Environment change, economy change and reducing conflict at source

At a time when fossil fuel burning, nationalism, ethnic and religious intolerance, and other retrograde steps are being promoted, the prospects for world peace and environmental systems stability may appear dim. Yet now is it the more important to continue to examine the sources of conflict. A major obstacle to general progress is the currently dominant economic practice and theory, which is here called the economy-as-usual, or economics-as-usual, as appropriate. A special obstacle to constructive change is the language in which economic matters are usually discussed. This language is narrow, conservative, technical and often obscure. The rapid changes in the environment (physical and living) are largely kept in a separate compartment. If, however, the partition is removed, economics -as-usual, with its dependence on growth and its widening inequality, is seen to be unsustainable. Radical economic change, for better or worse, is to be expected. Such change is here called economy change. The change could be for the better if it involved an expansion of the concept of economics itself, along the lines of oikonomia, a modern revival of a classical Greek term for management or household. In such an expanded view, not everything of economic value can be measured. It is argued that economics-as-usual is the source of much strife. Some features are indicated of a less conflictual economy - more just, cooperative and peaceful. These features include a dignified life available to all people as of right, the word 'wealth' being reconnected with weal, well and well-being, and 'work' being understood as including all useful activity

Tracking and capture of constant and varying velocity stimuli: a cross-species comparison of pigeons and humans

The mechanisms underlying tracking and capture of moving objects in non-human animals are poorly understood. This set of experiments sought to further explore aspects of anticipatory tracking in pigeons and to conduct comparisons with human participants. In Experiment 1a, pigeons were presented with two types of varying velocities (fast-slow-fast or slow-fast-slow) in separate phases. They were readily able to track and anticipate both of these motion types. To examine the effects of predictability on anticipatory tracking, Experiment 1b presented the pigeons with the same two varying velocities randomly intermixed within a session. This resulted in reduced capture success, later capture, and errors that no longer anticipated ahead of the motion, suggesting that the anticipatory mechanism had been disrupted. This implies that the mechanisms involved in pigeon tracking are different from the predictive extrapolation mechanism proposed in humans. Experiment 2 tested this by presenting adult humans with a tracking task that was similar to tasks previously received by the pigeons. The capture behavior of humans was similar to the pigeons, but the errors revealed different processes underlying their tracking behavior. © 2010 Springer-Verlag

The identity of belowground herbivores, not herbivore diversity, mediates impacts on plant productivity

Across many ecosystems, increases in species biodiversity generally results in greater resource acquisition by consumers. Few studies examining the impacts of consumer diversity on resource capture have focused on terrestrial herbivores, however, especially taxa that feed belowground. Here we conducted field mesocosm experiments to examine the effects of variation in species richness and composition within a community of wireworm herbivores on wheat plant productivity. Our experiments involved wireworm communities consisting of between one and three species, with all possible combinations of species represented. We found that the presence of wireworms reduced plant biomass and seed viability, but wireworm species richness did not impact these plant metrics. Species identity effects were strong, as two species, Limonius californicus and Selatosomus pruininus, had significantly stronger impacts on plants compared to L. infuscatus. Communities with either of the two most impactful species consistently had the greatest impact on wheat plants. The effects of wireworms were thus strongly dependent on the particular species present rather than the overall diversity of the wireworm community. More broadly, our study supports the general finding that the identity of particular consumer species within communities often has greater impacts on ecosystem functioning than species richness

Visually guided capture of a moving stimulus by the pigeon (Columba livia)

Although the pigeon is a popular model for studying visual perception, relatively little is known about its perception of motion. Three experiments examined the pigeons' ability to capture a moving stimulus. In Experiment 1, the effect of manipulating stimulus speed and the length of the stimulus was examined using a simple rightward linear motion. This revealed a clear effect of length on capture and speed on errors. Errors were mostly anticipatory and there appeared to be two processes contributing to response locations: anticipatory peck bias and lag time. Using the same birds as Experiment 1, Experiment 2 assessed transfer of tracking and capture to novel linear motions. The birds were able to capture other motion directions, but they displayed a strong rightward peck bias, indicating that they had learned to peck to the right of the stimulus in Experiment 1. Experiment 3 used the same task as Experiment 2 but with naïve birds. These birds did not show the rightward bias in pecking and instead pecked more evenly around the stimulus. The combined results indicate that the pigeon can engage in anticipatory tracking and capture of a moving stimulus, and that motion properties and training experience influence capture. © 2008 Springer-Verlag