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Search Results: 1 - 10 of 4416 matches for " Hideki Nakamura "
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Efficient Frontier via Production Functions and Mechanization  [PDF]
Hideki Nakamura
American Journal of Operations Research (AJOR) , 2017, DOI: 10.4236/ajor.2017.71004
Abstract: This study attempts to reconcile data envelopment analysis (DEA) with the production function approach in economics. We examine not only the inputs of capital and labor, but also the ranges of these inputs in production process steps, and endogenously derive a Leontief production function. The Leontief production functions shift northeasterly owing to mechanization, which is the replacement of labor inputs by capital inputs in some steps. Consequently, we describe the efficient frontier as the convex hull of the Leontief production functions. Furthermore, we consider the possibility of efficient production below the efficient frontier.
Factor Substitution and Employment  [PDF]
Hideki Nakamura
Modern Economy (ME) , 2018, DOI: 10.4236/me.2018.97074
Abstract: This paper explores how employment among an educated workforce depends on production technology represented by factor substitution and factor-augmenting technical progress. We consider a variant of the Diamond overlapping generations model that can explain the empirical finding about the elasticity of substitution being less than unity observed in some developed economies. Depending on factor substitution, a decline in the wage rate has positive and negative effects on employment. When the elasticity of substitution is less than unity, a low wage rate can imply a low employment rate as well as a low human capital level. Given the elasticity of substitution, being less than unity, labor-augmenting technical progress can decrease the employment rate and human capital level via a decrease in the marginal product of labor.
Multiple Equilibria between Fertility Rates and Pension Levels Based on the Target Level of Government Debt  [PDF]
Hideki Nakamura, Masaya Yasuoka
Theoretical Economics Letters (TEL) , 2011, DOI: 10.4236/tel.2011.13020
Abstract: We show that when the government has a target debt level, multiple equilibria exist in the relationship between fertility rates and pension levels. One is associated with a high fertility rate and a high pension level. The other is associated with a low fertility rate and a low pension level. If the government fails to provide adequate security for individuals during their retirement years, it would result in a failure of coordination between the government and individuals.
Should We Enhance or Restrict Technological Diffusion from Major to Minor Firms?  [PDF]
Hideki Nakamura, Takeshi Ikeda
Theoretical Economics Letters (TEL) , 2018, DOI: 10.4236/tel.2018.811146
Abstract: This study examines how technological diffusion from a major firm to a minor firm affects social welfare via R & D competition in an asymmetric Cournot duopoly. We assume that the minor firm can decrease its production cost because of the spillover effect arising through R & D by the major firm. R & D by the minor firm depends on the free-riding effect and a taking-away effect that removes market share from the major firm. If given a low R & D cost, both firms invest in R & D with an appropriate level of technological diffusion, we can obtain a high level of social welfare. However, an increase in the level of technological diffusion could make the major firm abandon R & D activity. Given a high R & D cost, a high level of welfare can be obtained only with a low level of technological diffusion because the potential presence of technological diffusion easily disrupts R & D by the major firm.
The Rohlin Property for Actions of $Z^{2}$ on UHF Algebras
Hideki Nakamura
Mathematics , 1996,
Abstract: We define a Rohlin property for actions of $Z^{2}$ on UHF algebras and show a noncommutative Rohlin type theorem. Among those actions with the Rohlin property, we classify product type actions up to outer conjugacy. In particular we present two classes of UHF algebras. For UHF algebras in one class, which includes the CAR algebra, there is one and only one outer conjugacy class of product type actions and for UHF algebras in the other class, contrary to the case of actions of $Z$, there are infinitely many outer conjugacy classesof product type actions.
A Rohlin Type Theorem for Automorphisms of Certain Purely Infinite $C^{\ast}$-Algebras
Hideki Nakamura
Mathematics , 1997,
Abstract: We show a noncommutative Rohlin type theorem for automorphisms of a certain class of purely infinite simple $C^{\ast}$-algebras. This class consists of the purely infinite unital simple $C^{\ast}$-algebras which are in the bootstrap category ${\cal N}$ and have trivial $K_{1}$-groups.
Dynamics of a string coupled to gravitational waves II - Perturbations propagate along an infinite Nambu-Goto string
Kouji Nakamura,Hideki Ishihara
Physics , 2000, DOI: 10.1103/PhysRevD.63.127501
Abstract: The perturbative modes propagating along an infinite string are investigated within the framework of the gauge invariant perturbation formalism on a spacetime containing a self-gravitating straight string with a finite thickness. These modes are not included in our previous analysis. We reconstruct the perturbation formalism to discuss these modes and solve the linearized Einstein equation within the first order with respect to the string oscillation amplitude. In the thin string case, we show that the oscillations of an infinite string must involve the propagation of cosmic string traveling wave.
Impact of Seven Valent Pneumococcal Conjugate Vaccine on Nasopharyngeal Carriage in Young Children in Okinawa, Japan  [PDF]
Hideki Akeda, Bin Chang, Yoshihisa Nakamura, Hirotsune Hamabata, Kenji Ameku, Takaya Toma, Eiichi Tamanaha, Makoto Ohnishi
World Journal of Vaccines (WJV) , 2015, DOI: 10.4236/wjv.2015.52011
Abstract: In Japan, the heptavalent pneumococcal conjugate vaccine (PCV7) became available in February 2010 and was subsidized by the national funding system from May 2011 in Okinawa, after which it was incorporated into the national immunization practice (NIP) in April 2013 using a 3 + 1 schedule for all infants. We conducted an annual survey in 2012 to determine the effect of PCV7 on nasopharyngeal colonization by pneumococcal serotypes and to analyze the risk factors for colonization in infants. Nasopharyngeal swabs for pneumococcal isolation and serotyping were obtained from infant 2 to 22 months of age before and after PCV7 immunization among 4 clinics in Okinawa, Japan. Between January 2012 and December 2012, nasopharyngeal swabs for bacterial cultures were obtained among 782 infants aged 2 to 22 months old and demographic data was obtained among 725 participant infants. Among the 725 evaluable infants, 193 pneumococcal strains were detected in 180 infants for an overall nasopharyngeal carriage of 24.8%. The main capsular serotypes isolated were 6C (16.1%), 19A (12.4%) and 15B (9.8%). Carriage of PCV7 serotypes accounted for 21.8% (42/193). The result of multivariate data analysis showed the pneumococcal carriage rate of non-PCV7 serotypes was significantly (P < 0.001) high in infant with siblings and daycare attendance. On the other hand, the result of multivariate data analysis showed that carriage rate of PCV7 serotype had only significantly high risk in infant with siblings and did not have a significant risk dependent on age and daycare attendance. Carriage PCV7 serotypes increased in the presence of other siblings, while PCV7 vaccination was shown to eliminate daycare attendance as a risk. The results of this study demonstrates that PCV7 vaccination decrease the overall nasopharyngeal carriage of PCV7 serotypes in vaccinated children including children at risk such as children attending day-care centers.
Dynamics of a string coupled to gravitational waves - Gravitational wave scattering by a Nambu-Goto straight string
Kouji Nakamura,Akihiro Ishibashi,Hideki Ishihara
Physics , 2000, DOI: 10.1103/PhysRevD.62.101502
Abstract: We study the perturbative dynamics of an infinite gravitating Nambu-Goto string within the general-relativistic perturbation framework. We develop the gauge invariant metric perturbation on a spacetime containing a self-gravitating straight string with a finite thickness and solve the linearized Einstein equation. In the thin string case, we show that the string does not emit gravitational waves by its free oscillation in the first order with respect to its oscillation amplitude, nevertheless the string actually bends when the incidental gravitational waves go through it.
The ATPase activity of molecular chaperone HSP60 is inhibited by immunosuppressant mizoribine  [PDF]
Masako Tanabe, Ryuichi Ishida, Fumiko Izuhara, Atsushi Komatsuda, Hideki Wakui, Kenichi Sawada, Michiro Otaka, Nobuhiro Nakamura, Hideaki Itoh
American Journal of Molecular Biology (AJMB) , 2012, DOI: 10.4236/ajmb.2012.22010
Abstract: The molecular chaperone HSP60 is a chaperonin homolog of GroEL. We had previously shown that the immunosuppressant mizoribine is bound directly to HSP60 and inhibited its chaperone activity. However, the inhibitory mechanisms of HSP60 by mizoribine have not yet been fully understood. In the present study, we investigated the influence of mizoribine on a folding cycle of HSP60 and co-chaperone HSP10. Our results showed that mizoribine inhibited the folding cycle of HSP60/HSP10. The ATPase activity of HSP60/HSP10 was decreased in the presence of mizoribine and the dissociation of HSP10 from HSP-60 was also decreased by mizoribine. The same functions of GroEL and/or GroES were slightly affected by mizoribine. Based on our findings, we discuss the inhibitory mechanisms of HSP60 by mizoribine.
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