32 research outputs found

    Executive Function in Very Preterm Children at Early School Age

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    We examined whether very preterm (≤30 weeks gestation) children at early school age have impairments in executive function (EF) independent of IQ and processing speed, and whether demographic and neonatal risk factors were associated with EF impairments. A consecutive sample of 50 children (27 boys and 23 girls) born very preterm (mean age = 5.9 years, SD = 0.4, mean gestational age = 28.0 weeks, SD = 1.4) was compared to a sample of 50 age-matched full-term controls (23 girls and 27 boys, mean age = 6.0 years, SD = 0.6) with respect to performance on a comprehensive EF battery, assessing the domains of inhibition, working memory, switching, verbal fluency, and concept generation. The very preterm group demonstrated poor performance compared to the controls on all EF domains, even after partialing out the effects of IQ. Processing speed was marginally related to EF. Analyses with demographic and neonatal risk factors showed maternal education and gestational age to be related to EF. This study adds to the emerging body of literature showing that very preterm birth is associated with EF impairments

    Identification of Genomic Regions Associated with Phenotypic Variation between Dog Breeds using Selection Mapping

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    Limits to reproduction and seed size-number trade-offs that shape forest dominance and future recovery

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    International audienceThe relationships that control seed production in trees are fundamental to understanding the evolution of forest species and their capacity to recover from increasing losses to drought, fire, and harvest. A synthesis of fecundity data from 714 species worldwide allowed us to examine hypotheses that are central to quantifying reproduction, a foundation for assessing fitness in forest trees. Four major findings emerged. First, seed production is not constrained by a strict trade-off between seed size and numbers. Instead, seed numbers vary over ten orders of magnitude, with species that invest in large seeds producing more seeds than expected from the 1:1 trade-off. Second, gymnosperms have lower seed production than angiosperms, potentially due to their extra investments in protective woody cones. Third, nutrient-demanding species, indicated by high foliar phosphorus concentrations, have low seed production. Finally, sensitivity of individual species to soil fertility varies widely, limiting the response of community seed production to fertility gradients. In combination, these findings can inform models of forest response that need to incorporate reproductive potential

    In zeven minuten bijgepraat over… samenwerken in Labs

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    Steeds vaker worden complexe vraagstukken uit de samenleving, ook wel ‘wicked problems’, met verschillende disciplines en stakeholders opgepakt. Deze samenwerking werkt als een vliegwiel om tot nieuwe kennis en oplossingen te komen als er geen eenvoudig antwoord is. Labs, hybride leeromgevingen, bieden studenten de kans om hier ervaring mee op te doen. Zo worden ze voorbereid op toekomstige samenwerkingen als professional. Welke vormen van samenwerken kom je tegen in labs? Welke competenties hebben studenten nodig in een samenwerking met verschillende disciplines? Leidt het deelnemen aan labs automatisch tot effectief samenwerken met andere disciplines? Hoe ontwikkelen studenten de competenties voor deze vormen van samenwerking? Wat vraagt dat van het ontwerp van een lab als leeromgeving? Antwoord op deze en andere vragen vind je in deze publicatie van het lectoraat Teaching, Learning & Technology zodat je in zeven minuten weer bent bijgepraat over samenwerken in een lab

    13C and 63,65Cu ENDOR studies of CO Dehydrogenase from Oligotropha carboxidovorans. Experimental Evidence in Support of a Copper–Carbonyl Intermediate

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    We report here an ENDOR study of an S = 1/2 intermediate state trapped during reduction of the binuclear Mo/Cu enzyme CO dehydrogenase by CO. ENDOR spectra of this state confirm that the (63,65)Cu nuclei exhibits strong and almost entirely isotropic coupling to the unpaired electron, show that this coupling atypically has a positive sign, aiso = +148 MHz, and indicate an apparently undetectably small quadrupolar coupling. When the intermediate is generated using (13)CO, coupling to the (13)C is observed, with aiso = +17.3 MHz. A comparison with the couplings seen in related, structurally assigned Mo(V) species from xanthine oxidase, in conjunction with complementary computational studies, leads us to conclude that the intermediate contains a partially reduced Mo(V)/Cu(I) center with CO bound at the copper. Our results provide strong experimental support for a reaction mechanism that proceeds from a comparable complex of CO with fully oxidized Mo(VI)/Cu(I) enzyme

    Identification, Purification, and Molecular Cloning of a Putative Plastidic Glucose Translocator

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    During photosynthesis, part of the fixed carbon is directed into the synthesis of transitory starch, which serves as an intermediate carbon storage facility in chloroplasts. This transitory starch is mobilized during the night. Increasing evidence indicates that the main route of starch breakdown proceeds by way of hydrolytic enzymes and results in glucose formation. This pathway requires a glucose translocator to mediate the export of glucose from the chloroplasts. We have reexamined the kinetic properties of the plastidic glucose translocator and, using a differential labeling procedure, have identified the glucose translocator as a component of the inner envelope membrane. Peptide sequence information derived from this protein was used to isolate cDNA clones encoding a putative plastidic glucose translocator from spinach, potato, tobacco, Arabidopsis, and maize. We also present the molecular characterization of a candidate for a hexose transporter of the plastid envelope membrane. This transporter, initially characterized more than 20 years ago, is closely related to the mammalian glucose transporter GLUT family and differs from all other plant hexose transporters that have been characterized to date

    <sup>13</sup>C and <sup>63,65</sup>Cu ENDOR studies of CO Dehydrogenase from <i>Oligotropha carboxidovorans</i>. Experimental Evidence in Support of a Copper–Carbonyl Intermediate

    No full text
    We report here an ENDOR study of an <i>S</i> = 1/2 intermediate state trapped during reduction of the binuclear Mo/Cu enzyme CO dehydrogenase by CO. ENDOR spectra of this state confirm that the <sup>63,65</sup>Cu nuclei exhibits strong and almost entirely isotropic coupling to the unpaired electron, show that this coupling atypically has a positive sign, <i>a</i><sub>iso</sub> = +148 MHz, and indicate an apparently undetectably small quadrupolar coupling. When the intermediate is generated using <sup>13</sup>CO, coupling to the <sup>13</sup>C is observed, with <i>a</i><sub>iso</sub> = +17.3 MHz. A comparison with the couplings seen in related, structurally assigned Mo­(V) species from xanthine oxidase, in conjunction with complementary computational studies, leads us to conclude that the intermediate contains a partially reduced Mo­(V)/Cu­(I) center with CO bound at the copper. Our results provide strong experimental support for a reaction mechanism that proceeds from a comparable complex of CO with fully oxidized Mo­(VI)/Cu­(I) enzyme

    The Arabidopsis sex1 Mutant Is Defective in the R1 Protein, a General Regulator of Starch Degradation in Plants, and Not in the Chloroplast Hexose Transporter

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    Starch is the major storage carbohydrate in higher plants and of considerable importance for the human diet and for numerous technical applications. In addition, starch can be accumulated transiently in chloroplasts as a temporary deposit of carbohydrates during ongoing photosynthesis. This transitory starch has to be mobilized during the subsequent dark period. Mutants defective in starch mobilization are characterized by high starch contents in leaves after prolonged periods of darkness and therefore are termed starch excess (sex) mutants. Here we describe the molecular characterization of the Arabidopsis sex1 mutant that has been proposed to be defective in the export of glucose resulting from hydrolytic starch breakdown. The mutated gene in sex1 was cloned using a map-based cloning approach. By complementation of the mutant, immunological analysis, and analysis of starch phosphorylation, we show that sex1 is defective in the Arabidopsis homolog of the R1 protein and not in the hexose transporter. We propose that the SEX1 protein (R1) functions as an overall regulator of starch mobilization by controlling the phosphate content of starch
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