Captive-born collared peccary (Pecari tajacu, Tayassuidae) fails to discriminate between predator and non-predator models

Captive animals may lose the ability to recognize their natural predators, making conservation programs more susceptible to failure if such animals are released into the wild. Collared peccaries are American tayassuids that are vulnerable to local extinction in certain areas, and conservation programs are being conducted. Captive-born peccaries are intended for release into the wild in Minas Gerais state, southeastern Brazil. In this study, we tested the ability of two groups of captive-born collared peccaries to recognize their predators and if they were habituated to humans. Recognition tests were performed using models of predators (canids and felids) and non-predators animals, as well as control objects, such as a plastic chair; a human was also presented to the peccaries, and tested as a separate stimulus. Anti-predator defensive responses such as fleeing and threatening displayswere not observed in response to predator models. Predator detection behaviors both from visual and olfactory cues were displayed, although they were not specifically targeted at predator models. These results indicate that collared peccaries were unable to recognize model predators. Habituation effects, particularly on anti-predator behaviors, were observed both with a 1-h model presentation and across testing days. Behavioral responses to humans did not differ from those to other models. Thus, if these animals were to be released into the wild, they should undergo anti-predator training sessions to enhance their chances of survival

Propagation of Tau aggregates.

Since 2009, evidence has accumulated to suggest that Tau aggregates form first in a small number of brain cells, from where they propagate to other regions, resulting in neurodegeneration and disease. Propagation of Tau aggregates is often called prion-like, which refers to the capacity of an assembled protein to induce the same abnormal conformation in a protein of the same kind, initiating a self-amplifying cascade. In addition, prion-like encompasses the release of protein aggregates from brain cells and their uptake by neighbouring cells. In mice, the intracerebral injection of Tau inclusions induced the ordered assembly of monomeric Tau, followed by its spreading to distant brain regions. Short fibrils constituted the major species of seed-competent Tau. The existence of several human Tauopathies with distinct fibril morphologies has led to the suggestion that different molecular conformers (or strains) of aggregated Tau exist

On tracer methods in computational hydrodynamics

The numerical treatment of the convection-di1Tusion equation by means of the traditional finite difference techniques is often accompanied by specific diiiiculties. 111 the following, tracer methods are presented offering some numerical and economical advantages. They are applied to passive tracers (waste or heated water) and to active ones (density)

Consideration of ocean tides in an OGCM and impacts on subseasonal to decadal polar motion excitation

Ocean induced changes of Earth's rotation are attributed either to tides or to variations of the general circulation. Analogously, numerical world ocean models can still be divided into Ocean General Circulation and tidal models, although a neglect of nonlinear interactions in favor of a linear superimposition of both components of motion is questionable. By means of a simultaneous simulation of the ocean's circulation and tides we estimate the importance of two oceanic effects with respect to excitation of polar motion: nonlinearities between circulation and long-period tides and the circulation induced potential due to loading and self-attraction of a baroclinic ocean. Comparing the linear superimposition of separate model simulations with the simultaneous calculation of circulation and tides it turns out that these second-order effects contribute about 8 to ocean induced changes in Earth's orientation

The axial angular momentum of the general circulation of the oceans

With the Hamburg geostrophic ocean general circulation model, the temporal variation of the angular momentum of the oceans is studied. The input wind stresses consist of climatological winds plus the deviations of the actual winds 1981-1989. The motion part of the angular momenta of the two hemispheres resembles the (counter-phase) behaviour of the corresponding atmospheric angular momentum. The dominating matter part however shows no phase shift between the hemispheres. The sum of the angular momenta of the solid Earth and the atmosphere is deduced from observations; in principle it should be inversely correlated to the oceanic angular momentum. A first attempt to recognize the correlation between these empirical data and the theoretical values is described