3,248 research outputs found
Communicative and linguistic development in preterm children: a longitudinal study from 12 to 24 months.
BACKGROUND: Research conducted on preterm children's linguistic skills has provided varying pictures, and the question of whether and to what extent preterm children are delayed in early language acquisition remains largely unresolved. AIMS: To examine communicative and linguistic development during the second year in a group of Italian children born prematurely using the 'Primo Vocabolario del Bambino' (PVB), the Italian version of the MacArthur-Bates Communicative Development Inventory. The primary goal was to compare action/gesture production, word comprehension, and word production, and the relationship between these three domains in preterm children and to normative data obtained from a large sample of Italian children born at term. A second aim was to address the longstanding debate regarding the use of chronological versus corrected gestational age in the assessment of preterm children's abilities. METHODS & PROCEDURES: Parents of twelve preterm children completed the PVB questionnaire at five age points during the children's second year, and scores were compared with those from a normative sample of full-term children and those of 59 full-term children selected as a control group from the normative sample for the PVB. OUTCOMES & RESULTS: Preterm children exhibited a delay in all three aspects of communication and language. In particular, communicative-linguistic age tended to lag approximately 3 months behind chronological age when children were between the ages of 12 and 24 months. When chronological age was used, preterm children's percentile scores for all three components of communication and language fell within the lower limits of the normal range, while scores calculated using corrected age either fell at or above the 50th percentile. CONCLUSIONS & IMPLICATIONS: Findings suggest that despite the significant biological risk engendered by premature birth, early communicative and linguistic development appears to proceed in a relatively robust fashion among preterm children, with tight relations across communicative domains as in full-term children. Employing both chronological and corrected gestational age criteria in the evaluation of preterm children's abilities may provide important information about their progress in language acquisition. This may be especially important during the initial stages of communicative and linguistic development, inasmuch as comparisons of the two sets of scores may provide clinicians with a way to distinguish children who may be at risk for language problems from those who may be expected to progress normally
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The unity and diversity of executive functions: A systematic review and re-analysis of latent variable studies.
Confirmatory factor analysis (CFA) has been frequently applied to executive function measurement since first used to identify a three-factor model of inhibition, updating, and shifting; however, subsequent CFAs have supported inconsistent models across the life span, ranging from unidimensional to nested-factor models (i.e., bifactor without inhibition). This systematic review summarized CFAs on performance-based tests of executive functions and reanalyzed summary data to identify best-fitting models. Eligible CFAs involved 46 samples (N = 9,756). The most frequently accepted models varied by age (i.e., preschool = one/two-factor; school-age = three-factor; adolescent/adult = three/nested-factor; older adult = two/three-factor), and most often included updating/working memory, inhibition, and shifting factors. A bootstrap reanalysis simulated 5,000 samples from 21 correlation matrices (11 child/adolescent; 10 adult) from studies including the three most common factors, fitting seven competing models. Model results were summarized as the mean percent accepted (i.e., average rate at which models converged and met fit thresholds: CFI â„ .90/RMSEA †.08) and mean percent selected (i.e., average rate at which a model showed superior fit to other models: ÎCFI â„ .005/.010/ÎRMSEA †-.010/-.015). No model consistently converged and met fit criteria in all samples. Among adult samples, the nested-factor was accepted (41-42%) and selected (8-30%) most often. Among child/adolescent samples, the unidimensional model was accepted (32-36%) and selected (21-53%) most often, with some support for two-factor models without a differentiated shifting factor. Results show some evidence for greater unidimensionality of executive function among child/adolescent samples and both unity and diversity among adult samples. However, low rates of model acceptance/selection suggest possible bias toward the publication of well-fitting but potentially nonreplicable models with underpowered samples. (PsycINFO Database Record (c) 2018 APA, all rights reserved)
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In vitro scanning saturation mutagenesis of proteins
The present invention combines PCR.TM. mutagenesis with in vitro transcription/translation and ELISA for the rapid generation and characterization of protein mutants. The PCR.TM. products are used directly as the template for the in vitro transcription/translation reactions and because no cloning steps are required, the in vitro saturation mutagenesis of one residue can be completed in duplicate within a week by a single investigator. This high throughput enables the saturation mutagenesis of numerous residues of interest, a process that can be described as in vitro scanning saturation mutagenesis. Compositions and methods of use of such a process are described herein.Board of Regents, University of Texas Syste
Editorial: Understanding Trajectories and Promoting Change From Early to Complex Skills in Typical and Atypical Development: A Cross-Population Approach
This Research Topic focuses on new research perspectives, methodologies, and protocols to understand trajectories and promote change in typical, at-risk, and atypical development. The interplay between early skills and the environment and the
connections between theoretical and interventionmodels with an interdisciplinary, cross-domain and cross-population approach are addressed. These findings have important implications for clinicians and practitioners, who should take into account the
specific characteristics of individual and interacting learning processes in planning interventions
Intern Self-Care: An Exploratory Study Into Strategy Use and Effectiveness
In this exploratory study, 363 interns were surveyed to assess the frequency of use and effectiveness of self-care strategies used during the internship year. Among the most frequently used strategies were family and friend social support, active problem solving, and humor. The most effective strategies were family and friend social support, seeking pleasurable experiences, and humor. A strong positive relationship was found between total scores for Frequency and Effectiveness subscales, and women reported significantly more use and effectiveness of strategies. Recommendations and resources are provided for interns and internship sites that seek to further understand and encourage intern self-care
Avalanche Dynamics in Wet Granular Materials
We have studied the dynamics of avalanching wet granular media in a rotating
drum apparatus. Quantitative measurements of the flow velocity and the granular
flux during avalanches allow us to characterize novel avalanche types unique to
wet media. We also explore the details of viscoplastic flow (observed at the
highest liquid contents) in which there are lasting contacts during flow,
leading to coherence across the entire sample. This coherence leads to a
velocity independent flow depth at high rotation rates and novel robust pattern
formation in the granular surface.Comment: 5 pages, 3 figures in color, REVTeX4, for smaller pdfs see
http://angel.elte.hu/~tegzes/condmat.htm
Low Rates of Pointing in 18-Month-Olds at Risk for Autism Spectrum Disorder and Extremely Preterm Infants: A Common Index of Language Delay?
Infants with an older sibling with an Autism Spectrum Disorder diagnosis (Sibs ASD) are at high risk for language delay (LD) as well as infants born preterm, especially those with an extremely low gestational age (ELGA, GA 64 28 weeks). Gestures play a crucial role in language development and delays in gesture production may have negative cascading effects on it. The present exploratory study examined gesture production in 18-month-old infants with different underlying risks for LD. Seventy monolingual United States infants (41 Sibs ASD with no eventual ASD diagnosis and 29 infants with a typically developing older sibling -Sibs TD) and 40 monolingual Italian infants (20 ELGA without major cerebral damages, congenital malformations or sensory impairments and 20 full-term - FT infants, GA 65 37 weeks) were included. Both groups were followed longitudinally from 18 to 24, 30, and 36 months (corrected for ELGA infants). A 30-minute mother-infant play session with age-appropriate toys was video recorded at 18 months of age. Deictic (requesting, pointing, showing and giving), conventional, and representational gestures spontaneously produced by infants were coded; rate per 10 min was calculated. LD was defined as a score 6410th percentile on the American English or Italian version of the MacArthur-Bates CDI on at least two time points between 18 and 36 months. Fifteen Sibs ASD and 9 ELGA infants were identified as infants with LD. Sibs ASD-LD and Sibs ASD-no LD produced fewer pointing gestures compared to Sibs TD (p = 0.038; p = 0.004); ELGA-LD infants produced significantly fewer pointing gestures than ELGA-no LD (p = 0.024) and FT (p = 0.006) infants. Low rates of pointing at 18 months are a marker of LD in Sibs ASD and ELGA infants. The potential implications of reduced pointing production and characteristics of different populations at risk for LD should be considered for understanding the emergence of LD
Recognition of specific sialoglycan structures by oral streptococci impacts the severity of endocardial infection.
Streptococcus gordonii and Streptococcus sanguinis are primary colonizers of the tooth surface. Although generally non-pathogenic in the oral environment, they are a frequent cause of infective endocarditis. Both streptococcal species express a serine-rich repeat surface adhesin that mediates attachment to sialylated glycans on mucin-like glycoproteins, but the specific sialoglycan structures recognized can vary from strain to strain. Previous studies have shown that sialoglycan binding is clearly important for aortic valve infections caused by some S. gordonii, but this process did not contribute to the virulence of a strain of S. sanguinis. However, these streptococci can bind to different subsets of sialoglycan structures. Here we generated isogenic strains of S. gordonii that differ only in the type and range of sialoglycan structures to which they adhere and examined whether this rendered them more or less virulent in a rat model of endocarditis. The findings indicate that the recognition of specific sialoglycans can either enhance or diminish pathogenicity. Binding to sialyllactosamine reduces the initial colonization of mechanically-damaged aortic valves, whereas binding to the closely-related trisaccharide sialyl T-antigen promotes higher bacterial densities in valve tissue 72 hours later. A surprising finding was that the initial attachment of streptococci to aortic valves was inversely proportional to the affinity of each strain for platelets, suggesting that binding to platelets circulating in the blood may divert bacteria away from the endocardial surface. Importantly, we found that human and rat platelet GPIbα (the major receptor for S. gordonii and S. sanguinis on platelets) display similar O-glycan structures, comprised mainly of a di-sialylated core 2 hexasaccharide, although the rat GPIbα has a more heterogenous composition of modified sialic acids. The combined results suggest that streptococcal interaction with a minor O-glycan on GPIbα may be more important than the over-all affinity for GPIbα for pathogenic effects
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Deficits in agency in schizophrenia, and additional deficits in body image, body schema, and internal timing, in passivity symptoms
Individuals with schizophrenia, particularly those with passivity symptoms, may not feel in control of their actions, believing them to be controlled by external agents. Cognitive operations that contribute to these symptoms may include abnormal processing in agency as well as body representations that deal with body schema and body image. However, these operations in schizophrenia are not fully understood, and the questions of general versus specific deficits in individuals with different symptom profiles remain unanswered. Using the projected-hand illusion (a digital video version of the rubber-hand illusion) with synchronous and asynchronous stroking (500 ms delay), and a hand laterality judgment task, we assessed sense of agency, body image, and body schema in 53 people with clinically stable schizophrenia (with a current, past, and no history of passivity symptoms) and 48 healthy controls. The results revealed a stable trait in schizophrenia with no difference between clinical subgroups (sense of agency) and some quantitative (specific) differences depending on the passivity symptom profile (body image and body schema). Specifically, a reduced sense of self-agency was a common feature of all clinical subgroups. However, subgroup comparisons showed that individuals with passivity symptoms (both current and past) had significantly greater deficits on tasks assessing body image and body schema, relative to the other groups. In addition, patients with current passivity symptoms failed to demonstrate the normal reduction in body illusion typically seen with a 500 ms delay in visual feedback (asynchronous condition), suggesting internal timing problems. Altogether, the results underscore self-abnormalities in schizophrenia, provide evidence for both trait abnormalities and state changes specific to passivity symptoms, and point to a role for internal timing deficits as a mechanistic explanation for external cues becoming a possible source of self-body input
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