356 research outputs found

    Evaluation of the composition, properties and fertility of Haplic Ferralsol on the fields abandoned for five years in the Republic of Chad

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    The article deals with the fertility of red ferralitic soils in the Republic of Chad. The studies were carried out in the period between 2016 and 2018 in the southern part of the province of Moundou on the red ferralitic soils (Haplic Ferralsol)of the Cotton-Chad farm, which cultivates cotton first of its formation. Haplic Ferralsols are characterized by significant reservoir thickness and are not rich in nutrients. The aim of our research was to study the composition and properties of the Haplic Ferralsols of the fields abandoned for five years for their use under cotton export culture. We have evaluated the morphological structure of the soil on neglected fields and its description by genetic horizons, studied the particle size distribution of the soil profile, its gross composition, cation exchange capacity, the content of exchangeable cations, and also considered the agrochemical and agrophysical properties of soil horizons. It has been established that Haplic Ferralsols have their own characteristics: red color, thick soil profile and a gradual transition between genetic horizons, and lightweight granulometric composition in the upper part of the profile. The basis of the gross chemical composition of Haplic Ferralsols is SiO2, Fe2O3 and Al2O3, the content of which varies depending on the depth of the soil profile within the ranges of 61.83ā€“82.73Ā %, 3.50ā€“6.40Ā % and 11.46ā€“29.25Ā % correspondingly. Haplic Ferralsols are characterized by a high cation exchange capacity (6.6ā€“11.1 сmol (eq)/kg). Among the exchangeable cations, calcium (Ca2+) is the most essential. Haplic Ferralsols are moderately provided with humus. In the upper soil layers (up to 42 cm), its content varied within 1.53ā€“1.66Ā %. Soils are characterized by acidic reactions ā€“ from moderately acidic in the upper horizons to very strongly acidic in the lower horizon. The content of mobile compounds of phosphorus and potassium in the profile is low and very low, respectively, 0.76ā€“1.09 mg/100 g and 0.05ā€“1.48 mg/100 g. According to its agrophysical properties, the soil may be used for cotton growing. In the upper soil layer (0ā€“42 cm) the bulk density is 1.36ā€“1.45 g/cm3, the total porosity is 45.9ā€“48.9Ā % and the field water-holding capacity is 22.4ā€“25.7 %

    Stability of the Autism Diagnostic Interviewā€”Revised from Pre-School to Elementary School Age in Children with Autism Spectrum Disorders

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    This study examined the stability of scores on the ADI-R from pre-school to elementary school age in children with autism spectrum disorders (ASD). Participants were 35 children who, at T1, all had a clinical diagnosis of ASD. On initial assessment (mean age 3.5 years; SD 0.6), all met ADI-R algorithm criteria for autism. ADI-R assessments were repeated at follow up (FU; mean age 10.5 years; SD 0.8). Changes in ADI-R total, domain and ADI-R algorithm item scores were assessed. Twentyeight children continued to score above the ADI-R cut-off for autism at FU, although significant decreases in ADI-R domain and item scores were also found. In conclusion, while classification of children according to ADI-R criteria, generally remained stable between pre-school and elementary school age, many children demonstrated significant improvements in symptom severity

    Developmental Trajectories in Siblings of Children with Autism: Cognition and Language from 4 Months to 7 Years

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    We compared the cognitive and language development at 4, 14, 24, 36, 54Ā months, and 7Ā years of siblings of children with autism (SIBS-A) to that of siblings of children with typical development (SIBS-TD) using growth curve analyses. At 7Ā years, 40% of the SIBS-A, compared to 16% of SIBS-TD, were identified with cognitive, language and/or academic difficulties, identified using direct tests and/or parental reports. This sub-group was identified as SIBS-A-broad phenotype (BP). Results indicated that early language scores (14ā€“54Ā months), but not cognitive scores of SIBS-A-BP and SIBS-A-nonBP were significantly lower compared to the language scores of SIBS-TD, and that the rate of development was also significantly different, thus pinpointing language as a major area of difficulty for SIBS-A during the preschool years

    A voxel-wise assessment of growth differences in infants developing autism spectrum disorder

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    Autism Spectrum Disorder (ASD) is a phenotypically and etiologically heterogeneous developmental disorder typically diagnosed around 4 years of age. The development of biomarkers to help in earlier, presymptomatic diagnosis could facilitate earlier identification and therefore earlier intervention and may lead to better outcomes, as well as providing information to help better understand the underlying mechanisms of ASD. In this study, magnetic resonance imaging (MRI) scans of infants at high familial risk, from the Infant Brain Imaging Study (IBIS), at 6, 12 and 24 months of age were included in a morphological analysis, fitting a mixed-effects model to Tensor Based Morphometry (TBM) results to obtain voxel-wise growth trajectories. Subjects were grouped by familial risk and clinical diagnosis at 2 years of age. Several regions, including the posterior cingulate gyrus, the cingulum, the fusiform gyrus, and the precentral gyrus, showed a significant effect for the interaction of group and age associated with ASD, either as an increased or a decreased growth rate of the cerebrum. In general, our results showed increased growth rate within white matter with decreased growth rate found mostly in grey matter. Overall, the regions showing increased growth rate were larger and more numerous than those with decreased growth rate. These results detail, at the voxel level, differences in brain growth trajectories in ASD during the first years of life, previously reported in terms of overall brain volume and surface area

    The Economic Resource Receipt of New Mothers

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    U.S. federal policies do not provide a universal social safety net of economic support for women during pregnancy or the immediate postpartum period but assume that employment and/or marriage will protect families from poverty. Yet even mothers with considerable human and marital capital may experience disruptions in employment, earnings, and family socioeconomic status postbirth. We use the National Survey of Families and Households to examine the economic resources that mothers with children ages 2 and younger receive postbirth, including employment, spouses, extended family and social network support, and public assistance. Results show that many new mothers receive resources postbirth. Marriage or postbirth employment does not protect new mothers and their families from poverty, but education, race, and the receipt of economic supports from social networks do

    Defining language impairments in a subgroup of children with autism spectrum disorder

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    Autism spectrum disorder (ASD) is diagnosed on the basis of core impairments in pragmatic language skills, which are found across all ages and subtypes. In contrast, there is significant heterogeneity in language phenotypes, ranging from nonverbal to superior linguistic abilities, as defined on standardized tests of vocabulary and grammatical knowledge. The majority of children are verbal but impaired in language, relative to age-matched peers. One hypothesis is that this subgroup has ASD and co-morbid specific language impairment (SLI). An experiment was conducted comparing children with ASD to children with SLI and typically developing controls on aspects of language processing that have been shown to be impaired in children with SLI: repetition of nonsense words. Patterns of performance among the children with ASD and language impairment were similar to those with SLI, and contrasted with the children with ASD and no language impairment and typical controls, providing further evidence for the hypothesis that a subgroup of children with ASD has co-morbid SLI. The findings are discussed in the context of brain imaging studies that have explored the neural bases of language impairment in ASD and SLI, and overlap in the genes associated with elevated risk for these disorders.M01 RR00533 - NCRR NIH HHS; R01 DC10290 - NIDCD NIH HHS; U19 DC03610 - NIDCD NIH HH

    Restricted and Repetitive Behavior and Brain Functional Connectivity in Infants at Risk for Developing Autism Spectrum Disorder

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    Background: Restricted and repetitive behaviors (RRBs), detectable by 12 months in many infants in whom autism spectrum disorder (ASD) is later diagnosed, may represent some of the earliest behavioral markers of ASD. However, brain function underlying the emergence of these key behaviors remains unknown. Methods: Behavioral and resting-state functional connectivity (fc) magnetic resonance imaging data were collected from 167 children at high and low familial risk for ASD at 12 and 24 months (n = 38 at both time points). Twenty infants met criteria for ASD at 24 months. We divided RRBs into four subcategories (restricted, stereotyped, ritualistic/sameness, self-injurious) and used a data-driven approach to identify functional brain networks associated with the development of each RRB subcategory. Results: Higher scores for ritualistic/sameness behavior were associated with less positive fc between visual and control networks at 12 and 24 months. Ritualistic/sameness and stereotyped behaviors were associated with less positive fc between visual and default mode networks at 12 months. At 24 months, stereotyped and restricted behaviors were associated with more positive fc between default mode and control networks. Additionally, at 24 months, stereotyped behavior was associated with more positive fc between dorsal attention and subcortical networks, whereas restricted behavior was associated with more positive fc between default mode and dorsal attention networks. No significant network-level associations were observed for self-injurious behavior. Conclusions: These observations mark the earliest known description of functional brain systems underlying RRBs, reinforce the construct validity of RRB subcategories in infants, and implicate specific neural substrates for future interventions targeting RRBs

    Development of cortical shape in the human brain from 6 to 24months of age via a novel measure of shape complexity

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    The quantification of local surface morphology in the human cortex is important for examining population differences as well as developmental changes in neurodegenerative or neurodevelopmental disorders. We propose a novel cortical shape measure, referred to as the ā€˜shape complexity indexā€™ (SCI), that represents localized shape complexity as the difference between the observed distributions of local surface topology, as quantified by the shape index (SI) measure, to its best fitting simple topological model within a given neighborhood. We apply a relatively small, adaptive geodesic kernel to calculate the SCI. Due to the small size of the kernel, the proposed SCI measure captures fine differences of cortical shape. With this novel cortical feature, we aim to capture comparatively small local surface changes that capture a) the widening versus deepening of sulcal and gyral regions, as well as b) the emergence and development of secondary and tertiary sulci. Current cortical shape measures, such as the gyrification index (GI) or intrinsic curvature measures, investigate the cortical surface at a different scale and are less well suited to capture these particular cortical surface changes. In our experiments, the proposed SCI demonstrates higher complexity in the gyral/sulcal wall regions, lower complexity in wider gyral ridges and lowest complexity in wider sulcal fundus regions. In early postnatal brain development, our experiments show that SCI reveals a pattern of increased cortical shape complexity with age, as well as sexual dimorphisms in the insula, middle cingulate, parieto-occipital sulcal and Broca's regions. Overall, sex differences were greatest at 6 months of age and were reduced at 24 months, with the difference pattern switching from higher complexity in males at 6 months to higher complexity in females at 24months. This is the first study of longitudinal, cortical complexity maturation and sex differences, in the early postnatal period from 6 to 24 months of age with fine scale, cortical shape measures. These results provide information that complement previous studies of gyrification index in early brain development
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