44 research outputs found
Entropy solutions to the Dirichlet problem for nonlinear diffusion equations with conservative noise
Motivated by porous medium equations with randomly perturbed velocity field,
this paper considers a class of nonlinear degenerate diffusion equations with
nonlinear conservative noise in bounded domains. The existence, uniqueness and
-stability of non-negative entropy solutions under the homogeneous
Dirichlet boundary condition are proved. The approach combines Kruzhkov's
doubling variables technique with a revised strong entropy condition that is
automatically satisfied by the solutions of approximate equations.Comment: 33 page
Three essays on empirical finance
This dissertation includes 3 papers in empirical finance. In chapter 1, since theory suggests a relationship between both volatility of volatility, variance risk premium, and the equity risk premium; we empirically investigate the relationship between volatility of volatility and the equity risk premium, and the relationship between the variance risk premium and the equity risk premium; we find that volatility of volatility alone explains 5 to 10% of the total variation of equity risk premium, and together with VIX data, it explains more than 20% of the total variation of equity premium; and we fail to find a significant relationship between volatility of volatility and the variance risk premium; we also use six measures of volatility of volatility based on non-parametric models, a GARCH model and VVIX data.
In chapter 2, we proposes a new way to measure the variance risk premium by applying a fractional cointegration relationship between implied variance and realized variance. To find the fractional cointegration coefficient between implied variance and realized variance, we develop a search method based on minimization of the score test statistic proposed by Robinson(1994). We use daily, weekly and monthly data of five stock market indexes (S&P500, S&P100, DJIA, NASDAQ100 and Russell2000) and their volatility indexes from the CBOE. We find our new measure improves the return prediction power of the variance risk premium both in-sample statically and out-of-sample dynamically, and the result is robust for the monthly data among all five indexes.
In chapter 3, by using submortgage data, we found that investors are being charged with a significant risk premium over owner occupants; besides that, they are also facing a more restricted loan; with the market getting hotter, this risk premium and restrictions are getting even worse. Being treated like that, our findings show that investors were actually not more risky than owner occupants in terms of both prepayment and default. We suspect the reason for this puzzle is that when the market getting hotter, there are more speculative investors who commit occupancy fraud to get a more favorable loan. And these speculative investors were actually recorded as owner occupants on loan documents, which increased our estimation of the hazard of owner occupants group. And our information asymmetry test actually reaffirmed our suspect. Therefore, this paper, for the first time, give statistical evidence on occupancy fraud, and we also proposed a statistical scanning way to reduce to potential occupancy fraud
LncRNA LCPAT1 Mediates Smoking/ Particulate Matter 2.5-Induced Cell Autophagy and Epithelial-Mesenchymal Transition in Lung Cancer Cells via RCC2
Background/Aims: Ecological studies have shown that air pollution and prevalence of cigarette smoking are positively correlated. Evidence also suggests a synergistic effect of cigarette smoking and PM2.5 exposure (Environmental Particulate Matter ≤ 2.5 µm in diameter) on lung cancer risk. We aimed to evaluate the interaction between smoking prevalence and PM2.5 pollution in relation to lung cancer mortality and determine its underlying mechanisms in vitro. Methods: “MOVER” method was used to analyze the interaction between smoking prevalence and PM2.5 pollution in relation to lung cancer mortality. Cell autophagy and malignant behaviors induced by cigarette smoke extract (CSE) and PM2.5 exposure were examined in vitro. Gene expression was examined by qRT-PCR and western blot. RNA and protein interaction was determined using a RNA binding protein immunoprecipitation assay. Results: An increased risk for lung cancer death (RERI (the relative excess risk) =0.28) was observed with a synergistic interaction between cigarette smoking and PM2.5 pollution. Cell migration, invasion, EMT (epithelial-mesenchymal transition) and autophagy were elevated when lung cancer cells were treated with CSE and PM2.5 in combination. A lncRNA, named lung cancer progression-association transcript 1 (LCPAT1), was up-regulated after the treatment of CSE and PM2.5, and knocking down the lncRNA impaired the effect of CSE and PM2.5 on lung cancer cells. In addition, LCPAT1 was shown to bind to RCC2, and RCC2 mediated the effect of LCPAT1 on cell autophagy, migration, invasion and EMT in lung cancer. Conclusions: Our results suggest that combined exposure to CSE and PM2.5 induces LCPAT1 expression, which up-regulates autophagy, and promotes lung cancer progression via RCC2
Treatment of Surgical Brain Injury by Immune Tolerance Induced by Peripheral Intravenous Injection of Biotargeting Nanoparticles Loaded With Brain Antigens
Once excessive, neurological disorders associated with inflammatory conditions will inevitably cause secondary inflammatory damage to brain tissue. Immunosuppressive therapy can reduce the inflammatory state, but resulting infections can expose the patient to greater risk. Using specific immune tolerance organs or tissues from the body, brain antigen immune tolerance treatment can create a minimal immune response to the brain antigens that does not excessively affect the body's immunity. However, commonly used immune tolerance treatment approaches, such as those involving the nasal, gastrointestinal mucosa, thymus or liver portal vein injections, affect the clinical conversion of the therapy due to uncertain drug absorption, or inconvenient routes of administration. If hepatic portal intravenous injections of brain antigens could be replaced by normal peripheral venous infusion, the convenience of immune tolerance treatment could certainly be greatly increased. We attempted to encapsulate brain antigens with minimally immunogenic nanomaterials, to control the sizes of nanoparticles within the range of liver Kupffer cell phagocytosis and to coat the antigens with a coating material that had an affinity for liver cells. We injected these liver drug-loaded nanomaterials via peripheral intravenous injection. With the use of microparticles with liver characteristics, the brain antigens were transported into the liver out of the detection of immune armies in the blood. This approach has been demonstrated in rat models of surgical brain injury. It has been proven that the immune tolerance of brain antigens can be accomplished by peripheral intravenous infusion to achieve the effect of treating brain trauma after operations, which simplifies the clinical operation and could elicit substantial improvements in the future
The Effects of Iron Deficiency on Blood to Brain Transport in Developing Rats
University of Minnesota M.S. thesis. 2019. Major: Integrated Biosciences. Advisor: Grant Anderson. 1 computer file (PDF); 96 pages.Iron deficiency is the most prevalent micronutrient deficiency in the world and is the major cause of iron deficiency anemia (IDA). IDA may cause motor, cognitive, and psychological dysfunction in infants and pre-school children. The impact of gestational and neonatal iron deficiency-induced angiogenesis/vasculogenesis on the neurovascular unit (NVU) integrity and functionality is still unknown. My central hypothesis is that developmental IDA leads to brain hypoxia and resultant impacts on the NVU including altered vascular permeability and blood-to-brain transport rates of nutrients, metabolites, and hormones. The results presented here tested this hypothesis and I found that iron deficiency increases glucose, lactate, and thyroxine blood-to-brain transport rates in neonatal rats. The NVU is not disrupted in iron-deficient neonatal rats. These findings provide insight into the pathophysiology of brain disorders related to iron deficiency and chronic hypoxia and contribute to our understanding of blood-to-brain transport in the chronic hypoxic and IDA developing brain
Numerical study on temperature field of the sandwich plate defects based on MATLAB
As for the defects of the plate whose length and width are more than 8 times larger than the thickness direction, the finite difference numerical calculations are carried out by using the software of MATLAB. The surface temperature of defects in different positions, different thickness defects, different heating heat flow and heating time, and defects under defects are analyzed correspondingly by the program. According to the temperature difference results of the flawless surface and the flawed surface, the feasibility of infrared thermal imaging to detect the defects of the sandwich plate is analyzed to ensure the processing quality of the sandwich plate
Thermal and Mechanical Properties of Recycled High Density Polyethylene/hemp Fiber Composites
Abstract Implementation of "green laws" in several countries hasgeneratedrenewed research interest in natural fibe
Coordinated Stability Control Strategy for Intelligent Electric Vehicles Using Vague Set Theory
Aiming at improving the tracking stability performance for intelligent electric vehicles, a novel stability coordinated control strategy based on preview characteristics is proposed in this paper. Firstly, the traditional stability control target is introduced with the two degrees of freedom model, which is realized by the sliding mode control strategy. Secondly, an auxiliary control target further amending the former one with the innovation formulation of the preview characteristics is established. At last, a multiple purpose Vague set leverages the contribution of the traditional target and the auxiliary preview target in various vehicle states. The proposed coordinated control strategy is analyzed on the MATLAB/CarSim simulation platform and verified on an intelligent electric vehicle established with A&D5435 rapid prototyping experiment platform. Simulation and experimental results indicate that the proposed control strategy based on preview characteristics can effectively improve the tracking stability performance of intelligent electric vehicles. In the double lane change simulation, the peak value of sideslip angle, yaw rate, and lateral acceleration of the vehicle is reduced by 13.2%, 11.4%, and 8.9% compared with traditional control strategy. The average deviations between the experimental and simulation results of yaw rate, lateral acceleration, and steering wheel angle are less than 10% at different speeds, which demonstrates the consistency between the experimental and the simulation results
Large-scale causal analysis of gut microbiota and six common complications of diabetes: a mendelian randomization study
Abstract Background This study aimed to reveal the association between the gut microbiota (GM) and six diabetic complications: diabetic hypoglycemia; ketoacidosis; nephropathy; neuropathy; retinopathy; and Charcot’s foot. Methods GM data were obtained from the MiBioGen consortium and Dutch Microbiome Project while data on the six diabetic complications were obtained from the FinnGen consortium. Two-sample Mendelian randomization (TSMR) was performed to explore the association between GM and the common diabetic complications. Inverse MR analysis was conducted to examine the effect of diabetic complications on the identified GM. Sensitivity tests were conducted to validate the stability of the results. Finally, multivariate MR (MVMR) was performed to determine whether GM had a direct influence on the diabetic complications. Results After multiple corrections, the inverse variance weighted (IVW) results predicted 61 suggestive markers between GM and six diabetic complications. In particular, the IVW results revealed that the Bacteroidia class and Bacteroidales order were positively associated with diabetic hypoglycemia while the Verrucomicrobiae class and Verrucomicrobiales order were positively associated with diabetic nephropathy. Based on the replication analysis, these results were identified to be stable. MVMR showed that the results remained stable after accounting for traditional risk factors. Conclusion Extensive causal associations were found between GM and diabetic complications, which may provide new insights into the mechanisms of microbiome-mediated complications of diabetes