Global existence and asymptotic behavior of the solutions to the 3D bipolar non-isentropic Euler–Poisson equation

In this paper, the global existence of smooth solutions for the three-dimensional (3D) non-isentropic bipolar hydrodynamic model is showed when the initial data are close to a constant state. This system takes the form of non-isentropic Euler–Poisson with electric field and frictional damping added to the momentum equations. Moreover, the L2-decay rate of the solutions is also obtained. Our approach is based on detailed analysis of the Green function of the linearized system and elaborate energy estimates. To our knowledge, it is the first result about the existence and L2-decay rate of global smooth solutions to the multi-dimensional non-isentropic bipolar hydrodynamic model

Prospective teachers’ confidence and mathematics conceptual knowledge for teaching in South Korea – Fraction division

We focused on both prospective teachers’ (PTs) confidence about their knowledge preparation and the extent of their knowledge of the specific topic of fraction division. The results revealed how these PTs’ confidence may or may not be supported by their knowledge preparation for teaching fraction division, a concept they would be expected to teach as part of the country's curriculum standards. The results also illustrated the importance of specifying knowledge components in mathematics in order to help build or support PTs’ confidence for classroom instruction

Recognizing and promoting interdisciplinary collaboration, leadership, and impact: award for interdisciplinary excellence in mathematics education (IEME award)

The presentation of the Award for Excellence in Mathematics Education to Roger E. Howe in 2015 officially launched the award, with the goal of recognizing work of lasting significance and impact in advancing mathematics education as an interdisciplinary field, linking mathematics, educational studies, and practice. From the beginning, this unique award has emphasized interdisciplinarity in mathematics education, highlighting the importance of boundary-crossing collaborations among mathematicians, mathematics educators, scholars in other related fields, and practitioners of mathematics. To emphasize the importance of interdisciplinary collaboration in mathematics education, starting in 2019, the name of the award is changed from “Excellence in Mathematics Education” to “Interdisciplinary Excellence in Mathematics Education”

Application and demonstr ation of Digital Maize Planting and Management System

Abstr act. Cooperating with Agriculture and Animal Husbandry Administrative Bureau of Dingxing County, Hebei province, we applied the agricultural information software of Digital Maize Planting and Management System to guide local maize production. This system can direct the maize production during the whole course including digital simulation and design of maize production, planting plan before sowing, optimal water and nitrogen operation, nitrogen pollution warning, economic benefits analysis and so on. This study tries to establish the foundation for information and digitalization of maize production and management. Keywor ds: Maize; Digital management; Demonstration 1 Intr oduction Agricultural information technology is to collect, store, transmit, handle, analyze and utilize the natural, economic and social information in the course of agricultural production, management and decision-making As the important content of agricultural information technology, crop simulation model has been becoming the core of agricultural production management and resource optimization management, and the basis of precision agriculture. After 50 years evolvement crop simulation model becomes more mature and possesses of more mechanism. America, Holand, England and Australia developed many crop models, some of which had been used in agriculture successfully such as DSSAT, SUCROS, EPIC, and RZWQ

Investigation of Key Parameters for Hydraulic Optimization of an Inlet Duct Based on a Whole Waterjet Propulsion Pump System

The hydraulic performance of an inlet duct directly affects the overall performance of a waterjet propulsion system. Key parameters for the hydraulic optimization of the inlet duct are explored using the computational fluid dynamics (CFD) technology to improve the hydraulic performance of the waterjet propulsion system. In the CFD simulation and experiment, an inlet duct with different flow and geometric parameters is simulated. By comparing grid sensitivity and different turbulence models, a suitable grid size and a turbulence model are determined. The comparison between the numerical simulation and the experiment shows that the numerical results are reliable. The results of the calculation and analysis of different speed cases show that the ship speed affects the efficiency of the waterjet propulsion system. In particular, the system efficiency increases first and then decreases with an increase in the ship speed. Under the conditions of constant ship speed and rotational speed, the influence of the length and dip angle of the inlet duct on the waterjet propulsion system is investigated using a single factor method. The results show that the dip angle has an obvious effect on the hydraulic performance of the inlet duct, and an extremely small angle of inclination will lead to poor flow patterns in the inlet passage. When the length is approximately six times the inlet duct outlet diameter, and the dip angle is 30°–35°, the hydraulic performance of the waterjet propulsion pump system is satisfactory

Anti-inflammatory effects of Neurotoxin-Nna, a peptide separated from the venom of Naja naja atra

BACKGROUND: Neurotoxin-Nna (NT), an analgesic peptide separated from the venom of Naja naja atra, has reported to have an exceptional specificity to block transmission of the nerve impulse by binding to the α- subunit of the nicotinic acetylcholine receptor in the membrane. However, little information is available on the anti-inflammatory effects of NT. Therefore, the anti-inflammatory activity of Neurotoxin-Nna was investigated in this study. METHODS: The anti-inflammatory effects of NT were evaluated by measuring its influence on several crucial factors in inflammatory pathways, including total antioxidant activity, antinociceptive effects in vivo, nuclear factor kappa B (NF-κB), polymorphonuclear cells (PMN), inducible nitric oxide synthase (iNOS), adhesion molecule (ICAM-1) and tactile hyperalgesia. RESULTS: NT treatment decreased the levels of tumor necrosis factor alpha (TNF-α) and interleukin 1 beta (IL-1β). NT treatment decreased the total antioxidant status (TAOS) and reduced CFA-induced tactile hyperalgesia in a dose-dependent manner. NT significantly inhibited regulation of NF-kappaB activation and the production of IL-1β, TNF-α, iNOS and CAM-1. Moreover, NT suppressed infiltration of PMN. CONCLUSIONS: Our results showed that NT reduced CFA-induced tactile hyperalgesia through inhibition inflammatory pathways in experimental inflammatory rats

Global Existence and Large Time Behavior of Solutions to the Bipolar Nonisentropic Euler-Poisson Equations

We study the one-dimensional bipolar nonisentropic Euler-Poisson equations which can model various physical phenomena, such as the propagation of electron and hole in submicron semiconductor devices, the propagation of positive ion and negative ion in plasmas, and the biological transport of ions for channel proteins. We show the existence and large time behavior of global smooth solutions for the initial value problem, when the difference of two particles’ initial mass is nonzero, and the far field of two particles’ initial temperatures is not the ambient device temperature. This result improves that of Y.-P. Li, for the case that the difference of two particles’ initial mass is zero, and the far field of the initial temperature is the ambient device temperature