Wolf–Rayet (WR) stars represent one of the final stages of massive stellar evolution. Relatively little is known about this short-lived phase and we currently lack reliable mass, distance, and binarity determinations for a representative sample. Here we report the first visual orbit for WR 140 ( = HD193793), a WC7 + O5 binary system known for its periodic dust production episodes triggered by intense colliding winds near periastron passage. The Infrared-Optical Telescope Array and Center for High Angular Resolution Astronomy interferometers resolved the pair of stars in each year from 2003 to 2009, covering most of the highly eccentric, 7.9 year orbit. Combining our results with the recently improved double-line spectroscopic orbit of Fahed et al., we find the WR 140 system is located at a distance

, Helicobacter enthusiasts gathered in Perth, Australia for the Fourth Western Pacific Helicobacter Congress to celebrate the 20th anniversary of the modern discovery of this organism by Barry Marshall and Robin Warren. The meeting included state-of-the-art lectures highlighting the breakthroughs

A new mechanism for the generation of quasi-zonal jets in the ocean

The compressive sensing (CS) framework aims to ease the burden on analog-to-digital converters (ADCs) by exploiting inherent structure in natural and man-made signals. It has been demon-strated that structured signals can be acquired with just a small number of linear measurements, on the order of the signal complexity. In practice, this enables lower sampling rates that can be more easily achieved by current hardware designs. The primary bottleneck that limits ADC sam-pling rates is quantization, i.e., higher bit-depths impose lower sampling rates. Thus, the decreased sampling rates of CS ADCs accommodate the otherwise limiting quantizer of conventional ADCs. In this thesis, we consider a different approach to CS ADC by shifting towards lower quantizer bit-depths rather than lower sampling rates. We explore the extreme case where each measurement is quantized to just one bit, representing its sign. We develop a new theoretical framework to analyze this extreme case and develop new algorithms for signal reconstruction from such coarsely quantized measurements. The 1-bit CS framework leads us to scenarios where it may be more appropriate to reduce bit-depth instead of sampling rate. We find that there exist two distinct regimes of operation that correspond to high/low signal-to-noise ratio (SNR). In the measurement

We study the generalizations of the well-known Lieb-Thirring inequality for the mag-netic Schrodinger operator with nonconstant magnetic eld. Our main result is the natu-rally expected magnetic Lieb-Thirring estimate on the moments of the negative eigenvalues for a certain class of magnetic elds (including even some unbounded ones). We develop a localization technique in path space of the stochastic Feynman-Kac representation of the heat kernel which eectively estimates the oscillatory eect due to the magnetic phase

), the very large size of this reservoir means that even small increases in the a large influence on atmospheric [CO2]. Global temperatures are n is strongly tem-transfer of C from se in atmospheric ng (Holland et al., temperature re-e, the realized e as of SOC decompo-ted future rates of SOC decomposition

cell balance equations

de nationalité suisse et originaire de Zurich (ZH) et Lucerne (LU) acceptée sur proposition du jury:

belowground functioning of tropical biomes

Responses of soil biological processes to elevated atmospheric [CO2] and nitrogen addition in a poplar plantation