Nuclear receptors play important roles in the maintenance of the endocrine system, regulation of organ differentiation, and fetal development. Endocrine disruptors exert their adverse effects by disrupting the endocrine system via various mechanisms. To assess the effects of endocrine disruptors on nuclear receptors, we developed a high-throughput method for identifying activators of nuclear receptors. Using this system, we found that triphenyltin and tributyltin were activators of peroxisome proliferator-activated receptor (PPAR) ␥ and retinoid X receptor. Because PPAR␥ is a master regulator of adipocyte differentiation, we assessed the effect of organotin compounds on preadipocyte 3T3-L1 cells. We found that organotin compounds stimulated differentiation of 3T3-L1 cells as well as expression of adipocyte marker genes.

Nature © Macmillan Publishers Ltd 19988 still accrete from the circumbinary disk, via gas streams that move across the tidal gap. Under these circumstances, accretion will occur preferentially into the lower mass component of the system, driving the mass ratio towards unity, as observed in L1551 IRS5.In the case of the visible T Tauri stars, which are sources more evolved than L1551 IRS5, there is evidence 7,8 that the stars constituting a close binary (that is, a pair with separation of less than 100 AU) have less millimetre emission than single stars or wide binaries. This result has been taken to indicate that the gravitational interactions between the members of the binary result in less massive disks. In the case of extremely young stars like L1551 IRS5, there are no data available yet to search for similar tendencies. Ⅺ Acknowledgements.We appreciate the open policy of the National Radio Astronomy Observatory, which is a facility of the US National Science Foundation operated under cooperative agreement by Associated Universities, Inc. In particular, we thank the NRAO personnel involved in the 7-mm upgrade. The 7-mm receivers used for these observations were built with the support of CONACyT, México. We thank A. Poveda for his comments on binary stars.

Abstract. We extend a previous type system for the π-calculus that guarantees deadlock-freedom. The previous type systems for deadlockfreedom either lacked a reasonable type inference algorithm or were not strong enough to ensure deadlock-freedom of processes using recursion. Although the extension is fairly simple, the new type system admits type inference and is much more expressive than the previous type systems that admit type inference. In fact, we show that the simply-typed λ-calculus with recursion can be encoded into the deadlock-free fragment of our typed π-calculus. To enable analysis of realistic programs, we also present an extension of the type system to handle recursive data structures like lists. Both extensions have already been incorporated into the recent release of TyPiCal, a type-based analyzer for the π-calculus.

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International audienceWe provide here a preliminary analysis of the ionospheric perturbations observed after the 11 March 2011 Tohoku Earthquake using a GPS-derived Total Electron Content (TEC) technique. Such anomalies are routinely observed after seismic events of magnitude M w = 6 and more. Here, we use the high density and the wide coverage of the Japanese Global Positioning System (GPS) network GEONET to image the ionosphere just after the main shock. We describe ionospheric perturbations with exceptional extension in amplitude and duration. As already seen in earlier events, a first intense signal is observed about 10 minutes after the seismic rupture; the first response consists in two modes: one propagating beyond 3 km/s and the other at nearly 1 km/s. A further analysis of TEC time series of the latter mode near the source shows the typical frequencies of acoustic resonance. Beyond 400 km from the source, both the tsunami induced gravity wave and a third mode are imaged, the latter for the first time. We show that the pattern of this slow (225 m/s ± 10 m/s) and long period gravity wave (1.8 ± 0.2 mHz) is most visible in the NorthWest of the epicentral area. This description is corroborated by a computation of the normal modes of the solid Earth-atmosphere system

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By introducing thick bulk GaN as a substrate, we improved the performance of an AlGaN-based ultraviolet (UV) light-emitting diode (LED). The output power exceeds 3 mW at the injection current of 100 mA under a bare-chip geometry. Internal quantum efficiency is estimated as more than 80%, and the peak wavelength is 352 nm. The maximum power exceeds 10 mW at a large current injection of 400 mA, with an operation voltage of less than 6 V. These results indicate that an efficient UV LED is intrinsically possible by the combination of appropriate device design and the nitride substrate. By introducing packaging technology to enhance extraction efficiency, we will have a compact and efficient UV light source in the wide wavelength range of 200–360 nm, similar to conventional longer-wavelength LEDs.

The high-color-rendering (HCR) potential of the light sources consisting of 350-nm ultraviolet light-emitting diodes (UV-LED) and three-basal-color phosphors was simulated and experimentally confirmed. By using an AlGaN-based UV-LED as an excitation source at the 350-nm wavelength, we measured fluorescence spectra of three-basal-color phosphors, and simulated the optimum phosphor mixture based on the Commission Internationale de l’Eclairage standard light sources D75, D65, D55, D50, C, and A, with HCR indexes (Ra) over 92. We confirmed the potential of HCR of this light source consisting of 350-nm UV-LED and three-basal-color phosphors, by obtaining Ra=86∼89 of the incandescent type of standard light source A experimentally. Such high Ra are due to the highly monochromatic UV-LED emission and the wide spectral separation between the UV excitation (350 nm) and visible fluorescences. This combination also provides a diffusive, nonglare light source with highly steady color independent of the emission orientation. We also examined the importance of the separation between the excitation wavelength and the fluorescence emission wavelength for practical lighting applications.