Existence of Solutions of Nonlinear Mixed Two-Point Boundary Value Problems for Third-Order Nonlinear Differential Equation

The authors use the upper and lower solution method to study the existence of solutions of nonlinear mixed two-point boundary value problems for third-order nonlinear differential equation  y′′′=f(x,y,y′,y′′),  y′(b)=h(y′(a)),  p(y(a),y(b),y′(a),y′(b))=0,  g(y(a),y(b),y′(a),y′(b),y′′(a),y′′(b))=0. Some new existence results are obtained by developing the upper and lower solution method. Some applications are also presented

A Differential Equation Model of HIV Infection of CD

An epidemic model of HIV infection of CD4+ T-cells with cure rate and delay is studied. We include a baseline ODE version of the model, and a differential-delay model with a discrete time delay. The ODE model shows that the dynamics is completely determined by the basic reproduction number R01, a unique endemic equilibrium exists and is globally stable in the interior of the feasible region. In the DDE model, the delay stands for the incubation time. We prove the effect of that delay on the stability of the equilibria. We show that the introduction of a time delay in the virus-to-healthy cells transmission term can destabilize the system, and periodic solutions can arise through Hopf bifurcation

Phase-Adjusted Estimation of the COVID-19 Outbreak in South Korea Under Multi-Source Data and Adjustment Measures: A Modelling Study

Based on the reported data from February 16, 2020 to March 9, 2020 in South Korea including confirmed cases, death cases and recovery cases, the control reproduction number was estimated respectively at different control measure phases using Markov chain Monte Carlo method and presented using the resulting posterior mean and 95% credible interval (CrI). At the early phase from February 16 to February 24, we estimate the basic reproduction number R0 of COVID-19 to be 4.79(95% CrI 4.38 - 5.2). The estimated control reproduction number dropped rapidly to Rc ≈ 0.32(95% CrI 0.19 - 0.47) at the second phase from February 25 to March 2 because of the voluntary lockdown measures. At the third phase from March 3 to March 9, we estimate Rc to be 0.27 (95% CrI 0.14 - 0.42). We predict that the final size of the COVID-19 outbreak in South Korea is 9661 (95% CrI 8660 - 11100) and the whole epidemic will be over by late April. It is found that reducing contact rate and enhancing the testing speed will have the impact on the peak value and the peak time

Persistence of an SEIR Model with Immigration Dependent on the Prevalence of Infection

We incorporate the immigration of susceptible individuals into an SEIR epidemic model, assuming that the immigration rate decreases as the spread of infection increases. For this model, the basic reproduction number, R0, is found, which determines that the disease is either extinct or persistent ultimately. The obtained results show that the disease becomes extinct as R01

Development of risk prediction model for cognitive impairment in patients with coronary heart disease: A study protocol for a prospective, cross-sectional analysis

BackgroundIschemic heart disease and degenerative encephalopathy are two main sources of disease burden for the global elderly population. Coronary heart disease (CHD) and cognitive impairment, as representative diseases, are prevalent and serious illnesses in the elderly. According to recent research, patients with CHD are more likely to experience cognitive impairment and their cognitive ability declines more quickly. Vascular risk factors have been associated with differences in cognitive performance in epidemiological studies, but evidence in patients with CHD is more limited. Inextricably linked between the heart and the brain. Considering the unique characteristics of recurrent cognitive impairment in patients with CHD, we will further study the related risk factors. We tried to investigate the potential predictors of cognitive impairment in patients with CHD through a prospective, cross-sectional study.MethodsThe cross-sectional study design will recruit 378 patients with CHD (≥65 years) from Xiyuan Hospital of China Academy of Chinese Medical Sciences. The subjects' cognitive function is evaluated with MoCA scale, and they are divided into cognitive impairment group and normal cognitive function group according to the score results. Demographic data, disease characteristics (results of coronary CT/ angiography, number of stents implanted, status of diseased vessels), laboratory tests (biochemistry, coagulation, serum iron levels, pulse wave velocity), metabolites (blood samples and intestinal metabolites), and lifestyle (smoking, alcohol consumption, sleep, physical activity) will be assessed as outcome indicators. Compare the two groups and the correlation analysis will be performed on the development of mild cognitive impairment. Mann-Whitney U or X2 test was selected to describe and evaluate the variation, and logistics regression analysis was employed to fit the prediction model. After that, do the calibration curve and decision curve to evaluate the model. The prediction model will be validated by a validation set.DiscussionTo explore the risk factors related to mild cognitive impairment (MCI) in patients with CHD, a new predictive model is established, which can achieve advanced intervention in the occurrence of MCI after CHD. Owing to its cross-sectional study design, the study has some limitations, but it will be further studied by increasing the observation period, adding follow-up data collection or prospective cohort study. The study has been registered with the China Clinical Trials Registry (ChiCTR2200063255) to conduct clinical trials

Do multiple large shareholders reduce agency problems in state-controlled listed firms? Evidence from China

Abstract(#br)In this article, we investigate how the emergence of an ownership structure with multiple large shareholders (MLS) affects principal-agent as well as principal-principal conflicts of interests in Chinese listed firms having the government as controlling shareholder. Thereby, we account for the source of MLS entry by distinguishing between a non-state investor buying shares when the government divests vs. retains its ownership stake. We find that MLS entry alleviates principal-agent problems, as evidenced by a lower managerial perk consumption and a higher pay-for-performance sensitivity of managerial compensation, as well as principal-principal problems, as reflected by a smaller ratio of related-party transactions and a lower labor redundancy. Interestingly, and except for the reduction in excess personnel, we find that the above effects arise only when the newly entered non-state investor accumulated a stake without corresponding government divestment. In contrast, the curtailing effect of MLS entry on labor redundancy only occurs when the government was willing to give up a non-trivial part of its ownership. In line with the above findings, we show that MLS entry significantly enhances the firm’s stock market valuation, with this effect predominantly arising from the anticipated reduction in excess personnel

Foaming behaviour of primary, secondary and tertiary aqueous solution of amine for the removal of carbon dioxide

This study is focusing on the effect by the usage of different amine in order to remove acid gases that is foaming. Foam is made up of thousands of gas filled bubbles. Bubbles are formed when a liquid film encapsulates gas. This research is to investigate the foaming behaviour on the different cases for the primary (monoethanolamine, MEA), secondary (diethanolamine, DEA) and tertiary (methyldiethanolamine, MDEA) amine on the effect of concentration, temperature and impurities. Effect of all this parameters will be evaluated based on height of foam and collapse time of foam. Nitrogen gas (N2) will be used in this experiments as bubble gas. For this work several hypothesis has been set according to respectively cases. The hypothesis of this study is a higher solution concentration of MEA will reduce the foaminess. Other hypothesis is a higher solution temperature of MEA and DEA will reduce the foaminess also. Effects of impurities toward foaming formation are classified as following: iron sulphide, for MDEA solution foaming decrease; sodium chloride, for MDEA solution tendency for formation of foam decrease; methanol, foaming decrease in MDEA solution. It is apparently iron sulphide meet the most influential contaminants to the foam formation at the same concentrations of all impurities studie

Antimicrobial Resistance, Virulence, and Genetic Characterization of Methicillin-Resistant Staphylococcus aureus Recovered from Ready-to-Eat (RTE) Food in China: A New Challenge for Food Safety

The objective of the present study was to determine the prevalence, antimicrobial resistance, virulence profiles, and molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) obtained from ready-to-eat (RTE) foods in China. Two hundred seventy-six RTE food-associated S. aureus isolates were collected from 25 provinces across China in 2018, then characterized by antimicrobial susceptibility testing, virulence factors detecting, multilocus sequence typing (MLST), spa typing, SCC mec typing and pulsed-field gel electrophoresis (PFGE). Two hundred fifty isolates (90.6%) were resistant to at least one antimicrobial agent; 73 (26.4%) isolates were multi-drug resistant (MDR). Thirty MRSA isolates were identified, among which nine toxin genes ( sea, seb, sec, sed, seh, selk, sell, selq , and tsst-1 ) were detected. Sixty percent (18/30) of the MRSA isolates harbored multiple toxin genes. Four virulence gene patterns were identified, with seb-selk-selq (30/30) being the most common pattern. Thirteen sequence types, as well as 13 spa and 4 SCC mec types were found among 30 MRSA isolates. The most prevalent MRSA lineages were CC59-t437-SCC mec IV/V (23.3% [7/30]), CC398-t011-SCC mec V (23.3% [7/30]), and CC1-t114-SCC mec IV (16.7% [5/30]). Our findings highlight the importance for the identification of prevalent clones, assessment of drug-resistance and virulence, and formulation of food safety measures for public health