Steady states and global dynamics of electrical activity in the cerebral cortex are investigated within the framework of a recent continuum model. It is shown that for a particular physiologically realistic class of models, at most three steady states can occur, two of which are stable. The global dynamics of spatially uniform activity states is studied and it is shown that in a physiologically realistic class of models, the adiabatic dynamics is governed by a second-order differential equation equivalent to that for the motion of a Newtonian particle in a potential in the presence of friction. This result is used to derive a simplified dynamical equation in the friction-dominated limit. Solutions of these equations are compared with those of the full global dynamics equations and it is found that they are adequate for time scales longer than approximately 100 ms provided dendritic integration times are less than approximately 10 ms.

Cs of high-level and low-level soccer players when sidestepping in response to projected, three-dimensional defender(s) and the traditionally used planned and unplanned arrow stimuli. Methods A three-dimensional motion analysis system captured the trunk and lower limb kinematics and ground reaction forces of 15 high-level and 15 low-level soccer players sidestepping in response to a one-defender scenario (1DS), two-defender scenario (2DS), arrow-planned condition (AP), and arrow-unplanned condition (AUNP). The temporal constraints imposed by the stimuli conditions resulted in increasing difficulty from AP, 1DS, 2DS, to AUNP. Selected joint kinematics and three-dimensional knee moments during the weight-acceptance phase of sidestepping were analyzed. Results Hip external rotation at initial foot contact was smaller when participants sidestepped in response to the projected defenders versus arrow conditions. Hip abduction was smallest in the AP, moderate in the defender scenarios, and largest in the AUNP. Peak knee valgus moments were 25% larger in the defender scenarios and 70% larger in the AUNP compared with the AP. High-level players exhibited decreased hip abduction and knee valgus moments in the 2DS compared with the low-level players. Conclusions Compared with the arrow conditions, sidestepping in response to the defender(s) resulted in different postures and knee moments, which further differentiated between high-level and low-level players in the complex 2DS. These findings highlight the effects of stimuli realism and complexity on the visual–perceptual–motor skill of sidestepping, which has implications for anterior cruciate ligament injury prevention....

We present a new, three-dimensional (3D) plotting library with advanced features, and support for standard and enhanced display devices. The library — s2plot — is written in c and can be used by c, c++, and fortran programs on GNU/Linux and Apple/OSX systems. s2plot draws objects in a 3D (x,y,z) Cartesian space and the user interactively controls how this space is rendered at run time. With a pgplot-inspired interface, s2plot provides astronomers with elegant techniques for displaying and exploring 3D data sets directly from their program code, and the potential to use stereoscopic and dome display devices. The s2plot architecture supports dynamic geometry and can be used to plot time-evolving data sets, such as might be produced by simulation codes. In this paper, we introduce s2plot to the astronomical community, describe its potential applications, and present some example uses of the library.

The seasonal variation of coronary heart disease mortality rates in New Zealand is analysed by age, sex and race using monthly national mortality data forthe period 1970–83. A35% variation from the winter peakto summer low is found in the crude mortality rate, but the size of the seasonal variation is age-dependent, being more pronounced in the elderly, and more so in males than in females. The hypothesis that respiratory infections are linked to coronary heart disease, and that their seasonal occurrence explains the seasonal variation in coronary rates, is examined by an analysis of the association between coronary disease and respiratory disease mortality rates. By partial correlation analysis and by examining the residual correlation after filtering the seasonal variation from both series, it is suggested that the season acts as a confounding factor to cause an apparent association between the two rates. After controlling for season there is a tenuous relationship, but It is apparent only in the elderly.