Stochastic Dominance Analysis of iShares

Country indices as represented by iShares exhibit non-normal return distributions with both skewness and kurtosis. Davidson and Duclos (2000) and Memmel (2003) provide procedures for determining the statistical significance of stochastic dominance measures and the Sharpe Ratio, respectively. This study uses these refinements to compare the performance of 18 country market indices. The iShares are indistinguishable when using the Sharpe Ratio as no significant differences are found. In contrast, stochastic dominance procedures identify dominant iShares. Although the results vary over time, stochastic dominance appears to be both more robust and discriminating than the CAPM in the ranking of the iShares.Stochastic dominance; Sharpe ratio; skewness; country index funds

Divergence of opinion and risk : an empirical analysis of the Ex Ante beliefs of institutional investors

Bibliography: p. [24-25

Towards a reconciliation of the comparable earnings, DCF and CAPM approaches to public utility rate regulation : an empirical analysis / BEBR No. 612

Title page includes summary.Includes bibliographical references (leaves [20-21])

Studies of thermionic materials for space power applications informal monthly report, sep. 1 - sep. 30, 1963

Thermionic materials for space power application - uranium carbide-zirconium carbide fuels and tungsten claddin

Studies of thermionic materials for space power applications informal monthly report, oct. 1 - oct. 31, 1963

Thermionic space power material - isostatic pressing, vapor deposited tungsten, high temperature properties, cesium thermionic cell life testing, and irradiation studie

A bacterial inflammation sensor regulates c-di-GMP signaling, adhesion, and biofilm formation

The reactive oxygen species produced during inflammation through the neutrophilic respiratory burst play profound roles in combating bacterial pathogens and regulating the microbiota. Among these, the neutrophilic oxidant bleach, hypochlorous acid (HOCl), is the most prevalent and strongest oxidizer and kills bacteria through non-specific oxidation of proteins, lipids, and DNA. Thus, HOCl can be viewed as a host-specific cue that conveys important information about what bacterial physiology and lifestyle programs may be required for successful colonization. Nevertheless, bacteria that colonize animals face a molecular challenge in how to achieve highly selective detection of HOCl due to its reactive and transient nature and chemical similarity to more benign and non-host-specific oxidants like hydrogen peroxide (H2O2). Here, we report that in response to increasing HOCl levels E. coli regulates biofilm production via activation of the diguanylate cyclase DgcZ. We show the molecular mechanism of this activation to be specific oxidation of a conserved cysteine that coordinates the zinc of its regulatory chemoreceptor zinc-binding (CZB) domain, forming a zinc-cysteine redox switch 685-fold more sensitive to oxidation by HOCl over H2O2. Dissection of the signal transduction mechanism through quantum mechanics, molecular dynamics, and biochemical analyses reveal how the cysteine redox state alters the delicate equilibrium of competition for Zn++ between the CZB domain and other zinc binders to relay the presence of HOCl through activating the associated GGDEF domain to catalyze c-di-GMP. We find biofilm formation and HOCl-sensing in vivo to be regulated by the conserved cysteine, and point mutants that mimic oxidized CZB states increase production of the biofilm matrix polymer poly-N-acetylglucosamine and total biofilm. We observe CZB-regulated diguanylate cyclases and chemoreceptors in phyla in which host-associated bacteria are prevalent and are possessed by pathogens that manipulate host inflammation as part of their colonization strategy. A phylogenetic survey of all known CZB sequences shows these domains to be conserved and widespread across diverse phyla, suggesting CZB origin predates the bacterial last universal common ancestor. The ability of bacteria to use CZB protein domains to perceive and thwart the host neutrophilic respiratory burst has implications for understanding the mechanisms of diseases of chronic inflammation and gut dysbiosis

Place-of-residence errors on death certificates for two contiguous U. S. counties

BACKGROUND: Based on death certificate data, the Texas Department of Health Bureau of Vital Statistics calculates age adjusted all-cause mortality rates for each Texas county yearly. In 1998 the calculated rates for two adjacent Texas counties was disparate. These counties contain one city (Amarillo) and are identical in size. This study examined the accuracy of recorded county of residence for deaths in the two counties in 1998. In our jurisdiction, the county of residence is assigned by funeral homes. METHODS: A random sample of 20% of death certificates was selected. The accuracy of the county of residence was verified by using a large area map, Tax Appraisal District records, and U.S. Census Bureau databases. Inaccuracies in recording the county or zip code of residence was recorded. RESULTS: Eighteen of 354 (5.4%) death certificates recorded the incorrect county and 21 of 354 (5.9%) of death certificates recorded the zip code improperly. There was a 14.4% county recording error rate for one county compared to a 0.82% for the other county. The zip code error rate was similar for the two counties (5.9% vs. 5.8%). Of the county errors, 83% occurred for addresses within a zip code that contained addresses in both counties. CONCLUSION: This study demonstrated a large error rate (14%) in recording county of residence for deaths in one county. A similar rate was not seen in an adjacent county. This led to significant miscalculation of mortality rates for two counties. We believe that errors may have arisen in part from use of internet programs by funeral homes to assign the county of residence. With some of these programs, the county is determined by zip code, and when a zip code straddles two counties, the program automatically assigns the county whose name appears first in the alphabet. This type of error could be avoided if funeral homes determined the county of residence from Tax Appraisal District or Census Bureau records, both of which are available on the internet. This type of error could also be avoided if vital statistics offices verified the county and zip code of residence using official sources

The quadruplex r(CGG)n destabilizing cationic porphyrin TMPyP4 cooperates with hnRNPs to increase the translation efficiency of fragile X premutation mRNA

The 5′ untranslated region of the FMR1 gene which normally includes 4–55 d(CGG) repeats expands to > 55–200 repeats in carriers of fragile X syndrome premutation. Although the levels of premutation FMR1 mRNA in carrier cells are 5–10-fold higher than normal, the amount of the product FMR protein is unchanged or reduced. We demonstrated previously that premutation r(CGG)n tracts formed quadruplex structures that impeded translation and lowered the efficiency of protein synthesis. Normal translation could be restored in vivo by the quadruplex r(CGG)n destabilizing action of CBF-A and hnRNP A2 proteins. Here we report that the quadruplex-interacting cationic porphyrin TMPyP4 by itself and in cooperation with CBF-A or hnRNP A2 also unfolded quadruplex r(CGG)n and increased the efficiency of translation of 5′-(CGG)99 containing reporter firefly (FL) mRNA. TMPyP4 destabilized in vitro a (CGG)33 intramolecular quadruplex structure and enhanced the translation of 5′-(CGG)99-FL mRNA in a rabbit reticulocyte lysate and in HEK293 cells. The efficiency of translation of (CGG)99-FL mRNA was additively increased in cells exposed to TMPyP4 together with CBF-A. Whereas low doses of TMPyP4, CBF-A or hnRNP A2 by themselves did not affect the in vivo utilization of (CGG)99-FL mRNA, introduction of TMPyP4 together with either protein synergistically augmented its translation efficiency

A bacterial inflammation sensor regulates c-di-GMP signaling, adhesion, and biofilm formation

Bacteria that colonize animals must overcome, or coexist, with the reactive oxygen species products of inflammation, a front-line defense of innate immunity. Among these is the neutrophilic oxidant bleach, hypochlorous acid (HOCl), a potent antimicrobial that plays a primary role in killing bacteria through nonspecific oxidation of proteins, lipids, and DNA. Here, we report that in response to increasing HOCl levels, Escherichia coli regulates biofilm production via activation of the diguanylate cyclase DgcZ. We identify the mechanism of DgcZ sensing of HOCl to be direct oxidation of its regulatory chemoreceptor zinc-binding (CZB) domain. Dissection of CZB signal transduction reveals that oxidation of the conserved zinc-binding cysteine controls CZB Zn2+ occupancy, which in turn regulates the catalysis of c-di-GMP by the associated GGDEF domain. We find DgcZ-dependent biofilm formation and HOCl sensing to be regulated in vivo by the conserved zinc-coordinating cysteine. Additionally, point mutants that mimic oxidized CZB states increase total biofilm. A survey of bacterial genomes reveals that many pathogenic bacteria that manipulate host inflammation as part of their colonization strategy possess CZB-regulated diguanylate cyclases and chemoreceptors. Our findings suggest that CZB domains are zinc-sensitive regulators that allow host-associated bacteria to perceive host inflammation through reactivity with HOCl