Studies on the dimer of o-ketosuccinamic acid indicate that its structure is 4,6-dihydroxy-2-oxo-piperidine&carboxamide-4,6-dicarboxylic acid. The dimer was converted in acid solution to 2-hydroxy-pyridine-4,6-dicarboxylic acid; ultraviolet spectral evidence was obtained for intermediates in this transformation and studies with L-[4J4C]asparagine conmrned the pathway. On hydrogenation the dimer...

We present an XMM-Newton spectrum of diffuse X-ray emission from within the solar system. The spectrum is dominated by probable C VI lines at 0.37 keV and 0.46 keV, an O VII line at 0.56 keV, O VIII lines at 0.65 keV and ∼ 0.8 keV, Ne IX lines at ∼ 0.92 keV, and Mg XI lines at ∼ 1.35 keV. This spectrum is consistent with that expected from charge exchange emission between the highly ionized sol...

Spectral partitioning methods use the Fiedler vector—the eigenvector of the second-smallest eigenvalue of the Laplacian matrix—to find a small separator of a graph. These methods are important components of many scientific numerical algorithms and have been demonstrated by experiment to work extremely well. In this paper, we show that spectral partitioning methods work well on bounded-degree pl...

A family of local spectral evolution kernels (LSEKs) are derived for analytically integrating a class of partial differential equations (PDEs) 0021-9 doi:10. * Co E-m o ot u 1⁄4 AðtÞ o 2 ox2 þ BðtÞ o ox þ CðtÞ u: The LSEK can solve the above PDEs with x-independent coefficients in a single step. They are utilized in operator splitting schemes to arrive at a local spectral time-splitting (LSTS) ...

We study the spectral and orientational dynamics of HDO molecules in aqueous solutions of different concentrations of tertiary butyl alcohol (TBA) and trimethylamine-N-oxide (TMAO). The spectral dynamics is investigated with femtosecond two-dimensional infrared spectroscopy of the O-H stretch vibration of HDO:D(2)O, and the orientational dynamics is studied with femtosecond polarization-resolve...

Spectral partitioning methods use the Fiedler vector|the eigenvector of the secondsmallest eigenvalue of the Laplacian matrix|to nd a small separator of a graph. These methods are important components of many scienti c numerical algorithms and have been demonstrated by experiment to work extremely well. In this paper, we show that spectral partitioning methods work well on bounded-degree planar...

The recent catalog of spectral types of Galactic O-type stars by MáızApellániz et al. has been used to study the differences between the frequencies of various subtypes of O-type stars in the field, in OB associations and among runaway stars. At a high level of statistical significance the data show that Ostars in clusters and associations have earlier types (and hence presumably larger masses ...

Parallel video servers provide highly scalable video-on-demand service for a huge number of clients. The conventional streamscheduling scheme does not use I/O and network bandwidth efficiently. Some other schemes, such as batching and streammerging, can effectively improve server I/O and network bandwidth efficiency. However, the batching scheme results in long startup latency and high reneging...

We study the rank structures of the matrices in Fourierand Chebyshev-spectral methods for differential equations with variable coefficients in one dimension. We show analytically that these matrices have a so-called low-rank property, not only for constant or smooth variable coefficients, but also for coefficients with steep gradients and/or high variations (large ratios in their maximum-minimu...