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Search Results: 1 - 10 of 5445 matches for " Rie Nakamura Ikeda "
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Evaluating Sleeping and Waking States of Infants: Consistency of Actigraph and Observational Data  [PDF]
Rie Nakamura Ikeda, Kiyoko Fukai
Creative Education (CE) , 2015, DOI: 10.4236/ce.2015.65053
Abstract: The objective was to evaluate sleeping and waking states of infants <6 months old. The design of study was comparing video-recorded and actigraphic data. Participants were thirteen healthy 3- to 5-month-old infants. At their homes, subjects wore an ankle actigraph for 1 h and were videotaped simultaneously. We performed per-minute analysis of video data using the method for observing newborns developed by Brazelton. Video and actigraphic data were compared each minute. The total concordance rate was 93.5%. Sleep/wake identification by actigraphy and visual observation correspond closely for infants.
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.
A New Metal Tag for Highly Selective and Sensitive Analyses of Amino Acids and Dipeptides by HPLC/ICP-MS  [PDF]
Daigo Iwahata, Kazuki Nakamura, Rie Yamada, Hiroshi Miyano, Naoyuki Yamada
Journal of Analytical Sciences, Methods and Instrumentation (JASMI) , 2013, DOI: 10.4236/jasmi.2013.32010
Abstract:

We have developed a novel metal tag, bis(ethylenediamine)-4'-methyl-4-carboxybipyridine-ruthenium N-succinimidyl ester (ECRS) for sensitive analysis of amino acids using high performance liquid chromatography/inductively coupled plasma mass spectrometry (HPLC/ICP-MS). ECRS is a functional reagent, containing an ester group at one end that can be activated to bind to amino group and a chelated ruthenium at the other. The activated ester was reacted briefly with amino groups under weakly alkaline conditions. The ruthenium was detected sensitively by ICP-MS. ECRS was reacted with 17 proteinogenic amino acids in borate buffer. The derivatives were separated by reversed phase HPLC and identified by quadrupole-based ICP-MS. ECRS was suitable for speciation; low molecular weight compounds containing amino groups. We have thus established a quantitative analytical method for amino acids and dipeptides. The detection limits of branched amino acids (signal-to-noise ratio of 3) were 1.5 nmol·L-1 in the standard solution (100 amol per injection).

Transport Coefficients of InSb in a Strong Magnetic Field
Hiroaki Nakamura,Kazuaki Ikeda,Satarou Yamaguchi
Physics , 1997,
Abstract: Improvement of a superconducting magnet system makes induction of a strong magnetic field easier. This fact gives us a possibility of energy conversion by the Nernst effect. As the first step to study the Nernst element, we measured the conductivity, the Hall coefficient, the thermoelectric power and the Nernst coefficient of the InSb, which is one of candidates of the Nernst elements. From this experiment, it is concluded that the Nernst coefficient is smaller than the theoretical values. On the other hand, the conductivity, the Hall coefficient ant the thermoelectric power has the values expected by the theory.
Geometric contribution to the measurement of thermoelectric power and Nernst coefficient in a strong magnetic field
Kazuaki Ikeda,Hiroaki Nakamura,Satarou Yamaguchi
Physics , 1997,
Abstract: On the measurement of thermoelectric power and Nernst coefficient, we used two kinds of shapes for a sample. One is "Bridge shape" and the other is, we call,"Fat-Bridge shape". The latter has 5 times wider main body than the former. We used pure n-InSb in this experiment, whose carrier condensation measured at 77K was $6.6 \times 10^{-14} cm^{-3}.$ The length of sample is 17mm and temperature difference induced between the edges in that direction were about $10^{\circ}$C or $100^{\circ}$C near a room temperature range of 0 to $100^{\circ}$C. Magnetic induction applied in the perpendicular direction to temperature gradient was in the range of 0 up to 4 Tesla. In the case of "Fat-Bridge shape", we detected about 10% smaller Nernst coefficient and 1 to 10% smaller thermoelectric power comparing to the "Bridge shape". We suppose this phenomena is due to the geometric contribution on the different shape of samples.
Physical Model of Nernst Element
Hiroaki Nakamura,Kazuaki Ikeda,Satarou Yamaguchi
Physics , 1998,
Abstract: Generation of electric power by the Nernst effect is a new application of a semiconductor. A key point of this proposal is to find materials with a high thermomagnetic figure-of-merit, which are called Nernst elements. In order to find candidates of the Nernst element, a physical model to describe its transport phenomena is needed. As the first model, we began with a parabolic two-band model in classical statistics. According to this model, we selected InSb as candidates of the Nernst element and measured their transport coefficients in magnetic fields up to 4 Tesla within a temperature region from 270K to 330K. In this region, we calculated transport coefficients numerically by our physical model. For InSb, experimental data are coincident with theoretical values in strong magnetic field.
First-principles calculation of transition-metal impurities in LaFeAsO
Kazuma Nakamura,Ryotaro Arita,Hiroaki Ikeda
Physics , 2010, DOI: 10.1103/PhysRevB.83.144512
Abstract: We present a systematic ab initio study based on density-functional calculations to understand impurity effects in iron-based superconductors. Effective tight-binding Hamiltonians for the d-bands of LaFeAsO with various transition-metal impurities such as Mn, Co, Ni, Zn, and Ru are constructed using maximally-localized Wannier orbitals. Local electronic structures around the impurity are quantitatively characterized by their onsite potential and transfer hoppings to neighboring sites. We found that the impurities are classified into three groups according to the derived parameters: For Mn, Co, and Ni, their impurity-3d levels measured from the Fe-3d level are nearly 0.3 eV, -0.3 eV, and -0.8 eV, respectively, while, for the Zn case, the d level is considerably deep as -8 eV. For the Ru case, although the onsite-level difference is much smaller as O(0.1) eV, the transfer integrals around the impurity site are larger than those of the pure system by 20% \sim 30%, due to the large spatial spread of the Ru-4d orbitals. We also show that, while excess carriers are tightly trapped around the impurity site (due to the Friedel sum rule), there is a rigid shift of band structure near the Fermi level, which has the same effect as carrier doping.
Advantage of Introducing Quantitative Light-Induced Fluorescence in School Dental Checkups  [PDF]
Koji Watanabe, Takashi Sasabe, Akihiro Nakamura, Kosuke Eda, Kosuke Tanase, Hidefumi Ikeda, Naoko Ohata, Yukiko Minohara, Kenshi Maki, Shigeru Watanabe
Health (Health) , 2018, DOI: 10.4236/health.2018.108083
Abstract: Background: Caries detection in school oral examinations insufficient accuracy. Objective: To evaluate advantages of introducing quantitative light-induced fluorescence-digital (QLF-D) in school oral examinations. Methods: Experiment No. 1. Early demineralized lesions in the upper and lower incisors and canines were visually inspected by three dentists and by QLF-D. The numbers of tooth planes with early demineralized lesions were compared between the methods. Experiment No. 2. Approximal demineralized lesions in molars were assessed by visual inspection, x-ray imaging, and QLF-D. The numbers of tooth planes with demineralized lesions were compared among the methods. Experiment No. 3. Plaque distribution was evaluated by QLF-D and a traditional staining method. The ratio of the diameter of plaque to tooth crown in the tooth axis direction in each method was calculated. The results were evaluated by Pearson’s correlation coefficient analysis and Bland-Altman plot. Results: Experiment No. 1. The three dentists found 0.67 tooth planes on average. QLF-D found 22 tooth planes with early demineralized lesions in the same samples. Experiment No. 2. Fourteen approximal tooth planes of molars were found to have demineralized lesions by x-ray imaging. QLF-D detected 71.4% of the tooth planes out of the 14, whereas visual inspection found 7.1%. Experiment No. 3. The Pearson’s correlation coefficient for the evaluations of plaque distribution between the QLF-D and traditional staining methods was 0.77 (P < 0.001). No statistically significant systematic error was found through the Bland-Altman Plot analysis. Conclusion: The results support introduction of QLF-D for use in school dental examinations.
Achieving MDG 4 in Sub-Saharan Africa: What Has Contributed to the Accelerated Child Mortality Decline in Ghana?
Haruyo Nakamura,Nayu Ikeda,Andrew Stickley,Rintaro Mori,Kenji Shibuya
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0017774
Abstract: Recent analyses have suggested an accelerated decline in child mortality in Ghana since 2000. This study examines the long-term child mortality trends in the country, relates them to changes in the key drivers of mortality decline, and assesses the feasibility of the country's MDG 4 attainment.
Physical Properties of Dense Cores in the Rho Ophiuchi Main Cloud and A Significant Role of External Pressures in Clustered Star Formation
Hajime Maruta,Fumitaka Nakamura,Ryoichi Nishi,Norio Ikeda,Yoshimi Kitamura
Physics , 2009, DOI: 10.1088/0004-637X/714/1/680
Abstract: Using the archive data of the H13CO+ (J=1-0) line emission taken with the Nobeyama 45 m radio telescope with a spatial resolution of about 0.01pc, we have identified 68 dense cores in the central dense region of the rho Ophiuchi main cloud. The H13CO+ data also indicates that the fractional abundance of H13CO+ relative to H2 is roughly inversely proportional to the square root of the H2 column density with a mean of 1.72 x 10^{-11}. The mean radius, FWHM line width, and LTE mass of the identified cores are estimated to be 0.045 +- 0.011 pc, 0.49 +- 0.14 km/s, and 3.4 +- 3.6 Msolar, respectively. The majority of the identified cores have subsonic internal motions. The virial ratio, the ratio of the virial mass to the LTE mass, tends to decrease with increasing the LTE mass and about 60 percent of the cores have virial ratios smaller than 2, indicating that these cores are not transient structures but self-gravitating. The detailed virial analysis suggests that the surface pressure often dominates over the self-gravity and thus plays a crucial role in regulating core formation and evolution. By comparing the rho Oph cores with those in the Orion A molecular cloud observed with the same telescope, we found that the statistical properties of the core physical quantities are similar between the two clouds if the effect of the different spatial resolutions is corrected. The line widths of the rho Oph cores appear to be nearly independent of the core radii over the range of 0.01 - 0.1 pc and deviate upwards from the Heyer & Brunt relation. This may be evidence that turbulent motions are driven by protostellar outflows in the cluster environment.
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