English‐monolingual children develop a shape bias early in language acquisition, such that they more often generalize a novel label based on shape than other features. Spanish‐monolingual children, however, do not show this bias to the same extent (Hahn & Cantrell, 2012). Studying children who are simultaneously learning both Spanish and English presents a unique opportunity to further investigate how this word‐learning bias develops. Thus, we asked how Spanish–English bilingual children (Mage = 21.31 months) perform in a novel‐noun generalization (NNG) task, specifically examining how past language experience (i.e. language exposure and vocabulary size) and present language context (i.e. whether the NNG task was conducted in Spanish or English) influence the strength of the shape bias. Participants completed the NNG task either entirely in English (N = 16) or entirely in Spanish (N = 16), as well as language understanding tasks in both English and Spanish to ensure that they understood what the experimenter was asking them to do. Parents completed a language exposure survey and vocabulary checklists in Spanish and English. There was a significant interaction between condition and choice type: Bilingual children in the English condition showed a shape bias in the NNG task, but bilingual children in the Spanish condition showed no reliable biases. No measures of past language experience were related to NNG task performance. These results suggest that when learning new words, bilingual children are attuned to the regularities of the present language context, and prior language experiences may play a more secondary role.
In two studies, we tested the relationship between children's label-learning experience and label-learning ability within diverse superordinate categories with complex perceptual organization (animals, clothing, foods). Using both quasi-experimental and experimental designs, we examined 18-and 24-month-old children's ability to generalize labels for novel members of superordinate categories as a product of their previous experience in learning labels for members of those categories. As predicted, children properly generalized more labels for members of the categories within which they had more label-learning experience than for members of the categories within which they had less label-learning experience. Results are consistent with the idea that children develop category-specific label-learning biases through their experience in learning labels for category members; they carry implications for multiple accounts of vocabulary acquisition and identify directions for future research.
Introduction: Despite progress in whole-organ decellularization and recellularization, maintaining long-term perfusion in vivo remains a hurdle to realizing clinical translation of bioengineered kidney grafts. The objectives for the present study were to define a threshold glucose consumption rate (GCR) that could be used to predict in vivo graft hemocompatibility and utilize this threshold to assess the in vivo performance of clinically relevant decellularized porcine kidney grafts recellularized with human umbilical vein endothelial cells (HUVECs).Materials and methods: Twenty-two porcine kidneys were decellularized and 19 were re-endothelialized using HUVECs. Functional revascularization of control decellularized (n = 3) and re-endothelialized porcine kidneys (n = 16) was tested using an ex vivo porcine blood flow model to define an appropriate metabolic glucose consumption rate (GCR) threshold above which would sustain patent blood flow. Re-endothelialized grafts (n = 9) were then transplanted into immunosuppressed pigs with perfusion measured using angiography post-implant and on days 3 and 7 with 3 native kidneys used as controls. Patent recellularized kidney grafts underwent histological analysis following explant.Results: The glucose consumption rate of recellularized kidney grafts reached a peak of 39.9 ± 9.7 mg/h at 21 ± 5 days, at which point the grafts were determined to have sufficient histological vascular coverage with endothelial cells. Based on these results, a minimum glucose consumption rate threshold of 20 mg/h was set. The revascularized kidneys had a mean perfusion percentage of 87.7% ± 10.3%, 80.9% ± 33.1%, and 68.5% ± 38.6% post-reperfusion on Days 0, 3 and 7, respectively. The 3 native kidneys had a mean post-perfusion percentage of 98.4% ± 1.6%. These results were not statistically significant.Conclusion: This study is the first to demonstrate that human-scale bioengineered porcine kidney grafts developed via perfusion decellularization and subsequent re-endothelialization using HUVEC can maintain patency with consistent blood flow for up to 7 days in vivo. These results lay the foundation for future research to produce human-scale recellularized kidney grafts for transplantation.
At 18 months of age, children frequently generalize (and overgeneralize) novel objects’ labels by shape (Landau et al., 1988). However, data from laboratory studies using ostensive word-learning paradigms indicate that, by three years of age, children generalize the labels of novel objects depending on the objects’ perceptual characteristics and taxonomy (Lavin & Hall, 2001; Jones et al., 1991). The current study sought to document this shift in children’s word-learning strategies using naturalistic data. We tracked children’s vocabularies over a six-month period of time (between 24-30 months of age) and classified their known words according to perceptual organization of the object categories to which they refer (e.g., shape-based, material-based). Children’s vocabulary sizes and rates of growth varied in meaningful ways between types of object categories and between the superordinate categories (e.g., animals, toys) to which the object categories belong. Findings carry implications for two popular accounts of vocabulary acquisition.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.