Characterizing pump line phase offset of a single-soliton Kerr comb by dual comb interferometry

We experimentally demonstrate phase retrieval of a single-soliton Kerr comb using electric field cross-correlation implemented via dual-comb interferometry. The phase profile of the Kerr comb is acquired through the heterodyne beat between the Kerr comb and a reference electro-optical comb with a pre-characterized phase profile. The soliton Kerr comb has a nearly flat phase profile, and the pump line is observed to show a phase offset which depends on the pumping parameters. The experimental results are in agreement with numerical simulations. Our all-linear approach enables rapid measurements (3.2 $\mu$s) with low input power (20 $\mu$W)

An Investigation of Cigarettes Smoking Behavior and Nicotine Dependence among Chinese Methamphetamine Users in Two Provinces

Objective. To survey cigarette behaviors and nicotine dependence among Chinese MA users, explore risk factors for high nicotine dependence, and analyze the relationship between nicotine dependence and MA-related euphoria and sexual impulse. Methods. A cross-sectional study, applying a self-designed questionnaire with the Fagerström Test for Nicotine Dependence (FTND) and Visual Analog Scale (VAS), was performed among 391 MA users in Beijing and Guangdong, China. Results. Most MA users were smokers, including 159 having high dependence on nicotine (HD users, FTND>5) and 197 low or medium dependent (LMD users, FTND≤5). Men or married users were more likely to be highly dependent than women or unmarried users. Higher MA dose and ever-use of ketamine or alcohol were associated with higher likelihood of high nicotine dependence. HD users reported significantly higher euphoria and stronger sexual impulse after using MA, indicated by higher VAS scores. Conclusions. Potential risk factors for high nicotine dependence among MA users may include male gender, being married, higher MA dosage, and ever-use of ketamine or alcohol, which should be taken into consideration in individualized health promotion on smoking cessation. Severe nicotine dependence was associated with stronger MA-related euphoria and sexual impulse and it should be confirmed by further studies

Landslide Inventory in the Downstream of the Niulanjiang River with ALOS PALSAR and Sentinel-1 Datasets

Landslide inventory and deformation monitoring is an essential task for human life and property security during the exploitation process of hydroelectric power resources. Synthetic Aperture Radar Interferometry (InSAR) is recognized as an effective tool for ground displacement monitoring with the advantages of wide coverage and high accuracy. In this study, we mapped the unstable slopes in the downstream of the Niulanjiang River with 22 ALOS PALSAR SAR images acquired from 2007 to 2011, and 90 Sentinel-1 SAR images from 2015 to 2019. A total of 94 active slopes are identified using a displacement map from the two datasets based on Small BAseline Subset (SBAS) InSAR analysis. By comparing the results from ALOS PALSAR and Sentinel-1 data stacks, we find that the number of active slopes increased dramatically. Several impact factors, e.g., earthquake, concentrated rainfall, and construction of hydropower stations, are discussed through time series analysis of typical landslides. Furthermore, nonlinear displacement of natural unstable slopes are found to be correlated with rainfall. A climate-driven model is used to qualify the relationship between rainfall and landslide displacement. Our results can provide valuable information for landslide detection and prevention

Landslide Inventory in the Downstream of the Niulanjiang River with ALOS PALSAR and Sentinel-1 Datasets

Landslide inventory and deformation monitoring is an essential task for human life and property security during the exploitation process of hydroelectric power resources. Synthetic Aperture Radar Interferometry (InSAR) is recognized as an effective tool for ground displacement monitoring with the advantages of wide coverage and high accuracy. In this study, we mapped the unstable slopes in the downstream of the Niulanjiang River with 22 ALOS PALSAR SAR images acquired from 2007 to 2011, and 90 Sentinel-1 SAR images from 2015 to 2019. A total of 94 active slopes are identified using a displacement map from the two datasets based on Small BAseline Subset (SBAS) InSAR analysis. By comparing the results from ALOS PALSAR and Sentinel-1 data stacks, we find that the number of active slopes increased dramatically. Several impact factors, e.g., earthquake, concentrated rainfall, and construction of hydropower stations, are discussed through time series analysis of typical landslides. Furthermore, nonlinear displacement of natural unstable slopes are found to be correlated with rainfall. A climate-driven model is used to qualify the relationship between rainfall and landslide displacement. Our results can provide valuable information for landslide detection and prevention

China’s water pricing reforms for irrigation: effectiveness and impact

Irrigation occupies a central position in China’s crop production. However, due to low per capita water resources, much worse, unevenly distributed over regions and time and the rapid increase of water diversions to non-irrigation sectors, irrigation water shortages have become a very serious problem. Without the adoption of effective measures this problem may even threaten China’s food security. Currently, irrigation efficiency is very low in general, irrigation water prices cannot fully recover water supply costs, and irrigation facilities are aging due to the lack of funding for O&M (operation & maintenance). Since water prices are regulated by the government, and not determined by the market, water prices did not work effectively in water allocation. The adoption of more economic incentive measures, such as increasing water prices, has become the main strategy of the Chinese government. Since 1 January 2004, China has carried out a new water pricing regulation. The main objectives of this regulation are that water price should be increased to fully recover water supply cost and that water should be treated as a market good. In non-irrigation sectors, the consensus is that water price could be charged to fully recover water supply cost. However, there is still controversy over the charge of irrigation water pricing. Indeed, increasing water price to fully recover supply cost may seriously affect grain production, and farmers’ income. Past studies in China on these issues mainly focused on the theoretical aspects of the problem, analyzing whether irrigation water price should be increased or not. Little studies have quantified the potential impact of the reforms in China. The following questions need to be elaborated: Are irrigation water pricing reforms effective?; What are the attitudes of the farmers towards the reforms?; How do farmers respond to water pricing reforms?; What comprehensive methods should be adopted to achieve the goals of the reforms? This project is based on the analysis of three case studies (Wudu, Jinghuiqu, and Shijin irrigation districts). Jinghuiqu is located in an arid region, Shijin is located in a semi-arid region and Wudu is located in the more humid Southwest. All the issues mentioned above, have been studied using econometric methods on the basis of the data gathered at the household, field canal, pump, and village level. The study reveals that the farmers’ ability to pay for irrigation water is still low and that the current water prices reflect the farmers’ willingness to pay, which implies that it is in fact very difficult to increase water prices further, let alone fully recover water supply cost. Farmers do not really participate in the irrigation management process, even at the field canal level, which limits the farmers’ willingness to pay. In areas confronted with severe water shortages, such as in the Jinghuiqu and Shijin irrigation districts, it is estimated that the volume of water use significantly affects wheat and maize yields, and the reduction of field water use will lead to the decline of grain production. In such cases, although increasing irrigation water price will encourage farmers to reduce water use, it may also force them to decrease their grain production. These measures affect the farmers’ revenues, which are largely dependent on crop production, thus increasing social inequities. Other policies need to protect weaker groups, such as poor farmers and farmers whose income mainly depends on crops. For instance, water property has still not been initialized and both irrigation bureaus and farmers lack incentives to adopt water-saving technologies. Initiating water property, expanding low-cost water-saving technologies, reforming irrigation management and fostering a water market are all important measures to achieve the policy goals of water-saving. At this point, it is necessary to emphasize that surface water price reforms may deeply affect groundwater resources use, especially in the conjunctive irrigation areas. Without the enhancement of groundwater resources management, saving surface water may lead to more overexploitation of groundwater resources, such was the case in the Jinghuiqu and Shijin irrigation districts. All in all, irrigation water price reforms represent a revolution when compared with traditional irrigation water resource management in China. Comprehensive and integrated policies should be carried out. China being such a large country, reforms cannot be uniform in all areas. Different areas, with different precipitation levels, should adopt different measures. In most parts of South China, volumetric water pricing is not appropriate, since this method requires large infrastructure investments. Collecting water fees on the basis of the farmers’ irrigated area is an alternative policy, although it requires involving farmers in the irrigation management process. Even in the northern regions, the standards of irrigation infrastructure should not be overemphasized and more attention should be paid to the cost-benefits analysis of irrigation investments

Characterizing pump line phase offset of a single-soliton Kerr comb by dual comb interferometry

We report phase retrieval of a single-soliton Kerr comb using electric field cross-correlation implemented via dual-comb interferometry. The phase profile of the Kerr comb is acquired through the heterodyne beat between the Kerr comb and an electro-optic comb with a pre-characterized phase profile. The soliton Kerr comb has a nearly flat phase profile, and the pump line is observed to show a phase offset which depends on the pumping parameters. The experimental results are in agreement with numerical simulations