2,693 research outputs found

    Effect of CH4_{4} addition on excess electron mobility in liquid Kr

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    The excess electrons mobility ÎŒ\mu has been measured recently in liquid mixtures of Kr and CH4_{4} as a function of the electric field up to E≈104V/cmE\approx 10^{4} V/cm and of the CH4_{4} concentration xx up to x≈10x \approx 10 % , at temperatures T≈130K,T\approx 130 K, fairly close to the normal boiling point of Kr (Tb≈120K)(T_{b}\approx 120 K)(folegani). We present here new data which extend the previous set in the region of low electric field. The experimental results are interpreted in terms of a kinetic model previously proposed to explain the concentration dependent behavior of ÎŒ\mu in liquid Ar--Kr and Ar--Xe mixtures. The main result is that CH4_{4} is more effective in enhancing energy--transfer rather than momentum--transfer in comparison with mixtures of liquified noble gases. The field dependence of ÎŒ\mu is quite complicate. In particular, at intermediate values of the field, there appears to be a crossover between two different electric--field dependent behaviors of ÎŒ.\mu. The electric field strength at crossover is well correlated with the concentration of CH4._{4}. This fact suggests that different excitations of the molecular solute might be involved in the momentum-- and energy--transfer processes for different values of the mean electron energy.Comment: 17, pages,7 figures, RevTeX4, submitted to J.Chem.Phy

    Use of Annual Self-Reseeding Legumes in an Oak Forest in Central Italy

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    A trial has been carried out for three years in an oak coppice geometrically thinned out of Mediterranean Central Italy, about the functioning of a pastoral system made by four different resources: native pasture, subterranean clover (Trifolium brachycalycinum Katzn. et Morley) in pure stand, strips thinned out and firebreaks improved with oversown subclover, all grazed by sheep. Subclover increased the forage yield and improved the palatabilty of the pasture and the regularity of grazing; the higher biomass intake by animals reduced the quantity of dried biomass in summer and contributed to keep low either fire hazards or flame diffusion speed. Data underlined the importance of deferred grazing and of the combination of different native or improved resources on the seasonal distribution of production and animal intake

    Electron drift velocity measurements in liquid krypton–methane mixtures

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    Abstract Electron drift velocities have been measured in liquid krypton, pure and mixed with methane at different concentrations (1–10% in volume) versus electric field strength, and a possible effect of methane on electron lifetime has been investigated. While no effect on lifetime could be detected, since lifetimes were in all cases longer than what measurable, a very large increase in drift velocity (up to a factor 6) has been measured

    (2-Aminobenzothiazole)-Methyl-1,1-bisphosphonic acids: Targeting matrix metalloproteinase 13 inhibition to the bone

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    Matrix Metalloproteinases (MMPs) are a family of secreted and membrane-bound enzymes, of which 24 isoforms are known in humans. These enzymes degrade the proteins of the extracellular matrix and play a role of utmost importance in the physiological remodeling of all tissues. However, certain MMPs, such as MMP-2, -9, and -13, can be overexpressed in pathological states, including cancer and metastasis. Consequently, the development of MMP inhibitors (MMPIs) has been explored for a long time as a strategy to prevent and hinder metastatic growth, but the important side effects linked to promiscuous inhibition of MMPs prevented the clinical use of MMPIs. Therefore, several strategies were proposed to improve the therapeutic profile of this pharmaceutical class, including improved selectivity toward specific MMP isoforms and targeting of specific organs and tissues. Combining both approaches, we conducted the synthesis and preliminary biological evaluation of a series of (2-aminobenzothiazole)-methyl-1,1-bisphosphonic acids active as selective inhibitors of MMP-13 via in vitro and in silico studies, which could prove useful for the treatment of bone metastases thanks to the bone-targeting capabilities granted by the bisphosphonic acid group

    Giorgio Rota. Safavid Envoys in Venice

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    This article is part of a larger collection of articles that shed light of the diplomatic world as it took shape between the Middle East and Europe during the early modern period. Giorgio Rota, drawing on a rich reservoir of published texts, documents and manuscripts in Italy (specifically Venice), provides a thorough, insightful study of how the Venetians practiced diplomacy in relations with envoys and ambassadors from Safavid Iran during the 16th and early 17th centuries. There were approx..

    The species identification problem in mirids (Hemiptera: Heteroptera) highlighted by DNA barcoding and species delimitation studies

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    Due to the difficulties associated with detecting and correctly identifying mirids, developing an accurate species identification approach is crucial, especially for potential harmful species. Accurate identification is often hampered by inadequate morphological key characters, invalid and/or outdated systematics, and biases in the molecular data available in public databases. This study aimed to verify whether molecular characterization (i.e. DNA barcoding) is able to identify mirid species of economic relevance and if species delimitation approaches are reliable tools for species discrimination. Cytochrome c oxydase 1 (cox1) data from public genetic databases were compared with new data obtained from mirids sampled in different Italian localities, including an old specimen from private collection, showing contrasting results. Based on the DNA barcoding approach, for the genus Orthops, all sequences were unambiguously assigned to the same species, while in Adelphocoris, Lygus and Trigonotylus there were over-descriptions and/or misidentifications of species. On the other hand, in Polymerus and Deraeocoris there was an underestimation of the taxonomic diversity. The present study highlighted an important methodological problem: DNA barcoding can be a good tool for pest identification and discrimination, but the taxonomic unreliability of public DNA databases can make this method useless or even misleading

    Going beyond children’s single-text comprehension:The role of fundamental and higher–level skills in 4th graders’ multiple-document comprehension

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    Background: Children's comprehension of single texts relies on both foundational and higher-level skills. These are also assumed to support multiple-document comprehension, but their relative importance has not been examined, to date. Multiple-document comprehension additionally requires the identification and use of information about each document's source. Aims: This study examined multiple-document comprehension in primary school-aged children. It sought to determine the relative importance of skills proposed to be common to both single-text and multiple-document comprehension (word reading fluency, verbal working memory, comprehension monitoring) and specific to the latter (source use). Single-text comprehension and prior topic knowledge were considered as moderator and control. Sample: Participants were 94 children in the fourth year (mean age = 9; 7 years; 52% females). Methods: Children read three documents on each of two topics (chocolate and video games). Multiple-document comprehension and source use were assessed through short essays. Independent measures of the fundamental and higher-level skills were used. Results: There was a significant direct and indirect influence of word reading fluency on comprehension of multiple documents on videogames and also an indirect influence of comprehension monitoring. Indirect influences of word reading fluency and comprehension monitoring on multiple-document comprehension for both topics were also apparent. Verbal working memory was not a unique predictor. When source information was identified, it was included to support the argument in the composition. Conclusions: Efficient word reading, comprehension monitoring, and single-text comprehension are important for multiple-document comprehension in young readers. Implications of these findings and differences between the two document sets are discussed

    Tolerance and Safety Evaluation in a Large Cohort of Healthy Infants Fed an Innovative Prebiotic Formula: A Randomized Controlled Trial

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    Background: the addition of oligosaccharides to infant formula has been shown to mimic some of the beneficial effects of human milk. The aim of the study was to assess the tolerance and safety of a formula containing an innovative mixture of oligosaccharides in early infancy. Methodology/Principal Findings: this study was performed as a multi-center, randomized, double-blind, placebo-controlled trial including healthy term infants. Infants were recruited before the age of 8 weeks, either having started with formula feeding or being fully breast-fed (breastfeeding group). Formula-fed infants were randomized to feeding with a regular formula containing a mixture of neutral oligosaccharides and pectin-derived acidic oligosaccharides (prebiotic formula group) or regular formula without oligosaccharides (control formula group). Growth, tolerance and adverse events were assessed at 8, 16, 24 and 52 weeks of age. The prebiotic and control groups showed similar mean weight, length and head circumference, skin fold thicknesses, arm circumference gains and stool frequency at each study point. As far as the anthropometric parameters are concerned, the prebiotic group and the control group did not attain the values shown by the breastfeeding group at any study point. The skin fold thicknesses assessed in the breastfeeding group at 8 weeks were strikingly larger than those in formula fed infants, whereas at 52 weeks were strikingly smaller. The stool consistency in the prebiotic group was softer than in the control group at 8, 16 and 24 weeks (p <0.001) and closer to that of the breastfeeding group. There was no difference in the incidence of adverse events between the two formula groups. Conclusions: our findings demonstrate the tolerability and the long term safety of a formula containing an innovative mixture of oligosaccharides in a large cohort of healthy infants

    Fewer Basins Will Follow Their Budyko Curves Under Global Warming and Fossil‐Fueled Development

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    The Budyko framework consists of a curvilinear relationship between the evaporative ratio (i.e., actual evaporation over precipitation) and the aridity index (i.e., potential evaporation over precipitation) and defines evaporation's water and energy limits. A basin's movement within the Budyko space illustrates its hydroclimatic change and helps identify the main drivers of change. On the one hand, long-term aridity changes drive evaporative ratio changes, moving basins along their Budyko curves. On the other hand, historical human development can cause river basins to deviate from their curves. The question is if basins will deviate or follow their Budyko curves under the future effects of global warming and related human developments. To answer this, we quantify the movement in the Budyko space of 405 river basins from 1901–1950 to 2051–2100 based on the outputs of seven models from the Coupled Model Intercomparison Project - Phase 6 (CMIP6). We account for the implications of using different potential evaporation models and study low- and high-emissions scenarios. We find considerable differences of movement in Budyko space regarding direction and intensity when using the two estimates of potential evaporation. However, regardless of the potential evaporation estimate and the scenario used, most river basins will not follow their reference Budyko curves (>72%). Furthermore, the number of basins not following their curves increases under high greenhouse gas emissions and fossil-fueled development SP585 and across dry and wet basin groups. We elaborate on the possible explanations for a large number of basins not following their Budyko curves
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