32 research outputs found

    Capturing Age-group Differences and Developmental Change with the BASC Parent Rating Scales

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    Estimation of age-group differences and intra-individual change across distinct developmental periods is often challenged by the use of age-appropriate (but non-parallel) measures. We present a short version of the Behavior Assessment System (Reynolds & Kamphaus, 1998), Parent Rating Scales for Children (PRS-C) and Adolescents (PRS-A), which uses only their common-items to derive estimates of the initial constructs optimized for developmental studies. Measurement invariance of a three-factor model (Externalizing, Internalizing, Adaptive Skills) was tested across age-groups (161 mothers using PRS-C; 200 mothers using PRS-A) and over time (115 mothers using PRS-C at baseline and PRS-A five years later) with the original versus short PRS. Results indicated that the short PRS holds a sufficient level of invariance for a robust estimation of age-group differences and intra-individual change, as compared to the original PRS, which held only weak invariance leading to flawed developmental inferences. Importance of test-content parallelism for developmental studies is discussed

    Physical Growth and Nonverbal Intelligence: Associations in Zambia

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    Objective: To investigate normative developmental body mass index (BMI) trajectories and associations of physical growth indicators—height, weight, head circumference (HC), and BMI—with nonverbal intelligence in an understudied population of children from sub-Saharan Africa. Study design: A sample of 3981 students (50.8% male), grades 3-7, with a mean age of 12.75 years was recruited from 34 rural Zambian schools. Children with low scores on vision and hearing screenings were excluded. Height, weight, and HC were measured, and nonverbal intelligence was assessed using the Universal Nonverbal Intelligence Test, Symbolic Memory subtest and Kaufman Assessment Battery for Children, Second Edition, Triangles subtest. Results: Students in higher grades had a higher BMI over and above the effect of age. Girls had a marginally higher BMI, although that for both boys and girls was approximately 1 SD below the international Centers for Disease Control and Prevention and World Health Organization norms. When controlling for the effect of age, nonverbal intelligence showed small but significant positive relationships with HC (r = 0.17) and BMI (r = 0.11). HC and BMI accounted for 1.9% of the variance in nonverbal intelligence, over and above the contribution of grade and sex. Conclusion: BMI-for-age growth curves of Zambian children follow observed worldwide developmental trajectories. The positive relationships between BMI and intelligence underscore the importance of providing adequate nutritional and physical growth opportunities for children worldwide and in sub-Saharan Africa in particular. Directions for future studies are discussed with regard to maximizing the cognitive potential of all rural African children

    Production of retroviral vectors in continuous high cell density culture

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    Abstract: Retroviral vectors derived from murine leukemia virus (MLV) are used in somatic gene therapy applications e.g. for genetic modification of hematopoietic stem cells. Recently, we reported on the establishment of a suspension viral packaging cell line (VPC) for the production of MLV vectors. Human embryonic kidney 293-F (HEK293-F) cells were genetically modified for this purpose using transposon vector technology. Here, we demonstrate the establishment of a continuous high cell density (HCD) process using this cell line. First, we compared different media regarding the maximum achievable viable cell concentration (VCC) in small scale. Next, we transferred this process to a stirred tank bioreactor before we applied intensification strategies. Specifically, we established a perfusion process using an alternating tangential flow filtration system. Here, VCCs up to 27.4E + 06 cells/mL and MLV vector titers up to 8.6E + 06 transducing units/mL were achieved. Finally, we established a continuous HCD process using a tubular membrane for cell retention and continuous viral vector harvesting. Here, the space-time yield was 18-fold higher compared to the respective batch cultivations. Overall, our results clearly demonstrate the feasibility of HCD cultivations for high yield production of viral vectors, especially when combined with continuous viral vector harvesting. Key points: • A continuous high cell density process for MLV vector production was established • The tubular cell retention membrane allowed for continuous vector harvesting • The established process had a 18-fold higher space time yield compared to a batc

    Getting something out of nothing: Analyzing patterns of null responses to improve data collection methods in sub-Saharan Africa

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    Careful development and adaptation of assessments is imperative for cultural psychological research. However, despite the best efforts, the use of assessments in new contexts can reveal atypical and/or unexpected patterns of performance. We found this to be the case in the testing of assessments to be used for a larger investigation of Specific Reading Disabilities in Zambia. In a sample of 207 children (100 female) from grades 2 to 7, we illustrated that assessment characteristics (i.e., stimulus type, answer choice, and response type) differentially impact patterns of responsiveness. The number of missing values was highest for assessments that (1) used written stimuli, (2) had an open-ended answer choice, and (3) required an action response. Age and socio-economic status explained some of the variance in responsiveness in selected, but not all assessments. Consideration of the impact of stimulus and response types when adapting assessments cross-linguistically and cross-culturally is essential

    School effects on non-verbal intelligence and nutritional status in rural Zambia

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    This study uses hierarchical linear modeling (HLM) to examine the school factors (i.e., related to school organization and teacher and student body) associated with non-verbal intelligence (NI) and nutritional status (i.e., body mass index; BMI) of 4204 3rd to 7th graders in rural areas of Southern Province, Zambia. Results showed that 23.5% and 7.7% of the NI and BMI variance, respectively, were conditioned by differences between schools. The set of 14 school factors accounted for 58.8% and 75.9% of the between-school differences in NI and BMI, respectively. Grade-specific HLM yielded higher between-school variation of NI (41%) and BMI (14.6%) for students in grade 3 compared to grades 4 to 7. School factors showed a differential pattern of associations with NI and BMI across grades. The distance to a health post and teacher’s teaching experience were the strongest predictors of NI (particularly in grades 4, 6 and 7); the presence of a preschool was linked to lower BMI in grades 4 to 6. Implications for improving access and quality of education in rural Zambia are discussed

    Production of influenza A virus defective interfering particles in a high cell density perfusion cultivation with continuous virus harvesting

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    Causing annual epidemics and occasional pandemics, influenza A virus (IAV) is a human pathogen that has severe impact on health and society. Defective interfering particles (DIPs) have been discussed as a potential antiviral therapeutic [1]. Most IAV DIPs are naturally occurring viral mutants harboring large internal deletions in at least one of their eight viral RNA (vRNA) segments. Due to these deletions, DIPs can only replicate in the presence of infectious standard virus (STV), compensating for the missing gene function. In a co-infection, the defective vRNA segment interferes with STV genome replication, which is causative for the therapeutic potential of the DIP. In the presented study, we report on the cell culture-based production and the evaluation of the antiviral potency of a DIP with a deletion in segment 1 vRNA, called DI244. Please click Download on the upper right corner to see the full abstract

    Identifying Learning Patterns of Children at Risk for Specific Reading Disability

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    Differences in learning patterns of vocabulary acquisition in children at risk (+SRD) and not at risk (SRD) for Specific Reading Disability (SRD) were examined using a microdevelopmental paradigm applied to the multi-trial Foreign Language Learning Task (FLLT; Baddeley et al., 1995). The FLLT was administered to 905 children from rural Chitonga-speaking Zambia. A multi-group Latent Growth Curve Model (LGCM) was implemented to study interindividual differences in intraindividual change across trials. Results showed that the +SRD group recalled fewer words correctly in the first trial, learned at a slower rate during the subsequent trials, and demonstrated a more linear learning pattern compared to the SRD group. This study illustrates the promise of LGCM applied to multi-trial learning tasks, by isolating three components of the learning process (initial recall, rate of learning, and functional pattern of learning). Implications of this microdevelopmental approach to SRD research in low-to-middle income countries are discussed

    Differences in Judgments of Creativity: How Do Academic Domain, Personality, and Self-Reported Creativity Influence Novice Judges’ Evaluations of Creative Productions?

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    Intelligence assessment is often viewed as a narrow and ever-narrowing field, defined (as per IQ) by the measurement of finely distinguished cognitive processes. It is instructive, however, to remember that other, broader conceptions of intelligence exist and might usefully be considered for a comprehensive assessment of intellectual functioning. This article invokes a more holistic, systems theory of intelligence—the theory of successful intelligence—and examines the possibility of including in intelligence assessment a similarly holistic measure of creativity. The time and costs of production-based assessments of creativity are generally considered prohibitive. Such barriers may be mitigated by applying the consensual assessment technique using novice raters. To investigate further this possibility, we explored the question: how much do demographic factors such as age and gender and psychological factors such as domain-specific expertise, personality or self-perceived creativity affect novices’ unidimensional ratings of creativity? Fifty-one novice judges from three undergraduate programs, majoring in three disparate expertise domains (i.e., visual art, psychology and computer science) rated 40 child-generated Lego creatures for creativity. Results showed no differences in creativity ratings based on the expertise domains of the judges. However, judges’ personality and self-perception of their own everyday creativity appeared to influence the way they scored the creatures for creativity

    Paired Associate Learning Tasks and their Contribution to Reading Skills

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    Associative learning has been identified as one of several non-linguistic processes involved in reading acquisition. However, it has not been established whether it is an independent process that contributes to reading performance on its own or whether it is a process that is embedded in other linguistic skills (e.g., phonological awareness or phonological memory) and, therefore, contributing to reading performance indirectly. Research has shown that performance on tasks assessing associative learning, e.g., paired-associate learning (PAL) tasks, is lower in children with specific reading difficulties compared to typical readers. We explored the differential associations of two distinct verbal-visual PAL tasks (the Bala Bbala Graphogame, BBG, and a Foreign Language Learning Task, FLLT) with reading skills (word reading and pseudo-word decoding), controlling for phonological awareness, rapid naming, and letter and digit span in children at risk for reading disabilities and their typically developing peers. Our study sample consisted of 110 children living in rural Zambia, ranging in age from 7 to 18 years old (48.1% female). Multivariate analyses of covariance were used to explore the group differences in reading performance. Repeated-measures ANCOVA was used to examine children’s learning across the PAL tasks. The differential relationships between both PAL tasks and reading performance were explored via structural equation modeling. The main result was that the children at risk for reading difficulties had lower performance on both PAL tasks. The BBG was a significant predictor for both word reading and pseudo-word decoding, whereas the FLLT—only for word reading. Performance on the FLLT partially mediated the association between phonological awareness and word reading. These results illustrate the partial independence of associative learning from other reading-related skills; the specifics of this relationship vary based on the type of PAL task administered

    Associations between household responsibilities and academic competencies in the context of education accessibility in Zambia

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    The relationship between education and socioeconomic status has been demonstrated in studies of the developed and the developing world, yet there are communities in which schooling is either not available to all children or not a preferred activity for all children. In this study, we investigated the differences between children in-school and out-of-school in rural and peri-urban communities of Zambia. As expected, we found that the children in-school performed higher in domains of adaptive behavior and on assessments of academic achievement (i.e., mathematics, reading). Somewhat unexpectedly, however, when controlling for socioeconomic status, home responsibilities (i.e., chores, work) were a positive predictor for the performance of the children out-of-school, but a negative predictor for the children in-school. The relationship between home responsibilities and academic performance may be bidirectional and differential; for example, our findings allow for the hypothesis that for in-school children chores take time away from the studies, but for out-of-school children they provide some limited mathematics exposure
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