Permanence and Global Attractivity of a Discrete Logistic Model with Impulses

By piecewise Euler method, we construct a discrete logistic equation with impulses. The constructed model is more easily implemented at computer and is a better analogue of the continuous-time dynamic system. The dynamic behaviors of the constructed model are investigated. Sufficient conditions which guarantee the permanence and the global attractivity of positive solutions of the model are obtained. Numerical simulations show the feasibility of the main results

Neocrangon orientalis, a new caridean shrimp species (Crustacea, Decapoda, Crangonidae) from the East China Sea

Han, Qingxi, Li, Xinzheng (2009): Neocrangon orientalis, a new caridean shrimp species (Crustacea, Decapoda, Crangonidae) from the East China Sea. Zootaxa 2050: 65-68, DOI: 10.5281/zenodo.18654

Simulation of negative pressure behavior using different shapes and positions of pressure inlet and seed hole diameters using ANSYS-CFX to optimize the structure of a pneumatic metering device designed for wheat

Abstract: the pneumatic precision metering device for wheat was innovated, designed and tested under laboratory conditions. Very good results were then obtained according to the precision seeding criteria based on quality of feed index (QFI), miss index (MIS) and multiple index (MULI). To optimize the structure of the design for gas stability before manufacturing, ANSYS-CFX was involved. Gas behavior was simulated under different shapes and positions for pressure inlet along with different seed hole diameters. According to the structure determined in ANSYS-CFX, the seed hole of 1.8 mm and cylindrical shape of pressure inlet was found to be the best among others, accordingly the deice was then manufactured and tested under laboratory and field conditions. The results from laboratory and field experiments were found to be in conformity with these of simulation, which indicated that ANSYS-CFX is a powerful and highly accurate application in optimizing the structure of such designs.   

Identification and Investigation on the sprits of Shi-you Nuo

the Nuo sprits of Shi-you Nuo have three properties. Itʼs mainly way that combines the history of Wu clan to expose its three properties and explores the deep relationship between Shi-you Nuo and Wu clan through researching the source of Nuo sprits so as to reveal the deep foundation about Shi-you Nuoʼs internal inheritance in the Wu clan. Shi-you Nuo experienced many times of adaptations, during the Ming and Qing dynasties at least went through three times of major adaptations. We can trace its evolution history with the ups and downs history of the Wu clan through the three major adaptations so as to interpret the Nuo spritsʼ identities of Shi-you Nuo.論

Research Notes : China : Inheritance of bloom on seed coat in soybean

Woodworth (1932, 1933) reported that three dominant genes (B1 B2 BJ) were necessary for the development of bloom on seed coat. Tang and Tai (1962) and Tang and Li (1964) pointed out that, in interspecific cross, Glycine max x G. formosana, complementary genes for bloom on seed coat existed, and the genetic constitutions for G. max were B1 B1 b2 b2 bJ bJ, those for G. formo-sana were B1 B1 B2 B2 BJ BJ. The purpose of this experiment was to give a further study on this character with more and new parental materials

Research Notes : China : Inheritance of some agronomic characters of interspecific crosses in soybeans

An attempt was made to investigate the inheritance, variation, and segregation of some agronomic characters of interspecific crosses in soybean. Effect of backcrossing with cultivated soybeans as recurrent parents was analyzed in order to find out reasonable and effective methods for utilizing wild and semi-wild soybean germplasms. The parents used in this study were Glycine max (L.) Merr. (Dongnong-33, Dongnong 4), G. gracilis Skvortz. (Long 79-4004, Long 79-3407-1) and G. soja Sieb. and Zucc. (Ji-50192)

Influence evaluation of producer services agglomeration on economic resilience: Evidence from China’s cities

As a new engine of economic development after urbanization’s structural deceleration stage in China, producer services agglomeration on urban economic resilience (ER) requires analysis. Using data from 264 prefecture-level cities and above in China after the global financial crisis, we examine producer services’ impact in terms of diversification (PSD) and specialization (PSS) on urban ER, and also the mediating effect of industrial structure upgrading (ISU). The results show that Cities with more diversified producer services are more resilient to crises, while the effect direction of PSS is the opposite. ISU is partly how PSD and PSS affect ER. Finally, producer services agglomeration’s impact on ER has significant regional heterogeneity. PSD is very conducive to urban ER in the economically developed eastern region and the less developed western region. The more specialized the development of producer services in eastern and north-eastern regions, the less conducive it is to enhancing ER. Our findings can help stabilize China’s economy and achieve high-quality economic development

Reducing short flows' latency in the internet

Short flows are highly valuable in the modern Internet and are widely used by applications in the form of web requests or with user interactions. These kinds of applications are extremely sensitive to latency. A small additional delay, like one or two round trip times (RTTs), may easily cause user frustration and lose usability of services. In the most desirable scenario, we want to finish these kinds of flows in one network RTT. Furthermore, we would like the network's RTT to be as close as possible to the speed of light. Unfortunately, in the current Internet, there are many unnecessary delays caused by different kinds of policies--in particular, transmission protocol and routing policies--driving us far away from this goal. This thesis aims at answering the following two questions: How can we optimize the transmission protocol to reduce short flows' latency as close as possible to one RTT and why are network RTTs still significantly larger than the speed-of-light latency? To reduce the transmission latency, we focused on the two main components of short flows, connection establishment and data transmission. ASAP, a new naming and transport protocol, is introduced to reduce the time spent on initial TCP connections. It merges functionality of DNS and TCP's connection establishment functions by piggybacking the connection establishment procedure atop the DNS lookup process. With the help of ASAP, the host is able to save up to two-thirds of the time spent on initial connection without exposing significant DoS vulnerabilities. For data transmission, we designed a new control rate mechanism, Halfback, which achieves low latency with limited bandwidth overhead and only requires sender-side changes. Halfback has an aggressive startup phase, finishing transmission for most short flows in one RTT, together with a Reverse-Ordering Proactively Retransmission phase which helps the host to recovery quickly from packet loss caused by the aggressive startup phase. Halfback is able to achieve 56% smaller flow completion time on average and three times smaller in the 99th percentile. RTT between two hosts is able to be more than 6 times the speed-of-light latency for Directed Optical Fiber. To understand the composition of RTT inflation, we break down the path inflation on the end-to-end path into its contribution factors. Based on our result, 7.2% is caused by network topology, 18.8% is contributed by inter-domain routing policies, 54.9% is caused by peering policies, and 25.6% is caused by intra-domain routing policies. This result shows that the main component of the path inflation is caused by peering policies which may require more attention for future research. Besides this, we also analyze the changes of the inflation caused by each contributing factor across five years. According to our analysis, the total inflation has been reduced by around 6% each year since 2010