中国流动人口卫生健康与计划生育动态调查数据:2009-2018年多波大规模全国性横断面调查

这篇数据论文介绍了2009~2018年中国流动人口动态调查(Chinese Migrants Dynamic Survey,CMDS)的数据。CMDS是原国家卫生和计划生育委员会组织开展的全国流动人口的多年度大规模全国性横断面调查。调查对象为15岁以上的国内流动人口,样本取自中国流动人口信息系统,采用多阶段分层抽样方法和概率比例-大小(probability proportional-to-size,PPS)聚类抽样策略进行抽样。2009年至2018年,共有来自23个省、5个自治区和4个直辖市的1,527,650名流动人口参与了该调查。调查工具是由原国家卫生和计划生育委员会组织设计的一系列具有高度继承性和一致性的调查问卷,问卷内容主要包括被调查者及其家庭成员的基本情况、流动状况、医疗保健或健康行为、公共卫生服务利用情况、社会保险情况、社会融合情况、计划生育情况等。该数据集是目前使用最广泛的关于中国流动人口的调查数据,提供了有关流动人口的流动模式、医疗卫生和健康行为、公共卫生服务、社会保障、社会融合和计划生育的信息,对医疗卫生规划、卫生决策和卫生公平研究具有重要价值。

Investigations of moiréartifacts induced by flux fluctuations in x-ray dark-field imaging

X-ray dark-field imaging using a grating interferometer has shown potential benefits for a variety of applications in recent years.X-ray dark-field image is commonly retrieved by using discrete Fourier transform from the acquired phasestepping data.The retrieval process assumes a constant phase step size and a constant flux for each stepped grating position.However,stepping errors and flux fluctuations inevitably occur due to external vibrations and/or thermal drift during data acquisition.Previous studies have shown that those influences introduce errors in the acquired phase-stepping data,which cause obvious moiréartifacts in the retrieved refraction image.This work investigates moiréartifacts in x-ray dark-field imaging as a result of flux fluctuations.For the retrieved mean intensity,amplitude,visibility and dark-field images,the dependence of moiréartifacts on flux fluctuation factors is theoretically derived respectively by using a first-order Taylor series expansion.Results of synchrotron radiation experiments verify the validity of the derived analytical formulas.The spatial frequency characteristics of moiréartifacts are analyzed and compared to those induced by phase-stepping errors.It illustrates that moiréartifacts can be estimated by a weighted mean of flux fluctuation factors,with the weighting factors dependent on the moiréphase and different greatly for each retrieved image.Furthermore,moiréartifacts can even be affected by object’s features not displayed in the particular contrast.These results can be used to interpret images correctly,identify sources of moiréartifacts,and develop dedicated algorithms to remove moiréartifacts in the retrieved multi-contrast images.

Analysis of refraction and scattering image artefacts in x-ray analyzer-based imaging

X-ray analyzer-based imaging(ABI) is a powerful phase-sensitive technique that can provide a wide dynamic range of density and extract useful physical properties of the sample. It derives contrast from x-ray absorption, refraction, and scattering properties of the investigated sample. However, x-ray ABI setups can be susceptible to external vibrations, and mechanical imprecisions of system components, e.g., the precision of motor, which are unavoidable in practical experiments. Those factors will provoke deviations of analyzer angular positions and hence errors in the acquired image data.Consequently, those errors will introduce artefacts in the retrieved refraction and scattering images. These artefacts are disadvantageous for further image interpretation and tomographic reconstruction. For this purpose, this work aims to analyze image artefacts resulting from deviations of analyzer angular positions. Analytical expressions of the refraction and scattering image artefacts are derived theoretically and validated by synchrotron radiation experiments. The results show that for the refraction image, the artefact is independent of the sample’s absorption and scattering signals. By contrast, artefact of the scattering image is dependent on both the sample’s refraction and scattering signals, but not on absorption signal.Furthermore, the effect of deviations of analyzer angular positions on the accuracy of the retrieved images is investigated,which can be of use for optimization of data acquisition. This work offers the possibility to develop advanced multi-contrast image retrieval algorithms that suppress artefacts in the retrieved refraction and scattering images in x-ray analyzer-based imaging.

Percutaneous Removal of Benign Breast Lesions with an Ultrasound-guided Vacuum-assisted System:Influence Factors in the Hematoma Formation

Objective To explore the influence factors in hematoma formation after removing benign breast lesions with an ultrasound-guided vacuum-assisted system.Methods A total of 232 females with 312 benign breast masses received excisional biopsy with ultrasoundguided vacuum-assisted system.The pathology of patients,results of hematoma development and outcome,influence factors for hematoma occurrence(nodule size,nodule location,number of nodule,breast shape,menstrual period,efficacy time of bandage,and application of hemostatic agents during the procedure) were recorded.Results Pathologic examination revealed fibroadenomas in 138 lesions,fibroadenosis in 127 lesions,intraductal papillomas in 39 lesions,inflammatory change in 4 lesions,retention cyst of the breast in 3 lesions,and benign phyllodes tumor in 1 lesion.Thirty hematomas were observed in patients(9.6%).Finally,97.0%hematomas were absorbed completely within 6 months follow-up.The incidence rates of hematoma were increased by 24.7%,10.0%,63.2%,13.9%in the nodule diameter larger or equal to 25 mm group,removal of larger or equal to two nodules once time from one patient group,menstrual period group,and larger and loose breast group,respectively(all P<0.05).However,the incidences were decreased by 60.6%in the bandage performed for 12-24 hours or beyond 24 hours group(P<0.05).The multiple logistic regression models revealed that nodule size(x^2=15.227,P<0.001),number of nodule(x^2=7.767,P=0.005),menstrual period(x^2=24.530,P<0.001),and breast shape(x^2=9.559,P=0.002) were independent risk factors associated with hematoma occurrence,but efficacy time of bandage was a protective factor associated with hematoma occurrence.Conclusion The occurrence of hematoma after the minimally invasive operation was associated with nodule size,number of nodule,menstrual period,breast shape,and efficacy time of bandage.

Two-dimensional shallow water equations with porosity and their numerical scheme on unstructured grids

In this study, porosity was introduced into two-dimensional shallow water equations to reflect the effects of obstructions, leading to the modification of the expressions for the flux and source terms. An extra porosity source term appears in the momentum equation. The numerical model of the shallow water equations with porosity is presented with the finite volume method on unstructured grids and the modified Roe-type approximate Riemann solver. The source terms of the bed slope and porosity are both decomposed in the characteristic direction so that the numerical scheme can exactly satisfy the conservative property. The present model was tested with a dam break with discontinuous porosity and a flash flood in the Toce River Valley. The results show that the model can simulate the influence of obstructions, and the numerical scheme can maintain the flux balance at the interface with high efficiency and resolution.

Quantitative coherence analysis of dual phase grating x-ray interferometry with source grating

Dual phase grating x-ray interferometry is compatible with common imaging detectors,and abandons the use of an absorption analyzer grating to reduce the radiation dose.When using x-ray tubes,an absorbing source grating must be introduced into the dual phase grating interferometer.In order to attain a high fringe visibility,in this work we conduct a quantitative coherence analysis of dual phase grating interferometry to find how the source grating affects the fringe visibility.Theoretical analysis shows that with the generalized Lau condition satisfied,the fringe visibility is influenced by the duty cycle of the source grating and the transmission through the grating bar.And the influence of the source grating profile on the fringe visibility is independent of the phase grating type.Numerical results illustrate that the maximum achievable fringe visibility decreases significantly with increasing transmission in the grating bar.Under a given transmission,one can always find an optimal duty cycle to maximize the fringe visibility.These results can be used as general guidelines for designing and optimizing dual phase grating x-ray interferometers for potential applications.

Output speed and flow of double-acting double-stator multi-pumps and multi-motors

The primary focus of this study was to investigate a series of novel motors and pumps,based on a new type of structure called double-stator.The double-stator structure can be used as pump or motor just based on the application requirements.A certain amount of pumps or motors can be formed in one shell,and these sub-pumps or sub-motors can work alone or be combined without influence on each other.So this kind of double-stator pump(motor) is called a multi-pump(multi-motor).Through the analysis of multifarious connection modes of the double-acting double-stator multi-pumps and multi-motors,the mathematical expressions of the output flow rate and the rotational speed are acquired.The results indicate that a quantity of different flow rates can be provided by one fixed-displacement multi-pump under the condition of unalterable driven speed by electromotor.Likewise,when supplied by settled input flow,without complex variable mechanism,the functions of double-speed,multiple-speed,and even differential connection can be obtained by employing the use of a double-stator multi-motor.The novel hydraulic transmission is made of such a double-stator multi-pump and multi-motor,and has broad application prospects.

Monitoring Value of Multimodal Magnetic Resonance Imaging in Disease Progression of Amyotrophic Lateral Sclerosis: A Prospective Observational Study

Background: Ongoing efforts have been made to identify new neuroimaging markers to track amyotrophic lateral sclerosis (ALS) progression. This study aimed to explore the monitoring value of multimodal magnetic resonance imaging (MRI) in the disease progression of ALS. Methods: From September 2015 to March 2017, ten patients diagnosed with ALS in Peking Union Medical College Hospital completed head MRI scans at baseline and during follow-up. Multimodal MRI analyses, including gray matter (GM) volume measured by voxel-based morphometry;cerebral blood flow (CBF) evaluated by arterial spin labeling;functional connectivity, including low-frequency fluctuation (fALFF) and regional homogeneity (ReHo), measured by resting-state functional MRI;and integrity of white-matter (WM) fiber tracts evaluated by diffusion tensor imaging, were performed in these patients. Comparisons of imaging metrics were made between baseline and follow-up using paired t-test. Results: In the longitudinal comparisons, the brain structure (GM volume of the right precentral gyri, left postcentral gyri, and right thalami) and perfusion (CBF of the bilateral temporal poles, left precentral gyri, postcentral gyri, and right middle temporal gyri) in both motor and extramotor areas at follow-up were impaired to different extents when compared with those at baseline (all P < 0.05, false discovery rate adjusted). Functional connectivity was increased in the motor areas (fALFF of the right precentral gyri and superior frontal gyri, and ReHo of right precentral gyri) and decreased in the extramotor areas (fALFF of the bilateral middle frontal gyri and ReHo of the right precuneus and cingulate gyri) (all P < 0.001, unadjusted). No significant changes were detected in terms of brain WM measures. Conclusion: Multimodal MRI could be used to monitor short-term brain changes in ALS patients.

Continuous positive airway pressure in children with severe pneumonia: a meta-analysis

Pneumonia is the leading cause of death among children aged 1-59 months worldwide[1].WHO recommends providing low flow oxygen by nasal cannula in pediatric patients with oxygen saturation<90%[2].With the provision of oxygen supplementation,some children still require further respiratory support such as mechanical ventilation due to the failure to maintain oxygen saturation and severe respiratory distress[3,4].However,mechanical ventilation may result in ventilator-induced lung injury[5].As a simple and minimally invasive technique,continuous positive airway pressure(CPAP)has been used in children with severe pneumonia[6,7],but its effect and safety are uncertain.Therefore,we performed a meta-analysis that compared CPAP with standard therapy or low-flow oxygen to figure out the effects and safety of CPAP.

Superior Mesenteric Artery Syndrome in a 20-year-old Athletic Female with Abdominal Pain

To the Editor： A 20-year-old female college student and soccer player presented to the Emergency Department with acute onset of abdominal pain, nausea, and vomiting. On the morning of presentation, she woke up with sudden onset of epigastric pain that was constant and 10/10 in severity. The patient denied any obstipation, constipation, diarrhea, any recent trauma to the abdomen, or any potential inciting event. Of note, the patient did endorse previous episodes of postprandial epigastric pain, but it was never this severe. Her past medical and surgical history was unremarkable.

Differences in East Asian summer monsoon responses to Asian aerosol forcing under different emission inventories

Opposite anthropogenic aerosol emission trends in Asia can lead to different responses of the climate.Here,we examined the responses of the East Asian summer monsoon(EASM)to changes in Asian anthropogenic aerosol emissions during 2006-2014 using a global aerosol/atmospheric chemistry-climate coupled model(BCC_AGCM2.0_CUACE/Aero)with two sets of emission inventories:the Community Emissions Data System(CEDS)inventory adopted by the Coupled Model Intercomparison Project Phase 6(CMIP6)and the inventory developed at Peking University(PKU).The changes in Asian anthropogenic aerosol emissions during 2006-2014 between the two inventories were remarkably different,particularly in eastern China where completely opposite trends were observed(i.e.,increase in the CEDS inventory,but significant reduction in the PKU inventory).The perturbation simulations with the Asian anthropogenic aerosol forcing from the two inventories showed opposite changes in aerosol optical depth,aerosol effective radiative forcing,cloud liquid water path,and total cloud cover in eastern China.The simulated‘dipole-type’changes(i.e.,increase in India but decrease in China)in Asian aerosols and the resulting changes in local radiation budget under the PKU inventory were consistent with the corresponding observations.The summer surface temperatures over eastern China decreased by 0-0.4 K because of the Asian anthropogenic aerosol forcing under the CEDS inventory,while they increased by 0.1-0.8 K under the PKU inventory.The weakening of the EASM index caused by the Asian aerosol forcing under the PKU inventory was twofold greater than that under the CEDS inventory(−0.4 vs.−0.2).The Asian‘dipole-type’aerosol forcing contributed to the observed summer‘southern drought and northern flood’phenomenon in eastern China during 2006-2014.The slow ocean-mediated response to the regional‘dipole-type’aerosol forcing dominated the weakening of the EASM circulation and the precipitation changes in eastern China in the total response.This study further confirms that the biases in anthropogenic aerosol emissions over Asia can affect the CMIP6-based regional climate attribution.