A STUDY OF THE POSTBUCKLING PATH OF CYLINDRICALLY CURVED PANELS OF LAMINATED COMPOSITE MATERIALS DURING LOADING AND UNLOADING

In this paper, Dynamic Relaxation Method is applied to study the postbuckling path of cylindrically curved panels of laminated composite materials during loading and unloading. The phenomenon that loading paths do not coincide with unloading paths has been found. Numerical results are given for cylindrically curved cross-ply panels subjected to uniform uniaxial compression under two types of boundary conditions. The influence of the number of layers, the panels curvature and the initial imperfection on the postbuckling paths is discussed.

EXPERIMENTAL STUDY ON DAMAGE TOLERANCE BEHAVIOUR OF COMPOSITE PANELS WITH SOFTENING STRIPS

In this paper an experimental study on damage tolerance behaviour of composite panels with softening strips is carried out. A prediction method of residual strength of panels with softening strips is proposed. The comparison between estimated and experimental results shows that the prediction method can be applied to design. In this paper the failure mechanisms are described.

Having a Partner and Having Children:Comparisons of Adults with Congenital Heart Disease and the General Population:A 15-Year Case-Control Study

Objectives:To examine whether patients with congenital heart disease(CHD)are less likely to have a partner or children than individuals from the general population.Methods:Longitudinal study with two assessments of the same patients(n=244)from a hospital population and controls(n=238)from the German Socio-Economic Panel(GSOEP)using parental education,patients age,and sex as matching criteria.The first patient study was conducted between 5/2003 and 6/2004,the second one between 5/2017 and 4/2019.Controls were drawn from GSOEP-surveys 2004 and 2018.CHD-severity was classified according to type of surgery:curative,reparative,or palliative.Living single was used as outcome measure,for offspring the outcome was having children or not.Results:Among women with CHD the rate of those living single was higher than among controls with the differences depending on disease complexity(curative:OR=5.5;reparative:OR=1.9;palliative:OR=2.7).No statistically significant differences between patients and controls emerged in the male study population.With respect to children a marked difference emerged between women with CHD and controls.Among patients the odds of having children were lower than among controls(curative:OR=0.3;reparative:OR=0.3;palliative:OR=0.2).The rate of patients with children with CHD(women:5.6%;men:4.9%)was higher than expected(1%)if compared with the general population.Conclusions:Using partnership and children as outcome criteria,patients with CHD are disadvantaged if compared to subjects from the general population.In female patients the social consequences of the disease turned out as more pervasive than in women.

Electricity Consumption and Spillover Effects A Dynamic Panel Data Approach

The paper intends to analyze economic factors that influence electricity consumption in the OECD economies. A special interest in this context is given to spillover effects of trade on electricity consumption. For this purpose, a model is constructed that using a dynamic panel study approach. The model is estimated in a GMM framework in which a dynamic procedure is conducted along the balanced growth path for electricity consumption in each economy. In advance, the long run dynamic behavior of prices, GDP, and trade induced spillover variables is determined. In a further step, the short run dynamic mechanism is pursued by estimating the partial adjustment dynamic coefficient on the target level of electricity consumption. The analysis is conducted for industrial, as well as residential electricity consumption. Alternatively, the same procedure is estimated by the application of a fixed period model. The model provides a benchmark tool for electricity policy decisions and for electricity consumption projections.

Relationship between Ambient Fine Particles and Ventricular Repolarization Changes and Heart Rate Variability of Elderly People with Heart Disease in Beijing, China

Objective To explore the effects of particulate matters less than 2.5 μm in aerodynamic diameter （PM2.5） on heart repolarization/depolarization and heart rate variability （HRV）. Methods We conducted a panel study for elderly subjects with heart disease in Beijing from 2007 to 2008. PM2.5 was measured at a fixed station for 20 h continuously each day while electrocardiogram （ECG） indexes of 42 subjects were also recorded repeatedly. Meteorological data was obtained from the China Meteorological Data Sharing Service System. A mixed linear regression model was used to estimate the associations between PMz.s and the ECG indexes. The model was adjusted for age, body mass index, sex, day of the week and meteorology. Results Significant adverse effects of PM2.5 on ECG indexes reflecting HRV were observed statistically and the strongest effect of PM2.s on HRV was on lag i day in our study. However, there were no associations between PM2.5 and ECG indexes reflecting heart repolarization/depolarization. Additionally, the effects of PM2.5 on subjects with hypertension were larger than on the subjects without hypertension. Conclusion This study showed ambient PM2.5could affect cardiac autonomic function of the elderly people with heart disease, and subjects with hypertension appeared to be more susceptive to the autonomic dysfunction induced by PM2.5.

Short-term exposure to ambient ozone associated with cardiac arrhythmias in healthy adults

Objective The exact biological mechanism whereby exposure to ambient ozone(O3)may contribute to clinical onset of cardiovascular events remains unclear.In this study,we aim to examine the impacts of O3 exposure on cardiac arrhythmias and potential pathways involved through autonomic dysfunction and myocardial injury.Methods Seventy-three non-smoking healthy adults were followed with 4 repeated measurements of 24-hour ambulatory arrhythmias,heart rate variability,ST-segment deviation,and blood pressure(BP)in Beijing,China,2014‒2016.Generalized additive mixed models coupled with distributed lag nonlinear models were constructed to evaluate the associations and potential interlinks between O3 exposure and outcome measurements.Results During the study period,24-hour average concentrations of ambient O3 were 47.4µg/m3(ranging from 1.0 to 165.9µg/m3).Increased risks of premature ventricular contraction and ventricular tachycardia were associated with interquartile range increases in O3 exposure during the last 5 days before each participant's clinic visit,with relative risks of 2.14(95%confidence interval[CI]:1.95 to 2.32)and 5.47(95%CI:3.51 to 7.43),respectively.Mediation analyses further showed that sympathetic activation,parasympathetic inhibition,and elevated BP levels,as well as heightened risks of ST-segment depression could mediate up to 47.74%of the risks of arrhythmias attributable to O3 exposure.Conclusion Our results suggest that short-term exposure to ambient O3 could prompt the genesis of arrhythmias partially through worsening autonomic function and myocardial burden.

A prospective study (SCOPE) comparing the cardiometabolic and respiratory effects of air pollution exposure on healthy and pre-diabetic individuals

Air pollution is known to be a major risk factor for cardiopulmonary disease, but this is unclear for cardiometabolic disease (e.g.diabetes). This is of considerable public health importance, given the nationwide epidemic of diabetes, accompanied by severe air pollution, in China. The evidence so far remained inadequate to answer questions of whether individuals with cardiometabolic dysfunctions are susceptible to air pollution and whether air pollution exacerbates diabetes development via certain biological pathways. In this manuscript, we summarize the results and limitations of studies exploring these two topics and elaborate our design of a prospective panel study (SCOPE) as a solution. We assessed and compared the health effect of air pollution among pre-diabetic individuals and matched healthy controls through four repeated clinical visits over 1 year. Comprehensive evaluation was made to both health endpoints and exposure. The primary biomarkers were assessed to reveal the impact on multiple biological pathways, including glycolipid metabolism and insulin resistance, endothelial function, and inflammation. Detailed chemical and size fractional components of particulate matter were measured in this study, along with the application of personal monitors.The work should increase our understanding of how air pollution affects individuals with cardiometabolic dysfunction and the underlying mechanisms.

Does Population Aging Hinder the Accumulation of Human Capital?Evidence from China

There is no consensus on the impact of population aging on education investment.To explore this question,we first build an overlapping generations(OLG)model to theoretically analyze the effect of population aging on human capital investment in China,and then test our theory by conducting an empirical study based on micro household data.We find the following.(1)Theoretically,the OLG model shows that population aging has a crowding-out effect on education investment.(2)Empirically,the results show that the share of education and training expenditures decreases by 5.27 percentage points as the ratio of old people in the household increases by 100 percentage points,which confirms the crowding-out effect of population aging on human capital investment.(3)The crowding-out effect is far more intense on urban households than on rural households since health care expenditures will be greater in urban areas as population aging increases.(4)A quantile regression indicates that the negative effect of population aging on the share of educational expenditure is concentrated in households with higher shares of education expenditures.We confirm the robustness of our results using regional fixed effect and instrumental variable(Ⅳ)regressions.