We test the goodness-of-fit of stochastic volatility (SV) models using the implied volatility index of the KOSPI200 options (VKOSPI). The likelihood ratio tests reject the Heston and Hull–White SV ...models, whether or not they include jumps. Our estimation results advocate the unconstrained constant elasticity of variance (CEV) model with return jumps for describing the physical-measure dynamics of the spot index. The sub-period analysis shows that there was a significant increase in the size and frequency of jumps during the crisis period, when compared to those in the normal periods.
•We test the fitness of stochastic volatility models in the CEV class using the VKOSPI.•The likelihood ratio tests reject both the Heston and Hull–White options pricing models.•The variance of variance is significantly elastic in the Korean market.
Mass mortality of farmed 1 yr old common carp Cyprinus carpio occurred at a carp farm in April 2022. In addition to high mortality, diseased fish exhibited papillomatous growths on the skin and fins, ...characteristic of carp pox. To investigate a possible viral cause, tissue samples were collected and nucleic acid was extracted using standard procedures. In a pooled sample from the gills and kidneys, carp edema virus (CEV) was detected by real-time PCR. In a skin tissue sample with papillomatous growths, cyprinid herpesvirus 1 (CyHV1) was detected by a conventional PCR targeting a conserved region of the DNA polymerase of cyprinid herpesviruses. PCR products were visualized through agarose gel electrophoresis, and the presence of CyHV1 DNA was confirmed by Sanger sequencing. This represents the first molecular confirmation of CyHV1 in common carp in Serbia.
Here, we report the characterization of 13 novel caprine/ovine enterovirus strains isolated from different regions in China during 2016-2021. Immunoperoxidase monolayer assay showed that these viral ...strains shared strong cross-reaction with the previously reported caprine enterovirus CEV-JL14. Alignment analysis of the complete nucleotide sequences revealed 79.2%-87.8% and 75.0%-76.7% sequence identity of these novel caprine enterovirus strains to CEV-JL14 and TB4-OEV, respectively. Phylogenetic analyses clustered these novel strains to EV-G based on the amino acid sequences of P1 and 2C+3CD. Moreover, phylogenetic analysis of these caprine enterovirus strains identified three new EV-G types using VP1 sequences. These results demonstrate the genetic variations and the evolution of caprine enterovirus.
Carp oedema virus (CEV) has distinct molecularly identified genogroups of viral mutations, denoted as I, IIa, and IIb. Failure to propagate CEV in vitro limits studies towards understanding its ...interactions with host cells. Here, virus isolates belonging to genogroup I collected during natural outbreaks in the Czech Republic were employed for routine CEV cultivation in monolayers of carp-derived primary cells, common carp brain (CCB) cells, and epithelioma papulosum cyprinid (EPC) cells. Induction of cytopathic effects (CPEs) was observed and recorded in affected cells. Cell survival rate was evaluated under serial dilutions of the CEV inoculum. Virus cell entry was quantified and visualized by qPCR and transmission electron microscopy, respectively. Study findings indicate primary gills epithelia likely present the most suitable matrix for CEV growth in vitro. Cells of the head kidney and spleen facilitate virus entry with microscopically confirmed CPEs and the presence of cytoplasmic pleomorphic virus particles. Cells of the trunk kidney and gonads are unlikely to permit virus cell entry and CPEs development. Although CEV cultivation in cell lines was inconclusive, EPC cells were CEV permissible. Monolayers of carp-derived primary cells show promise for CEV cultivation that could enable elaborate study of mechanisms underlying cellular binding and responses.
The method of marking video clips with action symbols is known as vision-based human activity recognition. Robust solutions to this problem have a variety of practical implementations. Due to ...differences in motion performance, recording environments, and inter-personal differences, the challenge is difficult. We specifically resolve these problems in this study work, and we solve imitations of state-of-the-art research. Projected human activity recognition is based on an amalgamation of CEV & SGM features. The proposed solution outperforms current models and produces state-of-the-art outcomes as compared to the best effectiveness of the control, according to experimental results on the datasets.
We develop and implement a method for maximum likelihood estimation in closed-form of stochastic volatility models. Using Monte Carlo simulations, we compare a full likelihood procedure, where an ...option price is inverted into the unobservable volatility state, to an approximate likelihood procedure where the volatility state is replaced by proxies based on the implied volatility of a short-dated at-the-money option. The approximation results in a small loss of accuracy relative to the standard errors due to sampling noise. We apply this method to market prices of index options for several stochastic volatility models, and compare the characteristics of the estimated models. The evidence for a general CEV model, which nests both the affine Heston model and a GARCHmodel, suggests that the elasticity of variance of volatility lies between that assumed by the two nested models.
Much of the work on the valuation of levered (and unlevered) warrants assumes that the volatility of the underlying state variable is constant. This paper extends the literature on warrant pricing to ...a more general assumption for the state variable process, the so-called constant elasticity of variance (CEV) process. The CEV model is well-known for its ability to capture some empirical observations found in the financial economics literature, namely the asymmetry between equity returns and volatility and the implied volatility skew. Using the CEV process, we are able to reduce pricing bias as the volatility becomes a function of the underlying state variable. We price European-style call warrants without restrictions on the debt maturity. When warrants have the same maturity as debt, it is possible to obtain closed-form solutions for warrants prices. When the maturity of warrants is different from the maturity of debt, prices can be computed numerically through very efficient and simple to implement valuation methodologies.
Mortality in wild fish populations represents a challenging issue for public fish health inspectors. When a single fish species is involved, an infective aetiology is frequently suspected, with focus ...on viral notifiable diseases. However, other viral agents not subjected to regulation and causing mortality in common carp have been reported such as carp edema virus (CEV). In mid‐June 2020, a severe common carp mortality was observed in an artificial lake in north‐east of Italy. Sleepy fish were noted some days before the beginning of the mortality itself, which lasted several days and involved over 340 adult specimens. During the outbreak, water temperature was around 15°C, water quality was normal, and no adverse meteorological events were reported in the area. Four specimens, which showed severe cutaneous hyperaemia and increased mucus production on skin and gills, were tested by bacteriological methods and virological analysis targeting the main carp pathogens. Molecular analysis performed on gills, kidney and brains from all the fish analysed resulted positive for CEV, which, based on anamnestic information and laboratory findings, was considered the responsible for the mortality event herein described.
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