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1.
This paper undertakes an in-sample and rolling-window comparative analysis of dependence, market, and portfolio investment risks on a 10-year global index portfolio of developed, emerging, and commodity markets. We draw our empirical results by fitting vine copulas (e.g., r-vines, c-vines, d-vines), IGARCH(1,1) RiskMetrics value-at-risk (VaR), and portfolio optimization methods based on risk measures such as the variance, conditional value-at-risk, conditional drawdown-at-risk, minimizing regret (Minimax), and mean absolute deviation. The empirical results indicate that all international indices tend to correlate strongly in the negative tail of the return distribution; however, emerging markets, relative to developed and commodity markets, exhibit greater dependence, market, and portfolio investment risks. The portfolio optimization shows a clear preference towards the gold commodity for investment, while Japan and Canada are found to have the highest and lowest market risk, respectively. The vine copula analysis identifies symmetry in the dependence dynamics of the global index portfolio modeled. Large VaR diversification benefits are produced at the 95% and 99% confidence levels by the modeled international index portfolio. The empirical results may appeal to international portfolio investors and risk managers for advanced portfolio management, hedging, and risk forecasting. 相似文献
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The taxonomy of the family Raspailiidae has always been controversial. The family was first included in the order Poecilosclerida. It was then allocated to the order Axinellida and later moved back to Poecilosclerida. Currently with the development of molecular tools it has been assigned to the order Axinellida. In this contribution we describe 10 species from the Mexican Pacific Ocean. Seven of them are new to science: Raspailia (Parasyringella) rubra sp. nov., Raspailia (Raspaxilla) hymani (Dickinson 1945), Raspailia (Raspaxilla) hyle (de Laubenfels 1930), Aulospongus cerebella (Dickinson 1945), Aulospongus californianus sp. nov., Aulospongus aurantiacus sp. nov., Eurypon patriciae sp. nov., Eurypon tylospinosum sp. nov., Eurypon diversicolor sp. nov. and Eurypon brunus sp. nov. We discuss the genus Eurypon and include a table for all the species described worldwide with some comments about this genus. http://www.zoobank.org/urn:lsid:zoobank.org:pub:D462084B-EE9C-4C61-884A-C9DB70003B4A 相似文献
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Carsten Lundby Jose A. L. Calbet Paul Robach 《Cellular and molecular life sciences : CMLS》2009,66(22):3615-3623
Hypoxia refers to environmental or clinical settings that potentially threaten tissue oxygen homeostasis. One unique aspect
of skeletal muscle is that, in addition to hypoxia, oxygen balance in this tissue may be further compromised when exercise
is superimposed on hypoxia. This review focuses on the cellular and molecular responses of human skeletal muscle to acute
and chronic hypoxia, with emphasis on physical exercise and training. Based on published work, it is suggested that hypoxia
does not appear to promote angiogenesis or to greatly alter oxidative enzymes in skeletal muscle at rest. Although the HIF-1
pathway in skeletal muscle is still poorly documented, emerging evidence suggests that muscle HIF-1 signaling is only activated
to a minor degree by hypoxia. On the other hand, combining hypoxia with exercise appears to improve some aspects of muscle
O2 transport and/or metabolism. 相似文献
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Coste B Xiao B Santos JS Syeda R Grandl J Spencer KS Kim SE Schmidt M Mathur J Dubin AE Montal M Patapoutian A 《Nature》2012,483(7388):176-181
Mechanotransduction has an important role in physiology. Biological processes including sensing touch and sound waves require as-yet-unidentified cation channels that detect pressure. Mouse Piezo1 (MmPiezo1) and MmPiezo2 (also called Fam38a and Fam38b, respectively) induce mechanically activated cationic currents in cells; however, it is unknown whether Piezo proteins are pore-forming ion channels or modulate ion channels. Here we show that Drosophila melanogaster Piezo (DmPiezo, also called CG8486) also induces mechanically activated currents in cells, but through channels with remarkably distinct pore properties including sensitivity to the pore blocker ruthenium red and single channel conductances. MmPiezo1 assembles as a ~1.2-million-dalton homo-oligomer, with no evidence of other proteins in this complex. Purified MmPiezo1 reconstituted into asymmetric lipid bilayers and liposomes forms ruthenium-red-sensitive ion channels. These data demonstrate that Piezo proteins are an evolutionarily conserved ion channel family involved in mechanotransduction. 相似文献
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Jose M. Icardo 《Cellular and molecular life sciences : CMLS》1988,44(11-12):909-909
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L. M. Morrison G. S. Bajwa H. J. Hernandez Elizabeth B. Cogswell Monica R. Stevens 《Cellular and molecular life sciences : CMLS》1972,28(12):1410-1411
Zusammenfassung Die überraschende Atheromatosehemmende Wirkung von Chondroitin-Sulfat konnte nun auch beiSaimiri scurea, einem Primaten mit hoher Inzidenz von Atheromatose, nachgewiesen werden.
Supported in part by grants from the Heart Institute of the National Institutes of Health, U. S. Public Health Service, John A. Hartford Foundation, Inc., and other donors. 相似文献
Supported in part by grants from the Heart Institute of the National Institutes of Health, U. S. Public Health Service, John A. Hartford Foundation, Inc., and other donors. 相似文献