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Maki T.,Japan Womens College of Physical Education
Progress of Theoretical Physics | Year: 2010

Static, rotationally symmetric solutions are investigated for the 2+1 dimensional Einstein-Maxwell-Dilaton theories. Some exact but not general solutions have been found for these theories by many authors. To find the general exact solutions with this symmetry for arbitrary dilaton couplings to Maxwell field and to a cosmological constant, we obtain the general and simple form of the field equations by introducing new variables. These equations can be interpreted as 'equations of motion' with a constraint equation in terms of the variables. It is shown that the 'equations of motion' are analytically integrable for some particular but physically important cases of dilaton couplings, for example, one of the cases of low-energy effective string action. As a result of the application of the method found in this paper, we obtain a new family of exact solutions of the 2-t-1 dimensional Einstein-Maxwell-Dilaton theory under the condition of ab = 1. Source

Nakamichi N.,Japan Womens College of Physical Education
Journal of Cognition and Development | Year: 2015

Recent studies indicate the need to investigate the sources of toddlers’ understanding of another person's pretense. The present study is a cultural and longitudinal extension of the work of Lillard and Witherington (2004), who claimed that mothers modify their behaviors during pretense and that the some of these behavior modifications help their toddlers understand maternal pretense. Experiment 1 investigated whether mothers would change their behaviors during pretense with a sample of 31 Japanese mother–infant pairs. Experiment 2, with a subsample of 20 mother–child pairs who had participated in Experiment 1, examined whether the maternal behavior modifications at 18 months predicted their toddlers’ understanding of pretense at 24 months. The results of Experiment 1 indicated that Japanese mothers smiled more frequently, gazed at their toddlers longer, used sound effects more frequently, and engaged in more frequent snack-related actions in a “pretense condition” than in a “real condition.” In addition, some of these behaviors were significantly related to their toddlers’ apparent understanding of pretense. Experiment 2 showed that both the frequency of maternal smiles and the number of sound effects in the pretense condition at 18 months predicted toddlers’ understanding of the pretense enacted by a strange adult at 24 months. This research indicates the impact of maternal behavior modifications during pretense on the development of symbolic thought in the 2nd year of life. © 2015, Published with license by Taylor & Francis. Source

Ogoh S.,Toyo University | Sato K.,Japan Womens College of Physical Education | Okazaki K.,Osaka City University | Miyamoto T.,Morinomiya University of Medical Sciences | And 4 more authors.
Anesthesia and Analgesia | Year: 2014

BACKGROUND: Spatially resolved near-infrared spectroscopy-determined frontal lobe tissue oxygenation (Sco2) is reduced with administration of phenylephrine, while cerebral blood flow may remain unaffected. We hypothesized that extracranial vasoconstriction explains the effect of phenylephrine on Sco2. METHODS: We measured Sco2 and internal and external carotid as well as vertebral artery blood flow in 7 volunteers (25 [SD 4] years) by duplex ultrasonography during IV infusion of phenylephrine, together with middle cerebral artery mean blood velocity, forehead skin blood flow, and mean arterial blood pressure. RESULTS: During phenylephrine infusion, mean arterial blood pressure increased, while Sco 2 decreased by -19% ± 3% (mean ± SE; P = 0.0005). External carotid artery (-27.5% ± 3.0%) and skin blood flow (-25.4% ± 7.8%) decreased in response to phenylephrine administration, and there was a relationship between Sco2 and forehead skin blood flow (Pearson r = 0.55, P = 0.042, 95% confidence interval [CI], = 0.025-0.84; Spearman r = 0.81, P < 0.001, 95% CI, 0.49-0.94) and external carotid artery conductance (Pearson r = 0.62, P = 0.019, 95% CI, 0.13 to 0.86; Spearman r = 0.64, P = 0.012, 95% CI, 0.17-0.88). CONCLUSIONS: These findings suggest that a phenylephrine-induced decrease in Sco2, as determined by INVOS-4100 near-infrared spectroscopy, reflects vasoconstriction in the extracranial vasculature rather than a decrease in cerebral oxygenation. Copyright © 2014 International Anesthesia Research Society. Source

Ogoh S.,Toyo University | Sato K.,Japan Womens College of Physical Education | Okazaki K.,Osaka City University | Miyamoto T.,Morinomiya University of Medical Sciences | And 3 more authors.
Journal of Cerebral Blood Flow and Metabolism | Year: 2013

The purpose of the present study was to assess the effect of heat stress-induced changes in systemic circulation on intra- and extracranial blood flows and its distribution. Twelve healthy subjects with a mean age of 22±2 (s.d.) years dressed in a tube-lined suit and rested in a supine position. Cardiac output (Q), internal carotid artery (ICA), external carotid artery (ECA), and vertebral artery (VA) blood flows were measured by ultrasonography before and during whole body heating. Esophageal temperature increased from 37.0±0.2°C to 38.4±0.2°C during whole body heating. Despite an increase in Q (59±31%, P<0.001), ICA and VA decreased to 83±15% (P=0.001) and 87±8% (P=0.002), respectively, whereas ECA blood flow gradually increased from 188±72 to 422±189 mL/minute (+135%, P<0.001). These findings indicate that heat stress modified the effect of Q on blood flows at each artery; the increased Q due to heat stress was redistributed to extracranial vascular beds. © 2013 ISCBFM. Source

Sato K.,Japan Womens College of Physical Education | Ogoh S.,Japan Womens College of Physical Education | Ogoh S.,Toyo University | Hirasawa A.,Japan Womens College of Physical Education | And 2 more authors.
Journal of Physiology | Year: 2011

The mechanism underlying the plateau or relative decrease in cerebral blood flow (CBF) during maximal incremental dynamic exercise remains unclear. We hypothesized that cerebral perfusion is limited during high-intensity dynamic exercise due to a redistribution of carotid artery blood flow. To identify the distribution of blood flow among the arteries supplying the head and brain, we evaluated common carotid artery (CCA), internal carotid artery (ICA), external carotid artery (ECA) and vertebral artery (VA) blood flow during dynamic exercise using Doppler ultrasound. Ten subjects performed graded cycling exercise in a semi-supine position at 40, 60 and 80% of peak oxygen uptake for 5 min at each workload. The ICA blood flow increased by 23.0 ± 4.6% (mean ± SE) from rest to exercise at 60%. However, at 80%, ICA blood flow returned towards near resting levels (9.6 ± 4.7%vs. rest). In contrast, ECA, CCA and VA blood flow increased proportionally with workload. The change in ICA blood flow during graded exercise was correlated with end-tidal partial pressure of CO 2 (r= 0.72). The change in ICA blood flow from 60% to 80% was negatively correlated with the change in ECA blood flow (r=-0.77). Moreover, there was a significant correlation between forehead cutaneous vascular conductance and ECA blood flow during exercise (r= 0.79). These results suggest that during high-intensity dynamic exercise the plateau or decrease in ICA blood flow is partly due to a large increase in ECA blood flow, which is selectively increased to prioritize thermoregulation. © 2011 The Authors. Journal compilation © 2011 The Physiological Society. Source

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