5,600 research outputs found
Resistance Stability of the Secondary Tiller of \u27Caldwell\u27 Wheat After the Primary Culm Was Infested With Virulent Hessian Fly (Diptera: Cecidomyiidae) Larvae
Secondary tiller resistance of \u27Caldwell\u27 wheat, Triticum aestivum, with the H6 gene for larval resistance to Hessian fly, Mayetiola destructor, was maintained, after the primary culm had been previously infested with virulent larvae. Earlier studies showed that a primary culm infested initially with a virulent larva allowed subsequent normally avirulent larvae to survive on that cultivar; however, in our study the resistance of secondary tillers was mainained even though the primary culm was infested earlier with virulent Hessian fly larvae. This gene stability for resistance is important for optimizing wheat yield of those cultivars that possess genes resistant to the Hessian fly that are tillering and infested with different biotypes
Thermal stability of the cu-ceo2 interface on silica and alumina, and its relation with activity in the oxidation reaction of co and the decomposition of n2o
Indexación: Scopus; Scielo.The effect of the support on the formation of the Cu-CeO2 interface and its thermal stability after calcination at 500, 700 and 900 °C is studied. The supports used are SiO2, because of its inert character, and Al2O3, because it can interact with the Cu and Ce species on the surface. The catalysts were characterized by BET, XRD, UV-vis DRS, and TPR with H2. The catalytic activity in the CO oxidation reactions with O2 at low temperature and the decomposition of N2O were selected to visualize the effect of temperature on the concentration of Cu-CeO2 interfacial sites. The results show that at a calcination temperature of 500 °C the formation of the Cu-CeO2 interface is favored over the SiO2 support. However, the stability of the Cu-CeO2 interface on SiO2 is much lower than on Al2O3, causing a substantial decrease of the interfacial sites calcining at 700 °C, and segregation of the Cu and Ce species on the surface of the silica, with complete loss of the catalytic activity in both reactions when calcining at 900 °C. In contrast, on alumina the Cu-CeO2 interface is more stable and presents a significant catalytic activity in both reactions, even when calcining at 900 °C. The characterization results show that the sintering process of Cu species and CeO2 particles is less on the alumina support due to the greater interaction of the Cu and Ce with this support. © 2018 Sociedad Chilena de Quimica.all rights reserved.https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0717-97072018000304102&lng=en&nrm=iso&tlng=e
Einstein-AdS action, renormalized volume/area and holographic RĂ©nyi entropies
IndexaciĂłn: Scopus.The authors thank D.E. DĂaz, P. Sundell and A. Waldron for interesting discussions. C.A. is a Universidad Andres Bello (UNAB) Ph.D. Scholarship holder, and his work is supported by DirecciĂłn General de InvestigaciĂłn (DGI-UNAB). This work is funded in part by FONDECYT Grants No. 1170765 “Boundary dynamics in anti-de Sitter gravity and gauge/gravity duality ” and No. 3180620 “Entanglement Entropy and AdS gravity ”, and CONICYT Grant DPI 20140115.We exhibit the equivalence between the renormalized volume of asymptotically anti-de Sitter (AAdS) Einstein manifolds in four and six dimensions, and their renormalized Euclidean bulk gravity actions. The action is that of Einstein gravity, where the renormalization is achieved through the addition of a single topological term. We generalize this equivalence, proposing an explicit form for the renormalized volume of higher even-dimensional AAdS Einstein manifolds. We also show that evaluating the renormalized bulk gravity action on the conically singular manifold of the replica trick results in an action principle that corresponds to the renormalized volume of the regular part of the bulk, plus the renormalized area of a codimension-2 cosmic brane whose tension is related to the replica index. Renormalized RĂ©nyi entropy of odd-dimensional holographic CFTs can thus be obtained from the renormalized area of the brane with finite tension, including the effects of its backreaction on the bulk geometry. The area computation corresponds to an extremization problem for an enclosing surface that extends to the AdS boundary, where the newly defined renormalized volume is considered. © 2018, The Author(s).https://link.springer.com/article/10.1007%2FJHEP08%282018%2913
Activity of alumina supported fe catalysts for N2O decomposition: Effects of the iron content and thermal treatment
Indexación: Scopus.The activity of Fe2O3/Al2O3 catalysts prepared by impregnation of Al2O3 with different amounts of Fe and calcination temperatures (650 and 900 °C) in the direct N2O decomposition reaction was studied. High calcination temperature was introduced to study the effect of "aging", which are the conditions prevailing in the process-gas option for N2O abatement. The catalysts were characterized by BET, XRD, UV-DRS, and H2-TPR. The incorporation of Fe promotes the alumina phase transition (g-Al2O3 to a-Al2O3) when the catalysts are calcined at 900 °C, which is accompanied by a decrease in the specifc area. The activity of the catalysts and the specifc surface area depend on Fe loading and calcination temperature. It was found that highly dispersed Fe species are more active than bulk type Fe2O3 particles. We conclude that Fe2O3/Al2O3 catalysts prepared by impregnation method are active in the decomposition of N2O, to be used at low or high reaction temperatures (tail-gas or process-gas treatments, respectively), as part of nitric acid production plant. © 2018 Sociedad Chilena de Quimica. All rights reserved.https://scielo.conicyt.cl/pdf/jcchems/v62n4/0717-9324-jcchems-62-04-3752.pd
SENSING IMMOBILIZED MOLECULES OF STREPTAVIDIN ON A SILICON SURFACE BY MALDI-TOF MASS SPECTROMETRY AND FLUORESCENCE MICROSCOPY
Indexación: Web of Science; Scielo.A hydrogen-terminated Si (111) surface was modified to form an aminoterminated monolayer for immobilization of streptavidin. Cleavage of an N-(ω-undecylenyl)-phthalimide covered surface using hidrazine yields an amino group-modified surface, which serves as a substrate for the attachment of biotin and subsequently streptavidin. We used surface analytical techniques to characterize the surface and to control the course of functionalization before the immobilization of streptavidin. To confirm the presence of the streptavidin Texas red on the surface two powerful techniques available in a standard biochemical laboratory are used, Fluorescence Microscopy and MALDI-TOF that allow us to detect and determine the immobilized streptavidin. This work provides an avenue for the development of devices in which the exquisite binding specificity of biomolecular recognition is directly coupled to a biosensor. In addition, we have demonstrated that MALDI-TOF and fluorescence microscopy are useful techniques for the characterization of silicon functionalized surfaces.http://ref.scielo.org/gm87c
Multi-level variation in labile characters
Labile characters, like behaviors, are phenotypes that are expressed repeatedly in the life of an individual. These types of characters allow individuals to adjust their phenotype to various levels of environmental variation, and therefore play a key role in the evolutionary process. Labile phenotypes are distinct because of their multi-level nature; individuals can differ in their average phenotypic expression (causing among-individual variation), but they can also vary their phenotype in each expression (causing within-individual variation). In order to understand the role of labile characters in the evolutionary process it is necessary to acknowledge that variation at each level is caused by different processes. Variation at the among-individual level is caused by genetic or environmental differences having a permanent effect on an individual’s phenotype, whereas variation at the within-individual level is caused by an individual’s adjustment of its phenotype to a changing environment. The implications of these multi layered effects in the expression of labile characters have been acknowledged by different fields of evolutionary ecology, but major areas of evolutionary research do not fully incorporated this idea. The general aim of my thesis was to fully integrate this multi-level nature in the study of the adaptive causes and evolutionary consequences of variation in labile characters. My thesis is composed of five chapters: the first three are conceptual and methodological works aimed at integrating the multi-level nature of labile characters into already existing evolutionary frameworks. The last two chapters describe, as a worked example, how the different levels of variation and covariation between (labile) fertilization related traits affect the evolution of the alternative reproductive strategies in a wild passerine bird (the great tit).
The first chapter is a conceptual work focusing on how to define and statistically characterize behavioral characters. We argue that behavioral characters can be studied using the “evolutionary character concept”. This framework was developed to study characters that only vary among individuals (i.e. “fixed characters”); therefore we extended this framework to include characters that also vary within-individuals. The second chapter of the thesis is a methodological work where we proposed a way to quantify multi-level variation in reaction norms, which allows the estimation of repeatability of plasticity. Behavioral ecologists have recently developed theory predicting the ecological conditions where repeatable vs. non-repeatable variation in phenotypic plasticity should evolve. However, there was no methodological framework to estimate repeatability of plasticity. Therefore, we proposed a study design and mixed effect model structure to estimate repeatability of plasticity. To help researchers use the proposed methodology, we developed an R simulation package to estimate bias, precision and accuracy for different sampling designs. The third chapter is an opinion paper that urges researchers to combine theory and methods developed in behavioral ecology and quantitative genetics to study phenotypic variation in a social context. Quantitative geneticists have developed a framework to study social evolution aimed at predicting the evolutionary response to selection of traits affected by the phenotypes of other individuals (the “social environment”). Phenotypes expressed in a social context, also called interactive phenotypes, exhibit a particular evolutionary dynamic because their environmental component is composed of genes and can thus evolve. Despite that fact that the effects of the social environment are commonly mediated by labile characters, this social evolution framework has not fully considered the multi-level nature of labile characters. Therefore, for chapter three we integrated the multi-level nature of labile characters in this social evolution framework.
The final two chapters focus, as a worked example, on within-pair and extra-pair reproductive behavior in great tits. For these chapters, we utilized the theoretical and methodological developments of the previous chapters to study the sources of evolutionary constraints on alternative fertilization routes in male great tits. One of the chapters has a more evolutionary perspective, while the other applies a more behavioral ecology view point. In chapter four we studied male extra-pair and within-pair reproduction as interactive phenotypes that are affected by the phenotypes of both the male and the female member of great tit breeding pairs. We showed that male fertilization strategies depend heavily on the phenotype of their female. This social environment effect should influence the evolutionary response to selection of male fertilization strategies, and could partly explain evolutionary stasis, observed in natural populations, in traits so closely linked to fitness. In chapter four we also studied whether trade-offs among- or within-individuals can constrain the phenotypic evolution of male alternative reproductive strategies. We showed that among-male trade-offs between within-pair and extra-pair reproduction could also be a source of evolutionary constrain. In chapter five, we corroborated the existence of trade-offs between alternative reproductive routes by studying whether within-pair and extra-pair fertilizations are obtained at the same time, allowing for the possibility of a trade-off between the two. We found that a male's extra-pair fertilization success is actually higher when it constrains his ability to secure within-pair fertilizations. This result is consistent with our finding that there is indeed a trade-off between extra-pair and within-pair reproduction in this species. The empirical works in this thesis highlight the importance of the social environment as a source of phenotypic variation in the expression of labile traits. But more generally, from the works in this thesis, we can conclude that to fully understand the role of labile characters in the evolutionary process it is necessary to acknowledge their multi-level nature
P2: DIFFERENTIAL EFFECTS OF ADJACENT-LETTER AND OPEN FLANKING BIGRAMS ON LEXICAL DECISION PERFORMANCE
Some models of word identification hypotheses units responsive to bigrams—letter pairs—that may not be adjacent in a letter-string stimulus. Grainger, Mathot, and Vitu (2014) and Palinski (2016) found, for words, responding was more efficient when flanking bigrams contained target-string letters than when they did not. They also found that responding was more efficient when flanking bigrams contained letters ordered as in the target than switched but whether flanking bigrams were ordered as in the target did not affect performance. Palinski (2016) replicated the results of Grainger et al. (2014) and conducted a second experiment that included four additional conditions in which the flanking bigrams consist of letters separated by one letter in the target (ex. FO FROG RG; RG FROG FO; OF FROG GR; GR FROG OF). Although, for nonadjacent letter bigrams, the pattern of performance over conditions was like that in Grainger et al. (2014) and Palinski (2016) Experiment 1, for adjacent bigrams, the pattern was different. To investigate the stability of these results, we repeated Palinski\u27s second experiment. We replicated her results. The effect of adjacent-letter flanking bigrams may depend on whether nonadjacent-letter flanking bigrams are encountered in the experiment.https://engagedscholarship.csuohio.edu/u_poster_2017/1037/thumbnail.jp
P2: DIFFERENTIAL EFFECTS OF ADJACENT-LETTER AND OPEN FLANKING BIGRAMS ON LEXICAL DECISION PERFORMANCE
Some models of word identification hypotheses units responsive to bigrams—letter pairs—that may not be adjacent in a letter-string stimulus. Grainger, Mathot, and Vitu (2014) and Palinski (2016) found, for words, responding was more efficient when flanking bigrams contained target-string letters than when they did not. They also found that responding was more efficient when flanking bigrams contained letters ordered as in the target than switched but whether flanking bigrams were ordered as in the target did not affect performance. Palinski (2016) replicated the results of Grainger et al. (2014) and conducted a second experiment that included four additional conditions in which the flanking bigrams consist of letters separated by one letter in the target (ex. FO FROG RG; RG FROG FO; OF FROG GR; GR FROG OF). Although, for nonadjacent letter bigrams, the pattern of performance over conditions was like that in Grainger et al. (2014) and Palinski (2016) Experiment 1, for adjacent bigrams, the pattern was different. To investigate the stability of these results, we repeated Palinski\u27s second experiment. We replicated her results. The effect of adjacent-letter flanking bigrams may depend on whether nonadjacent-letter flanking bigrams are encountered in the experiment.https://engagedscholarship.csuohio.edu/u_poster_2017/1037/thumbnail.jp
Resistance Stability of the Secondary Tiller of \u27Caldwell\u27 Wheat After the Primary Culm Was Infested With Virulent Hessian Fly (Diptera: Cecidomyiidae) Larvae
Secondary tiller resistance of \u27Caldwell\u27 wheat, Triticum aestivum, with the H6 gene for larval resistance to Hessian fly, Mayetiola destructor, was maintained, after the primary culm had been previously infested with virulent larvae. Earlier studies showed that a primary culm infested initially with a virulent larva allowed subsequent normally avirulent larvae to survive on that cultivar; however, in our study the resistance of secondary tillers was mainained even though the primary culm was infested earlier with virulent Hessian fly larvae. This gene stability for resistance is important for optimizing wheat yield of those cultivars that possess genes resistant to the Hessian fly that are tillering and infested with different biotypes
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