655 research outputs found

    Neuroanatomical Correlates of the Income-Achievement Gap

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    In the United States, the difference in academic achievement between higher- and lower-income students (i.e., the income-achievement gap) is substantial and growing. In the research reported here, we investigated neuroanatomical correlates of this gap in adolescents (N = 58) in whom academic achievement was measured by statewide standardized testing. Cortical gray-matter volume was significantly greater in students from higher-income backgrounds (n = 35) than in students from lower-income backgrounds (n = 23), but cortical white-matter volume and total cortical surface area did not differ significantly between groups. Cortical thickness in all lobes of the brain was greater in students from higher-income than lower-income backgrounds. Greater cortical thickness, particularly in temporal and occipital lobes, was associated with better test performance. These results represent the first evidence that cortical thickness in higher- and lower-income students differs across broad swaths of the brain and that cortical thickness is related to scores on academic-achievement tests.Bill & Melinda Gates FoundationNational Institutes of Health (U.S.) (Grant F32 HD079143-01)National Institutes of Health (U.S.) (Grant F32 MH095354-01

    Entorhinal cortex volume is associated with episodic memory related brain activation in normal aging and amnesic mild cognitive impairment

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    The present study examined the relationship between entorhinal cortex and hippocampal volume with fMRI activation during episodic memory function in elderly controls with no cognitive impairment and individuals with amnesic mild cognitive impairment (aMCI). Both groups displayed limited evidence for a relationship between hippocampal volume and fMRI activation. Smaller right entorhinal cortex volume was correlated with reduced activation in left and right medial frontal cortex (BA 8) during incidental encoding for both aMCI and elderly controls. However, during recognition, smaller left entorhinal cortex volume correlated with reduced activation in right BA 8 for the control group, but greater activation for the aMCI group. There was no significant relationship between entorhinal cortex volume and activation during intentional encoding in either group. The recognition-related dissociation in structure/function relationships in aMCI paralleled our behavioral findings, where individuals with aMCI displayed poorer performance relative to controls during recognition, but not encoding. Taken together, these results suggest that the relationship between entorhinal cortex volume and fMRI activation during episodic memory function is altered in individuals with aMCI.Illinois. Department of Public HealthNational Institute on Aging (Grant P01 AG09466)National Institute on Aging (Grant P30 AG10161)National Institute on Aging (Grant R01 AG017917)National Institute on Aging (Grant T32 AG000257

    Disclosing Jackson Pollock's palette in Alchemy (1947) by non-invasive spectroscopies

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    Alchemy (1947, Peggy Guggenheim Collection, Venice) is one of the most materic works by J. Pollock, whose palette is extensive, ranging from white to yellow, red, green, violet, blue, black, and silver. Each layer of color was laid on top of a previously dried one and effectively separated from the lower one forming a quite complex stratigraphy with colors intersecting each other. In this study, a non-invasive multi-technique method combining point analysis with Vis–NIR multispectral imaging has been exploited to give insights on the painting technique of the American abstract expressionist. The molecular identification of pigments, colorants and extenders contained in fifteen different paints has been achieved combining key spectral markers from elemental, electronic and vibrational spectroscopies. For those colors exhibiting similar hues but different chemical compositions, a mapping procedure based on false color rendering, obtained by properly mixing three spectral planes from the Vis–NIR multispectral imaging set, has been successfully applied. Relevant for the understanding of the evolution of Pollock's drip technique is the identification of both traditional oil-based paints and oil-modified alkyd media. Point analysis by reflection FTIR scattered throughout the painting enabled mapping the distinct use of traditional and new binding media among painted, squeezed and dripped paints

    Reward-Sensitive Basal Ganglia Stabilize the Maintenance of Goal-Relevant Neural Patterns in Adolescents

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    Maturation of basal ganglia (BG) and frontoparietal circuitry parallels developmental gains in working memory (WM). Neurobiological models posit that adult WM performance is enhanced by communication between reward-sensitive BG and frontoparietal regions, via increased stability in the maintenance of goal-relevant neural patterns. It is not known whether this reward-driven pattern stability mechanism may have a role in WM development. In 34 young adolescents (12.16–14.72 years old) undergoing fMRI, reward-sensitive BG regions were localized using an incentive processing task. WM-sensitive regions were localized using a delayed-response WM task. Functional connectivity analyses were used to examine the stability of goal-relevant functional connectivity patterns during WM delay periods between and within reward-sensitive BG and WM-sensitive frontoparietal regions. Analyses revealed that more stable goal-relevant connectivity patterns between reward-sensitive BG and WM-sensitive frontoparietal regions were associated with both greater adolescent age and WM ability. Computational lesion models also revealed that functional connections to WM-sensitive frontoparietal regions from reward-sensitive BG uniquely increased the stability of goal-relevant functional connectivity patterns within frontoparietal regions. Findings suggested (1) the extent to which goal-relevant communication patterns within reward-frontoparietal circuitry are maintained increases with adolescent development and WM ability and (2) communication from reward-sensitive BG to frontoparietal regions enhances the maintenance of goal-relevant neural patterns in adolescents’ WM. The maturation of reward-driven stability of goal-relevant neural patterns may provide a putative mechanism for understanding the developmental enhancement of WM

    Analysis of transient seepage through a river embankment by means of centrifuge modelling

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    Earthen river embankments are typically in unsaturated conditions during their lifetime and the degree of saturation within their bodies may vary significantly throughout the year, due to seasonalfluctuations of the river stage, as well as infiltrations of meteoric precipitation and evapotranspiration phenomena. Given the significant effects of partial saturation on the hydro-mechanical behaviour of soils, realistic assumptions on the actual water content distribution inside the embankments are essential forproperly modelling their response to hydraulic loadings. In this framework, centrifuge modelling is a useful tool to get insights into the evolution of saturation conditions of a water retaining structure during flood events. It allows for the direct observation of the groundwater flow process, which is hardly detectable at the prototype scale, enabling, at the same time, the validation and calibration of predictive numerical tools.In this paper, the results of a centrifuge test carried out on small-scale physical model of a compacted silty clayey sand embankment subjected to a simulated high-water event, at the enhanced gravity of 50-g, are presented and discussed. The physical model was carefully instrumented with potentiometers, miniaturized pore pressure transducers and tensiometers. Pore pressures and suctions measured during the experiment showed that the stationary flow conditions were reached only after an unrealistic hydrometric peak persistence. It therefore emerges that, for the design and/or the assessment of the safety conditions of a river embankment similar to the one tested, the simplified hypothesis of a steady-state seepage, in equilibrium with the maximum river stage expected could result, in many cases, an excessively conservative assumption

    The development of emotion regulation: an fMRI study of cognitive reappraisal in children, adolescents and young adults

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    The ability to use cognitive reappraisal to regulate emotions is an adaptive skill in adulthood, but little is known about its development. Because reappraisal is thought to be supported by linearly developing prefrontal regions, one prediction is that reappraisal ability develops linearly. However, recent investigations into socio-emotional development suggest that there are non-linear patterns that uniquely affect adolescents. We compared older children (10–13), adolescents (14–17) and young adults (18–22) on a task that distinguishes negative emotional reactivity from reappraisal ability. Behaviorally, we observed no age differences in self-reported emotional reactivity, but linear and quadratic relationships between reappraisal ability and age. Neurally, we observed linear age-related increases in activation in the left ventrolateral prefrontal cortex, previously identified in adult reappraisal. We observed a quadratic pattern of activation with age in regions associated with social cognitive processes like mental state attribution (medial prefrontal cortex, posterior cingulate cortex, anterior temporal cortex). In these regions, we observed relatively lower reactivity-related activation in adolescents, but higher reappraisal-related activation. This suggests that (i) engagement of the cognitive control components of reappraisal increases linearly with age and (ii) adolescents may not normally recruit regions associated with mental state attribution, but (iii) this can be reversed with reappraisal instructions.National Science Foundation (U.S.) (Grant BCS-0224342

    Fast Liquid Chromatography Coupled with Tandem Mass Spectrometry for the Analysis of Vanillic and Syringic Acids in Ice Cores

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    The development of new analytical systems and the improvement of the existing ones to obtain high-resolution measurements of chemical markers in samples from ice cores, is one of the main challenges the paleoclimatic scientific community is facing. Different chemical species can be used as markers for tracking emission sources or specific environmental processes. Although some markers, such as methane sulfonic acid (a proxy of marine productivity), are commonly used, there is a lack of data on other organic tracers in ice cores, making their continuous analysis analytically challenging. Here, we present an innovative combination of fast liquid chromatography coupled with tandem mass spectrometry (FLC-MS/MS) to continuously determine organic markers in ice cores. After specific optimization, this approach was applied to the quantification of vanillic and syringic acids, two specific markers for biomass burning. Using the validated method, detection limits of 3.6 and 4.6 pg mL-1for vanillic and syringic acids, respectively, were achieved. Thanks to the coupling of FLC-MS/MS with the continuous flow analytical system, we obtained one measurement every 30 s, which corresponds to a sampling resolution of a sample every 1.5 cm with a melting rate of 3.0 cm min-1. To check the robustness of the method, we analyzed two parallel sticks of an alpine ice core over more than 5 h. Vanillic acid was found with concentrations in the range of picograms per milliliter, suggesting the combustion of coniferous trees, which are found throughout the Italian Alps

    Brain function and clinical characterization in the Boston adolescent neuroimaging of depression and anxiety study

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    We present a Human Connectome Project study tailored toward adolescent anxiety and depression. This study is one of the first studies of the Connectomes Related to Human Diseases initiative and is collecting structural, functional, and diffusion-weighted brain imaging data from up to 225 adolescents (ages 14–17 years), 150 of whom are expected to have a current diagnosis of an anxiety and/or depressive disorder. Comprehensive clinical and neuropsychological evaluations and long-itudinal clinical data are also being collected. This article provides an overview of task functional magnetic resonance imaging (fMRI) protocols and preliminary findings (N = 140), as well as clinical and neuropsychological characterization of adolescents. Data collection is ongoing for an additional 85 adolescents, most of whom are expected to have a diagnosis of an anxiety and/or depressive disorder. Data from the first 140 adolescents are projected for public release through the National Institutes of Health Data Archive (NDA) with the timing of this manuscript. All other data will be made publicly-available through the NDA at regularly scheduled intervals. This article is intended to serve as an introduction to this project as well as a reference for those seeking to clinical, neurocognitive, and task fMRI data from this public resource

    Higher media multi-tasking activity is associated with smaller gray-matter density in the anterior cingulate cortex

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    Media multitasking, or the concurrent consumption of multiple media forms, is increasingly prevalent in today’s society and has been associated with negative psychosocial and cognitive impacts. Individuals who engage in heavier media-multitasking are found to perform worse on cognitive control tasks and exhibit more socio-emotional difficulties. However, the neural processes associated with media multi-tasking remain unexplored. The present study investigated relationships between media multitasking activity and brain structure. Research has demonstrated that brain structure can be altered upon prolonged exposure to novel environments and experience. Thus, we expected differential engagements in media multitasking to correlate with brain structure variability. This was confirmed via Voxel-Based Morphometry (VBM) analyses: Individuals with higher Media Multitasking Index (MMI) scores had smaller gray matter density in the anterior cingulate cortex (ACC). Functional connectivity between this ACC region and the precuneus was negatively associated with MMI. Our findings suggest a possible structural correlate for the observed decreased cognitive control performance and socio-emotional regulation in heavy media-multitaskers. While the cross-sectional nature of our study does not allow us to specify the direction of causality, our results brought to light novel associations between individual media multitasking behaviors and ACC structure differences

    Twist-2 Heavy Flavor Contributions to the Structure Function g2(x,Q2)g_2(x,Q^2)

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    The twist--2 heavy flavor contributions to the polarized structure function g2(x,Q2)g_2(x,Q^2) are calculated. We show that this part of g2(x,Q2)g_2(x,Q^2) is related to the heavy flavor contribution to g1(x,Q2)g_1(x,Q^2) by the Wandzura--Wilczek relation to all orders in the strong coupling constant. Numerical results are presented.Comment: 17 pages LATEX, 1 style files, 4 figure
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