276 research outputs found
Instanton-noninstanton transition in nonintegrable tunneling processes: A renormalized perturbation approach
The instanton-noninstanton (I-NI) transition in the tunneling process, which
has been numerically observed in classically nonintegrable quantum maps, can be
described by a perturbation theory based on an integrable Hamiltonian
renormalized so as to incorporate the integrable part of the map. The
renormalized perturbation theory is successfully applied to the two quantum
maps, the H\'enon and standard maps. In spite of different nature of tunneling
in the two systems, the I-NI transition exhibits very common characteristics.
In particular, the manifestation of I-NI transition is obviously explained by a
remarkable quenching of the renormalized transition matrix element. The
enhancement of tunneling probability after the transition can be understood as
a sudden change of the tunneling mechanism from the instanton to quite a
different mechanism supported by classical flows just outside of the
stable-unstable manifolds of the saddle on the top of the potential barrier.Comment: 6 pages, 4 figure
Double energy vulnerability in Japan
This paper presents initial insights into the intersection of domestic energy poverty and transport poverty in Japan, emphasising the vulnerable populations and geographic areas where these dual challenges are most pronounced. We use microdata derived from a governmental household budget survey to calculate the cost burdens arising from expenditure on domestic energy, and public and private transportation. The findings suggest that risk of experiencing high domestic energy burdens is strongly differentiated by income and age, being more prevalent in low-income households and where the lead householder is over 65. Transport cost burdens display a weaker association with demographic variables, and instead are strongly geographical with high-cost burdens most prevalent in rural and peri-urban areas. Low-income and older people who are also living in a spatially peripheral locality are at greatest risk of double-energy vulnerability. Japan's climatic diversity poses an additional challenge, with households in the northern regions of the country facing increased vulnerability due to colder winters and higher heating costs. We propose several policy recommendations arising from these findings, emphasising the need for nuanced strategies that are tailored to geographical context
Unaltered V̇O2 kinetics despite greater muscle oxygenation during heavy-intensity two-legged knee extension versus cycle exercise in humans
Relative perfusion of active muscles is greater during knee extension ergometry (KE) than cycle ergometry (CE). This provides the opportunity to investigate the effects of increased O₂ delivery (Q̇O₂) on deoxygenation heterogeneity among quadriceps muscles and pulmonary V̇O₂ kinetics. Using time-resolved near-infrared spectroscopy, we hypothesized that compared with CE the superficial vastus lateralis (VL), superficial rectus femoris and deep VL in KE would have 1) a smaller amplitude of the exercise-induced increase in deoxy[Hb+Mb] (related to the balance between V̇O₂ and Q̇O₂); 2) a greater amplitude of total[Hb+Mb] (related to the diffusive O₂ conductance); 3) a greater homogeneity of regional muscle deoxy[Hb+Mb]; and 4) no difference in pulmonary V̇O₂ kinetics. Eight participants performed square-wave KE and CE exercise from 20 W to heavy work rates. Deoxy[Hb+Mb] amplitude was less for all muscle regions in KE (P<0.05: superficial, KE 17-24 vs. CE 19-40; deep, KE 19 vs. CE 26 μM). Further, the amplitude of total[Hb+Mb] was greater for KE than CE at all muscle sites (P<0.05: superficial, KE 7-21 vs. CE 1-16; deep, KE 11 vs. CE -3 μM). Although the amplitude and heterogeneity of deoxy[Hb+Mb] was significantly lower in KE than CE during the first minute of exercise, the pulmonary V̇O₂ kinetics was not different for KE and CE. These data show that the microvascular Q̇O₂ to V̇O₂ ratio, and thus tissue oxygenation, was greater in KE than CE. This suggests that pulmonary and muscle V̇O₂ kinetics in young healthy humans are not limited by Q̇O₂ during heavy-intensity cycling
Obstacle Effects on Airflow and Containment Dispersion around a Naturally Ventilated Livestock Building
Rosana G. Moreira, Editor-in-Chief; Texas A&M UniversityThis is a Technical Paper from International Commission of Agricultural Engineering (CIGR, Commission Internationale du Genie Rural) E-Journal Volume 5 (2003): G. Zhang, A. Ikeguchi, J. Strom, S. Morsing, H. Takai, P. Ravn, and L. Okushima. Obstacle Effects on Airflow and Containment Dispersion around a Naturally Ventilated Livestock Building. Vol. V. December 2003
Greater (V)over dotO(2peak) is correlated with greater skeletal muscle deoxygenation amplitude and hemoglobin concentration within individual muscles during ramp-incremental cycle exercise
Citation: Okushima, D., Poole, D. C., Barstow, T. J., Rossiter, H. B., Kondo, N., Bowen, T. S., . . . Koga, S. (2016). Greater (V)over dotO(2peak) is correlated with greater skeletal muscle deoxygenation amplitude and hemoglobin concentration within individual muscles during ramp-incremental cycle exercise. Physiological Reports, 4(23), 12. doi:10.14814/phy2.13065It is axiomatic that greater aerobic fitness ((V)over dotO(2peak)) derives from enhanced perfusive and diffusive O-2 conductances across active muscles. However, it remains unknown how these conductances might be reflected by regional differences in fractional O-2 extraction (i.e., deoxy [Hb+Mb] and tissue O-2 saturation [StO2]) and diffusive O-2 potential (i.e., total[Hb+Mb]) among muscles spatially heterogeneous in blood flow, fiber type, and recruitment (vastus lateralis, VL; rectus femoris, RF). Using quantitative time-resolved near-infrared spectroscopy during ramp cycling in 24 young participants ((V)over dotO(2peak) range: similar to 37.4-66.4 mL kg(-1) min(-1)), we tested the hypotheses that (1) deoxy [Hb+Mb] and total[Hb+Mb] at (V)over dotO(2peak) would be positively correlated with (V)over dotO(2peak) in both VL and RF muscles; (2) the pattern of deoxygenation (the deoxy[Hb+Mb] slopes) during submaximal exercise would not differ among subjects differing in (V)over dotO(2peak). Peak deoxy [Hb+Mb] and StO2 correlated with (V)over dotO(2peak) for both VL (r = 0.44 and -0.51) and RF (r = 0.49 and -0.49), whereas for total[Hb+Mb] this was true only for RF (r = 0.45). Baseline deoxy[Hb+Mb] and StO2 correlated with (V)over dotO(2peak) only for RF (r = -0.50 and 0.54). In addition, the deoxy[Hb+Mb] slopes were not affected by aerobic fitness. In conclusion, while the pattern of deoxygenation (the deoxy[Hb+Mb] slopes) did not differ between fitness groups the capacity to deoxygenate [Hb+Mb] (index of maximal fractional O-2 extraction) correlated significantly with (V)over dotO(2peak) in both RF and VL muscles. However, only in the RF did total [Hb+Mb] (index of diffusive O-2 potential) relate to fitness
Early Spectroscopy of the 2010 Outburst of U Scorpii
We present early spectroscopy of the recurrent nova U~Sco during the outburst
in 2010. We successfully obtained time-series spectra at 0.37--0.44~d, where denotes the time from the discovery of the
present outburst. This is the first time-resolved spectroscopy on the first
night of U Sco outbursts. At ~d the H line consists
of a blue-shifted ( km s) narrow absorption component and a wide
emission component having triple peaks, a blue ( km s), a
central ( km s) and a red ( km s) ones. The
blue and red peaks developed more rapidly than the central one during the first
night. This rapid variation would be caused by the growth of aspherical wind
produced during the earliest stage of the outburst. At ~d the
H line has a nearly flat-topped profile with weak blue and red peaks at
km s. This profile can be attributed to a nearly
spherical shell, while the asphericity growing on the first night still
remains. The wind asphericity is less significant after d.Comment: 5 pages, 3 figures, Accepted for publication of PASJ Letter
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