1,071 research outputs found

    Kinetics and Mechanism of Hydrolysis of Benzimidazolylcarbamates

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    Synthesis of new 2-aminobenzimidazole-1-carbamates was accomplished by carbamoylation of 2-aminobenzimidazole using different substituted phenyl chloroformates. The aqueous hydrolysis of the new compounds was examined in the pH range 1-13 at 25 oC. The evaluated kinetic parameters led to the conclusion that up to pH 4 reaction proceeds by a bimolecular attack of water to the N-protonated substrate. This is the first time this behavior is described for carbamates, and can be ascribed to the higher basicity of the benzimidazolyl moiety when compared with the carbonyl oxygen. For higher values of pH, the results are consistent with a BAc2 mechanism with nucleophilic catalysis, but while between pH 4 and pH 7 water acts as the nucleophile, for pH> 7 the hydroxide ion is the acting species

    170 GBit/s transmission in an erbium-doped waveguide amplifier on silicon

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    Signal transmission experiments were performed at 170 Gbit/s in an integrated Al2O3:Er3+Al_2O_3:Er^{3+} waveguide amplifier to investigate its potential application in high-speed photonic integrated circuits. Net internal gain of up to 11 dB was measured for a continuous-wave 1532 nm signal under 1480 nm pumping, with a threshold pump power of 4 mW. A differential group delay of 2 ps between the TE and TM fundamental modes of the 5.7-cm-long amplifier was measured. When selecting a single polarization open eye diagrams and bit error rates equal to those of the transmission system without the amplifier were observed for a 1550 nm signal encoded with a 170 Gbit/s return-to-zero pseudo-random 2712^{7}-1 bit sequence

    Photoacoustic Assessment Of The In Vivo Genotypical Response Of Corn To Toxic Aluminium

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    Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)[No abstract available]1153341343ACRL; Association of College and Research Libraries; CAPES; Association of College and Research LibrariesCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

    Estimating additive and dominance variances for complex traits in pigs combining genomic and pedigree information

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    Knowledge of dominance effects should improve ge-netic evaluations, provide the accurate selection of purebred animals, and enable better breeding strategies, including the exploitation of het-erosis in crossbreeds. In this study, we combined genomic and pedi-gree data to study the relative importance of additive and dominance genetic variation in growth and carcass traits in an F2 pig population. Two GBLUP models were used, a model without a polygenic effect (ADM) and a model with a polygenic effect (ADMP). Additive effects played a greater role in the control of growth and carcass traits than did dominance effects. However, dominance effects were important for all traits, particularly in backfat thickness. The narrow-sense and broad-sense heritability estimates for growth (0.06 to 0.42, and 0.10 to 0.51, respectively) and carcass traits (0.07 to 0.37, and 0.10 to 0.76, respec-tively) exhibited a wide variation. The inclusion of a polygenic effect in the ADMP model changed the broad-sense heritability estimates only for birth weight and weight at 21 days of age

    Strange form factors in the context of SAMPLE, HAPPEX, and A4 experiments

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    The strange properties of the nucleon are investigated within the framework of the SU(3) chiral quark-soliton model assuming isospin symmetry and applying the symmetry conserving SU(3) quantization. We present the form factors GE,M0(Q2)G^0_{E,M}(Q^2), GMZ(Q2)G^Z_M(Q^2) and the electric and magnetic strange form factors GE,Ms(Q2)G^s_{E,M}(Q^2) incorporating pion and kaon asymptotics. The results show a fairly good agreement with the recent experimental data from the SAMPLE and HAPPEX collaborations. We also present predictions for future measurements including the A4 experiment at MAMI (Mainz).Comment: 10 pages with four figures. RevTeX4 is used. Few lines are changed. Accepted for publication in Phys.Rev.

    Pest kill rate as aggregate evaluation criterion to rank biological control agents: a case study with Neotropical predators of Tuta absoluta on tomato

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    AbstractTuta absoluta (Meyrick), a key pest of tomato, is quickly spreading over the world and biological control is considered as one of the control options. Worldwide more than 160 species of natural enemies are associated with this pest, and an important challenge is to quickly find an effective biocontrol agent from this pool of candidate species. Evaluation criteria for control agents are presented, with the advantages they offer for separating potentially useful natural enemies from less promising ones. Next, an aggregate parameter for ranking agents is proposed: the pest kill rate km. We explain why the predator's intrinsic rate of increase cannot be used for comparing the control potential of predators or parasitoids, while km can be used to compare both types of natural enemies. As an example, kill rates for males, females and both sexes combined of three Neotropical mirid species (Campyloneuropsis infumatus (Carvalho), Engytatus varians (Distant) and Macrolophus basicornis (Stål)) were determined, taking all life-history data (developmental times, survival rates, total nymphal and adult predation, sex ratios and adult lifespan) into account. Based on the value for the intrinsic rate of increase (rm) for T. absoluta and for the kill rate km of the predators, we predict that all three predators are potentially able to control the pest, because their km values are all higher than the rm of the pest. Using only km values, we conclude that E. varians is the best candidate for control of T. absoluta on tomato, with C. infumatus ranking second and M. basicornis last

    Relationship between childhood maltreatment and geriatric depression: the mediator effect of personality traits.

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    Childhood maltreatment is an important factor associated with adverse mental health outcomes including geriatric depression and the "big five" personality characteristics. The objective of this study was to evaluate a model where personality characteristics mediate the relationship between childhood maltreatment and geriatric depression. In this cross-sectional study, elderly subjects from socioeconomically disadvantaged neighborhoods of Porto Alegre, Brazil (n = 260) completed the Childhood Trauma Questionnaire (CTQ), NEO-Five Factor Inventory (NEO-FFI), and Mini International Neuropsychiatric Interview 5.0 (MINI plus). We used structural equation modeling (SEM) to evaluate the mediation hypothesis. The five personality factors (neuroticism, extraversion, agreeableness, openness, and conscientiousness) were related to childhood maltreatment and depression. Mediation analysis revealed that neuroticism and extraversion are complete mediators, agreeableness and conscientiousness are partial mediators, and openness is not a mediator. These findings support the hypothesis in which childhood maltreatment is associated with geriatric depression and mediated by personality factors. These results suggest that reducing the maladaptive personality trait in elderly people who suffered childhood maltreatment could prevent geriatric depression

    Strange nucleon form factors in the perturbative chiral quark model

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    We apply the perturbative chiral quark model at one loop to calculate the strange form factors of the nucleon. A detailed numerical analysis of the strange magnetic moments and radii of the nucleon, and also the momentum dependence of the form factors is presented.Comment: 18 pages, 6 figure

    Universality and scaling study of the critical behavior of the two-dimensional Blume-Capel model in short-time dynamics

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    In this paper we study the short-time behavior of the Blume-Capel model at the tricritical point as well as along the second order critical line. Dynamic and static exponents are estimated by exploring scaling relations for the magnetization and its moments at early stage of the dynamic evolution. Our estimates for the dynamic exponents, at the tricritical point, are z=2.215(2)z= 2.215(2) and θ=0.53(2)\theta= -0.53(2).Comment: 12 pages, 9 figure
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