Penalized Quadratic Inference Function-Based Variable Selection for Generalized Partially Linear Varying Coefficient Models with Longitudinal Data

Semiparametric generalized varying coefficient partially linear models with longitudinal data arise in contemporary biology, medicine, and life science. In this paper, we consider a variable selection procedure based on the combination of the basis function approximations and quadratic inference functions with SCAD penalty. The proposed procedure simultaneously selects significant variables in the parametric components and the nonparametric components. With appropriate selection of the tuning parameters, we establish the consistency, sparsity, and asymptotic normality of the resulting estimators. The finite sample performance of the proposed methods is evaluated through extensive simulation studies and a real data analysis

A Novel Modification Method of Stainless-steel Electrode for Sulfur Preparation by Reduction of Sulfur Dioxide

A novel modification method of stainless-steel electrode for reduction of sulfur dioxide to prepare sulfur was reported. Sulfur dioxide can spontaneously react with modified stainless-steel electrode at a rate of 12.77 mA/cm2 to produce sulfur under acidic conditions without additional energy. Evidence was found for the destruction of passive film on the stainless-steel surface in the process of modification which leads to the open circuit potential of stainless-steel electrode shift negatively to the reduction potential range of sulfur dioxide. When modified stainless steel was used as cathode in electrolysis, the contributions of impressed current and redox reaction made the sulfur yield up to 88% within 3 hours

Study on the Mineralogical and Geochemical Characteristics of Arsenic in Permian Coals: Focusing on the Coalfields of Shanxi Formation in Northern China

The Huainan Coalfield is a typical multi-coal seam coalfield. In order to systematically investigate the distribution, occurrence, and integration of arsenic (As) in Shanxi coal, 26 coal samples and three rock samples were collected in the No. 1 coal seam of Huainan coalfield. The minerals, major element oxides, and As were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), polarized light microscopy, X-ray fluorescence spectroscopy (XRF) and inductively coupled plasma-mass spectrometry (ICP-MS). The results indicated that the coals of Shanxi Formation were characterized by very low ash yields and low total sulfur contents. The identified minerals by XRD in the studied coals are dominated by kaolinite, quartz, calcite, and a lesser amount of pyrite. The As content ranges from 10.33 mg/kg to 95.03 mg/kg, with an average of 44.74 mg/kg. Compared with world coals, the studied coals have higher contents of As, which are characterized by enrichment. Based on statistical analyses, As shows an affinity to ash yield and possible association with silicate minerals. The contents of As in all occurrence fractions were ranked from high to low as follows: residual > Fe-Mn oxides > organic > exchangeable > carbonate. Using B, w(Sr)/w(Ba) and w(B)/w(Ga) geochemical parameter results to invert the depositional environment of the Huainan Shanxi Formation, a suitable coal-forming environment can cause relatively enriched As in coal

Profile inference on partially linear varying-coefficient errors-in-variables models under restricted condition

In this paper, we investigate the estimation and testing problems of partially linear varying-coefficient errors-in-variables (EV) models under additional restricted condition. The restricted estimators of parametric and nonparametric components are established based on modified profile least-squares method, and their asymptotic properties are also studied under some regularity conditions. Moreover, the modified profile Lagrange multiplier test statistic is constructed under additional restricted condition. It is shown that the modified profile Lagrange multiplier test statistic is asymptotically distribution-free and follows a Chi-squared distribution under the null hypothesis. Some simulation studies are carried out to assess the performance of the proposed methods. A real dataset is analyzed for illustration.Partially linear varying-coefficient models Errors-in-variables Restricted estimators Modified profile Lagrange multiplier test Confidence region

Search in One\u27s Hand: How Users Search a Mobile Library Catalog

With the rapid growth of mobile devices, mobile websites become an important channel of library resources and services. The mobile catalog is often significantly different from its desktop version in interface and features, but few studies of library catalog search behavior have been focused on mobile catalog searches. We present a study on user search behavior with a mobile library catalog based on transaction log analysis. We compared mobile and desktop catalog search behaviors and highlighted the similarities and differences, which could provide important evidence for improving mobile library catalogs\u27 search performance and usability

Multicropping Pattern Reveals Human Adaptation at the Wanbei Site (ca. 5.7–4.4 ka cal. BP) in the Middle and Lower Huai River Valley, China

The middle and lower Huai River Valley, located between the Yangtze and Yellow Rivers, was a key transitional zone for the northward spread of rice and southward migration of millet agriculture in central-eastern China during the Holocene. Knowing when millets spread here, how they were combined with rice in mixed farming, the reasons for their spread, and the temporal variation of cropping patterns is of crucial significance to the development of our understanding of ancient adaptation strategies adopted by human societies in response to climatic and cultural changes. Focusing on crops, phytolith analyses of the soil samples, in tandem with radiocarbon dating from the Wanbei site, reveal evidence of a multicropping pattern of combining rice (Oryza sative), broomcorn millet (Panicum miliaceum), and foxtail millet (Setaria italica) during the Dawenkou culture period between 5720 and 4426 cal. BP in the middle and lower Huai River Valley, China. The data show that rice was always the principal crop of the pattern, and that domesticated rice was developed during the early and middle Dawenkou culture periods. However, its domestication rate became lower during the late Dawenkou culture period. Broomcorn millet and foxtail millet with domesticated traits appeared only in lower proportions of the total produced throughout the period. The proportions of rice and foxtail millet increased slightly, while the proportions of broomcorn millet decreased over time. Finally, the formation of the multicropping pattern at Wanbei may have been primarily influenced by both the warm and wet climatic environment and the cultural exchange and communication between the Haidai region and the middle and lower Huai River Valley during the Dawenkou culture period. The findings in this paper may not only contribute to mapping the spatiotemporal route for the northward expansion of rice agriculture and southward spread of millet agriculture, but also assist in understanding the human adaptation strategies employed in eastern China during the Holocene

Tracing sulfate sources and transformations of surface water using multiple isotopes in a mining-rural-urban agglomeration area

Rapid urbanization and mining activities are exacerbating sulfate (SO42-) pollution in surface water, and the information on its sources and transformations is crucial for understanding the sulphur cycle in mining areas. In this study, the SO42- in the surface water of Huaibei mining area were monitored and the main sources of pollution and biogeochemical processes were identified using stable isotopes (δD, δ18O-H2O, δ34S-SO42- and δ18O-SO42-) and water chemistry. The results demonstrated the SO42- content in the Huihe River and Linhuan subsidence water area (SWA) is higher than that in other rivers and SWAs, which exceeded the environmental quality standard of surface water. The SO42- content of different rivers and SWAs showed seasonal differences, and the dry season was higher than the wet season. In addition, the SO42- in Tuohe River and Suihe River is primarily caused by urban sewage and agriculture activities, while in Zhonghu and Shuoxihu SWA is mainly contributed by natural evaporate dissolution. Notably, the input of SO42- in the Huihe River and Linhuan SWA caused by mining activities cannot be disregarded. The aerobic environment and isotopic fractionation of surface water indicate that sulfide oxidation is not the major cause of SO42- formation. This work has revealed the multiple sources and transformation mechanisms of SO42-, and provided a reference for the development of comprehensive management and effective remediation strategies of SO42- contamination in surface water around mining areas

Nitrogen fertilizer reduction in combination with Azolla cover for reducing ammonia volatilization and improving nitrogen use efficiency of rice

Background Excessive nitrogen (N) application rate with low N use efficiency (NUE) caused a considerable amount of N losses, especially ammonia volatilization (AV). Proper N fertilizer reduction (RN) could significantly reduce AV. However, continuous RN led to a nutrient deficiency in the soil and therefore negatively impacted the NUE and rice yield. Paddy Azolla, a good green manure, is considered as a promising measure to decrease AV and improve NUE and grain yield of rice. However, there is limited information on the integrated effects of RN and Azolla cover on the AV, NUE, and rice yield, especially in the highly fertilized rice-growing systems. Methods The experiment was conducted including eight treatments: the control (without N fertilizer and Azolla cover), Azolla cover without N fertilizer (A), farmer’s N application rate (FN), FN + Azolla cover (FNA), 15% RN from FN (RN15), RN15 + Azolla cover (RN15A). 30% RN from FN (RN30), RN30 + Azolla cover (RN30A). The integrated effects of N fertilizer reduction and Azolla cover on AV, NUE, and rice grain was evaluated. Results RN15A and RN30A substantially reduced total AV by 50.3 and 66.9% compared with FN, respectively, primarily due to the lower surface water ammonia concentrations and pH. RN improved the efficiency of Azolla cover on reducing AV, with 4.1–9.9% higher than for FN. Compared with the FN, RN15A and RN30A enhanced apparent N recovery efficiency (ANRE) by 46.5 and 39.1%, which might be responsible for the lower NH3 emission and the increased total N uptake / total chemical N applied. Furthermore, RN15A and RN30A reduced yield-scaled volatilization by 52.3 and 64.3% than for FN, respectively. Thus, combining 15–30% RN with Azolla cover may be a way to reduce AV and improve ANRE without decreasing rice grain yield