292 research outputs found

    “The dog chase the cat”: Grammaticality judgments by Hungarian-speaking children with language impairment

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    In a previous study of language production, a group of Hungarian-speaking children with language impairment (LI) committed a larger number of errors than typically developing peers on verb inflections that mark person, number, tense, and definiteness (Lukács et al. 2009b). However, the error forms produced often differed from the correct form by only a single dimension (e.g., person, number, tense, or definiteness) with no single dimension proving consistently problematic. In the present study, we sought to determine whether a similar pattern applied to the children’s understanding of verb inflections, as reflected in a grammaticality judgment task. We compared the performance of 17 Hungarian-speaking children with language impairment (LI) between ages 8;0 and 11;9 with typically developing children between 6;10 and 11;1 years individually matched on receptive vocabulary raw scores (VC) and also to a control group of children matched on chronological age (AC; between 8;1–12;1). We obtained grammaticality judgments for 68 sentences, including 56 ill-formed sentences that contained a single error of person, number, tense, definiteness, or morphophonology. As the AC group performed at ceiling, the analysis focused on comparisons between the LI and VC groups. Besides comparing accuracy scores in the two groups, we tested how well performance could be predicted by a test of grammatical comprehension (TROG) and a measure of nonword repetition ability obtained prior to the administration of the grammaticality judgment task. There were no significant group differences in the accuracy of grammaticality judgments. Both groups recognized well-formed sentences, and agreement errors of number, person or definiteness, significantly more accurately than tense or morphophonological errors. Although there was no difference between performance levels of the LI and the VC groups, we found differences between the two groups in the types of measures that were most closely tied to performance on the grammaticality judgment task. Performance in the LI group was strongly associated with nonword repetition span, while in the VC group, TROG performance was associated with grammaticality judgment performance. These results suggest that the same level and pattern of performance can be supported by different background mechanisms in typical and atypical language development

    Geographic Variation in Body Size and Weight of Willow Ptarmigan

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    Reports results of multiple range test comparisons of wing, tail and net body weight measurements of 2600 specimens collected in Alaska and adjacent Yukon Territory. Populations from different geographic areas showed statistically significant differences but uniformity within recognizable subspecies. Lagopus lagopus alascensis has the largest range in Alaska and occurs at least to Old Crow in the Yukon. L.l.albus occurs from central Yukon Territory eastward and south to northern British Columbia and west into Alaska in the upper Tanana valley and south of the Alaska Range to the Susitna River. L.l. alexandrae occupies the Alaska and Kenai Peninsulas and a narrow margin of the Gulf of Alaska coast south into British Columbia. L.l. murei is distributed on Kodiak Island, the Shumagins and the Aleutians from Unimak westward. The present distribution of these subspecies may be explained in part by their distribution at the time of the Wisconsin glaciation and their subsequent dispersal.Variations géographiques de la taille et du poids du Lagopède des saules. De multiples comparaisons de mesures des ailes, de la queue et du poids net de 2,600 spécimens de lagopède des saules (Lagopus lagopus) recueillis en Alaska et dans la partie adjacente du territoire du Yukon, ont démontré des différences statistiquement significatives entre les populations des différentes aires géographiques, mains ont aussi indiqué une surprenante uniformité parmi les populations désignées comme sous-espèces reconnaissables.Les précédentes distributions d'habitat, basées sur la couleur du plumage et la taille du bec, distinguaient L. l. alascensis de L. l. albus à la frontière Alaska-Yukon. Sur la base des nouvelles mesures, on croit que la population du L. l. alascensis plus gros s'étend vers l'Est dans le territoire du Yukon au moins jusqu'à Old Crow, tandis que le L. l. albus plus petit s'étend vers l'Ouest à travers l'Alaska, dans la haute vallée de la Tanana et au Sud de la chaîne alaskienne jusqu'à la Sustina. On suppose que la distribution présente des diverses sous-espèces du Logopède des saules en Alaska peut s'expliquer par leur distribution à l'époque de la glaciation wisconsienne et par leur dispersion subséquente

    The contributions of immediate retrieval and spaced retrieval to word learning in preschoolers with developmental language disorder

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    Background and Aims: Children with developmental language disorder (DLD) benefit from word learning procedures that include a mix of immediate retrieval and spaced retrieval trials. In this study, we examine the relative contribution of these two types of retrieval. Methods: We examine data from Haebig et al. (2019) in their study that compared an immediate retrieval condition and a condition of spaced retrieval that also included immediate retrieval trials. Participants were 4- and 5-year old children with DLD and same-age peers with typical language development. Each child learned novel (made-up) words referring to unusual plants and animals in both conditions. We examined the phonetic accuracy of the novel words used during the final learning trial and during recall tests 5 min and 1 week after learning. Results: On the final learning trial, the children were more phonetically accurate in using the novel words learned in the immediate retrieval condition. However, recall tests after the learning trials revealed a decrease in accuracy, especially for the children with DLD. After one week, accuracy was much lower for words in the immediate retrieval condition than for words in the mixed spaced-plus-immediate retrieval condition. For words learned in the mixed spaced-plus-immediate retrieval condition, accuracy was very stable across time for both groups. Conclusions: Immediate retrieval boosts the phonetic accuracy of new words in the short term but spaced retrieval promotes stability and increases the likelihood that short-term gains are maintained. Implications: When novel word learning is assessed at the level of phonetic accuracy, children with DLD can show declines over time not characteristic of children with typical language development. Spaced retrieval procedures augmented by immediate retrieval opportunities during learning appear to prevent such declines, leading to longer-lasting gains

    Simulating the Acquisition of Verb Inflection in Typically Developing Children and Children With Developmental Language Disorder in English and Spanish

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    Children with developmental language disorder (DLD) have significant deficits in language ability that cannot be attributed to neurological damage, hearing impairment, or intellectual disability. The symptoms displayed by children with DLD differ across languages. In English, DLD is often marked by severe difficulties acquiring verb inflection. Such difficulties are less apparent in languages with rich verb morphology like Spanish and Italian. Here we show how these differential profiles can be understood in terms of an interaction between properties of the input language, and the child\u27s ability to learn predictive relations between linguistic elements that are separated within a sentence. We apply a simple associative learning model to sequential English and Spanish stimuli and show how the model\u27s ability to associate cues occurring earlier in time with later outcomes affects the acquisition of verb inflection in English more than in Spanish. We relate this to the high frequency of the English bare form (which acts as a default) and the English process of question formation, which means that (unlike in Spanish) bare forms frequently occur in third-person singular contexts. Finally, we hypothesize that the pro-drop nature of Spanish makes it easier to associate person and number cues with the verb inflection than in English. Since the factors that conspire to make English verb inflection particularly challenging for learners with weak sequential learning abilities are much reduced or absent in Spanish, this provides an explanation for why learning Spanish verb inflection is relatively unaffected in children with DLD

    A multi-study examination of the role of repeated spaced retrieval in the word learning of children with developmental language disorder

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    Background Many children with developmental language disorders (DLD) have well-documented weaknesses in vocabulary. In recent years, investigators have explored the nature of these weaknesses through the use of novel word learning paradigms. These studies have begun to uncover specific areas of difficulty and have provided hints about possible intervention strategies that might help these children learn words more accurately and efficiently. Among the studies of this type are those that incorporate repeated spaced retrieval activities in the learning procedures. Methods In this study, we examined the data from four of these studies that employed the same types of participants (4- and 5-year-old children with DLD and same-age children with typical language development), research design, and outcome measures. The studies differed primarily in the type of learning condition that was being compared to a spaced retrieval condition. A mixed-effects modeling framework was used, enabling the data from the four studies and different outcome measures to be aggregated. Results Across the studies, more words in the repeated spaced retrieval condition were recalled than those in the comparison conditions. This was true regardless of outcome measure. Children with typical language development recalled more words than the children with DLD. Both groups benefited from spaced retrieval, though effects were larger for the group with DLD. Children recalled words as accurately 1 week after learning as they did at the 5-min mark; the two groups were essentially identical in this respect. Conclusions Overall, the findings support the continued refinement of these types of repeated spaced retrieval procedures, as they may have potential to serve as effective approaches to intervention

    Negation and the functional sequence

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    There exists a general restriction on admissible functional sequences which prevents adjacent identical heads. We investigate a particular instantiation of this restriction in the domain of negation. Empirically, it manifests itself as a restriction the stacking of multiple negative morphemes. We propose a principled account of this restriction in terms of the general ban on immediately consecutive identical heads in the functional sequence on the one hand, and the presence of a Neg feature inside negative morphemes on the other hand. The account predicts that the stacking of multiple negative morphemes should be possible provided they are separated by intervening levels of structure. We show that this prediction is borne out

    Association Study of Common Genetic Variants and HIV- 1 Acquisition in 6,300 Infected Cases and 7,200 Controls

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    Multiple genome-wide association studies (GWAS) have been performed in HIV-1 infected individuals, identifying common genetic influences on viral control and disease course. Similarly, common genetic correlates of acquisition of HIV-1 after exposure have been interrogated using GWAS, although in generally small samples. Under the auspices of the International Collaboration for the Genomics of HIV, we have combined the genome-wide single nucleotide polymorphism (SNP) data collected by 25 cohorts, studies, or institutions on HIV-1 infected individuals and compared them to carefully matched population-level data sets (a list of all collaborators appears in Note S1 in Text S1). After imputation using the 1,000 Genomes Project reference panel, we tested approximately 8 million common DNA variants (SNPs and indels) for association with HIV-1 acquisition in 6,334 infected patients and 7,247 population samples of European ancestry. Initial association testing identified the SNP rs4418214, the C allele of which is known to tag the HLA-B*57:01 and B*27:05 alleles, as genome-wide significant (p = 3.6×10−11). However, restricting analysis to individuals with a known date of seroconversion suggested that this association was due to the frailty bias in studies of lethal diseases. Further analyses including testing recessive genetic models, testing for bulk effects of non-genome-wide significant variants, stratifying by sexual or parenteral transmission risk and testing previously reported associations showed no evidence for genetic influence on HIV-1 acquisition (with the exception ofCCR5Δ32 homozygosity). Thus, these data suggest that genetic influences on HIV acquisition are either rare or have smaller effects than can be detected by this sample size

    IL-21 induces in vivo immune activation of NK cells and CD8+ T cells in patients with metastatic melanoma and renal cell carcinoma

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    PURPOSE: Human interleukin-21 (IL-21) is a class I cytokine previously reported in clinical studies on immune responsive cancers. Here we report the effects of systemic IL-21 therapy on the immune system in two phase 1 trials with this novel cytokine. EXPERIMENTAL DESIGN: Recombinant IL-21 was administered by intravenous bolus injection at dose levels from 1 to 100 microg/kg using two planned treatment regimens: thrice weekly for 6 weeks (3/week); or once daily for five consecutive days followed by nine dose-free days (5 + 9). The following biomarkers were studied in peripheral blood mononuclear cells (PBMC) during treatment: phosphorylation of STAT3, alterations in the composition of leukocyte subsets, ex vivo cytotoxicity, expression of effector molecules in enriched CD8(+) T cells and CD56(+) NK cells by quantitative RT-PCR, and gene array profiling of CD8(+) T cells. RESULTS: Effects of IL-21 were observed at all dose levels. In the 5 + 9 regimen IL-21 induced a dose dependent decrease in circulating NK cells and T cells followed by a return to baseline in resting periods. In both CD8(+) T cells and CD56(+) NK cells we found up-regulation of perforin and granzyme B mRNA. In addition, full transcriptome analysis of CD8(+) T cells displayed changes in several transcripts associated with increased cell cycle progression, cellular motility, and immune activation. Finally, cytotoxicity assays showed that IL-21 enhanced the ability of NK cells to kill sensitive targets ex vivo. CONCLUSIONS: IL-21 was biologically active at all dose levels administered with evidence of in vivo NK cell and CD8(+) T cell activation

    More stories on Th17 cells

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    For more than two decades, immunologists have been using the so-called Th1/Th2 paradigm to explain most of the phenomena related to adaptive immunity. the Th1/Th2 paradigm implied the existence of two different, mutually regulated, CD4(+) T helper subsets: Th1 cells, driving cell-mediated immune responses involved in tissue damage and fighting infection against intracellular parasites; and Th2 cells that mediate IgE production and are particularly involved in eosinophilic inflammation, allergy and clearance of helminthic infections. A third member of the T helper set, IL-17-producing CD4(+) T cells, now called Th17 cells, was recently described as a distinct lineage that does not share developmental pathways with either Th1 or Th2 cells. the Th17 subset has been linked to autoimmune disorders, being able to produce IL-17, IL-17F and IL-21 among other inflammatory cytokines. Interestingly, it has been reported that there is not only a cross-regulation among Th1, Th2 and Th17 effector cells but there is also a dichotomy in the generation of Th17 and T regulatory cells. Therefore, Treg and Th17 effector cells arise in a mutually exclusive fashion, depending on whether they are activated in the presence of TGF-beta or TGF-beta plus inflammatory cytokines such as IL-6. This review will address the discovery of the Th17 cells, and recent progress on their development and regulation.Crohn's and Colitis Foundation of AmericaNIHLa Jolla Inst Allergy & Immunol, La Jolla, CA 92037 USAUniversidade Federal de SĂŁo Paulo, Dept Microbiol Immunol & Parasitol, SĂŁo Paulo, BrazilUniversidade Federal de SĂŁo Paulo, Dept Microbiol Immunol & Parasitol, SĂŁo Paulo, BrazilNIH: RO1 AI050265-06Web of Scienc
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