Relationships between femoral strength evaluated by nonlinear finite element analysis and BMD,material distribution and geometric morphology

Precisely quantifying the strength of the proximal femur and accurately assessing hip fracture risk would enable those at high risk to be identified so that preventive interventions could be taken.Development of better measures of femoral strength using the clinically

New insights into traffic dynamics:a weighted probabilistic cellular automaton model

From the macroscopic viewpoint for describing the acceleration behaviour of drivers, a weighted probabilistic cellular automaton model （the WP model, for short） is proposed by introducing a kind of random acceleration probabilistic distribution function. The fundamental diagrams, the spatiotemporal patterns, are analysed in detail. It is shown that the presented model leads to the results consistent with the empiricaZ data rather well, nonlinear flow-density relationship existing in lower density regions, and a new kind of traific phenomenon called neo-synchronized flow. Furthermore, we give the criterion for distinguishing the high-speed and low-speed neo-synchronized flows and clarify the mechanism of this kind of traffic phenomenon. In addition, the result that the time evolution of distribution of headways is displayed as a normal distribution further validates the reasonability of the neo-synchronized flow. These findings suggest that the diversity and the randomicity of drivers and vehicles have indeed a remarkable effect on traffic dynamics.

The application of neural networks to comprehensive prediction by seismology prediction method

BP neural networks is used to mid-term earthquake prediction in this paper. Some usual prediction parameters of seismology are used as the import units of neural networks. And the export units of neural networks is called as the character parameter W_0 describing enhancement of seismicity. We applied this method to space scanning of North China. The result shows that the mid-term anomalous zone of W_0-value usually appeared obviously around the future epicenter 1~3 years before earthquake. It is effective to mid-term prediction.

TEST AND STUDY ON THE CONSTITUTIV ERELATIONSHIP OF DESERT SAND UNDER MOVING VEHICLE

The mechanical properties of the sand of Takelamagan desert in Xinjiang under moving vehicle are studied by soil dynamic triaxial test apparatus. The nonlinear elastic constitutive model of the sand under moving vehicle is established first. These results lay the foundations for studying the interaction between vehicle running gear and the sand of Takelamagan desert in Xinjiang. and developing sand vehicle.

Principles for managing marine ecosystems prone to tipping points

As climatic changes and human uses intensify,resource managers and other decision makers are taking actions to either avoid or respond to ecosystem tipping points,or dramatic shifts in structure and function that are often costly and hard to reverse.Evidence indicates that explicitly addressing tipping points leads to improved management outcomes.Drawing on theory and examples from marine systems,we distill a set of seven principles to guide effective management in ecosystems with tipping points,derived from the best available science.These principles are based on observations that tipping points(1)are possible everywhere,(2)are associated with intense and/or multifaceted human use,(3)may be preceded by changes in earlywarning indicators,(4)may redistribute benefits among stakeholders,(5)affect the relative costs of action and inaction,(6)suggest biologically informed management targets,and(7)often require an adaptive response to monitoring.We suggest that early action to preserve system resilience is likely more practical,affordable,and effective than late action to halt or reverse a tipping point.We articulate a conceptual approach to management focused on linking management targets to thresholds,tracking early-warning signals of ecosystem instability,and stepping up investment in monitoring and mitigation as the likelihood of dramatic ecosystem change increases.This approach can simplify and economize management by allowing decision makers to capitalize on the increasing value of precise information about threshold relationships when a system is closer to tipping or by ensuring that restoration effort is sufficient to tip a system into the desired regime.

THE INFLUENCE OF ARCTIC AND ANTARCTIC ICE ON SOUTHERN OSCILLATION

The analysis of the relationship between sea ice in Arctic and Antarctic, and the Southern Oscillation Index (SOI) variation on the temporal scale of month, season and year is made in this paper. The negative correlation between sea ice in Arctic and the SOI. and the positive correlation between sea ice in Antarctic and the SOI are found. The variation of sea ice in Antarctic Pacific seems to play an important role in the influence to atmosphere. Their nonlinear relationships present more strongly than the linear relationship between them. The relationship between sea ice in Arctic and Antarctic and the SOI in the early stage is investigated. Their variation shows periodic phenomena. The maximum correlation is used to build the model for forecasting the variation of the SOI on the condition of the sea ice in Arctic and Antarctic. The explained variance of the simulated series is greater than 0.90. There exists a 17-month period in the relationship between sea ice in Arctic and Antarctic and SOI. The existing of the common factor with larger scale is discussed in this paper.

Measuring the Imbalance of Regional Development from Outer Space in China

We develop a statistical framework to use the data of night-time-lights(DN)from satellite to augment official GDP measures,and a non-linear substitution relationship between DN and GDP is given.In this paper,we take advantage of DN instead of GDP to measure the imbalance of regional development(IRD)in China by using the method of bi-dimensional decomposition under the population-weighted coefficient of variation.The method enables us to analyze the contributions of DN components to within-region and between-regions inequality under the framework which has been proposed,we can get the conclusion that the imbalance between-regions rather than within-region is the main reason for the influence of IRD for the whole country in China.