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In the current work, synthesis of an amorphous NiCo-MOF with an ultra-high mass loading (10.3 mg cm−2) and an ultra-thick plate structure was achieved via a one-step solvothermal method.

A simple acid etching method is proposed to prepare a three-dimensional unified NiFe-LDH gas diffusion layer. Moreover, the experiment proved that the electrode followed the lattice oxygen mechanism and exhibited high electrocatalytic activity.

It is well known that the variability and complexity of projection proportionality factors of dual projective synchronization (DPS) can effectively enhance signal confidentiality. However, in most literatures, the proportionality factors are some simple fixed constants, which can't ensure high security of information. For two pairs of fractional-order hyperchaotic systems (FOHS), how to expand the projection proportionality factors to increase its complexity? Then, our work will propose a new synchronization type, i.e., Dual Function Matrix Projective Synchronization (DFMPS) and realize the DFMPS for FOHS for the first time. Firstly, based on the traditional DPS, we generalize the proportionality factors to a function matrix depending on time t, present the error functions and define the DFMPS. Then, for FOHS, the active controller and synchronization condition are designed and proved. At the same time, when the system is affected by parameter disturbances, the active controller can eliminate the influence of parameter disturbances to the system's DFMPS, which indicates that the proposed control strategy has strong robustness. Finally, the DFMPS of two pairs of fractional-order hyperchaotic Chen and Rabinovich systems are realized, and synchronizing analysis and system robustness analysis are verified by numerical simulation. Particularly, the DFMPS can be degenerated to dual antisynchronization, dual complete synchronization, DPS, modified DPS and dual matrix projective synchronization. This work extends the synchronization types for FOHS and offers a useful method to explore DFMPS for other fractional-order systems.

Background Maternal exposure to pesticides during early pregnancy is associated with increased risks of birth defects, while the association between maternal exposure to chemical fertilizer during pregnancy and the risk of birth defects remains unknown. Methods Data were from a population-based birth defects surveillance system between 2007 and 2012 in Pingding County, Shanxi Province, northern China. A total of 14 074 births with 235 birth defects were used to estimate spatial clustering and correlations at the village level. A population-based case–control study of 157 cases with birth defects and 204 controls was performed to investigate the association between maternal chemical fertilizer exposure and the risk of birth defects by a two-level logistic model. Results The total prevalence of birth defects between 2007 and 2012 was 167.0/10 000 births. The spatial analysis indicated a remarkable high-risk area of birth defects in the southeast of Pingding County and the use of chemical fertilizer was associated with the risk of birth defects at the village level. After adjusting for confounders at the individual level, mothers who live in villages with chemical fertilizer application ≥65 tons/y had an increased risk of birth defects (adjusted odds ratio 2.06 [95% confidence interval 1.23 to 3.46]) compared with those of Conclusions Our findings suggest that the risk of birth defects may be associated with the use of chemical fertilizer in rural northern China. The findings must be cautiously interpreted and need to be investigated on larger samples.

There is little evidence on the association between adverse childhood experiences (ACEs) and disability trajectories among middle-aged and older adults. This study aimed to investigate the association between ACEs and activities of daily living (ADL) trajectories over eight years of follow-up and the mediation role of different chronic diseases on this relationship.Prospective cohort study, eight-year follow-up.China Health and Retirement Longitudinal Study(CHARLS).A total of 10651 participants age 45 and over from CHARLS 2011 to 2018 were included in this study.Five ACEs exposure groups were formed based on the cumulative ACE scores. A 6-item ADL score was used, including bathing, dressing, eating, getting in/out of bed, using the toilet, and controlling urination, to measure the ADL disability, and the group-based trajectory model (GBTM) was used to identify the ADL disability trajectories. Multinomial logistic regression was performed to investigate the association between ACEs and ADL disability trajectory memberships, and KHB-method was used to estimate the contribution of different chronic diseases on this relationship.Of the 10651 participants, 9.64% showed a mild-increasing trajectory in terms of change in ADL score during follow-up, followed by the low-mild trajectory (32.00%) and low-low trajectory (58.36%). Compared with those without ACEs exposure, participants who had ≥4 ACEs were associated with an increased risk of being on low-mild trajectory (OR 1.32, 95%CI:1.11-1.57) and mild-increasing trajectory (OR 1.41, 95%CI: 1.06-1.89), respectively. Besides, mediation analysis revealed chronic diseases had a mediation effect in this association, with the largest effect from arthritis or rheumatism (over 60%), followed by digestive system disease (around 14%), respiratory disease (around 12%), and cardio-metabolic disease (around 5%).This study suggested that exposure to ACEs was associated with a higher risk of being worse ADL disability trajectories. Moreover, chronic disease accounts for a meaningful proportion of this association. Further studies are needed to clarify how chronic diseases mediate the association between ACEs and ADL disability trajectories.

In this paper, we make long-term predictions based on numbers of current confirmed cases, accumulative dead cases of COVID-19 in different regions in China by modeling approach. Firstly, we use the SIRD epidemic model (S-Susceptible, I-Infected, R-Recovered, D-Dead) which is a non-autonomous dynamic system with incubation time delay to study the evolution of the COVID-19 in Wuhan City, Hubei Province and China Mainland. According to the data in the early stage issued by the National Health Commission of China, we can accurately estimate the parameters of the model, and then accurately predict the evolution of the COVID-19 there. From the analysis of the issued data, we find that the cure rates in Wuhan City, Hubei Province and China Mainland are the approximately linear increasing functions of time t and their death rates are the piecewisely decreasing functions. These can be estimated by finite difference method. Secondly, we use the delayed SIRD epidemic model to study the evolution of the COVID-19 in the Hubei Province outside Wuhan City. We find that its cure rate is an approximately linear increasing function and its death rate is nearly a constant. Thirdly, we use the delayed SIR epidemic model (S-Susceptible, I-Infected, R-Removed) to predict those of Beijing, Shanghai, Zhejiang and Anhui Provinces. We find that their cure rates are the approximately linear increasing functions and their death rates are the small constants. The results indicate that it is possible to make accurate long-term predictions for numbers of current confirmed, accumulative dead cases of COVID-19 by modeling. In this paper the results indicate we can accurately obtain and predict the turning points, the end time and the maximum numbers of the current infected and dead cases of the COVID-19 in China. In spite of our simple method and small data, it is rather effective in the long-term prediction of the COVID-19.

Precipitation as the meteorological data is closely related to human life. For this reason, we hope to propose new method to forecast it more accurately. In this article, we aim to forecast precipitation by reservoir computing with some additional processes. The concept of reservoir computing emerged from a specific machine learning paradigm, which is characterized by a three-layered architecture (input, reservoir and output layers). What is different from other machine learning algorithms is that only the output layer is trained and optimized for particular tasks. Since the precipitation data is non-smooth, its prediction is very difficult via the classical methods of prediction of the nonlinear time series. For the predicated precipitation data, we take its first-order moving average to make it smoother, then take the logarithm of smoothed nonzero data and the same negative constant for smoothed zero data to obtain a new series. We train the obtained series by reservoir computing and get the predicated result of its future. After taking its exponent function, the predicated data for original precipitation data are obtained. It indicates that reservoir computing combined with other processes can potentially bring about the accurate precipitation forecast.

In this paper, we consider the complicated dynamics of a delay-based photonic reservoir computing system. Since conventional computer architectures are approaching their limit, it is imperative to find new, efficient and fast ways of data processing. Photonic reservoir computing (RC) is a promising way which combines the computational capabilities of recurrent neural networks with high processing speed and energy efficiency of photonics. As the RC system is very promising, we analyze its dynamics so that we can make better use of it. In this paper, we mainly focus on its double Hopf bifurcation. We first analyze the existence of double Hopf bifurcation points. Then we use DDE-BIFTOOL to draw the bifurcation diagrams with respect to two bifurcation parameters, i.e. feedback strength [Formula: see text] and delay [Formula: see text], and give a clear picture of the double Hopf bifurcation points of the system. These figures show stability switches and the existence of double Hopf bifurcation points. Finally, we employ the method of multiple scales to obtain their normal forms, use the method of normal form to unfold and classify their local dynamics. The classification and unfolding of these double Hopf bifurcation points are obtained. Three types of double Hopf bifurcations are found. We verify the results by numerical simulations and find its complicated behavioral dynamics. For example, there exist stable equilibrium, stable periodic and quasi-periodic solutions in distinct regions. The discovered rich dynamical phenomena can help us to choose suitable values of parameters to achieve excellent performance of RC.

The combination of Additive Increase and Multiplicative Decrease (AIMD) congestion control and Random Early Detection (RED) queue as a whole congestion control system plays a key role in the overwhelming success of the Internet. Thus it is important to investigate the periodic oscillations and complicated dynamics of the state-dependent delayed homogeneous Additive Increase and Multiplicative Decrease/Random Early Detection (AIMD/RED) congestion control system and its modified version fully in this paper. Firstly employing the semi-analytical method called as the harmonic balance method with alternating frequency/time (HB-AFT) domain technique, the approximate analytical expressions of periodic solutions of the generalized homogeneous-flow Additive Increase and Multiplicative Decrease/Random Early Detection (AIMD/RED) system with state-dependent round-trip delay are considered. We compare them with the results of numerical simulations by WinPP, they agree very well with each other. It demonstrates that the method employed here is versatile, valid, simple and effective. Then to the end of improving its modeling and performance, we modify the above model by taking an easy approximate dropping function. Furthermore, for the modified delayed homogeneous system, the approximate analytical expressions of periodic solutions are obtained accurately, and some complex dynamics are also presented. Four kinds of bi-stability, i.e., the coexistence of chaos and Period-3 solution, that of Period-1 and Period-2 solutions, that of Period-2 and Period-2 solutions, that of Period-4 and Period-2 solutions are disclosed. And a route to chaos, i.e., Period Doubling bifurcation to chaos, and the window of Period-3 to chaos are also discovered. The periodic oscillation can reduce the link utilization, induce the TCP stream synchronization services and further congestion. Chaotic oscillation may result in collapse. Therefore, all complex dynamical phenomena found in this paper are harmful and should be avoided. The obtained results can be very helpful for the researchers to have a better understanding of the mechanism of the network congestion control system, and they can select the parameters properly to improve the network stability and performance.

Since the outbreak of COVID-19, the severe acute respiratory syndrome coronavirus 2 genome is still mutating. Omicron, a recently emerging virus with a shorter incubation period, faster transmission speed, and stronger immune escape ability, is soaring worldwide and becoming the mainstream virus in the COVID-19 pandemic. It is especially critical for the governments, healthcare systems, and economic sectors to have an accurate estimate of the trend of this disaster. By using different mathematical approaches, including the classical susceptible-infected-recovered (SIR) model and its extensions, many investigators have tried to predict the outbreaks of COVID-19. In this study, we employed a novel model which is based upon the well-known susceptible-infected-removed (SIR) model with the time-delay and time-varying coefficients in our previous works. We aim to predict the evolution of the epidemics effectively in nine cities and provinces of China, including A City, B City, C City, D City, E City, F City, G City, H City and I Province. The results show it is effective to model the spread of the large-scale and sporadic COVID-19 induced by Omicron virus by the novel non-autonomous delayed SIR compartment model. The significance of this study is that it can provide the management department of epidemic control with theoretical references and subsequent evaluation of the prevention, control measures, and effects.

What is already known about this topic? Shanxi Province in northern China has been identified as a region with the highest prevalence of birth defects nationwide. With large amounts of financial support devoted for prevention and related interventions for birth defects, huge progress has been made as a 60% decrease in its prevalence was observed from 2009 to 2014. What is added by this report? The study presented a recent trend of adverse pregnancy outcomes (APOs) in Shanxi Province, a region with high prevalence of birth defects in China from 2007–2019. The prevalence of serious APOs including birth defects, stillbirths, and neonatal deaths remained at a relatively low level, yet macrosomia, low birth weight (LBW), preterm births, and spontaneous abortion comprised a majority of all APOs, with macrosomia showing an obvious upward trend from 2007 to 2012. What are the implications for public health practice? These findings provide new evidence for prevention and intervention strategies of APOs in northern China. Future research should focus on comprehensive interventions for multiple APOs, especially macrosomia, LBW, preterm births, and spontaneous abortion.

Introduction Macrosomia has short-term and long-term adverse health effects and is thus an important public health concern. Recent decades have witnessed increasing incidence of macrosomia in many countries. Methods The present study used a large population-based birth cohort study to depict incidence of macrosomia among live births in rural areas of Henan Province of China from 2013 to 2017. Results Among the 1,262,916 births, 82,353 were cases of macrosomia. The overall incidence of all types of macrosomia, of macrosomia with birth weight

Hypertension is a common and costly public health burden in China, while the interaction effects of individual and contextual level factors on the risk of hypertension remain unclear. This study aimed to investigate whether the interaction effects between individual education and regional chemical fertilizer consumption are associated with the risk of hypertension based on a cross-level interaction perspective. Data was from the China Hypertension Survey (CHS) study, which used a nationally representative sample, and was conducted between 2012 and 2015. A total of 379 467 participants aged over 18 years from 221 counties in 31 provinces were included. A cross-sectional study design and two-level logistic models were conducted to investigate the cross-level interaction between individual education and regional chemical fertilizer consumption on the risk of hypertension after adjusting for potential confounding variables. Compared to individuals with high education (college or more), the adjusted OR (95%CI) for hypertension among those in the high school, middle school, and elementary school or less was 1.16 (1.12-1.21), 1.25 (1.20-1.30), and 1.49 (1.43-1.55), respectively. The association between regional chemical fertilizer consumption and hypertension was not significant. Interaction analysis showed that regional chemical fertilizer consumption was associated with an increased risk of hypertension for individuals with lower education. These patterns were consistent after stratified by sex. This study provided evidence from the Chinese population that interaction between individual education and regional chemical fertilizer was associated with risk of hypertension. Future research and policy aimed to improve population health and reduce hypertension could address the regional context of population as well as individual factors.

In this paper, a model of active control system with state-dependent actuation time delay is investigated. Galerkin projection scheme is used to obtain its low dimensional approximation system. State-dependency and effect on dynamics and performance of actuation delay in this active control system are considered. The following results are obtained. Firstly, a state-dependent actuation delay is proposed, which has never been reported in the previous works. It displays that actuation delay is state-dependent. Secondly, employing Galerkin projection scheme, low dimensional approximation system of this delayed active control system is obtained. At last, its stability and Hopf bifurcation are investigated by Routh-Hurwitz Criterion and Hopf bifurcation theory. Using software WinPP, numerical simulation is executed and supports the theoretical results in this paper.

Background It's very common to see the onset of fever after percutaneous nephrolithotomy (PCNL), it's necessary to analyze the risk factors for the fever following PCNL, and to provide evidence for infection prevention after PCNL. Methods A total of 546 adult PCNL patients were included as study subjects and retrospective studies were performed. We collected clinical data of patients using a prospectively designed database. Univariate and multivariate logistic regression analyses were performed to identify the potential risk factors for the fever after PCNL. Results Of the included 546 PCNL patients, there were 82 fever patients and 464 no-fever patients following PCNL. Escherichia coli and Proteus mirabilis are the two most common infectious bacteria. Preoperative urinary tract infection (OR =4.38, 95% CI: 1.15-9.53), multiple access (OR =5.31, 95% CI: 1.23-10.75), diabetes (OR =4.97, 95% CI: 1.37-9.86), length of operation ≥60 min (OR =5.67, 95% CI: 2.24-13.42), estimated blood loss in PCNL ≥500 mL (OR=2.78, 95% CI: 2.32-3.61) were the independent risk factors associated with postoperative infection. Conclusions Effective control of urinary tract infection, reduction of access number, strict control of blood glucose, length of operation control, reduction of intraoperative bleeding should be considered as measures to prevent postoperative fever for patients with PCNL.

OBJECTIVES The study aimed to investigate the spatial variation of hypertension (HTN) and the associations between the risk of HTN and altitude, longitude, latitude in Chinese population. METHODS The newest China Hypertension Survey (CHS) study, which used a nationally representative sample, was conducted between 2012 and 2015. A total of 451 755 participants aged at least 18 years from 262 county-level regions in 31 provinces were analyzed to explore the geographical variations of HTN prevalence at county-level. A total of 444 375 participants were included in two-level logistic regression model to examine the association between HTN risk and exposure to altitude, longitude, and latitude after adjusting for potential confounding variables at individual level. RESULTS The findings of spatial analysis indicated that there were remarkably high and low HTN prevalence zones. High HTN prevalence zones extended from parts of the southeast to northern China and the northeast. The risk of HTN increased with increasing longitude, with adjusted odds ratios (aORs, 95% confidence interval [CI]) of 2.08 (1.04--4.18), 2.21 (1.15--4.22), 2.54 (1.31--4.93), 2.59 (1.32--5.08), and 2.81 (1.12--7.08) for longitudes of 90-100°E, 100-110°E, 110-120°E, 120-130°E, and at least 130°E, respectively, with a significant dose--response relationship that HTN risks increase as longitude rises from 90°E to ≥130°E(Ptrend

In the present study, I propose a novel fitting method to describe the outbreak of 2019-nCoV in China. The fitted data were selected carefully from the non-Hubei part and Hubei Province of China respectively. For the non-Hubei part, the time period of data collection corresponds from the beginning of the policy of isolation to present day. But for Hubei Province, the subjects of Wuhan City and Hubei Province were included from the time of admission to the Huoshenshan Hospital to present day in order to ensure that all or the majority of the confirmed and suspected patients were collected for diagnosis and treatment. The employed basic functions for fitting are the hyperbolic tangent functions$$\tanh (.)$$tanh(.)since in these cases the 2019-nCoV is just an epidemic. Subsequently, the 2019-nCoV will initially expand rapidly and tend to disappear. Therefore, the numbers of the accumulative confirmed patients in different cities, provinces and geographical regions will initially increase rapidly and subsequently stabilize to a plateau phase. The selection of the basic functions for fitting is crucial. In the present study, I found that the hyperbolic tangent functions$$\tanh (.)$$tanh(.)could satisfy the aforementioned properties. By this novel method, I can obtain two significant results. They base on the conditions that the rigorous isolation policy is executed continually. Initially, I can predict the numbers very accurately of the cumulative confirmed patients in different cities, provinces and parts in China, notably, in Wuhan City with the smallest relative error estimated to$$0.021\%$$0.021%, in Hubei Province with the smallest relative error estimated to$$0.012\%$$0.012%and in the non-Hubei part of China with the smallest relative error of$$-$$- 0.195% in the short-term period of infection. In addition, perhaps I can predict the times when the plateau phases will occur respectively in different regions in the long-term period of infection. Generally for the non-Hubei part of China, the plateau phase of the outbreak of the 2019-nCoV will be expected this March or at the end of this February. In the non-Hubei region of China it is expected that the epidemic will cease on the 30th of March 2020 and following this date no new confirmed patient will be expected. The predictions of the time of Inflection Points and maximum NACP for some important regions may be also obtained. A specific plan for the prevention measures of the 2019-nCoV outbreak must be implemented. This will involve the present returning to work and resuming production in China. Based on the presented results, I suggest that the rigorous isolation policy by the government should be executed regularly during daily life and work duties. Moreover, as many as possible the confirmed and suspected cases should be collected to diagnose or treat.

In this paper, we consider the complex dynamics of a fiscal dynamical model, which was improved from Wolfstetter classical growth cycle model by Sportelli et al. The main work of the present paper is to study the impact of fiscal policy delays on the national income adjustment processes using a dynamical method, such as double Hopf bifurcation analysis. We first use DDE-BIFTOOL to find the double Hopf bifurcation points of the system, and draw the bifurcation diagrams with two bifurcation parameters, i.e. the tax collection delay [Formula: see text] and the public expenditure decision-making delay [Formula: see text]. Then we employ the method of multiple scales to obtain two amplitude equations. By analyzing these amplitude equations, we derive the classification and unfolding of these double Hopf bifurcation points. And three types of double Hopf bifurcations are found. Finally, we verify the results by numerical simulations. We find complex dynamic behaviors of the system via the analytical method, such as stable equilibrium, stable periodic, quasi-periodic and phase-locked solutions in respective regions. The dynamical phenomena can help policy makers to choose a proper range of the delays so that they could effectively formulate fiscal policies to stabilize the economy.

Current progress in measuring the effect of the pandemic on mortality is limited. Few studies have comprehensively and systematically elucidated the mechanism through which the pandemic affects mortality and what indicators are valid to capture such an effect. This paper presents a comprehensive analysis regarding the multifaceted effects of coronavirus disease 2019 (COVID-19) on mortality and its measurements [i.e., confirmed deaths per million people (CDPMP), case fatality rate (CFR), infection fatality risk (IFR), excess mortality P-score (EMPS), and life expectancy (LE)]. It was revealed that both data collection efforts and measurements on mortality due to COVID-19 were far from perfect and discussed the importance of accurate, prompt, and accessible data by any government over the course of fighting against the COVID-19 pandemic. It is believed that the biggest challenge in measuring the effect of the COVID-19 pandemic on mortality lies not in the construction of indicators at the academic level, but in the collection of data at the practical level. Thus, it is suggested to take measures to better monitor the development of the pandemic and mitigate the increasing burdens borne by the public health systems by improving the tracking system of mortality, standardizing the diagnosis of COVID-19's deaths, and disclosing mortality data.

Previous studies in western populations have found consistent relationships between adverse childhood experiences and the development of mood and anxiety disorders, especially depressive symptoms in adolescence and adulthood.This study used a longitudinal design and analytic method to model depressive symptom trajectories from 2011 to 2018 among the middle-aged and elderly in China. This study also investigated the association between adverse childhood experiences and adulthood depressive symptoms in the Chinese population.Future public policy could consider early prevention and intervention on adverse childhood experiences to prevent adult depressive symptoms. Besides, it is essential to create safe, stable, and nurturing environments for children's development.

Whether maternal macro-environmental chemical fertilizer exposure has an association with the risk of preterm birth remains unclear. This study aimed to investigate the association between maternal exposure to chemical fertilizer during pregnancy and the risk of preterm birth. A total of 13,861 births, including 402 preterm birth from 313 villages in Pingding County, Shanxi Province, China, were analyzed to explore spatial variations of preterm birth risks at the village level. Spatial variations of preterm birth were visualized and tested with Disease Mapping, Moran’s I and G* Statistic. The spatial zero-inflated negative binomial model was used to evaluate the incidence rate ratio (IRR) of preterm birth in different chemical fertilizer consumption levels at the village level. A population-based case-control study was conducted including 153 preterm births cases and 204 controls at the household level. The two-level logistic regression model was performed to estimate the association between risks of preterm birth and maternal exposure to chemical fertilizer after adjusting confounding factors. The findings indicated a remarkably clustering effect in relative risks of preterm birth and identified a high-risk clustering region of preterm birth from the south-central to the southwest and a low-risk clustering region in the northern Pingding county. The results of the spatial zero-inflated negative binomial model showed that the risk of preterm birth in the villages with chemical fertilizer consumption≥100 tons was 2.82 (95% CI: 1.50–5.57) times higher than those with

This paper has attended to obtain the approximate analytical expressions of periodic solutions in the delayed non-smooth Internet TCP-RED congestion control system employing the semi-analytical method named as the harmonic balance method with alternating frequency/time (HB-AFT) domain technique. For the first time, the methodology presented herein provides the accurate approximate analytical expressions of periodic solutions, including the non-impacting periodic solutions and impacting periodic solutions, in the non-smooth dynamical system with time-delays. They agree very well with the results of numerical simulations by MATLAB. It implies that the proposed method in this paper is accurate and effective. Furthermore, rich dynamics of this delayed non-smooth system is discovered in the present paper. Three kinds of bi-stability, i.e. coexistence of asymptotically stable equilibrium and equilibrium, equilibrium and periodic solution, periodic solution and periodic solution, have been found in the system with the variation of the delay. And the grazing solution, the impacting solution traversing both the lower threshold Tmin and the larger threshold Tmax, and a route to chaos, i.e., intermittent to chaos, have been also obtained by varying the delay employing numerical method.

STUDY QUESTIONDoes maternal periconceptional no folic acid supplementation have an increased risk of neural tube defects (NTDs) associated with previous spontaneous abortion or first-trimester fever?SUMMARY ANSWERMaternal periconceptional no folic acid supplementation can increase the risk of NTDs associated with previous spontaneous abortion or first-trimester fever, independent of known confounding factors.WHAT IS KNOWN ALREADYMaternal periconceptional folic acid deficiency can increase the risk of NTDs. However, whether an interaction between periconceptional no folic acid supplementation and history of spontaneous abortion or first-trimester fever may have an increased risk of NTDs remains unknown.STUDY DESIGN, SIZE, DURATIONA population-based case–control study was performed including 104 nuclear families with offspring with NTDs and 100 control families with normal offspring between 1993 and 2002.PARTICIPANTS/MATERIALS, SETTING, METHODSWe investigated the potential interaction between periconceptional no folic acid use and a maternal history of spontaneous abortion or first-trimester fever in the risk for NTDs. Information on exposure factors was obtained at the onset of pregnancy, and pregnancy outcomes were collected during the first week after delivery or at the time of termination of the pregnancy. A multivariate logistic regression analysis was performed.MAIN RESULTS AND THE ROLE OF CHANCEThe interaction between periconceptional no folic acid use and a maternal history of spontaneous abortion markedly increased the risk of NTDs (adjusted odds ratio (aOR) 18.68, 95% CI, 4.43–78.76) after adjusting for potential confounding factors. The interaction coefficient was found to be 2.08, higher than 1, indicating that there is a significant interaction between two factors. Mothers who did not take periconceptional folic acid and had first-trimester fever had an increased risk of NTDs (aOR 21.81, 95% CI, 8.81–80.73). However, the interaction coefficient was found to be 0.62, less than 1, indicating that there is no significant interaction between two factors.LIMITATIONS, REASONS FOR CAUTIONA potential limitation was that the interval between the previous spontaneous abortion and the beginning of the subsequent pregnancy could not be estimated accurately, but was at least 1 year or more.WIDER IMPLICATIONS OF THE FINDINGSWe emphasize that a previous spontaneous abortion may represent a first occurrence of NTDs rather than be the cause of NTDs. Our findings indicate that mothers with a history of spontaneous abortion are ideal candidates for periconceptional folic acid supplementation.STUDY FUNDING/COMPETING INTEREST(S)This work was supported by National Natural Science Foundation of China (41871360) and Danone Nutrition Center for Dietary Nutrition Research and Education Foundation (DIC2015-05). There are no competing interests to declare.

State-dependent time-delayed systems are more realistic delayed systems in nature and human society. Their dynamic problems are hot issues and difficult questions due to the fact that the classical RFDE theory is not suitable for them any more. And its corresponding rigorous theory is to be established. The study on the existence and stability of their periodic solutions is an important topic and a difficult question. Compound TCP is a widely used transport control protocol, and proportional integral enhanced (PIE) queue policy is an effective and simple queue policy in the Internet. Thus it is significant to study the dynamics and control of the compound TCP-PIE system. In this paper, Period-1 oscillations of the state-dependent delayed TCP models with PIE queue management policy are predicted by the high-dimensional harmonic balance method (HDHBM). Compared with the traditional harmonic balance method, HDHBM avoids the complex integration of the Fourier coefficients of the nonlinear right hand of the systems by solving the time domain variables of the Fourier coefficients at equally spaced sub-time over the period of one cycle of motion. Thus it transforms the problem into a relatively simple nonlinear algebraic equations, which greatly reduces the computation. By HDHBM, the approximate expressions of the Period-1 solutions for this state-dependent delayed compound TCP-PIE system are obtained. We compare their amplitudes and phase portraits with those of the DDE-BIFTOOL. They agree well with each other. It suggests the validity, effectiveness and simplicity of the employed method. It also turns out that many parameters of the state-dependent delayed TCP model with PIE queue management policy play a very important role in its dynamic behaviours. It follows that PIE parameter μ and update time T may play the most important roles in the Compound TCP-PIE congestion control model and packet loss probability p ( t ˜ ) may dominate the dynamics and performances of the network. As a result, we should control the parameters in a proper range to achieve our desired network performances.

In this paper the dynamics of differential equation with two linearly state-dependent delays is considered, with particular attention focused on non-resonant double Hopf bifurcation. Firstly, we identify the sufficient and necessary conditions of the double Hopf bifurcation by formal linearization, linear stability analysis and Hopf bifurcation theorem. Secondly, in the first time the method of multiple scales (MMS) is employed to classify the dynamics in the neighborhoods of two kinds of non-resonant double Hopf bifurcation points, i.e. Cases III and Ib, in the bifurcation parameters plane. Finally, numerical simulation is executed qualitatively to verify the previously analytical results and demonstrate the rich phenomena, including the stable equilibrium, stable periodic solutions, bistability and stable quasi-periodic solution and so on. It also implies that MMS is simple, effective and correct in higher co-dimensional bifurcation analysis of the state-dependent DDEs. Besides, the other complicated dynamics, such as the switch between torus and phase-locked solution, period-doubling and the route of the break of torus to chaos are also found in this paper.