Dopamine receptor 4 promoter polymorphism modulates memory and neuronal responses to salience

Animal models and human functional imaging data implicate the dopamine system in mediating enhanced encoding of novel stimuli into human memory. A separate line of investigation suggests an association between a functional polymorphism in the promoter region for the human dopamine 4 receptor gene (DRD4) and sensitivity to novelty. We demonstrate, in two independent samples, that the -521Cmayor queT DRD4 promoter polymorphism determines the magnitude of human memory enhancement for contextually novel, perceptual oddball stimuli in an allele dose-dependent manner. The genotype-dependent memory enhancement conferred by the C allele is associated with increased neuronal responses during successful encoding of perceptual oddballs in the ventral striatum, an effect which is again allele dose-dependent. Furthermore, with repeated presentations of oddball stimuli, this memory advantage decreases, an effect mirrored by adaptation of activation in the hippocampus and substantia nigra/ventral tegmental area in C carriers only. Thus, a dynamic modulation of human memory enhancement for perceptually salient stimuli is associated with activation of a dopaminergic-hippocampal system, which is critically dependent on a functional polymorphism in the DRD4 promoter region.

Valor documental de los herbarios históricos: aportación de la exsiccata Flora Forestal Española al conocimiento de las cubiertas forestales de las provincias de Huelva y Sevilla (España)

Los herbarios, además de información botánica, pueden contener datos históricos de valor científico para el estudio de los montes y de su historia, como los recogidos en las colecciones de material que fue recolectado para la descripción y cartografía de las cubiertas forestales españolas. En este trabajo se sintetizan los datos obtenidos de la exsiccata Flora Forestal Española creada por investigadores del Instituto Forestal de Investigaciones y Experiencias- IFIE que, junto con información obtenida de documentos inéditos, evidencian la vinculación de esta colección a la realización de los mapas forestales y estudios de flora y vegetación provinciales; en particular a los de las provincias de Huelva y Sevilla, que quedaron inéditos, permitiendo precisar mejor su datación y aportando datos botánicos relevantes e información sobre el paisaje forestal anterior a las grandes repoblaciones con pinos y eucaliptos realizadas en el suroeste peninsular.

Modelling uncertainty of flood quantile estimation at ungauged sites by Bayesian networks

Prediction at ungauged sites is essential for water resources planning and management. Ungauged sites have no observations about the magnitude of floods, but some site and basin characteristics are known. Regression models relate physiographic and climatic basin characteristics to flood quantiles, which can be estimated from observed data at gauged sites. However, these models assume linear relationships between variables Prediction intervals are estimated by the variance of the residuals in the estimated model. Furthermore, the effect of the uncertainties in the explanatory variables on the dependent variable cannot be assessed. This paper presents a methodology to propagate the uncertainties that arise in the process of predicting flood quantiles at ungauged basins by a regression model. In addition, Bayesian networks were explored as a feasible tool for predicting flood quantiles at ungauged sites. Bayesian networks benefit from taking into account uncertainties thanks to their probabilistic nature. They are able to capture non-linear relationships between variables and they give a probability distribution of discharges as result. The methodology was applied to a case study in the Tagus basin in Spain.

Management of irrigation frequency and nitrogen fertilization to mitigate GHG and NO emissions from drip-fertigated crops

Drip irrigation combined with split application of fertilizer nitrogen (N) dissolved in the irrigation water (i.e. drip fertigation) is commonly considered best management practice for water and nutrient efficiency. As a consequence, its use is becoming widespread. Some of the main factors (water-filled pore space, NH4+ and NO3−) regulating the emissions of greenhouse gases (i.e. N2O, CO2 and CH4) and NO from agroecosystems can easily be manipulated by drip fertigation without yield penalties. In this study, we tested management options to reduce these emissions in a field experiment with a melon (Cucumis melo L.) crop. Treatments included drip irrigation frequency (weekly/daily) and type of N fertilizer (urea/calcium nitrate) applied by fertigation. Crop yield, environmental parameters, soil mineral N concentrations and fluxes of N2O, NO, CH4 and CO2 were measured during 85 days. Fertigation with urea instead of calcium nitrate increased N2O and NO emissions by a factor of 2.4 and 2.9, respectively (P < 0.005). Daily irrigation reduced NO emissions by 42% (P < 0.005) but increased CO2 emissions by 21% (P < 0.05) compared with weekly irrigation. We found no relation between irrigation frequency and N2O emissions. Based on yield-scaled Global Warming Potential as well as NO cumulative emissions, we conclude that weekly fertigation with a NO3−-based fertilizer is the best option to combine agronomic productivity with environmental sustainability. Our study shows that adequate management of drip fertigation, while contributing to the attainment of water and food security, may provide an opportunity for climate change mitigation.

Assessing the suitability of student interactions from Moodle data logs as predictors of cross-curricular competencies

In the past decades, online learning has transformed the educational landscape with the emergence of new ways to learn. This fact, together with recent changes in educational policy in Europe aiming to facilitate the incorporation of graduate students to the labor market, has provoked a shift on the delivery of instruction and on the role played by teachers and students, stressing the need for development of both basic and cross-curricular competencies. In parallel, the last years have witnessed the emergence of new educational disciplines that can take advantage of the information retrieved by technology-based online education in order to improve instruction, such as learning analytics. This study explores the applicability of learning analytics for prediction of development of two cross-curricular competencies – teamwork and commitment – based on the analysis of Moodle interaction data logs in a Master’s Degree program at Universidad a Distancia de Madrid (UDIMA) where the students were education professionals. The results from the study question the suitability of a general interaction-based approach and show no relation between online activity indicators and teamwork and commitment acquisition. The discussion of results includes multiple recommendations for further research on this topic.

Use efficiency of controlled release fertilizer on the growth of croton and petunia and N loss by leaching

The market of flowers and ornamentals such as croton (Codiaeum variegatum) and petunia (Petunia×hybrida Vilm.-Andr) have been created new technologies to constantly development, as one of the most promising segments of horticulture. Fertilization providing adequate nutrition and less leaching to the environment is the objective of numerous studies around the world. Therefore, two studies were conducted to evaluate the use of controlled release fertilizer (CRF) on the growth of two ornamental species, and N loss by leaching. The first experiment aim to evaluate sources and rates of CRF and water soluble fertilizer (WSF) on croton growth and nitrogen concentration on drained solution. Results showed that treatments with WSF and low rates of CRF provided higher plants growth, and the amount of N leached was higher for WSF treatments. The second experiment objective to compare plant performance and cost for strategies that potentially provide adequate nutrition during both the production and consumer phases for container-grown Petunia plants. In addition, two experiments were conducted to evaluate nutrient release in sand containers inside of the greenhouse and under controlled temperature conditions without plants. Results showed that during production phase all fertilizer treatments produced high quality plants, and during consumer phase, plants grown with WSF only during the production phase were nutrient-deficient, while plants receiving CRFs were still growing vigorously, especially in a high rate. The release rates of all CRF products were temperature-dependent. In conclusion CRF provided plant growth at the same rate that WSF, with less N leaching and extra cost less than U$0.065 per plant with CRF during production.

Culturable aerobic and facultative bacteria from the gut of the polyphagic dung beetle Thorectes lusitanicus Jeckel

Unlike other dung beetles, the Iberian geotrupid Thorectes lusitanicus exhibits polyphagous behavior; for example, it is able to eat acorns, fungi, fruits, and carrion in addition to the dung of different mammals. This adaptation to digest a wider diet has physiological and developmental advantages and requires key changes in the composition and diversity of the beetle's gut microbiota. In this study, we isolated aerobic, facultative anaerobic, and aerotolerant microbiota amenable to grow in culture from the gut contents of T. lusitanicus and resolved isolate identity to the species level by sequencing 16S rRNA gene fragments. Using BLAST similarity searches and maximum likelihood phylogenetic analyses, we were able to reveal that the analyzed fraction (culturable, aerobic, facultative anaerobic, and aerotolerant) of beetle gut microbiota is dominated by the phyla Proteobacteria, Firmicutes and Actinobacteria. Among Proteobacteria, members of the order Enterobacteriales (Gammaproteobacteria) were the most abundant. The main functions associated with the bacteria found in the gut of T. lusitanicus would likely include nitrogen fixation, denitrification, detoxification, and diverse defensive roles against pathogens.

Organic geochemistry on surface sediments from the Laptev Sea

Sediment samples from the Laptev Sea, taken during the 1993 RV Polarstern expedition ARK IX/4 and the RV Ivan Kireyev expedition TRANSDRIFT I, were investigated for the amount and composition of their organic carbon fractions. Of major interest was the identification of different processes controlling organic carbon deposition (i.e. terrigenous supply vs. surface water productivity). Long-chain unsaturated alkenones derived from prymnesiophytes, and fatty acids derived from diatoms and dinoflagellates, were analysed by means of gas chromatography and mass spectrometry. First results on the distribution of these biomarkers in surface sediments indicate that the surface water productivity signal is well preserved in the sediment data. This is shown by the distribution of the 16:1(n-7) and 20:5(n-3) fatty acids indicative for diatoms, and the excellent correlation with the chlorophyll a concentrations in the surface water masses and the biogenic-opal content and increased hydrogen indices of the sediments. The high concentration of these unsaturated fatty acids in shallow water sediments shows the recent deposition of the organic material. In deep-sea sediments, on the other hand, the concentrations are low. This decreased content is typical for phytoplankton material which has been degraded by microorganisms or autoxidation. In general, the alkenone concentrations are very low, suggesting low production rates by prymnesiophytes. Only at one station from the lower continental margin influenced by the inflow of Atlantic water masses, were some higher amounts of alkenones determined. Long-chain n-alkanes as well as high C/N ratios and low hydrogen indices indicate the importance of (fluvial) supply of terrigenous organic matter.

Macerals in surface sediments of the Laptev Sea (Arctic Ocean)

Surface sediments from the Laptev Sea and adjacent continental slope were studied for their composition of particulate organic matter (OM) by means of maceral analysis. The composition of macerals in sediments gives information about the environment, terrigenous supply from the hinterland, and marine OM. With reference to their biological sources, we distinguish between terrigenous and marine macerals. We found that the particulate OM in the surface sediments of the Laptev Sea is predominantly of terrigenous origin (mean: 78%). However, distinct variations exist when looking in detail. In the shelf area, sediments may contain up to 99% terrigenous OM. Freshwater algae occur directly north of the river mouths, reflecting the strong fluvial influence. Relatively high amounts of marine OM (20-40%) are restricted to the upper continental slope, the Vilkitsky Strait and west of the New Siberian Islands, explained by increased surface-water productivity due to increased fluvial nutrient supply, open-water conditions, and phytoplankton blooms at the ice-edge.

Distribution of clay minerals in surface sediments of the Eurasian Arctic Ocean

Clay-mineral distributions in the Arctic Ocean and the adjacent Eurasian shelf areas are discussed to identify source areas and transport pathways of terrigenous material in the Arctic Ocean. The main clay minerals in Eurasian Arctic Ocean sediments are illite and chlorite. Smectite and kaolinite occur in minor amounts in these sediments, but show strong variations in the shelf areas. These two minerals are therefore reliable in reconstructions of source areas of sediments from the Eurasian Arctic. The Kara Sea and the western part of the Laptev Sea are enriched in smectite, with highest values of up to 70% in the deltas of the Ob and Yenisey rivers. Illite is the dominant clay mineral in all the investigated sediments except for parts of the Kara Sea. The highest concentrations with more than 70% illite occur in the East Siberian Sea and around Svalbard. Chlorite represents the clay mineral with lowest concentration changes in the Eastern Arctic, ranging between 10 and 25%. The main source areas for kaolinite in the Eurasian Arctic are Mesozoic sedimentary rocks on Franz-Josef Land islands. Based on clay-mineral data, transport of the clay fraction via sea ice is of minor importance for the modern sedimentary budget in the Arctic basins.