225 research outputs found
Moving beyond perceptually focused word learning strategies
The current thesis aimed to explore potential contributing factors to the difficulty that young children may experience with moving past previously effective word learning strategies. The particular focus of this thesis was how children overcome an early tendency to focus on perceptual features as their basis for word meaning and the potentially greater difficulty that children may experience with linking words to relational concepts. These aims were explored through a series of experiments that looked at 2- to 5-year-oldsâ extensions of words (e.g. nouns, noun-noun compounds, verbs). Findings suggest: that childrenâs difficulty with correctly attributing meaning to words which are primarily defined by relations is truly due to their relational nature and not their dynamic nature; that childrenâs tendency to base word meanings on relations can be increased by explicitly highlighting the relation; that comparisons across more than one exemplars can help children attribute verb meaning to actions alone instead of an object-action combination; that inhibition ability may be a contributing factor in childrenâs ability to overcome their focus on perceptual features when understanding word meaning; and that children with autism spectrum disorders may not make use of some processes that typically developing children employ to move beyond basing word meaning on shared perceptual features
The benefit of simultaneously encountered exemplars and of exemplar variability to verb learning
AbstractYoung children are conservative when extending novel verbs to novel exemplars. We investigated whether multiple, simultaneously presented exemplars would aid young children's verb learning, as well as the importance of exemplar variability. Three-year-olds were taught novel verbs, while viewing either one action-scene featuring a novel action performed on a novel object, or two action-scenes side-by-side in which the action performed was the same but the object varied, or two action-scenes side-by-side in which no aspect of the scenes varied. They were asked to extend the novel verbs to one of two scenes: one that maintained the action and one that maintained the object. Findings indicated that children were only able to extend verbs correctly after viewing two action-scenes in which the content varied. These findings suggest that simultaneously presented exemplars of a verb can support verb learning in younger children, but only when the content of the exemplars varies.</jats:p
The role of inhibition in moving beyond perceptually focused noun extensions
When young children interpret novel nouns, they tend to be very much affected by the perceptual features of the referent objects, especially shape. This article investigates whether children might inhibit a prepotent tendency to base novel nouns on the shape of referent objects in order to base them on conceptual features (i.e. taxonomic object categories). The study tested 3- to 5-year old children on a noun extension task, alongside a test of their inhibition and more general executive control ability. Noun extensions were related to inhibition ability, independent of age. Noun extensions were not related to individual differences in the general executive control task. This suggests a potential role for inhibition in extension which is independent of other aspects of cognitive development. </jats:p
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Natural selection towards wild-type in composite cross populations of winter wheat
Most of our crops are grown in monoculture with single genotypes grown over wide acreage. An alternative approach, where segregating populations are used as crops, is an exciting possibility, but outcomes of natural selection upon this type of crop are not well understood. We tracked allelic frequency changes in evolving composite cross populations of wheat grown over ten generations under organic and conventional farming. At three generations, each population was genotyped with 19 SSR and 8 SNP markers. The latter were diagnostic for major functional genes. Gene diversity was constant at SSR markers but decreased over time for SNP markers. Population differentiation between the four locations could not be detected, suggesting that organic vs. non-organic crop management did not drive allele frequency changes. However, we did see changes for genes controlling plant height and phenology in all populations independently and consistently. We interpret these changes as the result of a consistent natural selection towards wild-type. Independent selection for alleles that are associated with plant height suggests that competition for light was central, resulting in the predominance of stronger intraspecific competitors, and highlighting a potential trade-off between individual and population performanc
Degradation of mangrove tissues by arboreal termites (\u3cem\u3eNasutitermes acajutlae\u3c/em\u3e) and their role in the mangrove C cycle (Puerto Rico): Chemical characterization and organic matter provenance using bulk ÎŽ\u3csup\u3e13\u3c/sup\u3eC, C/N, alkaline CuO oxidationâGC/MS, and solidâstate \u3csup\u3e13\u3c/sup\u3eC NMR
Arboreal termites are wood decaying organisms that play an important role in the first stages of C cycling in mangrove systems. The chemical composition of Rhizophora mangle, Avicennia germinans, and Laguncularia racemosa leaf, stem, and pneumatophore tissues as well as associated sediments was compared to that of nests of the termite Nasutitermes acajutlae. Nests gave ÎŽ13C values of â26.1 to â27.2â° (±0.1) and C/N of 43.3 (±2.0) to 98.6 (±16.2) which were similar to all stem and pneumatophores but distinct from mangrove leaves or sediments. Organic matter processed by termites yielded lignin phenol concentrations (Î, lambda) that were 2â4 times higher than stem or pneumatophores and 10â20 times higher than that of leaves or sediments, suggesting that the nests were more resistant to biodegradation than the mangrove vegetation source. 13C NMR revealed that polysaccharide content of mangrove tissues (50â69% C) was higher than that of the nests (46â51% C). Conversely, lignin accounted for 16.2â19.6% C of nest material, a threefold increase relative to living mangrove tissues; a similar increase in aromatic methoxyl content was also observed in the nests. Lipids (aliphatic and paraffinic moieties) were also important but rather variable chemical components of all three mangrove species, representing between 13.5 and 28.3% of the C content. Termite nests contained 3.14 Mg C haâ1 which represents approximately 2% of above ground C storage in mangroves, a value that is likely to increase upon burial due to their refractory chemical composition
Neuronal Antibodies in Children with or without Narcolepsy following H1N1-AS03 Vaccination
Type 1 narcolepsy is caused by deficiency of hypothalamic orexin/hypocretin. An autoimmune basis is suspected, but no specific antibodies, either causative or as biomarkers, have been identified. However, the AS03 adjuvanted split virion H1N1 (H1N1-AS03) vaccine, created to protect against the 2009 Pandemic, has been implicated as a trigger of narcolepsy particularly in children. Sera and CSFs from 13 H1N1-AS03-vaccinated patients (12 children, 1 young adult) with type 1 narcolepsy were tested for autoantibodies to known neuronal antigens including the N-methyl-D-aspartate receptor (NMDAR) and contactin-associated protein 2 (CASPR2), both associated with encephalopathies that include disordered sleep, to rodent brain tissue including the lateral hypothalamus, and to live hippocampal neurons in culture. When sufficient sample was available, CSF levels of melanin-concentrating hormone (MCH) were measured. Sera from 44 H1N1-ASO3-vaccinated children without narcolepsy were also examined. None of these patients' CSFs or sera was positive for NMDAR or CASPR2 antibodies or binding to neurons; 4/13 sera bound to orexin-neurons in rat brain tissue, but also to other neurons. MCH levels were a marginally raised (n = 8; p = 0.054) in orexin-deficient narcolepsy patients compared with orexin-normal children (n = 6). In the 44 H1N1-AS03-vaccinated healthy children, there was no rise in total IgG levels or in CASPR2 or NMDAR antibodies three weeks following vaccination. In conclusion, there were no narcolepsy-specific autoantibodies identified in type 1 narcolepsy sera or CSFs, and no evidence for a general increase in immune reactivity following H1N1-AS03 vaccination in the healthy children. Antibodies to other neuronal specific membrane targets, with their potential for directing use of immunotherapies, are still an important goal for future research.Peer reviewe
A Fully Integrated Real-Time Detection, Diagnosis, and Control of Community Diarrheal Disease Clusters and Outbreaks (the INTEGRATE Project):Protocol for an Enhanced Surveillance System
BACKGROUND:Diarrheal disease, which affects 1 in 4 people in the United Kingdom annually, is the most common cause of outbreaks in community and health care settings. Traditional surveillance methods tend to detect point-source outbreaks of diarrhea and vomiting; they are less effective at identifying low-level and intermittent food supply contamination. Furthermore, it can take up to 9 weeks for infections to be confirmed, reducing slow-burn outbreak recognition, potentially impacting hundreds or thousands of people over wide geographical areas. There is a need to address fundamental problems in traditional diarrheal disease surveillance because of underreporting and subsequent unconfirmed infection by patients and general practitioners (GPs); varying submission practices and selective testing of samples in laboratories; limitations in traditional microbiological diagnostics, meaning that the timeliness of sample testing and etiology of most cases remains unknown; and poorly integrated human and animal surveillance systems, meaning that identification of zoonoses is delayed or missed. OBJECTIVE:This study aims to detect anomalous patterns in the incidence of gastrointestinal disease in the (human) community; to target sampling; to test traditional diagnostic methods against rapid, modern, and sensitive molecular and genomic microbiology methods that identify and characterize responsible pathogens rapidly and more completely; and to determine the cost-effectiveness of rapid, modern, sensitive molecular and genomic microbiology methods. METHODS:Syndromic surveillance will be used to aid identification of anomalous patterns in microbiological events based on temporal associations, demographic similarities among patients and animals, and changes in trends in acute gastroenteritis cases using a point process statistical model. Stool samples will be obtained from patients' consulting GPs, to improve the timeliness of cluster detection and characterize the pathogens responsible, allowing health protection professionals to investigate and control outbreaks quickly, limiting their size and impact. The cost-effectiveness of the proposed system will be examined using formal cost-utility analysis to inform decisions on national implementation. RESULTS:The project commenced on April 1, 2013. Favorable approval was obtained from the Research Ethics Committee on June 15, 2015, and the first patient was recruited on October 13, 2015, with 1407 patients recruited and samples processed using traditional laboratory techniques as of March 2017. CONCLUSIONS:The overall aim of this study is to create a new One Health paradigm for detecting and investigating diarrhea and vomiting in the community in near-real time, shifting from passive human surveillance and management of laboratory-confirmed infection toward an integrated, interdisciplinary enhanced surveillance system including management of people with symptoms. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID):DERR1-10.2196/13941
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