Reconciling the Plant-Animal Interface: Convergence of Optimal Herbage Accumulation and Intake Rate by Sheep Grazing Tall Fescue

Aims This study evaluated the optimal herbage level from both plant and animal perspectives, through the adjustment of instantaneous herbage accumulation rate as estimed by the Gompertz curve model and short-term intake rate of sheep. Schedonorus arundinaceus (tall fescue) was used as an experimental model. Methods Weekly tall fescue herbage accumulation was measured during seven growth periods initiated on monthly intervals (October, November, and December 2015, and March, April, August and September 2016) with the initiation dates arranged in a randomized complete block design with four replicates. Total herbage mass, leaf lamina mass, pseudo-stem + sheath mass, senescent mass, and sward surface height were measured each week. Results We demonstrated that a pre-grazing sward surface height of 22.3 cm of tall fescue promoted concomitantly the maximum short-term intake rate of sheep and the instantaneous herbage accumulation rate in the spring and autumn periods. In general, the convergent point occurred after the maximum instantaneous leaf lamina accumulation rate and before the maximum instantaneous accumulation rate of pseudo-stem + sheath and senescent material. Conclusions We suggest the existence of a convergent point in which both primary and secondary production of pastoral ecosystems could be fostered, potentially reconciling the fundamental ecological dilemma of grazing systems.

Structure Optimization of Safety Investment of Petrochemical Port Enterprises

Safety investment is an essential guarantee to identify and manage potential security problems in petrochemical port enterprises. The reasonability of safety investment structure determines overall security risks in an enterprise. Based on the definition of risks, combining Cobb-Douglas production function with FTA probability model, and taking Gompertz curve model as the constraint condition, structure optimization model of safety investment is built in order to minimize risks and work out the safety investment structure of petrochemical port enterprises. According to the case study, the calculations indicate that safety investment in corporate management presents a larger growth rate than past years and that unsafe act of human being is the main factor accounting for the greatest probability of occurrence, which is consistent with previous accident investigation results as well as enterprise reality. This testifies that the model is effective and that the results can guide the allocation of safety investment of petrochemical port enterprises scientifically.

Research on Predictable Approach to Land Subsidence Based on TIN Model

The most common predictable approach to land subsidence is to choose, analyze and forecast a representative deformation observation points .If an uneven land subsidence (settlement) comes into being, the settlement rate of deformation observation points will be different. The analysis of the individual subsidence observation points can not reflect the true ground subsidence in the region . Instead, the comprehensive analysis of the information about all the deformation observation points can more objectively reflect the overall settlement of the region. This study makes use of all the observation points to establish a triangular mesh deformation, and uses the superposition of the Terrain surface TIN model and the design surface TIN model to obtain the earthvolume in the two surface triangular elements. Through the earthvolume, the size of the overall settlement of the ground situation can be indirectly reflected in order to adopt appropriate preventive measures . This paper studies the Earthvolume as a research object, employs Gompertz curve model to fit the data and design the forecast model to make accurate assessments.The research shows that this method can reflect the overall total ground settlement,and explore the laws of the land subsidence when an uneven settlement arises.