Nutrient Cycling and Plant Nutrition in Forest Ecosystems

Nutrient cycling is essential for maintaining nutrient supply to forest plants and for enhancing forest productivity. Nutrient cycling is also strongly linked to greenhouse gas emissions and thus to global climate change. Nutrient cycling and plant nutrition can be severely affected by anthropogenic and natural disturbance regimes. This Special Issue will provide an avenue to publish recent progress on research on nutrient cycling and plant nutrition in forest ecosystems and how nutrient cycling and plant nutrition are affected by disturbance regimes such as harvesting, atmospheric deposition and climate change

Design of One Dimensional Adjustment Platform Servo Control System Based on Neural Network

This paper designed a one dimensional adjustment of high precision servo control system, in order to provide individual comprehensive combat system high precision gun visual Angle. In servo control system hardware design based on DSP digital signal processing (DSP) chip as the CPU control circuit, in regard to algorithm, using the three layers BP neural network algorithm for PID integral gain and differential gain and intelligently adjusting proportion gain. On this basis, also analyzes the advantages and disadvantages of the traditional BP neural network algorithm, carries on the improvement. Vector using adaptive control, numerical optimization and introducing the steepness factor method, solve the contradiction between the stability and learning time, greatly improving the convergence speed and stability of the system performance, the static stability of the turntable accuracy is less than 3″, indicators reached the design requirements

The scale and evolutionary significance of horizontal gene transfer in the choanoflagellate

Background It is generally agreed that horizontal gene transfer (HGT) is common in phagotrophic protists. However, the overall scale of HGT and the cumulative impact of acquired genes on the evolution of these organisms remain largely unknown. Results Choanoflagellates are phagotrophs and the closest living relatives of animals. In this study, we performed phylogenomic analyses to investigate the scale of HGT and the evolutionary importance of horizontally acquired genes in the choanoflagellate Monosiga brevicollis. Our analyses identified 405 genes that are likely derived from algae and prokaryotes, accounting for approximately 4.4% of the Monosiga nuclear genome. Many of the horizontally acquired genes identified in Monosiga were probably acquired from food sources, rather than by endosymbiotic gene transfer (EGT) from obsolete endosymbionts or plastids. Of 193 genes identified in our analyses with functional information, 84 (43.5%) are involved in carbohydrate or amino acid metabolism, and 45 (23.3%) are transporters and/or involved in response to oxidative, osmotic, antibiotic, or heavy metal stresses. Some identified genes may also participate in biosynthesis of important metabolites such as vitamins C and K12, porphyrins and phospholipids. Conclusions Our results suggest that HGT is frequent in Monosiga brevicollis and might have contributed substantially to its adaptation and evolution. This finding also highlights the importance of HGT in the genome and organismal evolution of phagotrophic eukaryotes

The Study of Low-Light Sights Reliability Test System in High and Low Temperature Environment

In a certain period of time Products and system complete the required function under the condition of rules, the ability is called the reliability. Reliability is an important factor to reflect the quality of products, is the focus of the weapons and equipment quality. There is no guarantee reliability, even the most advanced equipment can not also play a role. In this paper, the design of test system is mainly used for small arms LOW-LIGHT SIGHTS sight reliability test. The shimmer sight reliability tests provide light stress, electrical stress, thermal stress and other stress environment. Detection shimmer sight working conditions, on failure of the automatic screening and recording

Methods to Improve the Teaching Effect of the Professional Course of the University

Aiming at the poor teaching effect of professional course in university, student interest is not high and show how to improve the important measures of the teaching effect of professional course in university and universities, starting from the view of teachers, effective preparation is the prerequisite to improve the professional teaching, effective classroom teaching is the effective guarantee to improve the teaching of professional course, advanced teaching methods is the fundamental guarantee to enhance the teaching of professional courses, starting from the perspective of students, learning interest is the basic power, improve the teaching of professional courses ability is the fundamental aim of improve the teaching of professional courses

Experimental Investigation of the Velocity Field in Buoyant Diffusion Flames Using PIV and TPIV Algorithm

We investigated a simultaneous temporally and spatially resolved 2-D velocity field above a burning circular pan of alcohol using particle image velocimetry (PIV). The results obtained from PIV were used to assess a thermal particle image velocimetry (TPIV) algorithm previously developed to approximate the velocity field using the temperature field, simultaneously captured by an infrared (IR) thermal camera. By tracing “thermal particles,” which were assumed to be virtual particles that corresponded to pixels of temperature values in successive IR images, the TPIV algorithm estimated a larger scale instantaneous velocity field than either a single-point velocity measurement (e.g., LDV) or the area velocity measurement such as PIV. Instantaneous velocity fields obtained from both methods are presented. Time series vertical velocity profiles and time-averaged velocity vector fields are compared. The comparison demonstrates the applicability and performance of the TPIV algorithm in wildfire research

Fire Behavior of Some Southern California Live Chaparral Fuels

Wildfire spread in living vegetation, such as chaparral in southern California, often causes significant damage to infrastructure and ecosystems. In order to study wildfire spread in living vegetation, four of the most common chaparral in southern California, chamise, manzanita, scrub oak and ceanothus, were burned and compared. The observed fire behavior included mass loss rate, flame height, temperature structure and velocity field above the burning fuel bed. It was observed that flame height increases mainly with heat release rate. By using successive images of the temperature field, a recently developed thermal particle image velocity (TPIV) algorithm was applied to estimate flow velocities in the vicinity of the flame. The results are generally in agreement with other experimental results obtained on gas and liquid fuels