Disappearances

The strange disappearances of James Lind.

Appearances and Disappearances: Motion Induced Blindness Meets Binocular Rivalry

Motion-induced blindness (MIB) and binocular rivalry (BR) are examples of multistable phenomena in which our perception varies despite constant retinal input. It has been suggested that both phenomena relate to visual awareness and share a common underlying mechanism. We tried to determine whether experimental manipulations of the target dot and the mask systematically affect MIB and BR in a no...

Chaos and population disappearances in simple ecological models.

A class of truncated unimodal discrete-time single species models for which low or high densities result in extinction in the following generation are considered. A classification of the dynamics of these maps into five types is proven: (i) extinction in finite time for all initial densities, (ii) semistability in which all orbits tend toward the origin or a semistable fixed point, (iii) bistab...

Spatial Autocorrelation and Local Disappearances in Wintering North American Birds

I examined the degree to which population sizes of North American wintering birds exhibit spatial synchrony (autocorrelation) and local disappearances based on 30 yr of Christmas Bird Counts. The primary goal of these analyses was to determine whether processes expected in metapopulations, including low spatial synchrony, frequent local disappearances, and colonization leading to population res...

Epidemiologic analysis of factors associated with local disappearances of native ranid frogs in Arizona.

We examined factors that may independently or synergistically contribute to amphibian population declines. We used epidemiologic case-control methodology to sample and analyze a large database developed and maintained by the Arizona Game and Fish Department that describes historical and currently known ranid frog localities in Arizona, U.S.A. Sites with historical documentation of target ranid ...