Search

An open question in migration research is how the removal of selective migration restrictions affects migrants' education decisions. I analyze this question in the Chinese context, in which the household registration system imposes selective rural-urban migration restrictions. The identification derives from a policy change that grants urban residency to a group of rural individuals based on their dates of birth. Using a regression discontinuity approach, I find that educational attainments for barely eligible rural residents decreased sharply after the reform. These effects are larger for males and for those able to permanently migrate to relatively rich areas. [ABSTRACT FROM AUTHOR]

The accurate detection and classification of diseased pine trees with different levels of severity is important in terms of monitoring the growth of these trees and for preventing and controlling disease within pine forests. Our method combines a DDYOLOv5 with a ResNet50 network for detecting and classifying levels of pine tree disease from remote sensing UAV images. In this approach, images are preprocessed to increase the background diversity of the training samples, and efficient channel attention (ECA) and hybrid dilated convolution (HDC) modules are introduced to DDYOLOv5 to improve the detection accuracy. The ECA modules enable the network to focus on the characteristics of diseased pine trees, and solve the problem of low detection accuracy caused by the similarities in color and texture between diseased pine trees and the complex backgrounds. The HDC modules capture the contextual information of targets at different scales; they increase the receptive field to focus on targets of different sizes, and address the difficulty of detection caused by large variations in the shapes and sizes of diseased pine trees. In addition, a low confidence threshold is adopted to reduce missed detections and a ResNet50 classification network is applied to classify the detection results into different levels of severity, in order to reduce the number of false detections and improve the classification accuracy. Our experimental results show that the proposed method improves the precision by 13.55%, the recall by 5.06% and the F1-score by 9.71% on 8 test images compared with YOLOv5. Moreover, the detection and classification results from our approach show that it outperforms classical deep learning object detection methods such as Faster R-CNN and RetinaNet. • A highly operable and low-cost UAV is used to monitor pine forest diseases. • A DDYOLOv5 network is constructed to detect diseased pine trees. • New modules are introduced to DDYOLOv5 to improve the feature extraction ability. • A ResNet50 network is used as the second phase to improve the accuracy. [ABSTRACT FROM AUTHOR]

The cylindrical resonator gyroscope (CRG) is a typical Coriolis vibratory gyroscope whose performance is determined by the Q factor and frequency mismatch of the cylindrical resonator. Enhancing the Q factor is crucial for improving the rate sensitivity and noise performance of the CRG. In this paper, for the first time, a monolithic cylindrical fused silica resonator with a Q factor approaching 8 ? 105 (ring-down time over 1 min) is reported. The resonator is made of fused silica with low internal friction and high isotropy, with a diameter of 25 mm and a center frequency of 3974.35 Hz. The structure of the resonator is first briefly introduced, and then the experimental non-contact characterization method is presented. In addition, the post-fabrication experimental procedure of Q factor improvement, including chemical and thermal treatment, is demonstrated. The Q factor improvement by both treatments is compared and the primary loss mechanism is analyzed. To the best of our knowledge, the work presented in this paper represents the highest reported Q factor for a cylindrical resonator. The proposed monolithic cylindrical fused silica resonator may enable high performance inertial sensing with standard manufacturing process and simple post-fabrication treatment. [ABSTRACT FROM AUTHOR]

Background: Health inequity is an important issue all around the world. The Chinese basic medical security system comprises three major insurance schemes, namely the Urban Employee Basic Medical Insurance (UEBMI), the Urban Resident Basic Medical Insurance (URBMI), and the New Cooperative Medical Scheme (NCMS). Little research has been conducted to look into the disparity in payments among the health insurance schemes in China. In this study, we aimed to evaluate the disparity in reimbursements for tuberculosis (TB) care among the abovementioned health insurance schemes. Methods: This study uses a World Health Organization (WHO) framework to analyze the disparities and equity relating to the three dimensions of health insurance: population coverage, the range of services covered, and the extent to which costs are covered. Each of the health insurance scheme's policies were categorized and analyzed. An analysis of the claims database of all hospitalizations reimbursed from 2010 to 2012 in three counties of Yichang city (YC), which included 1506 discharges, was conducted to identify the differences in reimbursement rates and out-of-pocket (OOP) expenses among the health insurance schemes. Results: Tuberculosis patients had various inpatient expenses depending on which scheme they were covered by (TB patients covered by the NCMS have less inpatient expenses than those who were covered by the URBMI, who have less inpatient expenses than those covered by the UEBMI). We found a significant horizontal inequity of healthcare utilization among the lower socioeconomic groups. In terms of financial inequity, TB patients who earned less paid more. The NCMS provides modest financial protection, based on income. Overall, TB patients from lower socioeconomic groups were the most vulnerable. Conclusion: There are large disparities in reimbursement for TB care among the three health insurance schemes and this, in turn, hampers TB control. Reducing the gap in health outcomes between the three health insurance schemes in China should be a focus of TB care and control. Achieving equity through integrated policies that avoid discrimination is likely to be effective. [ABSTRACT FROM AUTHOR]

Background: Tuberculosis (TB) patients in China encounter heavy financial burdens throughout the course of their treatment and it is unclear how China's health insurance systems affect the alleviation of this burden under the integrated approach. This study aimed to measure reimbursement for TB services under the New Cooperative Medical Scheme (NCMS) in rural China and to evaluate changes in catastrophic health expenditure (CHE) caused by the reimbursement policies. Methods: Reimbursement data were obtained from routine data systems for the NCMS in Yichang (YC) and Hanzhong (HZ). 1884 TB inpatients reimbursed by NCMS from 2010 to 2012 were included. Household surveys were conducted. A total of 494 TB patients under the NCMS were selected in this paper. 12 Focus Group Discussions (FGDs) were held. We measured the impact of the NCMS by counterfactual analysis, which analyzed the financial burden alleviation. Equity was assessed by Concentration Index (CI), and disaggregated by project sites. Results: TB inpatients were reimbursed with an effective reimbursement rate of 57.3 %. Average out-of-pocket (OOP) payments for outpatient and inpatient services after diagnosis were 1413 yuan and 430 yuan, and 3572 yuan and 3013 yuan in YC and HZ, respectively. The reimbursement level for TB outpatient care after diagnosis was very low due to a limited outpatient quota. TB patients in HZ incurred higher effective reimbursement rates, but the incidence of CHE remained higher. The reduction of CHE incidence after the NCMS showed no difference statistically (P > 0.05). The severity of CHE was alleviated slightly. CIs after reimbursement were all below zero and their absolute values were higher than those before reimbursement. Conclusions: Low reimbursement for TB patients could lead to heavy financial burden. Poor TB patients incurred high rates of CHE. The NCMS was found to be a protective factor for CHE, but the impact was modest and the equity of CHE did not improve. The NCMS reimbursement policies should be improved in the future to include a more comprehensive coverage of care. Supplemental programs may be necessary to expand coverage for TB care. [ABSTRACT FROM AUTHOR]

ABSTRACT A series of highly soluble aromatic polyimides with excellent thermal properties were fabricated by traditional two-step polycondensation reaction of dianhydride monomer 4,4′-(4,4′-isopropylidenediphenoxy)bis(phthalic anhydride) or 4,4-(hexafluoroisopropylidene)diphthalic anhydride with diamine monomer 1,3-bis(4-aminophenoxy)benzene or 1,3-bis(3-aminopropyl) tetramethyldisiloxane in N,N-dimethylacetylamide solvent. Results revealed that copolyimide of PI-4 containing trifluoromethyl and tetramethyldisiloxane possessed excellent solubility and remarkable thermal properties. PI-4 could dissolve well in common low boiling point solvents such as THF of up to 80 mg/mL and acetone of 40 mg/mL. Moreover, the 10% weight loss temperature of the PI-4 was 539°C and the Tg value of the PI-4 was 311°C. PI-4 might be easily cast into flexible and tough films applied in optoelectronic devices. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41713. [ABSTRACT FROM AUTHOR]

Obstructive sleep apnea (OSA) is an independent cardiovascular risk factor to which autonomic nervous dysfunction has been reported to be an important contributor. Ninety subjects recruited from the sleep center of a single medical center were divided into four groups: normal snoring subjects without OSA (apnea hypopnea index, AHI = 5, n = 11), mild OSA (5 ≤ AHI < 15, n = 10), moderate OSA (15 ≤ AHI < 30, n = 24), and severe OSA (AHI ≥ 30, n = 45). Demographic (i.e., age, gender), anthropometric (i.e., body mass index, neck circumference), and polysomnographic (PSG) data were recorded and compared among the different groups. For each subject, R-R intervals (RRI) from 10 segments of 10-minute electrocardiogram recordings during non-rapid eye movement sleep at stage N2 were acquired and analyzed for heart rate variability (HRV) and sample entropy using multiscale entropy index (MEI) that was divided into small scale (MEISS, scale 1-5) and large scale (MEILS, scale 6-10). Our results not only demonstrated that MEISS could successfully distinguish normal snoring subjects and those with mild OSA from those with moderate and severe disease, but also revealed good correlation between MEISS and AHI with Spearman correlation analysis (r = -0.684, p < 0.001). Therefore, using the two parameters of EEG and ECG, MEISS may serve as a simple preliminary screening tool for assessing the severity of OSA before proceeding to PSG analysis. [ABSTRACT FROM AUTHOR]

A series of hyperbranched polyimides were successfully synthesized by condensation polymerization of A2-type dianhydride monomer 2,2-bis(3,4-dicarboxylphenyl) hexafluoropropane dianhydride (6FDA) and B′B2-type triamine monomer 2,4,6-triaminopyrimidine (TAP). Polymers with different branching degrees (DB) and terminated groups were obtained by changing the monomer addition order and the monomer molar ratio. Fourier transform infrared spectroscopy and 1H NMR were used to verify the structure of the prepared polyimides, which indicated that the amino group still existed in all the products. The DB of the polymers indicated by 1H NMR increased from 30% to 79% with the molar ratio of TAP:6FDA decreasing from 1:1 to 1:2. The absolute molecular weights were measured by size-exclusion chromatography with multi-angle laser light-scattering detection, which suggested that the highest molecular weight would be obtained when the molar ratio of amino groups:anhydride groups of the monomers was 3:3.2. With the DB increasing, the d-spacing values indicated by wide angle X-ray diffraction increased from 5.15 Å to 5.68 Å and the UV − visible spectra of the polymers exhibited decreasing cut-off wavelengths. The 5% weight loss temperature in nitrogen increased with decreasing content of TAP monomer, and the glass transition temperatures of the obtained polyimides decreased from 282 °C to 258 °C with increasing DB. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Microbes play an essential role in ecosystem functions, including carrying out biogeochemical cycles, but are currently considered a black box in predictive models and all global biodiversity debates. This is due to (i) perceived temporal and spatial variations in microbial communities and (ii) lack of ecological theory explaining how microbes regulate ecosystem functions. Providing evidence of the microbial regulation of biogeochemical cycles is key for predicting ecosystem functions, including greenhouse gas fluxes, under current and future climate scenarios. Using functional measures, stable-isotope probing, and molecular methods, we show that microbial (community diversity and function) response to land use change is stable over time. We investigated the change in net methane flux and associated microbial communities due to afforestation of bog, grassland, and moorland. Afforestation resulted in the stable and consistent enhancement in sink of atmospheric methane at all sites. This change in function was linked to a niche-specific separation of microbial communities (methanotrophs). The results suggest that ecological theories developed for macroecology may explain the microbial regulation of the methane cycle. Our findings provide support for the explicit consideration of microbial data in ecosystem/climate models to improve predictions of biogeochemical cycles. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study is to evaluate the clinical, pathologic, and computed tomography (CT) and/or magnetic resonance imaging (MRI) findings of hepatic angiomyolipoma (HAML) and to improve the diagnostic efficacy of the tumor. Materials and methods: Clinical, pathologic, and imaging findings were retrospectively evaluated in 18 patients with HAML. Two patients underwent both CT and MRI, ten underwent CT alone, and six underwent MRI alone. Unenhanced and contrast-enhanced examinations were performed in all patients. Imaging characteristics, such as the lesion location, lesion diameter, presence of early draining veins, attenuation/signal intensity of the lesions on imaging, and enhancement pattern were reviewed. Results: There were 3 male and 15 female patients. HAML was seen as a well-defined, solitary mass on imaging with medium size (mean diameter, 5.9 cm). Fat was detected in ten patients. Calcification was noted in two patients and cystic degeneration was seen in one patient. Hepatic cirrhosis and capsule were not detected in all patients. The mean attenuation values exceeded 120 hounsfield units (HU) in 11 patients (91.7%). Peripherally decreasing enhancement rim as well as early draining vein was seen in 15 patients (83.3%). The early draining veins were all hepatic veins. Tumor vessels were noted in all patients. Conclusion: The presence of early draining vein, peripheral decreasing enhancement rim, and the absence of tumor capsule in the hypervascular hepatic tumor on CT and/or MRI together with normal alpha fetal protein may be helpful for the diagnosis of HAML in non-cirrhotic liver. [ABSTRACT FROM AUTHOR]

In this paper, a progressive design learning approach is proposed in the course of "applied electronics" to help students to develop system design skills through an optoelectronic sensing project. This project offers a progressive guideline to lead student teams to design, build, and troubleshoot their optoelectronic systems. Such a system contains a light-source current stabilizer, a photodiode amplifier, a microcontroller system (including input and output), and optomechanical devices. In this approach, students are motivated to learn the required knowledge and skills in a future professional capacity. Those skills include designing specification, realizing teamwork and communication, and developing a variety of optoelectronic sensing techniques. Through this project, an optoelectronic sensing system is established called a spatial radiance distribution measurement system for various light sources. In particular, this kind of system is useful and important for LED industries. The course evaluations have been obtained from class- mates and instructors and these results indicate that the objectives of this course are achieved. [ABSTRACT FROM AUTHOR]

This paper proposes a remote education system, Virtual Photonics Experiments Network (V-PEN), for teaching photonics experiments. In this approach, teaching and learning photonics become easier by the V-PEN. A design procedure for transforming real experiments to online experiments is also proposed, and a Michelson interference system as an example is employed to describe the procedures of the online experiments. This photonics experiment platform has been used for a semester. The survey of learners' feedback is also presented. [ABSTRACT FROM AUTHOR]

A micro ball tip is a core component of high precision coordinate measuring machines. The present micro ball tips cannot satisfy the high-precision measuring requirements of high aspect ratio microstructures due to their large diameter and low accuracy. In the previous study, we fabricated a micro monolithic tungsten ball tip by using arc discharge and surface tension principles. However, the fabrication success rate of forming a micro ball tip is less than 10%. In the present study, the Taguchi method has been applied to increase the fabrication success rate, and it has increased to 57.5%. The output response is evaluated in terms of the diameter, roundness, and center offset of the tungsten probe ball tips. The smaller-the-better signal-to-noise ratio is applied to analyze the influence of various parameters. The proposed parameters can be used to increase the fabrication success rate and accuracy of the monolithic probe ball tip. [ABSTRACT FROM AUTHOR]

Pt/SiO 2 -Al 2 O 3 (Pt/SA) is commonly used as diesel oxidation catalysts (DOC) in industry, but it could be seriously deactivated caused by H 2 O at long-term high temperature. In this paper, the inhibition mechanism of water on Pt/SA for NO oxidation was studied. The fresh Pt/SA (Pt/SA-F) was treated in an air flow with/without 10% H 2 O at 700 °C for 10 h to obtain the hydrothermally/thermally aged catalysts named as Pt/SA-HA and -A, respectively. NO oxidation tests showed that Pt/SA-HA had lower activity than Pt/SA-A. A series of characterizations proved H 2 O didn't affected Pt states and support structure as they were similar over two aged catalyst. 1H NMR and In-situ DRIFTS testified that water deactivation was a result of the acidity loss of catalysts, which inhibited the decomposition and desorption of reaction intermediate, finally resulting in bad NO oxidation activity. [Display omitted] • H 2 O inhibition mechanism at hydrothermal aging on Pt/SiO 2 -Al 2 O 3 for NO oxidation was investigated. • H 2 O leaded to the loss of Brönsted acid sites (like-bridge Al-OH-Si). • The loss of acid sites induced by H 2 O suppressed decomposition of nitrate species resulting in low NO activity. [ABSTRACT FROM AUTHOR]

The preferable conditions for tungsten filling and process parameters on tungsten film properties effect were investigated. The tungsten filling was improved obviously when H 2 flow is 1000 sccm, which is ascribed to slower deposition rate. Properly reducing H 2 flow could reduce tungsten deposition rate. For every H 2 flow reduction of 100 sccm, the film thickness was reduced by 58.5 Å. Decrease nucleation time to 7 s, it was conducive to tungsten filling as well. Researched showed that tungsten filling could be better optimized by reducing H 2 flow to 1000 sccm and nucleation time to 7 s simultaneously. The connect through (CT) holes contact resistance (R C) value of new conditions (H2 flow:1000 sccm, nucleation time:7 s) was lower than that of baseline (H2 flow:1600 sccm, nucleation time:10 s) no matter in the N-well or in the P-well, and the drop range was between 9% and 12%. The devices yield of new conditions was 93.7%, slightly higher than that of baseline. Unlabelled Image • For every H 2 flow reduction of 100 sccm, the film thickness was reduced by 58.5 Å. • The tungsten filling was improved obviously when H 2 flow is 1000 sccm and nucleation time is 7 s. • The CT holes R C value of new conditions is lower 9% ~ 12% than that of baseline. • The devices yield of new conditions is 93.7%, slightly higher than that of baseline. [ABSTRACT FROM AUTHOR]

Driven by climate change, periods of dominating glacial and fluvial erosion have both sculpted mountain ranges during the Quaternary. To understand the evolution of mountain landforms, there is considerable interest in knowing which erosion agent leads to more incision, how glacial thermal regime impacts erosion and landscape development, and whether glacial erosion can result in increased relief. To investigate the relative efficiency of glacial and fluvial erosion, and the influence of glacial thermal regime on topography, we compare two different mountain ranges–the Qionglai Shan (monsoonal temperate glaciation) and Lenglongling (subcontinental glaciation) in western China. We use a 1-D model to construct presumptive fluvial longitudinal profiles if glaciation had not occurred, and compare these with the actual glacial profiles to obtain relative incision rates of fluvial and glacial erosion. Results demonstrate that glacial incision is smaller than fluvial incision in Lenglongling and larger than fluvial incision in the Qionglai Shan, which may be influenced by different tectonics and glacier types. Topographic analysis of glacial and fluvial valleys with similar drainage areas show that glacial erosion results in valley widening, local valley relief increase induced by isostatic uplift, and slope gradient increase in Lenglongling. However, there is no local valley relief and slope increase observed in the Qionglai Shan, which may reflect slope process responses to threshold hillslope limiting the height above valley bottoms. • Different relative efficiency of glacial and fluvial incision on the Tibetan Plateau. • Relief increase is influenced by isostatic uplift and threshold hillslope angles. • Tectonic uplift and glacier types control incision rate variations for rivers and glaciers. [ABSTRACT FROM AUTHOR]

Selective attention modulates sensory cortical activity. It remains unclear how auditory cortical activity represents stimuli that differ behaviorally. We designed a cross-modality task in which mice made decisions to obtain rewards based on attended visual or auditory stimuli. We recorded auditory cortical activity in behaving mice attending to, ignoring, or passively hearing auditory stimuli. Engaging in the task bidirectionally modulates neuronal responses to the auditory stimuli in both the attended and ignored conditions compared to passive hearing. Neuronal ensemble activity in response to stimuli under attended, ignored and passive conditions are readily distinguishable. Furthermore, ensemble activity under attended and ignored conditions are in closer states compared to passive condition, and they share a component of attentional modulation which drives them to the same direction in the population activity space. Our findings suggest that the ignored condition is very different from the passive condition, and the auditory cortical sensory processing under ignored, attended and passive conditions are modulated differently. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to articles about publication pressure on physicians in China.