Given the sudden outbreak of the COVID-19 pandemic, a timely study on the impacts of and policy response to the pandemic on rural poverty in China is critically important because China has aimed to ...completely eradicate extreme poverty by the end of 2020. This paper uses data from the latest round of a nationally representative household panel survey to examine the impacts of the pandemic on rural poverty in China. Our data show that 11.9% of sample households were ever officially registered as poor households between 2013 and 2019, and this poverty incidence fell to 2.7% by the end of 2019. In the middle February of 2020, 23% of the households who have graduated from poverty since 2013 perceived that they would fall back into poverty due to the COVID-19. Among those never poor households, 7.1% perceived that they would possibly fall into poverty due to the pandemic. Results from both descriptive and multivariate analyses consistently show the interruptions that the pandemic caused in off-farm employment is an important channel that led households to perceive of falling back into or falling into poverty. We also find households in the bottom four quintiles when ranked in terms of household income per capita are much more likely to perceive themselves of falling back into or falling into poverty during this pandemic than those in the richest quintile. Meanwhile, our results show that the education and age of household heads, as well as being from Hubei Province matter in explaining household perception about falling back into or falling into poverty in some cases but not all. The paper concludes with a set of policy responses that China has taken to mitigate the impact of COVID-19 pandemic on poverty alleviation.
Single-stranded DNA (ssDNA)-binding proteins (SSBs) play a central role in cells by participating in DNA metabolism, including replication, repair, recombination, and replication fork restart. SSBs ...are essential for cell survival and thus an attractive target for potential anti-pathogen chemotherapy. In this study, we determined the crystal structure and examined the size of the ssDNA-binding site of an SSB from
serovar Typhimurium LT2 (SeSSB), a ubiquitous opportunistic pathogen which is highly resistant to antibiotics. The crystal structure was solved at a resolution of 2.8 Å (PDB ID 7F25), indicating that the SeSSB monomer possesses an oligonucleotide/oligosaccharide-binding (OB) fold domain at its N-terminus and a flexible tail at its C-terminus. The core of the OB-fold in the SeSSB is made of a six-stranded β-barrel capped by an α-helix. The crystal structure of the SeSSB contained two monomers per asymmetric unit, which may indicate the formation of a dimer. However, the gel-filtration chromatography analysis showed that the SeSSB forms a tetramer in solution. Through an electrophoretic mobility shift analysis, we characterized the stoichiometry of the SeSSB complexed with a series of ssDNA dA homopolymers, and the size of the ssDNA-binding site was determined to be around 22 nt. We also found the flavanonol taxifolin, also known as dihydroquercetin, capable of inhibiting the ssDNA-binding activity of the SeSSB. Thus, this result extended the SSB interactome to include taxifolin, a natural product with a wide range of promising pharmacological activities.
The objective of this study was to build models to predict complete pathologic response (pCR) after neoadjuvant chemoradiotherapy (nCRT) in esophageal squamous cell carcinoma (ESCC) patients using ...radiomic features. A total of 55 consecutive patients pathologically diagnosed as having ESCC were included in this study. Patients were divided into a training cohort (44 patients) and a testing cohort (11 patients). The logistic regression analysis using likelihood ratio forward selection was performed to select the predictive clinical parameters for pCR, and the least absolute shrinkage and selection operator (LASSO) with logistic regression to select radiomic predictors in the training cohort. Model performance in the training and testing groups was evaluated using the area under the receiver operating characteristic curves (AUC). The multivariate logistic regression analysis identified no clinical predictors for pCR. Thus, only radiomic features selected by LASSO were used to build prediction models. Three logistic regression models for pCR prediction were developed in the training cohort, and they were able to predict pCR well in both the training (AUC, 0.84-0.86) and the testing cohorts (AUC, 0.71-0.79). There were no differences between these AUCs. We developed three predictive models for pCR after nCRT using radiomic parameters and they demonstrated good model performance.
The electrophoresis and electric conduction of a suspension of charged spherical particles in a salt‐free solution are analyzed by using a unit cell model. The linearized Poisson‐Boltzmann equation ...(valid for the cases of relatively low surface charge density or high volume fraction of the particles) and Laplace equation are solved for the equilibrium electric potential profile and its perturbation caused by the imposed electric field, respectively, in the fluid containing the counterions only around the particle, and the ionic continuity equation and modified Stokes equations are solved for the electrochemical potential energy and fluid flow fields, respectively. Explicit analytical formulas for the electrophoretic mobility of the particles and effective electric conductivity of the suspension are obtained, and the particle interaction effects on these transport properties are significant and interesting. The scaled zeta potential, electrophoretic mobility, and effective electric conductivity increase monotonically with an increase in the scaled surface charge density of the particles and in general decrease with an increase in the particle volume fraction, keeping each other parameter unchanged. Under the Debye‐Hückel approximation, the dependence of the electrophoretic mobility normalized with the surface charge density on the ratio of the particle radius to the Debye screening length and particle volume fraction in a salt‐free suspension is same as that in a salt‐containing suspension, but the variation of the effective electric conductivity with the particle volume fraction in a salt‐free suspension is found to be quite different from that in a suspension containing added electrolyte.
Indoor service robots accumulate errors when its own reference map differs from the true environment such as when furniture has been rearranged in an area. This results in poor localization accuracy ...when pose estimation relies on outdated maps. Traditional methods address this issue by rebuilding the reference map from scratch. In this article, we propose a histogram of oriented depth model (HODM) and its extraction approach using laser rangefinders and RGBD cameras. HODM aims to provide a light and robust localization module so that mobile robots work in environments required by rearrangement from time to time. The key concept of HODM is based on using histogram-based model matching for estimating indoor primary structures and floor layouts. HODM localization will use an HODM map as a reference in scan matching, and the experimental results show that the localization error is lower than traditional non-HODM-based localization methods. In the same indoor location, the mapping process is only required once. The HODM approach presented in this article shows two major contributions. First, the localization error is lower even with an outdated reference map when compared with traditional localization methods, and, second, the computational time of HODM is fast. We validate this proposed method through numerical simulations and actual experiments in our laboratory using our experimental mobile robot developed in our NTU-iCeiA robotics laboratory.
This article develops a high-stiffness, high-precision, hybrid tool center point (TCP) mode and a skew force free model-based (SFFMB) synchronous gantry-type design for a hybrid gantry-robot machine. ...For the new SFFMB synchronous gantry-type design, newly developed active/passive control models are presented to prevent gantry skew. The force ratio between the slave and master axes is generated, and experimental results show that the driving currents for the master/slave linear motor axes are lower when the SFFMB synchronous control function is enabled. This function makes the machine move smoothly even when deviations from squareness occur. These design approaches aim to improve the accuracy and performance at high speed to reduce the working cycle time for a machine with multiple degrees of freedom. This article makes three contributions to the literature. First, by considering the skew force issue, a new SFFMB synchronous gantry-type design is proposed to prevent gantry skew phenomenon. Second, to ensure exact omnidirectional linear movement, a novel hybrid TCP mode is proposed to decouple coordinate transformations into individual translation and rotation components. Third, based on the SFFMB synchronous control strategy and the hybrid TCP mode, we propose an effective calibration method to enhance the TCP accuracy. The new SFFMB synchronous gantry-type design and the accurate hybrid TCP mode are experimentally verified and demonstrated using a hybrid gantry-robot machine developed in our laboratory, which is based on our proposed synchronous control strategy.
The objective of this paper is to have an intelligent service robot that not only autonomously estimates the environment structure but also simultaneously detects the commonly recognized ...symbols/signs in the building. The result is an information-enriched map constructed by the environment geometry from a laser ranger and the indoor indicators from visual image. To implement this enriched map, multisensor fusion techniques, i.e., covariance intersection and covariance union, are tactically utilized for robust pose association and sign estimation. Furthermore, an improved alignment technique is applied to promote the mapping precision in a single simultaneous localization and mapping process with the posterior convenience. Additionally, a 2.5-D environment enriched map has been rapidly constructed with the Mesa SwissRanger. We have successfully experimentally demonstrated the proof of concept and summarized it in the conclusion.
Atopic dermatitis (AD) is a chronic inflammatory cutaneous disease that affects 30.48% of young children; thus, there is a need for epidemiological studies in community settings. Web-based ...questionnaires (WBQs) are more convenient, time-saving, and efficient than traditional surveys, but the reliability of identifying AD through WBQs and whether AD can be identified without the attendance of doctors, especially in community or similar settings, remains unknown.
This study aimed to develop and validate a web-based instrument for infantile AD identification (electronic version of the modified Child Eczema Questionnaire eCEQ) and to clarify the possibility of conducting WBQs to identify infantile AD without the attendance of doctors in a community-representative population.
This study was divided into 2 phases. Phase 1 investigated 205 children younger than 2 years to develop and validate the eCEQ by comparison with the diagnoses of dermatologists. Phase 2 recruited 1375 children younger than 2 years to implement the eCEQ and verify the obtained prevalence by comparison with the previously published prevalence.
In phase 1, a total of 195 questionnaires were analyzed from children with a median age of 8.8 (IQR 4.5-15.0) months. The identification values of the eCEQ according to the appropriate rules were acceptable (logic rule: sensitivity 89.2%, specificity 91.5%, positive predictive value 97.1%, and negative predictive value 72.9%; statistic rule: sensitivity 90.5%, specificity 89.4%, positive predictive value 96.4%, and negative predictive value 75%). In phase 2, a total of 837 questionnaires were analyzed from children with a median age of 8.4 (IQR 5.2-14.6) months. The prevalence of infantile AD obtained by the eCEQ (logic rule) was 31.9% (267/837), which was close to the published prevalence (30.48%). Based on the results of phase 2, only 20.2% (54/267) of the participants identified by the eCEQ had previously received a diagnosis from doctors. Additionally, among the participants who were not diagnosed by doctors but were identified by the eCEQ, only 6.1% (13/213) were actually aware of the possible presence of AD.
Infantile AD can be identified without the attendance of doctors by using the eCEQ, which can be easily applied to community-based epidemiological studies and provide acceptable identification reliability. In addition, the eCEQ can also be applied to the field of public health to improve the health awareness of the general population.
In this paper, we present a biped walking trajectory generator based on the three-mass with angular momentum model using model predictive control. This approach aims to decrease the modeling error ...and decrease zero moment point (ZMP) horizon, so that high ZMP tracking accuracy and immediate generation are achieved. The contribution of this approach is the use of the three-mass with angular momentum model, the reduction of modeling error, and the enhancement of ZMP tracking performance and walking stability. This method allows online walking pattern modification, so that unexpected emergency can be dealt with by immediately changing trajectories. In addition, this proposed method is validated through numerical simulations, and the proof-of-concept experiments are conducted using an experimental robot developed in our laboratory.
An indoor localization and monitoring system for robots and people is an important issue in robotics research. Although several monitoring systems are currently under development by previous ...investigators, these issues remain significant difficulties. For instance, the pyroelectric IR (PIR) system provides less accurate information of human location and is restricted when there are multiple targets. Furthermore, the RF localization system is constrained by its limited accuracy. In this study, we propose an indoor localization and monitoring system based on a wireless and PIR (WPIR) sensory fusion system. We develop a sensor-network-based localization method called the WPIR inference algorithm. This algorithm determines the fused position from both the PIR localization system and RF signal localization system, which utilize the received signal strength propagation model. We have developed and experimentally demonstrated a WPIR sensory fusion system, which can be successfully applied in localizing multiple targets based on two robots and two people in this study. With an accurate localization mechanism for the indoor environment, the provision of appropriate services for people can be realized.
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