Option pricing in random field models with stochastic volatility for the term structure of interest rates

In this dissertation, we introduce a general interest rate modeling framework by looking at yield curves in a Hilbert space, and bridge the popular HJM factor models with more recent random field models. Then we study the problem of vanilla interest rate option (cap) pricing under the random field model. This will be a generalization of Kennedy paper in the sense that the volatility will also follow a random field process instead of being deterministic. In particular, we consider both cases in which the two random fields for forward rates and volatilities are independent or correlated. In the computation of option prices, we have proposed a log-normal approximation of the summary statistics - integrated volatility, for the independent case and have proposed a trivariate Gaussian approximation for the correlated case. The approximations will enable us to compute option prices much faster than the usual brute force Monte Carlo method which introduces certain discretization error. Finally, we perform simulation studies of a MCMC estimation procedure for a special random field model with one factor stochastic volatility

The motion characteristics of a cylinder vehicle in the oblique water-exit process

The hydrodynamic model of a vehicle exiting the water surface obliquely has been analyzed. The analyzed object is a cylinder vehicle and its motion characteristics. Two methods have been used to simulate the water-exit process under the same conditions: Numerical Simulation Method (NSM) and Theoretical Model Solution Method (TMSM). The comparison results of the two methods can validate the hydrodynamic model founded in this paper. Different initial angles and different initial velocities have been simulated by this hydrodynamic model and the numerical simulation has been analyzed. The analysis reveals the rule of change of altitude and position of the vehicle in the water-exit process, and its motion after it exits the water surface. This paper explains why it is more difficult for the vehicle to exit the water obliquely than vertically. The results show that the hydrodynamic model of the water exiting vehicle can be used to research the exiting water motion characteristics. The models simulate the physics of motion realistically and this hydrodynamic model can be used as a foundation for the future research of the stability and control of a vehicle exiting the water

UTR introns, antisense RNA and differentially spliced transcripts between Plasmodium yoelii subspecies

Additional file 1. Evaluation of RNA quality from the two NSM parasite samples in agarose gel (a), and a flow chart of data processing and analysis (b)

Minimum Thrust of a Morphing Unmanned Submersible Aerial Vehicle in the Water-to-Air Motion

This study proposes a new water-to-air motion pattern that combines morphing with power switch. Under the conditions of this pattern, the vehicle needs a certain thrust to avoid falling back after jumping out of the water. The minimum thrust is among the most important design parameters of a vehicle. The water-exit and take-off dynamic models of the vehicle are constructed through the force and motion analysis before and after morphing. The control model of the vehicle is created by analysing the control problem in the take-off motion. The minimum thrust at different initial water-exit angles is computed using the optimum searching algorithm. The following law is then established: the greater the initial water-exit angle, the smaller the minimum thrust required in the air. Such a relationship becomes insignificant when the initial water-exit angle exceeds 40°

Radiotracer technique optimization for breast cancer internal mammary sentinel lymph node biopsy

Background and purpose: The modified injection technique developed in Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences has significantly improved the visualization rate of internal mammary sentinel lymph nodes (IMSLN), however there is still a gap between the visualization rate of IMSLN obtained by this technique and that of axillary sentinel lymph nodes (ASLN). The study aimed to further improve the IMSLN visualization rate and promote the widespread use of internal mammary sentinel lymph node biopsy (IM-SLNB) by optimizing the modified injection technique. Methods: A total of 159 patients with primary breast cancer were enrolled in a prospective group and divided into the optimized radiotracer technique group (group A, n=81) and the modified injection technique group (group B, n=78). In group A, 99mTc-sulfur colloid was injected averagely into parenchyma in the gland's three most abundant regions under ultrasound guidance (total radioactive intensity 1.0-1.3 mCi; 0.8-1.0 mL/point). In group B, 99mTc-sulfur colloid was injected averagely into the parenchyma of the breast at 6 and 12 points under ultrasound guidance (total radioactive intensity 1.0-1.3 mCi; 0.8-1.0 mL/point). Single photon emission computed tomography (SPECT)/computed tomography (CT) lymphoscintigraphy was performed preoperatively, and the sentinel lymph nodes were detected intraoperatively by γ probe. In this study, we evaluated the differences in IMSLN and ASLN visualization rates between the groups, and also analyzed the factors that may affect the IMSLN visualization rate. Results: There was no statistically significant difference in visualization rate of IM-SLN measured by preoperative SPECT/CT between the two groups (P=0.806). The intraoperative visualization rate of IM-SLN was significantly higher in group A than in group B (87.65% vs 70.51%, P=0.008). Analysis of subgroups showed that the intraoperative visualization rate of IMSLN was 92.31% and 83.33% (P=0.315) in group A patients aged ≤50 years and >50 years, respectively, and the intraoperative visualization rate of IMSLN was significantly higher in group B patients aged ≤50 years than in patients aged >50 years (81.58% vs 60.00%, P=0.037). The median in vitro radioactivity count of IMSLN was significantly higher in group A than in group B (160.50 vs 59.00, P=0.005). Conclusion: The optimized radiotracer technique can effectively increase the lymphatic drainage and uptake in the internal mammary region of the radiotracer, which can significantly improve the visualization rate of IM-SLN without affecting the visualization rate of ASLN, and is conducive to the promotion and application of IM-SLNB

Analysis of the operational status of the three-level referral system for urologic ultrasound screening and risk factors for renal pelvic dilatation in high-risk children

BackgroundCongenital Anomalies of the Kidney and Urinary Tract (CAKUT) are the primary cause of end-stage renal disease in children, early diagnosis and treatment can significantly improve the kidney function. Among CAKUT, renal pelvis dilatation (RPD) due to various causes has the highest detection rate, which can be detected early by postnatal ultrasound screening. Since 2010, the Children's Hospital of Fudan University (CHFU), together with the Minhang District Maternal and Child Health Hospital (MCH) and Community Health Centres (CHCs) of Minhang District has created a three-level referral system for urological ultrasound screening. This study aims to describe the operation of a three-level referral system for ultrasound screening of CAKUT and to select risk factors of RPD in high-risk children.MethodsThe operation of the three-level referral system was assessed by analyzing the screening volume, screening rate, referral rate, and follow-up rate; risk factors of RPD in high-risk children were selected by chi-square test and multivariate logistic regression.ResultsA total of 16,468 high-risk children were screened in ten years, and the screening volume was maintained at about 1,500 cases per year; the screening rate showed a linear increase, from 36.8% in 2010 to 98.2% in 2019; the referral rate from the CHCs to the MCH was 89.9% significantly higher after 2015 than that of 84.7% from 2010 to 2015; the follow-up rate after 2015 was 71.0% significantly higher than that of 46.3% from 2010 to 2015. Multivariate logistic regression analysis showed that the risk of RPD was 1.966 times higher in males than in females, and the risk of moderate to severe RPD was 2.570 times higher in males than in females; the risk of RPD in preterm children was 1.228 times higher than that of full-term children; and the risk of RPD was 1.218 times higher in twins than in singles.ConclusionsThe screening volume of the three-level referral system has remained stable over a decade, with significantly higher screening, referral, and follow-up rates. Males, preterm, and twins are risk factors of RPD in high-risk children; males are also risk factors for moderate to severe RPD in high-risk children

Expression of Hemolysin Is Regulated Under the Collective Actions of HapR, Fur, and HlyU in Vibrio cholerae El Tor Serogroup O1

The biotype El Tor of serogroup O1 and most of the non-O1/non-O139 strains of Vibrio cholerae can produce an extracellular pore-forming toxin known as cholera hemolysin (HlyA). Expression of HlyA has been previously reported to be regulated by the quorum sensing (QS) and the regulatory proteins HlyU and Fur, but lacks the direct evidence for their binding to the promoter of hlyA. In the present work, we showed that the QS regulator HapR, along with Fur and HlyU, regulates the transcription of hlyA in V. cholerae El Tor biotype. At the late mid-logarithmic growth phase, HapR binds to the three promoters of fur, hlyU, and hlyA to repress their transcription. At the early mid-logarithmic growth phase, Fur binds to the promoters of hlyU and hlyA to repress their transcription; meanwhile, HlyU binds to the promoter of hlyA to activate its transcription, but it manifests direct inhibition of its own gene. The highest transcriptional level of hlyA occurs at an OD600 value of around 0.6–0.7, which may be due to the subtle regulation of HapR, Fur, and HlyU. The complex regulation of HapR, Fur, and HlyU on hlyA would be beneficial to the invasion and pathogenesis of V. cholerae during the different infection stages

Prevalence, antibiotic susceptibility, and genomic analysis of Vibrio alginolyticus isolated from seafood and freshwater products in China

IntroductionThis study characterized Vibrio alginolyticus isolated from seafood and freshwater products in China (2020).Methods and ResultsIn total, 122 (95.31%) V. alginolyticus isolates were resistant to at least 1 antibiotic category, and 2 (1.56%) isolates were resistant to at least 3 antibiotic categories and belong to multi-drug resistance (MDR) isolates. A high prevalence rate was observed to be blaCARB (98.04%) encoding beta-lactam resistance, followed by tet (97.06%) encoding tetracycline resistance and fos (4.90%) encoding resistance to fosfomycin. Among the 57 V. alginolyticus isolates, the commonest virulence genes were type III secretion system translocated gene vopD, vopB, and vcrH (54.4%, 31/57), type III secretion system regulated gene tyeA (54.39%), followed by vscI and vscF (50.88%) encoded type III secretion system inner rod protein and needle protein, respectively. Multilocus sequence typing (MLST) showed considerable genetic diversity, with 34 distinct sequence types (STs) identified among 55 isolates. ST421 (n = 5), ST166 (n = 4), ST523 (n = 3), ST516 (n = 3), and ST507 (n = 3) were dominant STs among 55 V. alginolyticus isolates.DiscussionThese findings highlight the widespread occurrence of V. alginolyticus in both freshwater and seafood products, underscoring the critical need for vigilant monitoring of these bacteria. Such measures are essential for ensuring effective food safety management and safeguarding public health