The purpose of this study is to investigate the relationship between the Shannon entropy procedure and the Jensen–Shannon divergence (JSD) that are used as item selection criteria in cognitive ...diagnostic computerized adaptive testing (CD-CAT). Because the JSD itself is defined by the Shannon entropy, we apply the well-known relationship between the JSD and Shannon entropy to establish a relationship between the item selection criteria that are based on these two measures. To understand the relationship between these two item selection criteria better, an alternative way is also provided. Theoretical derivations and empirical examples have shown that the Shannon entropy procedure and the JSD in CD-CAT have a linear relation under cognitive diagnostic models. Consistent with our theoretical conclusions, simulation results have shown that two item selection criteria behaved quite similarly in terms of attribute-level and pattern recovery rates under all conditions and they selected the same set of items for each examinee from an item bank with item parameters drawn from a uniform distribution U(0.1, 0.3) under post hoc simulations. We provide some suggestions for future studies and a discussion of relationship between the modified posterior-weighted Kullback–Leibler index and the G-DINA (generalized deterministic inputs, noisy “and” gate) discrimination index.
Three induces are discussed to study the new dynamics properties both analytically and numerically for noise-induced Fitzhugh-Nagumo system; the three induces are as follows: Lyapunov exponent, the ...density distribution of trajectories and power spectrum; the numerical experiment indicated that the noise can induce the system to quite regular dynamics, including coherence resonance (in the case of uncoupling) and stochastic synchronization (in the case of coupling), noise can control the dynamics properties and some other new phenomena that the synchronization takes place only for some moderate noise intensity is also found for the first time.
By comprehensive analysis on the depositional system and on the main controlling factors of reservoirs in the Upper Triassic Xujiahe Formation in Sichuan Basin, the formation conditions of ...high-quality reservoirs under low-porosity and low-permeability background were studied. Except the transitional facies of Xu-1 member, other members of Xujiahe Formation are of terrestrial deposit, with alluvial fan, fluvial, fan-delta, fluvial-delta, and lacustrine deposit systems developed. Both the facies belt distribution and paleogeographic evolution are closely related to the regional tectonic movement. The original sedimentary facies belt (sandbar microfacies of main stem of braided river) and later denudation co-control the distribution of favorable reservoirs, and the quartz overgrowth and cementation is one of the controlling factors of the tight sandstones. The favorable reservoirs are mainly developed in the high-energy channel of delta plain, with medium-coarse sandstone as the best lithology. Combined with the analysis data of effective thickness and physical property, the favorable reservoirs in the Xu-2, 4, 6 members were evaluated and predicted comprehensively. The results indicate that the center and south of Sichuan are the most favorable reservoir distribution areas.
The karst area in Southwestern China is regarded as one of the most vulnerable ecological zones,characterized by low environmental capacity,high sensitivity of environmental variation,and low ...resilience of ecosystems to catastrophic variations. Soil fauna are important components of terrestrial ecosystems and play significant roles in maintaining the functions and stability of ecosystems. Based on meta-analysis,the present study evaluated the community characteristics of soil fauna in the Karst region,Southwest China,by analyzing the soil fauna species composition,their vertical distribution,and the influence of rocky desertification on soil fauna density and group numbers. Publications related to studies of soil fauna ecology studies carried out in the Karst region of Southwest China,which were published between January 1,1990 to October 31,2016,were retrieved from the Web of Science and China Knowledge Resource Integrated Database (CNKI) by using key words of soil fauna,soil animal,soil invertebrates,soil micro-arthropods,and karst both in Chinese and English.A total of 34 publications were selected for meta-analysis after literature filtering and quality evaluation. Results of metaanalysis,using R langue for statistical analysis,showed that soil fauna belonged to 5 phyla,15 classes,and 31 groups (classes or orders) in the Karst region of Southwest China. Soil macro-fauna were dominated by Hymenoptera and Coleoptera. Soil micro-fauna and soil meso-fauna were dominated by soil mites and collembolan. The density of soil microfauna and meso-fauna ranged from 6.0 × 103 to 1.9 × 104 individuals m-2. Soil fauna density and group numbers in summer and autumn were significantly higher than those in winter and spring. Rocky desertification in the Karst region,Southwest China,significantly decreased soil fauna density?P < 0. 01,MD =-7799. 6,95% CI:-10822. 24 --4776. 99? and group numbers?P < 0.01,MD =-1.9,95% CI:-2.89 --1.09?. Soil fauna individuals significantly decreased with soil depth?P < 0. 01,MD =-23. 4,95% CI:-0. 31 --0. 16?,showing an obvious phenomenon of soil surface layer accumulation. These results indicate that soil fauna group numbers were high,while the density was low. Nevertheless,soil fauna density was possibly underestimated because of the lack of soil nematodes data in most of the retrieved original publications. Because of the importance of soil fauna in ecosystems,greater attention should be paid to the soil fauna communities and their ecological functions,especially for biodiversity protection and the recovery of vulnerable ecosystems in the Karst region,Southwest China.
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•The adsorption mechanism between polyethylene glycol and Li2Sx was described.•PEG exhibits a chemical energy for shuttle effect of soluble Li2Sx.•N doped PEG exhibits a stronger ...binding energy for Li2Sx.
Lithium-sulfur batteries are deemed to be state-of-the-art secondary. However, some challenging issues like the shuttle of polysulfide prevent their commercial applications. Polyethylene glycol (PEG) was designed as the cathode or separator coating material to meet these challenges. Here, the relevant properties of PEG400 are systemically investigated using density functional theory computations. PEG400 has been showed to exhibit moderate binding energy for all the polysulfides except S8 because of chemical interactions. In particular, PEG400 was modified with N, and it was found that the adsorption effects between soluble Li2Sn and N-doped PEG400 were significantly improved.
We investigated the effect of entrepreneurial satisfaction on personal initiative using a sample of 581 entrepreneurs in China. Entrepreneurial satisfaction was classified into 2 dimensions: ...satisfaction with income and satisfaction with firm size. The moderating roles of institutional
trust and industry attractiveness were examined. We found that entrepreneur's personal initiative was lower for those who were more satisfied with their entrepreneurial progress, particularly satisfaction with firm size. Regarding the contingency effect, industry attractiveness assuaged the
negative relationship between entrepreneurial satisfaction and personal initiative, but institutional trust did not. The study promotes understanding about Chinese entrepreneurial behaviors and has relevant practical implications for policymakers and new venture management.
Testate amoebae are sensitive indicators of substrate moisture in peaflands. Over the last decades, they have been studied to reconstruct hydrological changes since the Holocene. However, these ...studies have been geographically restricted to North America and Europe. We conducted the first investigation of testate amoebae on the largest continental fresh water wetland in the Sanjiang Plain, China. The objectives of this study were to provide baseline data on the ecology of testate amoebae in the peatlands of Northeast China and to assess the potential of using them as environmental indicators in this ecosystem. We examined modem testate amoeba assemblages and species-environmental relationships at 46 microsites within 5 waterlogged depressions. The environmental parameters measured included： depth to water table, pH, and loss on ignition. The results showed that the dominant species were Trinema complanatum type, Euglypha rotunda type, Euglypha strigosa type, and Centropyxis cassis type. Redundancy analysis demonstrates that water table depth has the most important effect on testate amoeba assemblages, explaining 16.7% （p=0.002） of the total variance, pH was not a statistically significant factor for testate amoeba assemblages. Weighted averaging and weighted averaging partial least squares models were used to build transfer functions for depth to water table. The best performing transfer function was generated by the weighted averaging partial least squares model with an r^2LOSO of 0.62 and RMSEPLoso of 6.96 era. Results indicate that testate amoebae in waterlogged depression peatland have the potential to be used as indicators for hydrological changes and for palaeohydrologic reconstructions in the Sanjiang Plain.
Fine particulate matter (PM2.5) is an important haze index, and the researches on the evolutionary characteristics of the PM2.5 concentration will provide a fundamental and guiding prerequisite for ...the haze prediction. However, the past researchers were usually based on the overall time-domain evolution information of PM2.5. Since the temporal evolution of PM2.5 concentration is nonstationary, previous studies might neglect some important localization features that the evolution has various predominant periods at different scales. Therefore, we applied the wavelet transform to study the localized intermittent oscillations of PM2.5. First, we analyze the daily average PM2.5 concentration collected from the automatic monitoring stations. The result reveals that the predominant oscillation period does vary with time. There exist multiple oscillation periods on the scale of 14–32 d, 62–104 d, 105–178 d and 216–389 d and the 298d is the first dominant period in the entire evolutionary process. Moreover, we want to figure out whether the temporal characteristics of PM2.5 in the days with heavy haze also have localized intermittent periodicities. We select the hourly average PM2.5 concentration in 120 h when the haze pollution is serious. We find that the principal period has experienced two abrupt shifts and the energy at the 63-hour scale is the most powerful. The results in these two independent analyses come into the same conclusion that the multiscale features shown in the temporal evolution of PM2.5 cannot be ignored and may play an important role in the further haze prediction.
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•The evolutionary characteristics of PM2.5 vary with time.•Wavelet transform is powerful to capture the temporal features of PM2.5 concentration at different scales.•In the temporal characteristics of PM2.5 from 2014 to 2017, there exist multiple oscillation periods.•The time scale of 216-389 d is the predominant oscillation period of the PM2.5 daily evolution.•In the evolution of PM2.5 in 120 hours, the dominant period experiences two abrupt changes.
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