The evolution of courtship displays in Galliformes

Species in Galliformes have elaborate ritual courtship displays,often including strutting,fluffing of tail or head feathers,and vocal sounds that serve as excellent examples of sexual selection.According to the male orientation to the female while either posturing or moving,these courtship displays of gallinaceous species can be classified into three categories:1)‘frontal displays’,2)‘lateral displays’,and 3)‘both frontal and lateral displays’.Questions regarding which category of displays is the ancestral state and the evolutionary history of courtship displays in Galliformes remain unanswered.We collected and classified 131 species in terms of their courtship displays into the three categories listed above and carried out a large-scale comparative analysis to reveal the evolutionary trajectory of this trait.We found that the ancestral state of courtship displays of Galliformes involves both relatively short and straightforward frontal and lateral elements(i.e.,the category of‘both frontal and lateral displays’).Furthermore,ancestral trait reconstructions suggest that transitions from‘lateral displays’to‘frontal displays’occurred more frequently than the other way around(i.e.,from‘frontal displays’to‘lateral displays’).In addition,some transitions occurred from‘both frontal and lateral displays’to‘lateral displays’but not from‘both frontal and lateral displays’to‘frontal displays’.Ancestral state reconstruction of courtship displays at the root of the Galliformes phylogeny supports the‘both frontal and lateral displays’first scenario.This original state then evolved towards two extremes,either‘frontal displays’or‘lateral displays’,with more complicated and elaborate display components.Moreover,subsequent transitions occurred from‘lateral displays’to‘frontal displays’much more frequently than the other way around during the evolutionary history,indicating positive selection of‘frontal displays’.

Risk Analysis of Information System Security Based on Distance of Information-State Transition

The configuration of information system security policy is directly related to the information asset risk, and the configuration required by the classified security protection is able to ensure the optimal and minimum policy in the corresponding security level. Through the random survey on the information assets of multiple departments, this paper proposes the relative deviation distance of security policy configuration as risk measure parameter based on the distance of information-state transition（DIT） theory. By quantitatively analyzing the information asset weight, deviation degree and DIT, we establish the evaluation model for information system. With example analysis, the results prove that this method conducts effective risk evaluation on the information system intuitively and reliably, avoids the threat caused by subjective measurement, and shows performance benefits compared with existing solutions. It is not only theoretically but also practically feasible to realize the scientific analysis of security risk for the information system.

Bayesian Networks for the Age Classification of Living Individuals: A Study on Transition Analysis

Over the past few decades,age estimation of living persons has represented a challenging task for many forensic services worldwide.In莒eneral,the process for age estimation includes the observation of the degree of maturity reached by some physical attributes,such as dentition or several ossification centers.The estimated chronological age or the probability that an individual belongs to a meaningful class of ages is then obtained from the observed degree of maturity by means of various statistical methods.Among these methods,those developed in a Bayesian framework offer to users the possibility of coherently dealing with the uncertainty associated with age estimation and of assessing in a transparent and logical way the probability that an examined individual is younger or older than a given age threshold.Recently,a Bayesian network for age estimation has been presented in scientific literature;this kind of probabilistic graphical tool may facilitate the use of the probabilistic approach.Probabilities of interest in the network are assigned by means of transition analysis,a statistical parametric model,which links the chronological age and the degree of maturity by means of specific regression models,such as logit or probit models.Since different regression models can be employed in transition analysis,the aim of this paper is to study the influence of the model in the classification of individuals.The analysis was performed using a dataset related to the ossifications status of the medial clavicular epiphysis and results support that the classification of individuals is not dependent on the choice of the regression model.

Transition characteristics for a small tail-sitter unmanned aerial vehicle

Research on the transition phase of tail-sitter Unmanned Aerial Vehicles(UAVs)is crucial for trajectory planning and performance analysis.This study focuses on the analysis of the transition characteristics and path of a small dual-rotor tail-sitter UAV,including static and dynamic computations.The system input time delay and actuator dynamics are specifically considered during the dynamic analysis,and these actual physical properties ensure that the computation results are reliable and reasonable.The UAV steady-state limit is obtained through static analysis,which is also adopted to verify the correctness of the dynamic results.In regard to the dynamic analysis,several typical transition approaches are computed based on different initial states and optimization objective functions,and the different computations are applicable under specific task conditions.The off-line dynamic results of the transition path and actuator output sequence could also be adopted as reference values for the transition process during real flight.A comparison of the static and dynamic results illustrates the necessity of combining these two methods for UAV transition characteristic analysis.Furthermore,the UAV conceptual parameters related to the transition path are also studied,and the obtained quantitative characteristics provide feedback for the UAV conceptual design.

"Weather" transit is reliable? Using AVL data to explore tram performance in Melbourne,Australia

This paper uses automatic vehicle location （AVL） records to investigate the effect of weather conditions on the travel time reliability of on-road rail transit, through a case study of the Melbourne streetcar （tram） network. The datasets available were an extensive historica; AVL dataset as well as weather observations. The sample size used in the analysis included all trips made over a period of five years （2006-2010 inclusive）, during the morning peak （7 am-9 am） for fifteen randomly selected radial tram routes, all traveling to the Melbourne CBD create a linear model Ordinary least square （OLS） regression analysis was conducted to with tram travel time being the dependent variable. An alternative formulation of the model is also compared. Travel time was regressed on various weather effects including precipitation, air temperature, sea level pressure and wind speed; as well as indicator variables for weekends, public holidays and route numbers to investigate a correlation between weather condition and the on-time performance of the trams. The results indicate that only precipitation and air temperature are significant in their effect on tram travel time. The model demonstrates that on average, an additional millimeter of precipitation during the peak period adversely affects the average travel time during that period by approximately 8 s, that is, rainfall tends to increase the travel time. The effect of air temperature is less intuitive, with the model indicating that trams adhere more closely to schedule when the temperature is different in absolute terms to the mean operating conditions （taken as 15 ℃）.