Word learning is a notoriously difficult induction problem because meaning is underdetermined by positive examples. How do children solve this problem? Some have argued that word learning is achieved by means of inference: young word learners rely on a number of assumptions that reduce the overall hypothesis space by favoring some meanings over others. However, these approaches have difficulty explaining how words are learned from conversations or text, without pointing or explicit instruction. In this research, we propose an associative mechanism that can account for such learning. In a series of experiments, 4-year-olds and adults were presented with sets of words that included a single nonsense word (e.g. dax). Some lists were taxonomic (i.,e., all items were members of a given category), some were associative (i.e., all items were associates of a given category, but not members), and some were mixed. Participants were asked to indicate whether the nonsense word was an animal or an artifact. Adults exhibited evidence of learning when lists consisted of either associatively or taxonomically related items. In contrast, children exhibited evidence of word learning only when lists consisted of associatively related items. These results present challenges to several extant models of word learning, and a new model based on the distinction between syntagmatic and paradigmatic associations is proposed.

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Crystallization control of the hard polyester segments is an important way to design the final properties of a thermoplastic polyester elastomer (TPEE). In this work, the crystallization behavior of TPEE with nanosilica as the nucleating agent was studied. Three kinds of nanosilica with various sizes and surface treatments were chosen for nucleation design. The results reveal that all types of nanosilicas have evident nucleating effects, leading to a remarkable increase of the crystallization temperature of TPEE even by about 30 °C. However, the overall crystallization process is highly dependent on the particle size and surface treatment of silica because it is closely related to the nucleation ability of the particles and alteration of the system viscosities. The crystallization temperature of TPEE is more sensitive to the surface treatment of silica, while its crystallization rate shows a higher dependence on the particle size of silica. This work provides a facile way to well tailor crystallization of TPEE.

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