32 research outputs found
The influence of oceanographic processes on contourite features:A multidisciplinary study of the northern South China Sea
Contourite processes associated with the overflow of Pacific Deep Water within the Luzon Trough: Conceptual and regional implications
Overflows through oceanic gateways govern the exchange of water masses in the world's ocean basins. These exchanges also involve energy, salinity, nutrients, and carbon. As such, the physical features that control overflow can exert a strong influence on regional and global climate. Here, we present the first description of sedimentary processes generated by the overflow of Pacific Deep Water (OPDW). This mass flows southward at approximately 2000–3450 m water depth within the Luzon Trough (gateway) from the Pacific Ocean into the South China Sea. OPDW can be divided into: a) a lower, denser layer (including an associated weak counter-current), which has generated a large contourite depositional system (CDS-1) that includes large erosional (channel and moat), depositional (mounded and plastered drift), and mixed (terrace) contourite features along the trough bottom and walls, and b) an upper mixing layer, which has not generated any significant depositional or erosional contourite features. Where OPDW does not reach the seafloor, it is underlain by bottom water that circulates more sluggishly but has generated a second contourite depositional system (CDS-2) made of a large sheet-like drift. The OPDW flow has generally enhanced since the middle to late Miocene, except in the shallower northernmost corridor. In the deeper main trough, reductions in width and depth of the gateway by Taiwan orogenic events have likely accelerated the overflow. The latest significant enhancening may promote widespread development of contourite depositional systems along the South China Sea's lower continental slope and adjacent deeper areas. This work highlights the importance of gateway-confined overflows in controlling the morphology and sedimentary evolution of adjacent deep marine sedimentary systems. A clear understanding of overflow processes and their products is essential for decoding tectonic control in oceanographic or paleoceanographic processes
Improving detection and notification of tuberculosis cases in students in Shaanxi province, China: an intervention study
<p>Abstract</p> <p>Background</p> <p>Cooperation between different public and private health institutes involved in tuberculosis (TB) control has proven to enhance TB control in different settings. In China, such a mechanism has not been set up yet between Centers for Disease Control (CDCs) and university hospitals despite an increased TB incidence among students. This study aims to improve arrival of TB suspects identified by universities at the CDCs in order to manage them under standardized, directly observed treatment-short course (DOTS) conditions according to the National Tuberculosis Programme (NTP) guidelines.</p> <p>Methods</p> <p>Five matched pairs of universities were randomly assigned to the control and intervention group. After a baseline survey, a cooperation mechanism between local CDCs and university hospitals was set up in the intervention group. The effects on referral of TB suspects to the local CDC, tracing by the local CDC, and arrival at the local CDCs were assessed. Differences were tested by means of the chi-square test.</p> <p>Results</p> <p>During the baseline survey, the referral, tracing and arrival rates were between 37% and 46%. After implementation of the cooperation mechanism, these rates had not changed in the control group but increased significantly in the intervention group: the referral, tracing and arrival rates were 97%, 95%, and 93%, respectively.</p> <p>Conclusions</p> <p>It is feasible and effective to set up cooperation between CDCs and university hospitals to increase the number of TB suspects examined by CDCs and increase the number of TB patients treated under DOTS conditions. These public-public mix (PPM) activities should be expanded to cover all other university hospitals in China.</p
A novel control strategy for load converter of renewable energy under unbalanced loading
In this paper, a novel control strategy for the load converter supplying the unbalanced AC load in the renewable energy resources system is presented. This novel control strategy is implemented in the a-b-c coordinate, so reference-frame transformation from a-b-c coordinate to d-q-0 rotating coordinate and inverse transformation from d-q-0 rotating coordinate to a-b-c coordinate are not required which decreases the controller operation time comparing with conventional d-q-0 controller. The control algorithm results in balanced and sinusoidal load voltages under unbalanced AC loading. The unbalanced load is characterized in both the a-b-c and d-q-0 coordinates. Also, the mathematical model of the load converter in both a-b-c and d-q-0 coordinates is derived by using the average large signal model. Then, two control strategies for the load converter are presented. The first one uses the conventional d-q-0 controller to ensure the voltage and current regulation. The second one is this novel proposed control strategy based on the power conservation theory. The two control strategies have been applied to the reference voltages generation of the load converter. The performance of the load converter with these two control strategies is compared with each other. Simulation and experimental results show the validity and capability of the novel proposed control strategy
Analysis of land use dynamic econometric change in Chaohu basin from 2000 to 2015
Chaohu basin is located in the central economic belt, as an important part of the Yangtze River Basin. Based on the data of land use classification from 2000 to 2015, this paper makes a dynamic econometric analysis on the spatial structure of land use in Chaohu basin. The results show that: (1) The agricultural land has been in a downward trend from 2000 to 2015. However, the construction land has been increasing. From 2005 to 2010, the change of agriculture and the construction land have reached the maximum value, which are -0.279% and 1.814%, respectively. (2) During 2000-2015, every five years, the change of land use degree in Chaohu basin is greater than 0. The land use in the study area is in the development period, among which the change of land use from 2000 to 2005 is the largest. (3) The information entropy of land use in Chaohu basin is more than 1, and the change of information entropy is more than 0, which indicates that the information entropy is on the rise and the land use is in disorder. The results are of practical significance to the ecological security and optimal regulation of Chaohu Basin
A Hierarchical Representation Model Based on Longformer and Transformer for Extractive Summarization
Automatic text summarization is a method used to compress documents while preserving the main idea of the original text, including extractive summarization and abstractive summarization. Extractive text summarization extracts important sentences from the original document to serve as the summary. The document representation method is crucial for the quality of the generated summarization. To effectively represent the document, we propose a hierarchical document representation model Long-Trans-Extr for Extractive Summarization, which uses Longformer as the sentence encoder and Transformer as the document encoder. The advantage of Longformer as sentence encoder is that the model can input long document up to 4096 tokens with adding relative a little calculation. The proposed model Long-Trans-Extr is evaluated on three benchmark datasets: CNN (Cable News Network), DailyMail, and the combined CNN/DailyMail. It achieves 43.78 (Rouge-1) and 39.71 (Rouge-L) on CNN/DailyMail and 33.75 (Rouge-1), 13.11 (Rouge-2), and 30.44 (Rouge-L) on the CNN datasets. They are very competitive results, and furthermore, they show that our model has better performance on long documents, such as the CNN corpus
A Hierarchical Representation Model Based on Longformer and Transformer for Extractive Summarization
Automatic text summarization is a method used to compress documents while preserving the main idea of the original text, including extractive summarization and abstractive summarization. Extractive text summarization extracts important sentences from the original document to serve as the summary. The document representation method is crucial for the quality of the generated summarization. To effectively represent the document, we propose a hierarchical document representation model Long-Trans-Extr for Extractive Summarization, which uses Longformer as the sentence encoder and Transformer as the document encoder. The advantage of Longformer as sentence encoder is that the model can input long document up to 4096 tokens with adding relative a little calculation. The proposed model Long-Trans-Extr is evaluated on three benchmark datasets: CNN (Cable News Network), DailyMail, and the combined CNN/DailyMail. It achieves 43.78 (Rouge-1) and 39.71 (Rouge-L) on CNN/DailyMail and 33.75 (Rouge-1), 13.11 (Rouge-2), and 30.44 (Rouge-L) on the CNN datasets. They are very competitive results, and furthermore, they show that our model has better performance on long documents, such as the CNN corpus
Analysis, design and implementation of a non-isolated switched inductor/capacitor converter with low voltage spikes
In order to take the advantage of boost capability and filtering characteristics of the switched inductor/capacitor, a non-isolated switched inductor/capacitor (NSI/C) converter is proposed. The topological structure of the non-isolated switched inductor/capacitor converter is analyzed in detail, and the DC steady-state model is established in continuous conduction mode (CCM). The voltage gain of the converter and the stress of the switch in the converter are theoretically deduced and compared with the existing converters; the parameter design of the inductance and capacitance is calculated. The simulation model was built in MATLAB/Simulink, and the correctness of the theoretical calculation for the proposed converter was verified by simulation results. Finally, the experimental prototypes of the proposed converter and the non-isolated high step-up (NHS) converter were built. Through the comparison of experimental results, the feasibility and validity of the design scheme for the proposed converter are verified.Published versionThis work was financially supported by Key Research and Development Project of Hebei Province (18214302D) and (19212101D), Open Project of Provincial Collaborative Innovation Center of Industrial Energy-saving and Power Quality Control, Anhui Province (KFKT201504), Natural Science Foundation of Hebei Province (F2018205178)
Development and psychometric testing of the Knowledge, Attitudes and Practices (KAP) questionnaire among student Tuberculosis (TB) Patients (STBP-KAPQ) in China
Abstract Background TB outbreaking in schools is extremely complex, and presents a major challenge for public health. Understanding the knowledge, attitudes and practices among student TB patients in such settings is fundamental when it comes to decreasing future TB cases. The objective of this study was to develop a Knowledge, Attitudes and Practices Questionnaire among Student Tuberculosis Patients (STBP-KAPQ), and evaluate its psychometric properties. Methods This study was conducted in three stages: item construction, pilot testing in 10 student TB patients and psychometric testing, including reliability and validity. The item pool for the questionnaire was compiled from literature review and early individual interviews. The questionnaire items were evaluated by the Delphi method based on 12 experts. Reliability and validity were assessed using student TB patients (n = 416) and healthy students (n = 208). Reliability was examined with internal consistency reliability and test-retest reliability. Content validity was calculated by content validity index (CVI); Construct validity was examined using exploratory factor analysis (EFA) and confirmatory factor analysis (CFA); The Public Tuberculosis Knowledge, Attitudes and Practices Questionnaire (PTB-KAPQ) was applied to evaluate criterion validity; As concerning discriminant validity, T-test was performed. Results The final STBP-KAPQ consisted of three dimensions and 25 items. Cronbach’s α coefficient and intraclass correlation coefficient (ICC) was 0.817 and 0.765, respectively. Content validity index (CVI) was 0.962. Seven common factors were extracted by principal factor analysis and varimax rotation, with a cumulative contribution of 66.253%. The resulting CFA model of the STBP-KAPQ exhibited an appropriate model fit (χ2/df = 1.74, RMSEA = 0.082, CFI = 0.923, NNFI = 0.962). STBP-KAPQ and PTB-KAPQ had a strong correlation in the knowledge part, and the correlation coefficient was 0.606 (p < 0.05). Discriminant validity was supported through a significant difference between student TB patients and healthy students across all domains (p < 0.05). Conclusions An instrument, “Knowledge, Attitudes and Practices Questionnaire among Student Tuberculosis Patients (STBP-KAPQ)” was developed. Psychometric testing indicated that it had adequate validity and reliability for use in KAP researches with student TB patients in China. The new tool might help public health researchers evaluate the level of KAP in student TB patients, and it could also be used to examine the effects of TB health education
China: A qualitative study
to tuberculosis control and prevention in undergraduates in Xi’an