In bar-probe partial report experiments, subjects are presented with a brief array of letters, followed by a cue that singles out a target letter. Using this procedure, V. M. Townsend (1973) reported a counterintuitive effect: As the duration of a cue was increased, target performance decreased dramatically. The aim of the present study was to isolate the locus of the cue-duration effect. To th...

Rare cells can be difficult to analyze because they either occur in low numbers or coexist with a more abundant cell type, yet their detection is crucial for diagnosing disease and maintaining human health. In this tutorial review, we introduce the concept of microfluidic stochastic confinement for use in detection and analysis of rare cells. Stochastic confinement provides two advantages: (1) ...

Differences in learning patterns of vocabulary acquisition in children at risk (+SRD) and not at risk (-SRD) for Specific Reading Disability (SRD) were examined using a microdevelopmental paradigm applied to the multi-trial Foreign Language Learning Task (FLLT; Baddeley et al., 1995). The FLLT was administered to 905 children from rural Chitonga-speaking Zambia. A multi-group Latent Growth Curv...

The origin of altruism is a fundamental problem in evolution, and the maintenance of biodiversity is a fundamental problem in ecology. These two problems combine with the fundamental microbiological question of whether it is always advantageous for a unicellular organism to grow as fast as possible. The common basis for these three themes is a trade-off between growth rate and growth yield, whi...

Three experiments examined the dynamic attributes of timbre by evaluating the role of onsets in similarity judgments. In separate experiments, subjects heard complete orchestral instrument tones, the onsets of those tones, and tones with the onsets removed ("remainders"). Ratings for complete tones corresponded to those for onsets, indicating that the salient acoustic attributes r,,• complete *...

What are the evolutionary consequences of gene duplication? One answer is speciation, according to a model initially called Reciprocal Silencing and recently expanded and renamed Divergent Resolution. This model shows how the loss of different copies of a duplicated gene in allopatric populations (divergent resolution) can promote speciation by genetically isolating these populations should the...

Samples of blood from 49 cancer cases were examined for free cancer cells. Cells identified as cancer cells were found in the blood of four. Cells which looked highly suspicious of being cancer cells were isolated from the blood of nine other cases. No conclusion was possible regarding the type of cells in eight cases. This illustrates the difficulty of cytological diagnosis and shows the need ...

On the species problem the interests of genetics, taxonomy, and ecology converge to a remarkable extent, and it seems that only through coordination of the methods of these several disciplines can satisfactory progress in this field be made. Where closely-related species, or populations very nearly attaining the rank of species, are involved, the problem attains a maximum of complexity; it is j...

The recognition of the vast numbers of bacteriophages in the biosphere has prompted a renewal of interest in understanding their morphological and genetic diversity, and elucidating the evolutionary mechanisms that give rise to them. We have approached these questions by isolating and characterizing a collection of mycobacteriophages that infect a common bacterial host, Mycobacterium smegmatis....

Many natural or artificial systems are considered to be complex because we experience the greatest difficulties of expressing their external behaviors in a satisfactory mathematical form. The structural approach proposes a different methodology consisting in isolating and modeling the nodes of complexity of a system by a fine analysis of their internal organization.