Sur le potentiel de pression-gravitation pour le mouvement d’un gaz à transformation adiabatique

pp.65-91We consider the equation system of motion of a gas with adiabatic transformation, for which we define the functional for the potential energy due to gravitation and pression, and we prove that the distribution of density and temperature of the rest state minimizes this functional. The technical difficulty for this proof resides in the fact that the class of admissible functions for this functional is not convex

Melanogenesis in the retinal pigment epithelial cell of the chick embryo. Dopa-reaction and electron microscopic autoradiography of 3 H-dopa

The intracellular pathways involved in melanogenesis i

Interhemispheric conjugacy of auroral poleward expansion observed by conjugate imaging riometers at 67゜ and 75゜- 77゜ invariant latitude

Interhemispheric conjugacy of auroral poleward expansion was studied using conjugate imaging riometers at ～67° inv. (invariant latitude) (Syowa Station, Antarctica, and Tjomes, Iceland) and at 75-77° inv. (Zhongshan Station, Antarctica; Longyearbyen, Svalbard and Danmarkshavn, Eastern Greenland). Ninety poleward expansion events at ～67° inv. observed in 1992-1993 were analyzed. The expansion at this latitude was characterized by a continuous poleward motion of cosmic noise absorption (CNA) bands with a velocity distribution that peaked at 1-1.5 km/s at a polar ionospheric altitude of ～90 km. The velocity distribution has another apparent peak at 3-5 km/s when measurements are made along the meridian. However, ～60% of the events forming this peak are overestimated because the motion of the CNA region\u27s front was observed while the front was tilted away from the east-west direction. The difference in expansion velocities between conjugate stations remained within ±30% for half of the events. The time lag between the passage of a CNA band over conjugate stations was typically between 30-60 s. The product of this time lag and the poleward expanding velocity provides the location of the actual conjugate point. For 87% of the total number of events, the conjugate point for Syowa was located within ±200 km of Tjornes. The poleward expansion observed at 75°-77° inv. was characterized by a stepwise progression of CNA bands to higher latitudes. In other words, new CNA bands formed 50-180 km poleward of the preceding CNA band. The appearance of a new CNA band was often associated with an equatorward motion of the preceding CNA band. Equatorward moving CNA bands are thought to be located in a closed fieldline. The persistence of this band for several minutes was explained by pitch angle scattering of the trapped electrons as a result of a very stretched fieldline configuration in which the fieldline curvature was comparable to the Larmor radius of the trapped electrons. Although the conjugate pair used at these latitudes was displaced longitudinally by ～500 km, conjugacy was generally good. If a time lag of ±15 min is allowed, 52% of the CNA events observed at Longyearbyen had a counterpart at Zhongshan, and 40% had a counterpart at Danmarkshavn. This rather high level of conjugacy suggests that the characteristic longitudinal extent of the poleward expanding CNA bands is on the order of 500 km in the polar ionosphere

1994 Multi-site Broadband Seismic Observation at Sakurajima Volcano, Japan

Broadband observation of volcanic earthquakes has been recently conducted at many volcanoes. At the Sakurajima Volcano in Japan, one of the most active volcanoes all over the world, we conducted two broadband seismic observations successfully in last three years. However, they left some problems in terms of the number of observation sites and recording systems. This paper reports the outline of our third observation using three broadband seismometers (Streckeisen STS-II) with continuous recording at the Sakurajima Volcano from February 18 to March 28, 1994. This observation is distinguished from the previous two by the three stations operating continuously over the entire period. Although the Sakurajima Volcano had very low seismic activities during this observation period, we observed some kinds of volcanic earthquake, A-type and B-type earthquakes and volcanic tremors, particularly one series of interesting clone events

Curvature effects on surface electron states in ballistic nanostructures

The curvature effect on the electronic states of a deformed cylindrical conducting surface of variable diameter is theoretically investigated. The quantum confinement of electrons normal to the curved surface results in an effective potential energy that affects the electronic structures of the system at low energies. This suggests the possibility that ballistic transport of electrons in low-dimensional nanostructures can be controlled by inducing a local geometric deformation.Comment: 11 pages, 3 figure

2-ピリドン誘導体を親ジェンとするDiels-Alder反応の分子軌道法による考察

Diels-Alder reactions of 4-substituted 2(1H)-pyridones with 2, 3-dimethyl-1, 3-butadiene were studied using ab initio molecular orbital method. Yields of adducts were roughly consistent with calculated activation energies. It was shown that the isomerization of cisadduct to trans-one was difficult to occur by searching the reaction path and calculating the energies of transition states

Hepcidin Expression in Iron Overload Diseases Is Variably Modulated by Circulating Factors

Hepcidin is a regulatory hormone that plays a major role in controlling body iron homeostasis. Circulating factors (holotransferrin, cytokines, erythroid regulators) might variably contribute to hepcidin modulation in different pathological conditions. There are few studies analysing the relationship between hepcidin transcript and related protein expression profiles in humans. Our aims were: a. to measure hepcidin expression at either hepatic, serum and urinary level in three paradigmatic iron overload conditions (hemochromatosis, thalassemia and dysmetabolic iron overload syndrome) and in controls; b. to measure mRNA hepcidin expression in two different hepatic cell lines (HepG2 and Huh-7) exposed to patients and controls sera to assess whether circulating factors could influence hepcidin transcription in different pathological conditions. Our findings suggest that hepcidin assays reflect hepatic hepcidin production, but also indicate that correlation is not ideal, likely due to methodological limits and to several post-trascriptional events. In vitro study showed that THAL sera down-regulated, HFE-HH and C-NAFLD sera up-regulated hepcidin synthesis. HAMP mRNA expression in Huh-7 cells exposed to sera form C-Donors, HFE-HH and THAL reproduced, at lower level, the results observed in HepG2, suggesting the important but not critical role of HFE in hepcidin regulation