Search

Objective To investigate the circumstances that lead to acute exacerbation readmission of elderly patients with chronic obstructive pulmonary disease (COPD) within 30 days and to explore the influencing factors of readmission using a structural equation model to provide evidence for medical staff so that effective intervention measures can be taken. Methods The convenience sampling method was used to select 1120 elderly patients with COPD from the respiratory departments of thirteen general hospitals in the Ningxia region, China, from April 2019 to August 2020, who then completed a survey questionnaire. The survey questionnaire contained a general data questionnaire and the modified Medical Research Council, activities of daily living, geriatric depression scale and COPD assessment test scales. Results The readmission rate of patients with COPD presenting with acute exacerbation within 30 days was determined to be 21.52%. Therefore, the modified model measures data accurately. The results showed that seasonal factors, family rehabilitation, age factors and overall health status were direct factors in the acute exacerbation readmission of patients with COPD within 30 days of hospital discharge. Smoking is not only a direct factor for acute exacerbation readmission within 30 days but also an indirect factor through disease status; disease status and chronic disease are not only direct factors for acute exacerbation readmission within 30 days but also indirect factors through the patient’s overall health status. Conclusions The rate of patients with COPD presenting with acute exacerbation within 30 days is high; while taking measures to prevent readmission based on influencing factors that directly impact admission rates, attention should also be paid to the interaction between these factors.

The purpose of this paper is to study the approximate optimality condition for composite convex optimization problems with a cone-convex system in locally convex spaces, where all functions involved are not necessarily lower semi-continuous. By using the properties of the epigraph of conjugate functions, we introduce a new regularity condition and give its equivalent characterizations. Under this new regularity condition, we derive necessary and sufficient optimality conditions of \(\varepsilon \)-optimal solutions for the composite convex optimization problem. As applications of our results, we derive approximate optimality conditions to cone-convex optimization problems. Our results extend or cover many known results in the literature.

In this paper, we consider robust optimal solutions for a convex optimization problem in the face of data uncertainty both in the objective and constraints. By using the properties of the subdifferential sum formulae, we first introduce a robust-type subdifferential constraint qualification, and then obtain some completely characterizations of the robust optimal solution of this uncertain convex optimization problem. We also investigate Wolfe type robust duality between the uncertain convex optimization problem and its uncertain dual problem by proving duality between the deterministic robust counterpart of the primal model and the optimistic counterpart of its dual problem. Moreover, we show that our results encompass as special cases some optimization problems considered in the recent literature.

This paper is concerned with the boundedness of solutions of a new chaotic system. For this system, the global exponential attractive set and positively invariant set are derived based on generalized Lyapunov function theory and the extremum principle of function. Furthermore, we can conclude that the rate of the trajectories of the system going from the exterior of the attractive set ? ? to the interior of the attractive set ? ? is an exponential rate. The rate of the trajectories is also obtained. Numerical simulations are presented to show the effectiveness of the proposed scheme.

In this paper, by using the properties of the epigraph of the conjugate functions, we introduce some closedness conditions and investigate some characterizations of these closedness conditions. Then, by using these closedness conditions, we obtain some Farkas-type results for a constrained fractional programming problem with DC functions. We also show that our results encompass as special cases some programming problems considered in the recent literature.

This paper is concerned with generalized second-order contingent epiderivatives of frontier and solution maps in parametric vector optimization problems. Under some mild conditions, we obtain some formulas for computing generalized second-order contingent epiderivatives of frontier and solution maps, respectively. We also give some examples to illustrate the corresponding results.

In this paper, we present a duality theory for fractional programming problems in the face of data uncertainty via robust optimization. By employing conjugate analysis, we establish robust strong duality for an uncertain fractional programming problem and its uncertain Wolfe dual programming problem by showing strong duality between the deterministic counterparts: robust counterpart of the primal model and the optimistic counterpart of its dual problem. We show that our results encompass as special cases some programming problems considered in the recent literature. Moreover, we also show that robust strong duality always holds for linear fractional programming problems under scenario data uncertainty or constraint-wise interval uncertainty, and that the optimistic counterpart of the dual is tractable computationally.

In this paper, we deal with extended Ky Fan inequalities (EKFI) with DC functions. Firstly, a dual scheme for (EKFI) is introduced by using the method of Fenchel conjugate function. Under suitable conditions, weak and strong duality assertions are obtained. Then, by using the obtained duality assertions, some Farkas-type results which characterize the optimal value of (EKFI) are given. Finally, as applications, the proposed approach is applied to a convex optimization problem (COP) and a generalized variational inequality problem (GVIP).

In this paper, by virtue of lower Studniarski derivatives of set-valued maps, relationships between lower Studniarski derivative of a set-valued map and its profile map are discussed. Some results concerning sensitivity analysis are obtained in parametrized vector optimization.

A total of 2,402 cases of arsenic-related skin lesions (as of 2002) in a few villages of China's Southwest Guizhou Autonomous Prefecture represent a unique case of endemic arseniasis related with indoor combustion of high arsenic coal. A significant difference of skin lesion prevalence was observed between two clans of different ethnicities (Hmong and Han) in one of the hyperendemic villages in this prefecture. This study was focused on a possible involvement of GST T1 and M1 polymorphisms in risk modulation of skin lesions and in the body burden of As in this unique case of As exposure. GST T1 and M1 polymorphisms were genotyped by an allele-specific PCR-based procedure. Total As contents in hair and urine samples as well as environmental samples of the homes of the two ethnic clans were analyzed. No significant deviations in the population frequencies of GST T1 and M1 0/0 genotypes or their combination were recorded between diagnosed skin lesion patients and asymptomatic individuals in both clans. Significantly higher As contents in hair and urine were observed in GSTM1 0/0 carriers, not in GSTT1 0/0 carriers. After stratified by ethnicity and gender, a statistically significant association of the GSTM1 0/0 genotype and higher As content in hair was only confirmed in the subgroups of ethnic Han clan members and all male villagers, not in ethnic Hmong clan members or in females. GST T1 and M1 homozygous deletions were not associated with an increased susceptibility to skin lesions in long-term exposure to indoor combustion of high As coal. The polymorphic status at the locus of GSTM1 might modulate individual's body burden of total As in some Chinese ethnic groups.

Since the shelterbelt systems of 1,092,260 hm2 have been established for thirteen years from 1978, have formed 526,541 networks and protected 13,619,400 hm2 land in western part of Northeast region of China. According to the research work we did in the last five years, the results of research project showed that the shelterbelts had improved the environment significantly. A parameter of comprehensive effects of temperature, moisture and wind in the networks (Ec = 246.52−12.17E+0.58T+6.58U) which is an active method to estimate the effects of shelterbelt on farmland, is around 21.1–30.9mm/month improving the moisture state in dry season, helping the crop yield increasing on the average by 19.8%. The effective accumulated temperature (⩾ 10°C) increases by 71°C; the cropland area which suffered from wind and frost damage decreases by 80–90%, the grass coverage on the pastureland and grass production increases by 13% and by 49.4–72%, rough protein, rough fat and nitrogen-free extract of grass increase by 3.34%, 2.4% and 8.4% separately. A large number of fixing sand plantation has been established for over thirty years on shifting in Kerqin sand land; most sand duncs were stable; a great results got from 2,000hm2, experimental area in this region; the atmospheric transport dust decrease by 2,253t/y; absorbed dust 11.1t/ y and people’s eyes sick decrease by 75%. The sandy ecological system develops a relative stable plantation system, the grass, shrubs increase to 200 species from 20 species, insects increase to 400 from 30 species, birds to 60 species and other animals increase to 20 from a few species, the fungi increase to over 200 species.