2,266 research outputs found
Holding a commodity futures index fund in a globally diversified portfolio: A placebo effect?
An increasing number of investors are including futures-based commodity index funds in their portfolios. The argument is that these funds increase diversification, enhance returns and serve as an inflation hedge. Much of the recent literature served to reinforce these ideas. We update the literature by examining recent data on returns and volatility. We further extend the literature by comparing the efficient frontiers of globally diversified stock and bond portfolios with and without the inclusion of futures index funds. We find little difference between the portfolios. Additionally, the returns from such funds do not appear significantly different than zero. They also lag the returns on spot commodities which have lagged inflation over the long haul.Commodity futures index fund, stationary bootstrap, efficient portfolio frontier
Iron-mediated Preparation of Vinylcyclopropanes. Scope, Mechanism, and Applications
The addition of stabilized carbon nucleophiles to tricarbonyl(1-methoxycarbonylpentadienyl)iron(1+) cation (1a) proceeds via attack at C2 on the face of the ligand opposite the Fe(CO)3 group to generate tricarbonyl(pentenediyl)iron complexes 2. Oxidation of complexes 2 affords vinylcyclopropanecarboxylates in good yield. In general, the relative stereochemistry about the cyclopropane ring reflects reductive elimination with retention of configuration. In cases where the C2 substituent is bulky (i.e., 2b) the major cyclopropane product 9b represents ring closure with inversion at C3. A mechanism involving π−σ−π rearrangement of the initially oxidized (pentenediyl)iron species is proposed to account for these results. Experiments which probe the stereochemistry of deuterium labeling in the vinyl group of the vinylcyclopropanecarboxylate products were carried out, and these results are consistent with the proposed mechanism. This methodology for the preparation of vinylcyclopropanecarboxylates was applied to the synthesis of 2-(2‘-carboxycyclopropyl)glycines (+)-22 and (−)-23 and the cyclopropane triester (−)-26
Potential of Geo-neutrino Measurements at JUNO
The flux of geoneutrinos at any point on the Earth is a function of the
abundance and distribution of radioactive elements within our planet. This flux
has been successfully detected by the 1-kt KamLAND and 0.3-kt Borexino
detectors with these measurements being limited by their low statistics. The
planned 20-kt JUNO detector will provide an exciting opportunity to obtain a
high statistics measurement, which will provide data to address several
questions of geological importance. This paper presents the JUNO detector
design concept, the expected geo-neutrino signal and corresponding backgrounds.
The precision level of geo-neutrino measurements at JUNO is obtained with the
standard least-squares method. The potential of the Th/U ratio and mantle
measurements is also discussed.Comment: 8 pages, 6 figures, an additional author added, final version to
appear in Chin. Phys.
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