Time-Varying Optimal Hedge Ratio for Brent Oil Market

This paper examines the optimal hedging ratio (OHR) for the Brent Crude Oil Futures using daily data over the period 1990/17/8-2014/11/3. To estimate OHR, we employ multivariate BEKK MV-GARCH model. At last, the efficiency of this approach are compared with the constant OHR captured from OLS through Edrington's index

Onset heart rate of microvolt-level T-wave alternans provides clinical and prognostic value in nonischemic dilated cardiomyopathy

AbstractObjectivesThis study was designed to determine the prognostic value of onset heart rate (OHR) in T-wave alternans (TWA) in patients with nonischemic dilated cardiomyopathy (DCM).BackgroundOne of the current major issues in DCM is to prevent sudden cardiac death (SCD). However, the value of the OHR of TWA as a prognostic indicator in DCM remains to be elucidated.MethodsWe prospectively investigated 104 patients with DCM undergoing TWA testing. The end point of this study was defined as SCD, documented sustained ventricular tachycardia/ventricular fibrillation. Relations between clinical parameters and subsequent outcome were evaluated.ResultsForty-six patients presenting with TWA were assigned to one of the following two subgroups according to OHR for TWA of ≤100 beats/min: group A (n = 24) with OHR ≤100 beats/min and group B (n = 22) with 100 < OHR ≤ 110 beats/min. T-wave alternans was negative in 37 patients (group C) and indeterminate in 21 patients. The follow-up result comprised 83 patients with determined TWA. During a follow-up duration of 21 ± 14 months, there was a total of 12 arrhythmic events, nine of which included three SCDs in group A, two in group B and one in group C. The forward stepwise multivariate Cox hazard analysis revealed that TWA with an OHR ≤100 beats/min and left ventricular ejection fraction were independent predictors of these arrhythmic events (p = 0.0001 and p = 0.0152, respectively).ConclusionsThe OHR of TWA is of additional prognostic value in DCM

Resistance to organic hydroperoxides requires ohr and ohrR genes in Sinorhizobium meliloti

<p>Abstract</p> <p>Background</p> <p><it>Sinorhizobium meliloti </it>is a symbiotic nitrogen-fixing bacterium that elicits nodules on roots of host plants <it>Medicago sativa</it>. During nodule formation bacteria have to withstand oxygen radicals produced by the plant. Resistance to H₂O₂and superoxides has been extensively studied in <it>S. meliloti</it>. In contrast resistance to organic peroxides has not been investigated while <it>S. meliloti </it>genome encodes putative organic peroxidases. Organic peroxides are produced by plants and are highly toxic. The resistance to these oxygen radicals has been studied in various bacteria but never in plant nodulating bacteria.</p> <p>Results</p> <p>In this study we report the characterisation of organic hydroperoxide resistance gene <it>ohr </it>and its regulator <it>ohrR </it>in <it>S. meliloti</it>. The inactivation of <it>ohr </it>affects resistance to cumene and ter-butyl hydroperoxides but not to hydrogen peroxide or menadione <it>in vitro</it>. The expression of <it>ohr </it>and <it>ohrR </it>genes is specifically induced by organic peroxides. OhrR binds to the intergenic region between the divergent genes <it>ohr </it>and <it>ohrR</it>. Two binding sites were characterised. Binding to the operator is prevented by OhrR oxidation that promotes OhrR dimerisation. The inactivation of <it>ohr </it>did not affect symbiosis and nitrogen fixation, suggesting that redundant enzymatic activity exists in this strain. Both <it>ohr </it>and <it>ohrR </it>are expressed in nodules suggesting that they play a role during nitrogen fixation.</p> <p>Conclusions</p> <p>This report demonstrates the significant role Ohr and OhrR proteins play in bacterial stress resistance against organic peroxides in <it>S. meliloti</it>. The <it>ohr </it>and <it>ohrR </it>genes are expressed in nodule-inhabiting bacteroids suggesting a role during nodulation.</p

Transcriptional regulation of tetrachloroethene respiration in Sulfurospirillum species

Energy conservation via organohalide respiration (OHR), comprising the reductive dehalogenation of halogenated organic compounds, is an inducible process in OHR capable Sulfurospirillum species. This work adds a first global RNA sequence of the well-studied Sulfurospirillum multivorans, a proteome and an acetylome of Sulfurospirillum halorespirans and two new Sulfurospirillum genomes that enlarge the repertoire of omics data allowing for future comparative analyses of organohalide-respiring bacteria. The differential RNA sequencing allowed for the identification of eight transcriptional units forming the tetrachloroethene regulon. A two-component system involved in tetrachloroethene signal transduction has been unambiguously identified in vivo and in vitro. The respective OmpR-family response regulator was functionally characterized. The results emphasize its role in promoting different transcriptional activation mechanisms induced by binding a cis-regulatory element containing a consensus sequence identified as a direct CTATW repeat separated by 17 bp. In S. multivorans, OHR is also subject to a unique memory effect in terms of a long-term transcriptional downregulation of the genes involved in OHR. This retentive memory effect in OHR gene regulation is now identified in a second species (S. halorespirans) suggesting a broader distribution of this regulatory phenomenon. Both acetylation pattern of the two-component system and the amount of bioavailable norcobamide cofactor were identified as potential factors affecting the memory effect. This study represents a major step towards the elucidation of the regulatory network controlling OHR gene expression in Sulfurospirillum species and might aid investigation of OHR regulation in other bacteria as well. Additionally, the first published acetylome of Campylobacterota helps to study other ecologically or medically important species of this clade

Gene regulation by redox-sensitive Burkholderia thailandensis OhrR and its role in bacterial killing of Caenorhabditis elegans

© 2018 American Society for Microbiology. Fatty acid hydroperoxides are involved in host-pathogen interactions. In both plants and mammals, polyunsaturated fatty acids are liberated during infection and enzymatically oxidized to the corresponding toxic hydroperoxides during the defensive oxidative burst that is designed to thwart the infection. The bacterial transcription factor OhrR (organic hydroperoxide reductase regulator) is oxidized by organic hydroperoxides, as a result of which the ohr gene encoding organic hydroperoxide reductase is induced. This enzyme converts the hydroperoxides to less toxic alcohols. We show here that OhrR from Burkholderia thailandensis represses expression of ohr. Gene expression is induced by cumene hydroperoxide and to a lesser extent by inorganic oxidants; however, Ohr contributes to degradation only of the organic hydroperoxide. B. thailandensis OhrR, which binds specific sites in both ohr and ohrR promoters, as evidenced by DNase I footprinting, belongs to the 2-Cys subfamily of OhrR proteins, and its oxidation leads to reversible disulfide bond formation between conserved N- and C-terminal cysteines in separate monomers. Oxidation of the N-terminal Cys is sufficient for attenuation of DNA binding in vitro, with complete restoration of DNA binding occurring on addition of a reducing agent. Surprisingly, both overexpression of ohr and deletion of ohr results in enhanced survival on exposure to organic hydroperoxide in vitro. While Δohr cells are more virulent in a Caenorhabditis elegans model of infection, ΔohrR cells are less so. Taken together, our data suggest that B. thailandensis OhrR has several unconventional features and that both OhrR and organic hydroperoxides may contribute to virulence

Visions: Art Outside the Box at the Ohr-O\u27Keefe Museum of Art in Biloxi, Mississippi

The Ohr-O\u27Keefe Museum of Art in Biloxi, Mississippi, is the preeminent repository for the works of visionary Biloxi-born pottery master George E. Ohr (1857-1918). During his youth, Ohr was an apprentice to potter Joseph Fortune Meyer for approximately one year in New Orleans. It was during this time that he began to hone his artistic skills and to learn the mechanics of the pottery trade. After his apprenticeship, he traveled to potteries in sixteen states and numerous World\u27s Fairs to learn about techniques and glazes. He came back from his travels and assisted Meyer once again in New Orleans at the New Orleans Art Pottery, which was formed to glaze and fire pottery for the Ladies Decorative Arts League and operated under the auspices of Tulane University. Through this combination of traveling and apprenticing, Ohr developed his own vanguard style and manipulation of the clay medium. His once unappreciated and unvalued ceramic art pieces were embraced by the art world during the latter part of the twentieth century and exhibited in such venues as the Metropolitan Museum of Art, the American Museum of Ceramic Art and the Smithsonian Institution\u27s National Museum of American History. Converse to aesthetic notions that were pervasive during the late-nineteenth century, Ohr\u27s whimsical and abstract ceramic masterpieces are injected with a delightful sense of humor; he did, after all, proclaim himself as The Mad Potter of Biloxi . He is widely considered to be a pioneer of the Modernist movement, and his inimitable art pieces continue to expand the boundaries of American art as a whole. While Ohr\u27s aesthetic originality and expert craftsmanship have been embraced only since the late-twentieth century, the Ohr O\u27Keefe Museum of Art stands to bear witness to a host of innovative artists for years to come. In tandem with the innovative spirit of George E. Ohr, the Museum proudly presents its newest exhibition, Visions: Art Outside the Box , which encompasses the self-revelatory work of five artists with deep Mississippi and Louisiana roots: Theodore Brooks, Martin Green, Charles W. St. Julien, Dr. Charles Smith and Willie White. These artists inhabit various mediums but all exemplify the visionary artistic experience of self-reflection, inventiveness, imagination and expression. This culturally rich and exceedingly diverse collection provides insight into the artistic heritage that pervades the Mississippi Gulf Coast

Condition Optimization for The Analysis of Risperidone and 9-0H-Risperidone by High-Performance Liquid Chromatography

Risperidone (RIS) is one of the most widely used atypical antipsychotics for treating schizophrenia in hospitals. RIS is metabolized by the liver and produces the primary active metabolite  9-OH-Risperidone (9-OHR). In the process of RIS metabolism, it is suspected that there are gene polymorphisms that cause variations in patient responses. Analysis of RIS and 9-OHR levels in the patient's blood can help to explain the various responses. High-Performance Liquid Chromatography (HPLC) is the most popular method to analyze RIS and 9-OHR, but many deficiencies were found in the chromatograms in the previous study. This research aims to obtain optimal conditions of the analysis prior to method validation. Condition optimization by optimizing the wavelength, composition of the mobile phase, pH, flow rate, and particle size of the stationary phase. The results showed that the wavelength was 279 nm, the mobile phase was 0.05 M KH2PO4 pH 3.7: acetonitrile (94:6, v/v) plus 0.3% triethylamine, and the flow rate was 1.2 ml/min in the stationary phase (LiChroCART® RP 18; 250x4 mm; 10 µm) being the optimal condition. This method is suggested to continue method validation for analyzing RIS and 9-OHR in the serum or plasma