On the Diversification Effect in Solvency II for Extremely Dependent Risks

In this article, we investigate the validity of diversification effect under extreme-value copulas, when the marginal risks of the portfolio are identically distributed, which can be any one having a finite endpoint or belonging to one of the three maximum domains of attraction. We show that Value-at-Risk (V@R) under extreme-value copulas is asymptotically subadditive for marginal risks with finite mean, while it is asymptotically superadditive for risks with infinite mean. Our major findings enrich and supplement the context of the second fundamental theorem of quantitative risk management in existing literature, which states that V@R of a portfolio is typically non-subadditive for non-elliptically distributed risk vectors. In particular, we now pin down when the V@R is super or subadditive depending on the heaviness of the marginal tail risk. According to our results, one can take advantages from the diversification effect for marginal risks with finite mean. This justifies the standard formula for calculating the capital requirement under Solvency II in which imperfect correlations are used for various risk exposures

Serum tartrate-resistant acid phosphatase 5b activity as a prognostic marker of survival in breast cancer with bone metastasis

<p>Abstract</p> <p>Background</p> <p>Serum tartrate-resistant acid phosphatase 5b (TRACP 5b) activity is a marker of osteoclast number and is elevated in breast cancer (BC) patients with extensive bone metastasis, which might in turn reflect the tumour burden. We tested the hypothesis that baseline serum TRACP 5b activity and its interval change are potential prognostic markers of survival in BC patients with bone metastasis.</p> <p>Methods</p> <p>We analyzed the data from previous prospective studies. A total of 100 patients with newly diagnosed bone metastasis were included. Cox proportional regression model was used to evaluate the correlation between the overall survival time (OS) and baseline serum TRACP 5b activity and its interval changes. The least significant change (LSC) of TRACP 5b was calculated from data obtained from 15 patients with early BC.</p> <p>Results</p> <p>Estrogen receptor status (Hazard Ratio (HR) = 0.397; <it>p </it>= 0.003) and visceral metastasis (HR = 0.492; <it>p </it>= 0.0045) were significantly correlated with OS. The OS was significantly shorter in those patients with higher baseline TRACP 5b activity based on a cut-off value to delineate the highest tertile (HR = 3.524; <it>p </it>< 0.0001). Further analysis demonstrated that among patients in the highest tertile, OS was significantly longer in those patients who had achieved a decrease of serum TRACP 5b activity greater than the LSC (38.59%) (<it>p </it>= 0.0015).</p> <p>Conclusions</p> <p>We found that TRACP 5b activity and its interval change after treatment bore a prognostic role in BC patients with bone metastasis and a high baseline serum TRACP 5b activity. Further prospective phase II study is necessary to confirm these results.</p

A minimal representation of SOe (2, 2n-2)

Algebraic properties of a nninirnal representation of SOe(2,2n-2), n[is greater then or equal to] 4, are studied. This representation is a ladder representation, it has the minimal possible Gelfand-Kirillov dimension for any infinite dimensional representation, its annihilator in the universal enveloping algebra is the Joseph ideal, it remains irreducible when restricted to SOe(l,2n - 2) and it is unitarily equivalent to an induced representation upon restriction

Restriction fragment length polymorphism analysis of vibrio cholerae strains associated with a cholera outbreak in Hong Kong

We studied Vibrio cholerae El Tor isolates associated with an outbreak of cholera among Vietnamese refugees interned in Hong Kong. The restriction fragment length polymorphism of the enterotoxin gene was used as an epidemiological marker. All outbreak strains were indistinguishable. They were distinct from strains isolated in Hong Kong prior to the outbreak.link_to_subscribed_fulltex

Genetic relationships and virulence factors among classical enteropathogenic Escherichia coli serogroup O126 strains

Thirty-nine Escherichia coli strains of the enteropathogenic (EPEC) serogroup O126 isolated from sporadic and outbreak cases of infantile diarrhoea between 1982 and 1988 were studied. These strains consisted of four serotypes showing close genetic relationships between their virulence markers, outer-membrane protein and lipopolysaccharide profiles, and electrophoretic types by multilocus enzyme electrophoresis. None of these strains exhibited localised adherence to HEp-2 cells or the attaching-effacing properties of classical typeI EPEC. Ofthe 39 strains, 31 wereofserotype O126:H12 and enterotoxigenic; one strain was serotype O126:H10 and enteroaggregative. The remaining six strains of serotype O126:H21 and one strain of serotype O126:H8 harboured no known virulence factors for diarrhoeagenic E. coli.link_to_OA_fulltex

Molecular epidemiology of Vibrio cholerae in Hong Kong

We studied restriction fragment length polymorphism of the enterotoxin genes of isolates of Vibrio cholerae El Tor, indistinguishable by bacteriophage typing, which were collected in Hong Kong since 1978. Using this approach, we could distinguish indigenous and exogenous strains obtained from different sources and epidemiological settings.link_to_subscribed_fulltex

Clonal origin, restricted natural distribution, and conservation of virulence factors in isolates of enterotoxigenic Escherichia coli serogroup O126

Enterotoxigenic Escherichia coli serogroup O126 isolates have been isolated in Hong Kong since 1982 from sporadic cases of infantile diarrhea and from one outbreak in a neonatal ward. A 64-megadalton plasmid encoding colonization factor antigen I and heat-stable enterotoxin was identified in all 23 isolates. Enterotoxigenic E. coli strains producing heat-stable enterotoxin from different regions of Southeast Asia were collected and compared by biotyping, antibiotic resistance patterns, and plasmid profiles. Restriction endonuclease digestion of plasmids and subsequent Southern blot analysis with the heat-stable enterotoxin gene probe of representative strains showed a unique plasmid was harbored by all heat-stable enterotoxin-producing O126 strains tested. These results are consistent with conservative inheritance of enterotoxin plasmids within enterotoxigenic E. coli strains over a 2-year period in Hong Kong.link_to_subscribed_fulltex

Restriction fragment length polymorphism analysis of Vibrio cholerae strains associated with a cholera outbreak in Hong Kong.

We studied Vibrio cholerae El Tor isolates associated with an outbreak of cholera among Vietnamese refugees interned in Hong Kong. The restriction fragment length polymorphism of the enterotoxin gene was used as an epidemiological marker. All outbreak strains were indistinguishable. They were distinct from strains isolated in Hong Kong prior to the outbreak