880 research outputs found

    Insecticidal Activity Of Plant Lectins And Potential Application In Crop Protection

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    Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Lectins constitute a complex group of proteins found in different organisms. These proteins constitute an important field for research, as their structural diversity and affinity for several carbohydrates makes them suitable for numerous biological applications. This review addresses the classification and insecticidal activities of plant lectins, providing an overview of the applicability of these proteins in crop protection. The likely target sites in insect tissues, the mode of action of these proteins, as well as the use of lectins as biotechnological tools for pest control are also described. The use of initial bioassays employing artificial diets has led to the most recent advances in this field, such as plant breeding and the construction of fusion proteins, using lectins for targeting the delivery of toxins and to potentiate expected insecticide effects. Based on the data presented, we emphasize the contribution that plant lectins may make as tools for the development of integrated insect pest control strategies.20220142033FUNDECTFINEPCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    A New Derivation of the CPT and Spin-Statistics Theorems in Non-Commutative Field Theories

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    We propose an alternative axiomatic description for non-commutative field theories (NCFT) based on some ideas by Soloviev to nonlocal quantum fields. The local commutativity axiom is replaced by the weaker condition that the fields commute at sufficiently large spatial separations, called asymptotic commutativity, formulated in terms of the theory of analytic functionals. The question of a possible violation of the CPT and Spin-Statistics theorems caused by nonlocality of the commutation relations [x^μ,x^ν]=iθμν[\hat{x}_\mu,\hat{x}_\nu]=i\theta_{\mu\nu} is investigated. In spite of this inherent nonlocality, we show that the modification aforementioned is sufficient to ensure the validity of these theorems for NCFT. We restrict ourselves to the simplest model of a scalar field in the case of only space-space non-commutativity.Comment: The title is new, and the analysis in the manuscript has been made more precise. This revised version is to be published in J.Math.Phy

    LINGUAGEM E SUBJETIVIDADE EM NIETZSCHE E FOUCAUL

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    Este artigo aborda as relações entre linguagem e subjetividade tomando como mote o pensamento de Nietzsche e de Foucault. Nietzsche trabalhou a questão da linguagem pelo menos em dois momentos cruciais de sua pesquisa: na juventude, em textos como Sobre verdade e mentira no sentido extra-moral, e na maturidade, como no Livro V de A gaia ciência e em outras publicações da época. Foucault também conferiu atenção ao tema em fases diferentes de sua produção. Já suas primeiras publicações, como a “Introdução a Binswanger”, constituíam pesquisas acerca do tema da linguagem, bem como As palavras e as coisas, até finalmente, em seus últimos textos, tratar a questão da relação entre a linguagem, a produção de verdade e a constituição de si. Percorreremos brevemente essas diferentes fases do pensamento dos dois autores para tentar encontrar relações de toque entre linguagem e subjetividade tal como cada um deles as concebeu e, por fim, demonstrar em que Foucault se afasta de Nietzsche nos seus últimos escritos no que tange a uma relação entre linguagem e subjetividade, em direção a uma política da verdade

    Neural network decoder for topological color codes with circuit level noise

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    A quantum computer needs the assistance of a classical algorithm to detect and identify errors that affect encoded quantum information. At this interface of classical and quantum computing the technique of machine learning has appeared as a way to tailor such an algorithm to the specific error processes of an experiment --- without the need for a priori knowledge of the error model. Here, we apply this technique to topological color codes. We demonstrate that a recurrent neural network with long short-term memory cells can be trained to reduce the error rate ϵL\epsilon_{\rm L} of the encoded logical qubit to values much below the error rate ϵphys\epsilon_{\rm phys} of the physical qubits --- fitting the expected power law scaling ϵLϵphys(d+1)/2\epsilon_{\rm L} \propto \epsilon_{\rm phys}^{(d+1)/2}, with dd the code distance. The neural network incorporates the information from "flag qubits" to avoid reduction in the effective code distance caused by the circuit. As a test, we apply the neural network decoder to a density-matrix based simulation of a superconducting quantum computer, demonstrating that the logical qubit has a longer life-time than the constituting physical qubits with near-term experimental parameters.Comment: 10 pages, 9 figures; V2: updated text and figure

    Positive Allosteric Modulation of Kv Channels by Sevoflurane: Insights into the Structural Basis of Inhaled Anesthetic Action.

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    Inhalational general anesthesia results from the poorly understood interactions of haloethers with multiple protein targets, which prominently includes ion channels in the nervous system. Previously, we reported that the commonly used inhaled anesthetic sevoflurane potentiates the activity of voltage-gated K+ (Kv) channels, specifically, several mammalian Kv1 channels and the Drosophila K-Shaw2 channel. Also, previous work suggested that the S4-S5 linker of K-Shaw2 plays a role in the inhibition of this Kv channel by n-alcohols and inhaled anesthetics. Here, we hypothesized that the S4-S5 linker is also a determinant of the potentiation of Kv1.2 and K-Shaw2 by sevoflurane. Following functional expression of these Kv channels in Xenopus oocytes, we found that converse mutations in Kv1.2 (G329T) and K-Shaw2 (T330G) dramatically enhance and inhibit the potentiation of the corresponding conductances by sevoflurane, respectively. Additionally, Kv1.2-G329T impairs voltage-dependent gating, which suggests that Kv1.2 modulation by sevoflurane is tied to gating in a state-dependent manner. Toward creating a minimal Kv1.2 structural model displaying the putative sevoflurane binding sites, we also found that the positive modulations of Kv1.2 and Kv1.2-G329T by sevoflurane and other general anesthetics are T1-independent. In contrast, the positive sevoflurane modulation of K-Shaw2 is T1-dependent. In silico docking and molecular dynamics-based free-energy calculations suggest that sevoflurane occupies distinct sites near the S4-S5 linker, the pore domain and around the external selectivity filter. We conclude that the positive allosteric modulation of the Kv channels by sevoflurane involves separable processes and multiple sites within regions intimately involved in channel gating

    Decolorization of a chromophore molecule with immobilized horseradish peroxidase / Descoloração de uma molécula de cromóforo com peroxidase de rábano imobilizada

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    The enzymes can modify some effluent characteristics in order to increase the degradability, or the bioconversion of liquid  effluents. The oxireductases, laccases and peroxidases have been used due their high potentiality in many environmental treatments of natural and synthetic organic compounds as dyes, phenols and polyphenolics molecules. The performance of immobilized horseradish peroxidase on aminopropyl glass beads was investigated in this work in a decolorization reaction of methylene blue colorant. The experiments were conducted in batch conditions during 3 hours, with different aqueous solutions of peroxide hydrogen (H2O2) concentration solutions (2-10 mg/L), methylene blue (ME)  (5-20 mg/L) and the pH in the range from 4 to 8, according an experimental design proposed by the software STATISTICA®. After 3 hours of treatment the reduction of  the color was 60% when comparing to the original color and 50% when the immobilized enzymes were reused in five sequential batch treatment cycles for a 10 mg/L of H2O2 solution, 20 mg/L of ME  and pH 8.0.  Working in continuous process with two microreactors in series the system showed a good performance with 97% of decolorization in the first 15 minutes. After 1 hour of continuous treatment the percentage of the color removing was around 70%.

    Biophysical characterization of the first ultra-cyclist in the world to break the 1,000 km barrier in 24-h non-stop road cycling: A case report

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    A plethora of factors determine elite cycling performance. Those include training characteristics, pacing strategy, aerodynamics, nutritional habits, psychological traits, physical fitness level, body mass composition, and contextual features; even the slightest changes in any of these factors can be associated with performance improvement or deterioration. The aim of the present case report is to compare the performances of the same ultra-cyclist in achieving two world records (WR) in 24 h cycling. We have analyzed and compared the distance covered and speed for each WR. The 24 h period was split into four-time intervals (0–6 h; > 6–12 h; > 12–18 h; > 18–24 h), and we compared the differences in the distance covered and speed between the two WRs. For both WRs, a strong negative correlation between distance and speed was confirmed (r = –0.85; r = –0.89, for old and new WR, respectively). Differences in speed (km/h) were shown between the two WRs, with the most significant differences in 12–18 h (Δ = 6.50 km/h). For the covered distance in each block, the most significant differences were observed in the last part of the cycling (Δ = 38.54 km). The cyclist effective surface area (ACd) was 0.25 m2^{2} less and 20% more drag in the new WR. Additionally, the mechanical power was 8%, the power to overcome drag was 31%, and the power-weight ratio was 8% higher in the new WR. The mechanical efficiency of the cyclist was 1% higher in the new WR. Finally, the heart rate (HR) presented significant differences for the first 6 h (Old WR: 145.80 ± 5.88 bpm; New WR: 139.45 ± 5.82 bpm) and between the 12 and 18 h time interval (Old WR: 133.19 ± 3.53 bpm; New WR: 137.63 ± 2.80 bpm). The marginal gains concept can explain the performance improvement in the new WR, given that the athlete made some improvements in technical specifications after the old WR

    Reclassification of Parapterulicium Corner (Pterulaceae, Agaricales), contributions to Lachnocladiaceae and Peniophoraceae (Russulales) and introduction of Baltazaria gen. nov.

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    The genus Parapterulicium was first introduced to accommodate two Brazilian species of coralloid fungi with affinities to Pterulaceae (Agaricales). Despite the coralloid habit and the presence of skeletal hyphae, other features, notably the presence of gloeocystidia, dichophyses and papillate hyphal ends, differentiate this genus from Pterulaceae sensu stricto. Fieldwork in Brazil resulted in the rediscovery of two coralloid fungi identifiable as Parapterulicium, the first verified collections of this genus since Corner's original work in the 1950s. Molecular phylogenetic analyses of nrITS and nrLSU sequences from these modern specimens revealed affinities with the /peniophorales clade in the Russulales, rather than Pterulaceae. The presence of distinctive hyphal elements, homologous to the defining features of /peniophorales, is consistent with the phylogenetic evidence and thus clearly distinguished Parapterulicium and its type species P. subarbusculum from Pterulaceae, placing this genus within /peniophorales. Parapterulicium was also found to be polyphyletic so Baltazaria gen. nov. is proposed to accommodate P. octopodites, Scytinostroma galactinum, S. neogalactinum and S. eurasiaticogalactinum also within /peniophorales

    Supersymmetric Field-Theoretic Models on a Supermanifold

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    We propose the extension of some structural aspects that have successfully been applied in the development of the theory of quantum fields propagating on a general spacetime manifold so as to include superfield models on a supermanifold. We only deal with the limited class of supermanifolds which admit the existence of a smooth body manifold structure. Our considerations are based on the Catenacci-Reina-Teofillatto-Bryant approach to supermanifolds. In particular, we show that the class of supermanifolds constructed by Bonora-Pasti-Tonin satisfies the criterions which guarantee that a supermanifold admits a Hausdorff body manifold. This construction is the closest to the physicist's intuitive view of superspace as a manifold with some anticommuting coordinates, where the odd sector is topologically trivial. The paper also contains a new construction of superdistributions and useful results on the wavefront set of such objects. Moreover, a generalization of the spectral condition is formulated using the notion of the wavefront set of superdistributions, which is equivalent to the requirement that all of the component fields satisfy, on the body manifold, a microlocal spectral condition proposed by Brunetti-Fredenhagen-K\"ohler.Comment: Final version to appear in J.Math.Phy
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