2,505 research outputs found
Endocannabinoid Metabolome of Human Breast Milk
Human breast milk (HBM) is an extremely complex yet fascinating biofluid tailored to meet an infant’s nutritional requirements for development. Amongst the nutrients present in HBM, the long-chain polyunsaturated fatty acids (LCPUFAs) are of high importance due to the pivotal role they play in infant cognitive and visual development, and growth. In addition, the LCPUFAs are precursors to endocannabinoids (EC) which are endogenous lipid mediators. EC exert metabolic responses including appetite and food intake regulation, and they have been identified to play a role in establishing the suckling response of the newborn that is needed to nurse. Thus, we aimed to characterize and quantify the EC present in HBM, termed the EC metabolome (ECM). HBM samples were collected from two different populations, one in Guatemala (n = 26) and the other one in the United States (n = 24). We collected HBM at different lactation stages: transitional (2 weeks postpartum) and mature (4 weeks and 16-24 weeks postpartum) milk. Using liquid chromatography-mass spectrometry analyses, we identified 15 members of the ECM in both lactation stages: arachidonoylethanolamine, palmitoylethanolamine, oleoylethanolamine, docosahexaenoylethanolamine, eicoapentaenoylethanolamine, eicosenoylethanolamine, arachidonoylglycerol, palmitoyglycerol, oleoylglycerol, docosahexaenoylglycerol, eicosapentaenoylglycerol, eiconenooylglycerol, arachidonic acid, docosahexaenoic acid, and eicosapentaenoic acid. Overall, members in the glycerol group were higher in concentration than those of the ethanolamide group. To date, the mechanisms of action and the role of the ECM in HBM and infant development are not fully understood. Data from the present study provides a foundation to develop future studies to help elucidate how the ECM modulates infant health and development
Rapid absolute plate motion changes inferred from high-resolution relative spreading reconstructions: A case study focusing on the South America plate and its Atlantic/Pacific neighbors
The reconstruction of past plate motions relative to a deemed–to–be–fixed hotspot reference frame relies on the sparse occurrence of intraplate volcanism. Consequently, this absolute reference frame often features a temporal resolution that exceeds the rapid kinematic changes observed in plate–to–plate spreading reconstructions, changes recently shown to occur within less than 5 Ma. In this work we put forward an alternative method based on the study of high–resolution relative plate motion data sets. By studying time periods featuring a relatively high probability of plate motion change across multiple spreading ridges, we are able to identify and quantify (likely) changes in absolute plate motion. Specifically, we implement such approach and provide well–defined estimates for the absolute plate motion changes of South America and neighboring plates Nubia, Antarctica, Somalia, North America and Pacific. We find that kinematic changes for all these plates occur between 9 and 5 Ma. For South America, we identify a change also between 14 and 10 Ma. Lastly, we estimate the torque–variations required upon these plates to generate the inferred kinematic changes, which we find to be between ∼5⋅1023 and ∼20⋅1024 N ⋅ m
An amplitude-phase (Ermakov-Lewis) approach for the Jackiw-Pi model of bilayer graphene
In the context of bilayer graphene we use the simple gauge model of Jackiw
and Pi to construct its numerical solutions in powers of the bias potential V
according to a general scheme due to Kravchenko. Next, using this numerical
solutions, we develop the Ermakov-Lewis approach for the same model. This leads
us to numerical calculations of the Lewis-Riesenfeld phases that could be of
forthcoming experimental interest for bilayer graphene. We also present a
generalization of the Ioffe-Korsch nonlinear Darboux transformationComment: FTC, 11 pp, 5 figure
Eficacia in vitro de cinco pastas dentales pediátricas en la inhibición de Streptococcus mutans ATCC 25175.
The present in vitro study compared the inhibitory action of five pediatric toothpastes against Streptococcus mutans ATCC 25175. Materials and Methods: Cross-sectional, comparative and experimental study. The microorganism Streptococcus mutans ATCC 25175 was inoculated onto solid culture medium of Müeller-Hinton supplemented with blood, then the plates were inoculated with five pediatric toothpastes: Oral B Stages, Colgate Smiles, Aquafresh My Little Teeth, Dentito and Denture Kids. Samples were incubated at 37°C for 48 hours. Subsequently the inhibition halos were measured; the experiment was repeated 20 times for each sample. Statistical analysis was performed with ANOVA complemented with Tukey's test. Results: Oral B Stages yielded a mean inhibitory halo of 23.2mm, Colgate Smiles an average of 21.7mm, Aquafresh My Little Teeth of 13.6mm, Dentito of 18.5mm, and Denture Kids a mean of 23.0mm. When performing the ANOVA test, it was found that there was a significant difference in the inhibitory action of pediatric toothpastes (p<0.005) and when using Tukey's multiple comparison test, Oral B and Denture Kids presented similar inhibitory action. Conclusion: All toothpastes presented inhibitory action against Streptococcus mutans ATCC 25175. A significant difference between their effectiveness was observed. Oral B Stages showed the greatest degree of inhibition.El presente estudio in vitro comparo la eficacia inhibitoria de cinco pastas dentales pediátricas frente a la bacteria Streptococcus mutans ATCC25175. Material y Métodos: El estudio fue transversal, comparativo y experimental. Se inoculó Streptococcus mutans ATCC 25175 en un medio de cultivo Müeller-Hinton complementado con sangre, luego a las placas cultivadas se le inocularon cincopastas dentales pediátricas: Oral B Stages, Colgate Smiles, Aquafresh My LittleTeeth, Dentito y Denture Kids. Se incubó a 37ºC por 48 horas y posteriormente semidió los halos de inhibición, se replicó el experimento 20 veces para cada uno. El análisis estadÃstico se realizó con el test de ANVA complementado con el test de Tukey. Resultado: Oral B Stages generó una media inhibitoria de 23,2mm, ColgateSmiles una media de 21,7mm, Aquafresh My Little Teeh de 13,6mm, Dentitode 18,5mm y finalmente Denture Kids una media de 23,0mm. Al realizar laprueba ANOVA se encontró que hay diferencia significativa en la acción inhibitoriade las pastas dentales pediátricas (p<0.005) y al emplear la prueba Tukey (comparación de múltiples) la pasta Oral B y Denture Kids presentaron acción inhibidora similar. Conclusión: Todas las pastas presentaron acción inhibitoria sobre Streptococcus mutans ATCC 25175 existiendo diferencia significativa entre la efectividad de estas, con la pasta Oral B Stages demuestrando mayor acción inhibitoria
Inceasing the fuel utilization in Gen-II BWR with reduced-moderation square lattice fuel assemblies
Evaluation of the Agreements of the National Reforestation Program in the Santiago de Quito, Palmira, Pistishi and Compud parishes, Chimborazo Province
The objective of this study was to evaluate the Forest Restoration agreements, by means of sampling the equivalent of 10% of the entire ground surface and 10% of the total land, in which control points were established in order to estimate the planted area; for the verification of land for reforestation, the control points were issued from the central office, which were located in the field with GPS; then the systematization of the data collected in the field was carried out. In the Palmira parish, the area evaluated showed 39.38 ha (74.94%) in which there were indications of planting, and 12.84 ha (26.06%) that did not show signs of planting; 57 farms were evaluated, of which 14 (71.93%) presented evidence of planting and 16 farms (28.07%) had no such evidence. In the Pistishi parish, the area evaluated had 36.27 ha (93.81%) in which there were signs of planting, and 2.39 ha (6.19%) that did not show signs of planting; 29 farms were evaluated, of which 22 (75.86%) presented evidence of planting and 2 (24.14%) had no evidence of planting. The properties evaluated in the Santiago de Quito and Compud parishes were considered for reforestation.
Keywords: forest restoration, inventory, biodiversity, reforestation.
Resumen
El objetivo del trabajo fue evaluar los convenios de Restauración Forestal, mediante un muestreo equivalente al 10% de toda la superficie y el 10% del total de los predios, en los que se establecieron puntos de control con la finalidad de estimar la superficie plantada; para la verificación de predios para la reforestación, desde central fue emitido los puntos de control los mismos que fueron ubicados en campo con GPS; seguidamente se realizó la sistematización de los datos recogidos en campo. En la parroquia Palmira se evalúo un área plantada de 39,38 ha (74,94%) en el que se registró indicios de haberse plantado, 12,84 ha (26,06%) no presento indicios de plantación; se evaluaron 57 predios de los cuales 14 (71,93%) presentó plantaciones y 16 predios (28,07%) no se registra indicios de plantación. En ella Parroquia Pistishi se evalúo un área de 36,27 ha (93,81%) en el que se registró indicios de plantación, 2,39 ha (6,19%) no presento indicios de plantación; se evaluaron 29 predios de los cuales 22 (75,86%) presentó evidencias de plantación y 2 (24,14%) no se registra indicios de plantación. Los predios evaluados en las parroquias Santiago de Quito y Compud fueron consideraron para la reforestación.
Palabras clave: restauración forestal, inventario, biodiversidad, reforestación
Estimation of Carbon Content in the Páramo Ecosystem of Pasa Population, Ambato Canton, Tungurahua Province
The stored carbon content was determined based on a randomized stratified experimental design by type of vegetation; three sampling units of 400 m2 each were installed, from 3600–4100 m.s.n.m., with intervals of 150 m of altitude. The inventory of herbaceous vegetation was taken using the GLORIA method. For the sampling of the aerial biomass and necromass in the plot, circular subplots were constructed, and the samples were collected in 4 quadrants of 0.25 m2, two in each subplot. Samples of 0–20, 20–40 and 40–60 cm were taken from the soil profile, and the percentage of organic carbon in the soil and the apparent density were evaluated. The results indicate a floristic diversity represented by 44 species, 39 of herbaceous vegetation and 5 of tree vegetation. The carbon content stored in aerial biomass returned a value of 83.88 tC⋅ha−1 for herbaceous vegetation and 158.50 tC⋅ha−1 in tree vegetation, and in terms of necromass, returned values of 0.89 tC-ha−1 and 7.40 tC-ha−1, respectively. The carbon stored in the soil at a depth of 20 cm is 111.84 tC- ha−1 for herbaceous vegetation and 122.45 tC-ha−1 for tree vegetation.
Keywords: ecosystem, paramo, tree vegetation, carbon, biomass.
Resumen
Se determinó el contenido de carbono almacenado en base a un diseño experimental estratificado al azar por tipo de vegetación, se instalaron tres unidades de muestreo de 400 m2 cada una, a partir de 3600–4100 m.s.n.m; con intervalos de 150 m de altitud. El inventario de la vegetación herbácea mediante el método GLORIA, Para el muestreo de la biomasa aérea y necromasa en la parcela se anidaron subparcelas circulares, se recolecto las muestras en 4 cuadrantes de 0.25m2 dos en cada subparcela. En el comportamiento suelo se tomaron muestras de 0–20 cm, 20–40 cm y de 40–60 cm, se evaluó el porcentaje de carbono orgánico en el suelo y la densidad aparente. Los resultados indican una diversidad florÃstica representada por 44 especies, 39 de la vegetación herbácea y 5 de la vegetación arbórea. El contenido de carbono almacenado en la biomasa aérea reporto un valor de 83,88 tCâ‹…ha−1 para vegetación herbácea y de 158,50 tCâ‹…ha−1 en la vegetación arbórea, en cuanto a necromasa con valores de 0,89 tC-ha−1 y de 7,40 tC-ha−1 respectivamente. El carbono almacenado en el suelo a 20 cm de profundidad es de 111.84 tC-ha−1 la vegetación herbácea y de 122,45 tC-ha−1 para la vegetación arbórea.
Palabras clave: ecosistema, paramo, vegetación arbórea, carbono, biomasa
Overview and Outlook of the Computational Activities at KIT for the Safety Assessment and the Radiological Risk Prediction of Nuclear Power Plants
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