77 research outputs found
Multi-assets Asian rainbow options pricing with stochastic interest rates obeying the Vasicek model
Asian rainbow options provide investors with a new option solution as an effective tool for asset allocation and risk management. In this paper, we address the pricing problem of Asian rainbow options with stochastic interest rates that obey the Vasicek model. By introducing the Vasicek model as the change process of the stochastic interest rate, based on the non-arbitrage principle and the stochastic differential equation, the number of assets of the Asian rainbow option is expanded to n dimensions, and the pricing formulas of the Asian rainbow option with multiple (n) assets under the Vasicek interest rate model are obtained. The multi-asset pricing results under stochastic interest rates provide more possibilities for Asian rainbow options. Furthermore, Monte Carlo simulation experiments show that the pricing formula is accurate and efficient under double stochastic errors. Finally, we perform parameter sensitivity analysis to further justify the pricing model
HLA-DRB1 May Be Antagonistically Regulated by the Coordinately Evolved Promoter and 3′-UTR under Stabilizing Selection
HLA-DRB1 is the most polymorphic MHC (major histocompatibility complex) class II gene in human, and plays a crucial role in the development and function of the immune system. Extensive polymorphisms exist in the promoter and 3′-UTR of HLA-DRB1, especially a LTR (Long terminal repeat) element in the promoter, which may be involved in the expression regulation. However, it remains unknown how the polymorphisms in the whole promoter region and 3′-UTR to regulate the gene expression. In this study, we investigated the extensive polymorphisms in the HLA-DRB1 promoter and 3′-UTR, and how these polymorphisms affect the gene expression in both independent and jointly manners. It was observed that most of the haplotypes in the DRB1 promoter and 3′-UTR were clustered into 4 conserved lineages (H1, H2, H3 and H4), and showed high linkage disequilibrium. Compared with H1 and H2 lineage, a LTR element in the promoter of H3 and H4 lineage significantly suppressed the promoter activity, whereas the activity of the linked 3′-UTR increased, leading to no apparent difference in the final expression product between H1/H2 and H3/H4 lineage. Nevertheless, compared with the plasmid with a promoter and 3′-UTR from the same lineage, the recombinant plasmid with a promoter from H2 and a 3′-UTR from H3 showed about double fold increased luciferase activity, Conversely, the recombinant plasmid with a promoter from H3 and a 3′-UTR from H2 resulted in about 2-fold decreased luciferase activity. These results indicate that the promoter and 3′-UTR of HLA-DRB1 may antagonistically regulate the gene expression, which may be subjected to stabilizing selection. These findings may provide a novel insight into the mechanisms of the diseases associated with HLA-DRB1 genes
Phase I study of the Syk inhibitor sovleplenib in relapsed or refractory mature B-cell tumors
Sovleplenib (HMPL-523) is a selective spleen tyrosine kinase (Syk) inhibitor with antitumor activity in preclinical models of B-cell malignancy. We conducted a dose-escalation and dose-expansion phase I study of sovleplenib in patients with relapsed/refractory mature Bcell tumors. Dose escalation followed a 3+3 design; patients received oral sovleplenib (200-800 mg once daily [q.d.] or 200 mg twice daily [b.i.d.], 28-day cycles). During dose expansion, patients were enrolled into four cohorts per lymphoma classification and treated at the recommended phase 2 dose (RP2D). Overall, 134 Chinese patients were enrolled (dose escalation, n=27; dose expansion, n=107). Five patients experienced dose-limiting toxicities: one each of amylase increased (200 mg q.d.), febrile neutropenia (800 mg q.d), renal failure (800 mg q.d.), hyperuricemia and blood creatine phosphokinase increased (200 mg b.i.d.) and blood bilirubin increased and pneumonia (200 mg b.i.d.). RP2D was determined as 600 mg (>65 kg) or 400 mg (≤65 kg) q.d. The primary efficacy end point of independent review committee–assessed objective response rate in indolent B-cell lymphoma was 50.8% (95% CI, 37.5–64.1) in 59 evaluable patients at RP2D (follicular lymphoma: 60.5%, marginal zone lymphoma: 28.6%, lymphoplasmacytic lymphoma/Waldenström macroglobulinemia, 0%). The most common (≥10% patients) grade ≥3 treatment-related adverse events in the doseexpansion phase were decreased neutrophil count (29.9%), pneumonia (12.1%) and decreased white blood cell count (11.2%). Pharmacokinetic exposures increased doseproportionally with ascending dose levels from 200–800 mg, without observed saturation. Sovleplenib showed antitumor activity in relapsed/refractory B-cell lymphoma with acceptable safety. Further studies are warranted
Three Essays on Oil Industry and Public Policy
This thesis provides both empirical and theoretical evidence on the effects of public policies on the oil industry. In Chapter 1, I examine the impacts of prorationing and compulsory unitization to solve the common pool problem; in Chapter 2, I provide empirical evidence of the relationship between taxation and producers' extraction paths under a new horizontal drilling technology; in Chapter 3, I build a theory model which analyzes a specific royalty-exemption program.
In Chapter 1, I use a difference-in-difference methodology to examine the effects of prorationing and compulsory unitization on the U.S.oil production. The empirical result indicates that both unitization and prorationing increased the well-head price. In addition, unitization restricted the production, but prorationing raised the production. Unitization also mitigated the congestion of producing wells, while prorationing encouraged producers to operate more producing wells than necessary. However, the effectiveness of solving the common pool problem was still limited for both policies, because neither of them could sustain the value of well production.
In Chapter 2, I probe the impacts of taxation on oil extraction paths from horizontal wells. I use a fixed effect method to study the horizontal well incentive program in Manitoba. The empirical results suggest that producers tilt their extraction paths downward before they start to pay the tax. There is also a reduction in oil production after producers pay the tax.
In Chapter 3, I use an optimal control model to illustrate how a royalty-exemption program will affect the oil extraction path over time. The royalty-exemption program is defined as a program that grants oil producers an upfront royalty-free volume at the beginning of their production, they pay the royalty after this volume is used up. I find that because the royalty payment is foreseen in the future, producers start to adjust their production at the royalty-free period. When the royalty is in effect, it can either induce producers to produce at a lower rate and extend the well life, or encourage them to extract more and shorten the well's production life, depending on when producers start to pay the royalty
CariesXrays: Enhancing Caries Detection in Hospital-Scale Panoramic Dental X-rays via Feature Pyramid Contrastive Learning
Dental caries has been widely recognized as one of the most prevalent chronic diseases in the field of public health. Despite advancements in automated diagnosis across various medical domains, it remains a substantial challenge for dental caries detection due to its inherent variability and intricacies. To bridge this gap, we release a hospital-scale panoramic dental X-ray benchmark, namely “CariesXrays”, to facilitate the advancements in high-precision computer-aided diagnosis for dental caries. It comprises 6,000 panoramic dental X-ray images, with a total of 13,783 instances of dental caries, all meticulously annotated by dental professionals. In this paper, we propose a novel Feature Pyramid Contrastive Learning (FPCL) framework, that jointly incorporates feature pyramid learning and contrastive learning within a unified diagnostic paradigm for automated dental caries detection. Specifically, a robust dual-directional feature pyramid network (D2D-FPN) is designed to adaptively capture rich and informative contextual information from multi-level feature maps, thus enhancing the generalization ability of caries detection across different scales. Furthermore, our model is augmented with an effective proposals-prototype contrastive regularization learning (P2P-CRL) mechanism, which can flexibly bridge the semantic gaps among diverse dental caries with varying appearances, resulting in high-quality dental caries proposals. Extensive experiments on our newly-established CariesXrays benchmark demonstrate the potential of FPCL to make a significant social impact on caries diagnosis
UCST-Type Thermoresponsive Polymers in Synthetic Lubricating Oil Polyalphaolefin (PAO)
This
Article reports a family of UCST-type thermoresponsive polymers, poly(alkyl
methacrylate)s with an appropriate alkyl pendant length in an industrially
important nonvolatile organic liquid polyalphaolefin (PAO). The cloud
point (CP) can be readily tuned over a wide temperature range by changing
the alkyl pendant length; at a concentration of 1 wt % and similar
polymer molecular weights, the CP varies linearly with the (average)
number of carbon atoms in the alkyl pendant. PAO solutions of ABA
triblock copolymers, composed of a PAO-philic middle block and thermoresponsive
outer blocks with appropriate block lengths, undergo thermoreversible
sol–gel transitions at sufficiently high concentrations. The
discovery of thermoresponsive polymers in PAO makes it possible to
explore new applications by utilizing PAO’s unique characteristics
such as thermal stability, nonvolatility, superior lubrication properties,
and so on. Two examples are presented: thermoresponsive physical gels
for control of optical transmittance and injectable gel lubricants
Syntheses of 4‑(Heteroaryl)cyclohexanones via Palladium-Catalyzed Ester α‑Arylation and Decarboxylation
An alternative synthesis of 4-(heteroaryl)cyclohexanones
is described
featuring a palladium-catalyzed ester α-arylation followed by
decarboxylation. The substrate scope is broad with a wide range of
heteroaryl halides. In particular, the reaction robustness is demonstrated
by the synthesis of >10 g of 4-(pyrazin-2-yl)cyclohexanone with
85%
overall yield
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