592 research outputs found

    The Effect of Growth Environment and Salinity on Lipid Production and Composition of Salicornia virginica

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    Finding a viable and sustainable source of renewable energy is a global task. Biofuels as a renewable energy source can potentially be a viable option for sustaining long-term energy needs. Biodiesel from halophytes shows great promise due to their ability to serve not only as a fuel source, but a food source as well. Halophytes are one of the few biomass plant species that can tolerate a wide range of saline conditions. We investigate the feasibility of using the halophyte, Salicornia virginica as a biofuel source by conducting a series of experiments utilizing various growth and salinity conditions. The goal is to determine if the saline content of Salicornia virginica in our indoor growth vs outdoor growth conditions has an influence on lipid recovery and total biomass composition. We focused on using standard lipid extraction protocols and characterization methods to evaluate twelve Salicornia virginica samples under six saline values ranging from freshwater to seawater and two growth conditions. The overall goal is to develop an optimal lipid extraction protocol for Salicornia virginica and potentially apply this protocol to halophytes in general

    Separating the influences of prereading skills on early word and nonword reading

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    The essential first step for a beginning reader is to learn to match printed forms to phonological representations. For a new word, this is an effortful process where each grapheme must be translated individually (serial decoding). The role of phonological awareness in developing a decoding strategy is well known. We examined whether beginning readers recruit different skills depending on the nature of the words being read (familiar words vs. nonwords). Print knowledge, phoneme and rhyme awareness, rapid automatized naming (RAN), phonological short-term memory (STM), nonverbal reasoning, vocabulary, auditory skills, and visual attention were measured in 392 prereaders 4 and 5 years of age. Word and nonword reading were measured 9 months later. We used structural equation modeling to examine the skills–reading relationship and modeled correlations between our two reading outcomes and among all prereading skills. We found that a broad range of skills were associated with reading outcomes: early print knowledge, phonological STM, phoneme awareness and RAN. Whereas all of these skills were directly predictive of nonword reading, early print knowledge was the only direct predictor of word reading. Our findings suggest that beginning readers draw most heavily on their existing print knowledge to read familiar words

    The development of sentence-interpretation strategies in monolingual German-learning children with and without specific language impairment

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    Previous research on sentence comprehension conducted with German-learning children has concentrated on the role of case marking and word order in typically developing children. This paper compares, the performance of German-learning children with language impairment (age 4-6 years) and without language impairment (aged 2-6, 8-9 years) in two experiments that systematically vary the cues animacy, case marking; word-order, and subject-verb agreement. The two experiments differ with regard to the choice of case marking: in the first it is distinct but in the second it is neutralized. The theoretical framework is the competition model developed by Bates and Mac Whinney and their collaborators, a variant of the parallel distributed processing models. It is hypothesized that children of either population first appreciate the cue animacy that can be processed locally, that is, "on the spot," before they turn to more distributed cues leading ultimately up to subject-verb agreement, which presupposes the comparison of various constituents before an interpretation can be established. Thus agreement is more "costly" in processing than animacy or the (more) local cue initial NP. In experiment I with unambiguous case markers it is shown that the typically developing children proceed from animacy to the nominative (predominantly in coalition with the initial NP) to agreement, while in the second experiment with ambiguous case markers these children turn from animacy to the initial NP and then to agreement. The impaired children also progress from local to distributed cues. Yet, in contrast to the control group, they do not acknowledge the nominative in coalition with the initial NP in the first experiment but only in support of agreement. However, although they do not seem to appreciate distinct case markers to any large extent in the first experiment, they are irritated if such distinctions are lacking: in experiment II all impaired children turn to. animacy (some in coalition with the initial NP and/or particular word orders). In the discussion, the relationship between short-term memory and processing as well as the relationship between production and comprehension of case markers and agreement are addressed. Further research is needed to explore in more detail "cue costs" in sentence comprehension

    Analyzing false memories in children with associative lists specific for their age

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    Two experiments attempted to resolve previous contradictory findings concerning developmental trends in false memories within the Deese-Roediger-McDermott (DRM) paradigm by using an improved methodology-constructing age-appropriate associative lists. The research also extended the DRM paradigm to preschoolers. Experiment 1 (N = 320) included children in three age groups (preschoolers of 3-4 years, second-graders of 7-8 years, and preadolescents of 11-12 years) and adults, and Experiment 2 (N = 64) examined preschoolers and preadolescents. Age-appropriate lists increased false recall. Although preschoolers had fewer false memories than the other age groups, they showed considerable levels of false recall when tested with age-appropriate materials. Results were discussed in terms of fuzzy-trace, source-monitoring, and activation frameworks

    Computer simulations of developmental change: The contributions of working memory capacity and long-term knowledge

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    Increasing working memory (WM) capacity is often cited as a major influence on children’s development and yet WM capacity is difficult to examine independently of long-term knowledge. A computational model of children’s nonword repetition (NWR) performance is presented that independently manipulates long-term knowledge and WM capacity to determine the relative contributions of each in explaining the developmental data. The simulations show that (1) both mechanisms independently cause the same overall developmental changes in NWR performance; (2) increase in long-term knowledge provides the better fit to the child data; and (3) varying both long-term knowledge and WM capacity adds no significant gains over varying long-term knowledge alone. Given that increases in long-term knowledge must occur during development, the results indicate that increases in WM capacity may not be required to explain developmental differences. An increase in WM capacity should only be cited as a mechanism of developmental change when there are clear empirical reasons for doing so

    A New Mint1 Isoform, but Not the Conventional Mint1, Interacts with the Small GTPase Rab6

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    Small GTPases of the Rab family are important regulators of a large variety of different cellular functions such as membrane organization and vesicle trafficking. They have been shown to play a role in several human diseases. One prominent member, Rab6, is thought to be involved in the development of Alzheimer’s Disease, the most prevalent mental disorder worldwide. Previous studies have shown that Rab6 impairs the processing of the amyloid precursor protein (APP), which is cleaved to ÎČ-amyloid in brains of patients suffering from Alzheimer’s Disease. Additionally, all three members of the Mint adaptor family are implied to participate in the amyloidogenic pathway. Here, we report the identification of a new Mint1 isoform in a yeast two-hybrid screening, Mint1 826, which lacks an eleven amino acid (aa) sequence in the conserved C-terminal region. Mint1 826, but not the conventional Mint1, interacts with Rab6 via the PTB domain. This interaction is nucleotide-dependent, Rab6-specific and influences the subcellular localization of Mint1 826. We were able to detect and sequence a corresponding proteolytic peptide derived from cellular Mint1 826 by mass spectrometry proving the absence of aa 495–505 and could show that the deletion does not influence the ability of this adaptor protein to interact with APP. Taking into account that APP interacts and co-localizes with Mint1 826 and is transported in Rab6 positive vesicles, our data suggest that Mint1 826 bridges APP to the small GTPase at distinct cellular sorting points, establishing Mint1 826 as an important player in regulation of APP trafficking and processing

    Development of intuitive rules: Evaluating the application of the dual-system framework to understanding children's intuitive reasoning

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    This is an author-created version of this article. The original source of publication is Psychon Bull Rev. 2006 Dec;13(6):935-53 The final publication is available at www.springerlink.com Published version: http://dx.doi.org/10.3758/BF0321390

    The effectiveness of classroom vocabulary intervention for adolescents with language disorder

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    Purpose Phonological-semantic intervention has been shown to be effective in enhancing the vocabulary skills of children with language disorder in small-group or individual settings. Less is known about vocabulary interventions for adolescents with language disorder in whole-class models of delivery. The current study investigated the effectiveness of phonological-semantic vocabulary intervention for adolescents with language disorder, delivered by secondary school teachers within science lessons. Methods Seventy-eight adolescents with language disorder, aged 11 – 13 years, were taught science curriculum words by teachers in class, under two conditions: 1) 10 words taught through usual teaching practice; and 2) 10 matched words taught using an experimental intervention known as Word Discovery, which embedded phonological-semantic activities into the teaching of the syllabus. Ten similar control words received no intervention. Word knowledge was assessed pre-intervention, post-intervention, and follow-up. Results At pre-intervention, measures of depth of word knowledge and expressive word use did not differ between usual teaching practice and experimental words. At post-intervention, depth of knowledge of experimental words was significantly greater than that of usual teaching practice words. This significant advantage was not maintained at follow-up, although depth of knowledge for experimental words remained significantly higher at follow-up than at preintervention. At post-intervention, expressive use of experimental words was significantly greater than that of usual teaching practice words, and this significant difference was maintained at follow-up. There was no change in students’ depth of knowledge or expressive use of no-intervention words over time, confirming that the findings were not due to maturity or practice effects. Conclusion The experimental intervention was more effective than usual teaching practice in increasing the word knowledge of participants. Clinical and teaching implications include the importance of intervening during the adolescent years, with classroom vocabulary intervention being a viable option for collaborative teacher and speech and language therapy/pathology practice
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