14,191 research outputs found
A structural, spectroscopic and theoretical study of the triphenylphosphine chalcogenide complexes of tungsten carbonyl, [W(XPPh3)(CO)5], X=O, S, Se
The series [W(XPPh3)(CO)5], X=O, S, Se has been structurally determined by X-ray crystallography and fully characterised spectroscopically to provide data for comparing the bonding of the Ph3PX ligands to the metal. The P-X-W angles are 134.3°, 113.2° and 109.2°, respectively, for X=O, S, Se. The bonding has been analysed using EHMO calculations which suggest that lower P-X-W angles depend on the relative importance of Ï-bonding, which in turn depends on the chalcogen in the order X=Se > S > O. The effect is enhanced by lower energies of the metal Ï and Ï orbital energies
Recent changes in U.S. family finances: evidence from the 2001 and 2004 Survey of Consumer Finances
Reviews changes in the income and wealth of U.S. families between 2001 and 2004. The discussion draws on data from the Federal Reserve Board's triennial Survey of Consumer Finances for those years and also uses evidence from earlier years of the survey to place the 2001-04 changes in a broader context.Consumers ; Consumption (Economics)
Changes in U.S. family finances from 2004 to 2007: evidence from the Survey of Consumer Finances
The Federal Reserve Board's Survey of Consumer Finances for 2007 provides insights into changes in family income and net worth since the 2004 survey. The survey shows that, over the 2004-07 period, the median value of real (inflation-adjusted) family income before taxes was little changed, while mean income climbed 8.5 percent. Unlike family income over this period, both median and mean net worth increased; the median rose 17.7 percent, and the mean rose 13.0 percent. This article reviews these and other changes in the financial condition of U.S. families, including developments in assets, liabilities, and debt payments.Consumer surveys ; Households - Economic aspects
Synthesis and alkyne-coupling chemistry of cyclomanganated 1- and 3-acetylindoles, 3-formylindole and analogues
The syntheses are reported of new cyclomanganated indole derivatives (1-acetyl-ÎșO-indolyl-ÎșC2)dicarbonylbis(trimethylphosphite)manganese (2), (1-methyl-3-acetyl-ÎșO-indolyl-ÎșC2)tetracarbonylmanganese (4), (3-formyl-ÎșO-indolyl-ÎșC2)tetracarbonylmanganese (5a) and (1-methyl-3-formyl-ÎșO-indolyl-ÎșC2)tetracarbonylmanganese (5b). The unusually complicated crystal structure of 5b has been determined, the first for a cyclomanganated aryl aldehyde.
The preparations of a mitomycin-related pyrrolo-indole and related products by thermally promoted and oxidatively (Me3NO) initiated alkyne-coupling reactions of the previously known complex (1-acetyl-ÎșO-indolyl-ÎșC2)tetracarbonylmanganese (1) are reported for different alkynes and solvents. X-ray crystal structures are reported for the dimethyl acetylenedicarboxylate coupling product of 1 (dimethyl 1-methyl-l-hydroxypyrrolo[1,2a]-indole-2,3-dicarboxylate; 6a), and an unusually-cyclised triple insertion product 8 from the coupling of acetylene with 4, in which a cyclopentadiene moiety is η3-allyl-coordinated to Mn through only one double bond and an exocyclic carbon, but which rearranges on heating to an η5-cyclopentadienyl complex
CHARACTERISTICS OF MANGROVE DIAMONDBACK TERRAPINS (MALACLEMYS TERRAPIN RHIZOPHORARUM) INHABITING ALTERED AND NATURAL MANGROVE ISLANDS
The Mangrove Diamondback Terrapin, (Malaclemys terrapin rhizophorarum) is dependent on a very broad array of the services provided by the mangrove ecosystem. We sought to evaluate both the turtles and their habitat by an integrated assessment of physical, chemical, and physiological parameters. Extreme site fidelity of the turtles to mangrove habitat was evident along with a strong female biased sex ratio. We provide blood serum values and microbial cultures as baselines from these turtles in the wild. Salmonella sp., a potentially zoonotic pathogen, was isolated from one female. Ultimately, the health of these turtle populations may be reflective of the integrity of the mangrove system on which they depend
Revealing Cosmic Rotation
Cosmological Birefringence (CB), a rotation of the polarization plane of
radiation coming to us from distant astrophysical sources, may reveal parity
violation in either the electromagnetic or gravitational sectors of the
fundamental interactions in nature. Until only recently this phenomenon could
be probed with only radio observations or observations at UV wavelengths.
Recently, there is a substantial effort to constrain such non-standard models
using observations of the rotation of the polarization plane of cosmic
microwave background (CMB) radiation. This can be done via measurements of the
-modes of the CMB or by measuring its TB and EB correlations which vanish in
the standard model. In this paper we show that correlations-based
estimator is the best for upcoming polarization experiments. The based
estimator surpasses other estimators because it has the smallest noise and of
all the estimators is least affected by systematics. Current polarimeters are
optimized for the detection of -mode polarization from either primordial
gravitational waves or by large scale structure via gravitational lensing. In
the paper we also study optimization of CMB experiments for the detection of
cosmological birefringence, in the presence of instrumental systematics, which
by themselves are capable of producing correlations; potentially mimicking
CB.Comment: 10 pages, 3 figures, 2 table
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