transforms. A necessary and sufficient condition for an irreducible connection to have a resolution of the ramified singularity is determined as an analogy of the blowing up of plane curve singularities. We also relate the irregularity of Komatsu and Malgrange of connections to the intersection numbers and the Milnor numbers of plane curve germs. Finally, we shall define an analogue of Puiseux characteristics for connections and find an invariant of the family of connections with the fixed Puiseux characteristic by means of the structure of iterated torus knots of the plane curve germs.
Moduli spaces of meromorphic connections, quiver varieties, and integrable deformations
Kazuki Hiroe
Mathematics , 2015,
Abstract: This is a note in which we first review symmetries of moduli spaces of stable meromorphic connections on trivial vector bundles over the Riemann sphere, and next discuss symmetries of their integrable deformations as an application. In the study of the symmetries, a realization of the moduli spaces as quiver varieties is given and plays an essential role.
Methylome Diversification through Changes in DNA Methyltransferase Sequence Specificity
Yoshikazu Furuta,Hiroe Namba-Fukuyo,Tomoko F. Shibata,Tomoaki Nishiyama,Shuji Shigenobu,Yutaka Suzuki,Sumio Sugano,Mitsuyasu Hasebe,Ichizo Kobayashi
PLOS Genetics , 2014, DOI: doi/10.1371/journal.pgen.1004272
Abstract: Epigenetic modifications such as DNA methylation have large effects on gene expression and genome maintenance. Helicobacter pylori, a human gastric pathogen, has a large number of DNA methyltransferase genes, with different strains having unique repertoires. Previous genome comparisons suggested that these methyltransferases often change DNA sequence specificity through domain movement—the movement between and within genes of coding sequences of target recognition domains. Using single-molecule real-time sequencing technology, which detects N6-methyladenines and N4-methylcytosines with single-base resolution, we studied methylated DNA sites throughout the H. pylori genome for several closely related strains. Overall, the methylome was highly variable among closely related strains. Hypermethylated regions were found, for example, in rpoB gene for RNA polymerase. We identified DNA sequence motifs for methylation and then assigned each of them to a specific homology group of the target recognition domains in the specificity-determining genes for Type I and other restriction-modification systems. These results supported proposed mechanisms for sequence-specificity changes in DNA methyltransferases. Knocking out one of the Type I specificity genes led to transcriptome changes, which suggested its role in gene expression. These results are consistent with the concept of evolution driven by DNA methylation, in which changes in the methylome lead to changes in the transcriptome and potentially to changes in phenotype, providing targets for natural or artificial selection.
Age and Gender-Related Differences in Physical Functions of the Elderly Following One-Year Regular Exercise Therapy  [PDF]
Hiroe Sugimoto, Shinichi Demura, Yoshinori Nagasawa
Health (Health) , 2014, DOI: 10.4236/health.2014.68101
Abstract: Reports on physical functions during maintenance period of the elderly with cardiac and other serious diseases are limited. This study aims to clarify age and gender-related differences in their physical functions. Participants included 167 elderly individuals (males, 78; mean age, 76.5 years; SD = 6.0 years; females, 89; mean age, 75.5 years; SD = 4.5 years) who participated in a 1-year regular exercise therapy twice a week. The following eight physical function tests were selected: grip strength, 10-m obstacle walking time, one-legged balance with eyes open, sit-ups, sitting trunk flexion, 6-min walk, stepping by sitting position, and a timed up & go (TUG). Two-way analysis of variance was used to examine mean differences by gender and age: young elderly group (aged 65 - 74 years) and old elderly group (aged ≥ 75 years). In the grip strength, sit-ups, 6-min walk, 10-m obstacle walking time, stepping by sitting position, and sitting trunk flexion tests, males were superior in the former four tests, and females were superior in the latter two tests. The young elderly group was superior in all tests except for sit-ups compared with the old elderly group. The balance during one-legged with eyes open test was superior in males compared with females in the young elderly group, but decreased in males in the old elderly group. In conclusion, physical functions of the elderly during maintenance period are different between genders. Muscle strength, muscle endurance, whole-body endurance, and walking ability are superior in males, whereas flexibility and agility are superior in females. The old elderly group was inferior in all the elements of physical function except muscle endurance.
The Relationship between Living Environment and Oral Function in Elderly Japanese  [PDF]
Naoko Morisaki, Hiroe Uchida, Akiko Miyagawa
Advances in Applied Sociology (AASoci) , 2019, DOI: 10.4236/aasoci.2019.92006
Abstract: This study aims to clarify the current state of oral function among elderly people and to analyze the relation with basic attributes. The subjects of the survey were dependent elderly people receiving nursing care in Japan. We examined the subjects’ age, sex, level of care required, living environment (home or facility), and oral functions. Tongue pressure and oral diadochokinesis (OD) were used to evaluate oral function. The relationship between the basic attributes of the elderly subjects and the oral function evaluation value was analyzed by multiple regression analysis. The average value of tongue pressure was 24.70 ± 10.20 Pa. The average value of OD was 4.7 ± 1.4 for /pa/, 4.6 ± 1.3 for /ta/, and 4.3 ± 1.3 for /ka/. Tongue pressure was found to be significantly related to the degree of care required (p < 0.01). The OD recognized syllables of /pa/, /ta/, /ka/ were significantly related to the degree of need for care and living environment (p < 0.05). The living environment is thought to affect oral function.
Is the Tokyo Foreign Exchange Market Efficient from Two Perspectives of Forward Bias and Anomaly?  [PDF]
Yutaka Kurihara
Modern Economy (ME) , 2011, DOI: 10.4236/me.2011.24067
Abstract: This paper examines the efficiency of the Tokyo Foreign Exchange Market from two perspectives. One is whether or not forward bias in this market has existed and the other is the effect of interventions in the market with a focus on whether or not a day-of-the-week anomaly exists in it. Empirical results show that forward exchange rates are a biased predictor of future spot exchange rates; however, there are some anomalies in the market. The findings suggest the conclusion that this market has not been completely efficient.
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