Variational Iteration Method for Solving the Generalized Degasperis-Procesi Equation

We introduce the variational iteration method for solving the generalized Degasperis-Procesi equation. Firstly, according to the variational iteration, the Lagrange multiplier is found after making the correction functional. Furthermore, several approximations of un+1(x,t) which is converged to u(x,t) are obtained, and the exact solutions of Degasperis-Procesi equation will be obtained by using the traditional variational iteration method with a suitable initial approximation u0(x,t). Finally, after giving the perturbation item, the approximate solution for original equation will be expressed specifically

Caffeine Reduces 11β-Hydroxysteroid Dehydrogenase Type 2 Expression in Human Trophoblast Cells through the Adenosine A2B Receptor

Maternal caffeine consumption is associated with reduced fetal growth, but the underlying molecular mechanisms are unknown. Since there is evidence that decreased placental 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) is linked to fetal growth restriction, we hypothesized that caffeine may inhibit fetal growth partly through down regulating placental 11β-HSD2. As a first step in examining this hypothesis, we studied the effects of caffeine on placental 11β-HSD2 activity and expression using our established primary human trophoblast cells as an in vitro model system. Given that maternal serum concentrations of paraxanthine (the primary metabolite of caffeine) were greater in women who gave birth to small-for-gestational age infants than to appropriately grown infants, we also studied the effects of paraxanthine. Our main findings were: (1) both caffeine and paraxanthine decreased placental 11β-HSD2 activity, protein and mRNA in a concentration-dependent manner; (2) this inhibitory effect was mediated by the adenosine A2B receptor, since siRNA-mediated knockdown of this receptor prevented caffeine- and paraxanthine-induced inhibition of placental 11β-HSD2; and (3) forskolin (an activator of adenyl cyclase and a known stimulator of 11β-HSD2) abrogated the inhibitory effects of both caffeine and paraxanthine, which provides evidence for a functional link between exposure to caffeine and paraxanthine, decreased intracellular levels of cAMP and reduced placental 11β-HSD2. Taken together, these findings reveal that placental 11β-HSD2 is a novel molecular target through which caffeine may adversely affect fetal growth. They also uncover a previously unappreciated role for the adenosine A2B receptor signaling in regulating placental 11β-HSD2, and consequently fetal development

Crop rotation model for contract farming with constraints on similar profits

In China, investors have contracts with smallholder farmers to plant organic vegetable crops. The objective of the smallholder farmers is to maximize profits per unit of farm area, and minimize the differences in profits between farmers. Farmers’ profits are a function of the crop rotation scheduling and the achieved prices. Here we propose an operational model that considers a crop rotation scheduling for an investor that offers contracts to many smallholder farmers. A heuristic algorithm was designed to identify the optimal rotation scheduling that would achieve both objectives of maximizing prices and minimizing the profit differences between smallholder farmers. Real data from a Chinese company was used to parameterize the model. Model results indicate that significant improvements in profits and farmers equality could be obtained if an optimal crop rotation scheduling would be used

Effects of Fe3P Addition on Sintering Behaviors and Magnetic Properties of Fe-P Alloys Sintered at Low Temperatures

In this paper, we demonstrate that trace amounts of P addition can activate the sintering of carbonyl powder and influence the magnetic properties of the sintered materials. Fe-x P (x = 0, 0.6, 0.8, 1.0, 1.2, 1.4, and 1.6 wt.%) samples were fabricated by doping carbonyl powder with different amounts of Fe3P. They were sintered at 1000 °C in argon for 2 h. The sintering of the Fe-0 wt.% P sample was interrupted by the ferrite-austenite transformation at 912 °C due to the low diffusion rate of the austenite. The addition of P can stabilize the ferrite, and suppress the ferrite-austenite transformation. Therefore, all the P-containing samples shrank continuously throughout the whole sintering process, which showed improved sintering densities compared to the P-free sample. However, the sintering density did not increase monotonously with increasing P content. The Fe-1.4 wt.% P and Fe-1.6wt.% P samples easily got oxidized during sintering, and the densification process was thus influenced by the P-containing oxide particles. As a result, the Fe-1.2 wt.% P sample exhibited the highest sintering density (7.664 g/cm3) and the best magnetic properties (coercive force 172 A/m)

Geochemical characteristics and sedimentary environment of source rocks in the Qiangtang Basin: New discoveries from the upper Triassic Xiaochaka formation in the Woruoshan Mountain

Clarifying the sedimentary environment and main controlling factors of source rocks is significant for the oil and gas exploration in the Qiangtang Basin. Based on the detailed observation results, this study analyzed the organic geochemical characteristics and trace metals of source rocks in the Upper Triassic Xiaochaka Formation in the Woruoshan Mountain and investigated the depositional conditions and their implications for the formation of source rocks. The source rocks of the Xiaochaka Formation mainly consist of dark mudstones with low-medium abundance of organic matter. They have type II2-III kerogen and middle thermal maturity. This strata had a warm and humid climate during its deposition. Affected by the sea-level fluctuation, the depositional water columns of this strata evolved from freshwater to brackish water and then freshwater from bottom to top. The Xiaochaka Formation deposited in the oxic water columns overall with high paleoproductivity. The formation of the Xiaochaka source rocks in the Woruoshan mainly is the “productivity model” controlled by paleoclimate and freshwater flux. The warm and humid paleoclimate and freshwater transport contributed to the high paleoproductivity of water columns and counteracted the unfavorable preservation conditions. As a result, type Ⅱ2-Ⅲ source rocks were finally formed

The effect of operational parameters on the characteristics of gas–solid flow inside the COREX shaft furnace

The COREX shaft furnace is of great importance to the whole C-3000 process. There are many problems with the operation of the COREX shaft furnace, especially with gas and burden distribution, that have as yet been little studied. The present work establishes a three-dimensional quarter model. After validation by operating data in Baosteel, the model is used to investigate the gas utilization rate and the metallization rate of the COREX shaft furnace. The parameters, including the reducing gas flow, the volume fraction of gas phase, and the multilayered burden, are systematically investigated. The results show that the reducing gas flow has a great influence on the gas utilization rate and the metallization rate, while the volume fraction of gas phase has a more significant effect on the metallization rate than on the gas utilization rate. In order to obtain a higher metallization rate, the reducing gas flow needs to be adjusted step by step and the volume fraction of gas phase needs to be increased. In addition, ore and coke need to be discharged separately in order to increase the solid metallization rate

Nonlinear expression and visualization of nonmetric relationships in genetic diseases and microbiome data

Abstract Background The traditional methods of visualizing high-dimensional data objects in low-dimensional metric spaces are subject to the basic limitations of metric space. These limitations result in multidimensional scaling that fails to faithfully represent non-metric similarity data. Results Multiple maps t-SNE (mm-tSNE) has drawn much attention due to the construction of multiple mappings in low-dimensional space to visualize the non-metric pairwise similarity to eliminate the limitations of a single metric map. mm-tSNE regularization combines the intrinsic geometry between data points in a high-dimensional space. The weight of data points on each map is used as the regularization parameter of the manifold, so the weights of similar data points on the same map are also as close as possible. However, these methods use standard momentum methods to calculate parameters of gradient at each iteration, which may lead to erroneous gradient search directions so that the target loss function fails to achieve a better local minimum. In this article, we use a Nesterov momentum method to learn the target loss function and correct each gradient update by looking back at the previous gradient in the candidate search direction. By using indirect second-order information, the algorithm obtains faster convergence than the original algorithm. To further evaluate our approach from a comparative perspective, we conducted experiments on several datasets including social network data, phenotype similarity data, and microbiomic data. Conclusions The experimental results show that the proposed method achieves better results than several versions of mm-tSNE based on three evaluation indicators including the neighborhood preservation ratio (NPR), error rate and time complexity