11,529 research outputs found
Non-dual modal operators as a basis for 4-valued accessibility relations in Hybrid logic
The modal operators usually associated with the notions of possibility and necessity are classically duals. This paper aims to defy that duality in a paraconsistent environment, namely in a Belnapian Hybrid logic where both propositional variables and accessibility relations are four-valued. Hybrid logic, which is an extension of Modal logic, incorporates extra machinery such as nominals – for uniquely naming states – and a satisfaction operator – so that the formula under its scope is evaluated in the state whose name the satisfaction operator indicates.
In classical Hybrid logic the semantics of negation, when it appears before compound formulas, is carried towards subformulas, meaning that eventual inconsistencies can be found at the level of nominals or propositional variables but appear unrelated to the accessibility relations. In this paper we allow inconsistencies in propositional variables and, by breaking the duality between modal operators, inconsistencies at the level of accessibility relations arise. We introduce a sound and complete tableau system and a decision procedure to check if a formula is a consequence of a set of formulas. Tableaux will be used to extract syntactic models for databases, which will then be compared using different inconsistency measures. We conclude with a discussion about bisimulation
Biosynthesis, chemical structure, and structure-activity relationship of orfamide lipopeptides produced by Pseudomonas protegens and related species
Orfamide type cyclic lipopeptides (CLPs) are biosurfactants produced by Pseudomonas and involved in lysis of oomycete zoospores, biocontrol of Rhizoctonia and insecticidal activity against aphids. In this study, we compared the biosynthesis, structural diversity, in vitro and in planta activities of orfamides produced by rhizosphere-derived Pseudomonas protegens and related Pseudornonas species. Genetic characterization together with chemical identification revealed that the main orfamide compound produced by the P. protegens group is orfamide A, while the related strains Pseudomonas sp. CMR5c and CMR12a produce orfamide B. Comparison of orfamide fingerprints led to the discovery of two new orfamide homologs (orfamide F and orfamide G) in Pseudornonas sp. CMR5c. The structures of these two CLPs were determined by nuclear magnetic resonance (NMR) and mass spectrometry (MS) analysis. Mutagenesis and complementation showed that orfamides determine the swarming motility of parental Pseudomonas sp. strain CMR5c and their production was regulated by luxR type regulators. Orfamide A and orfamide B differ only in the identity of a single amino acid, while orfamide B and orfamide G share the same amino acid sequence but differ in length of the fatty acid part. The biological activities of orfamide A, orfamide B, and orfamide G were compared in further bioassays. The three compounds were equally active against Magnaporthe oryzae on rice, against Rhizoctonia solani AG 4-HGI in in vitro assays, and caused zoospore lysis of Phytophthora and Pythium. Furthermore, we could show that orfamides decrease blast severity in rice plants by blocking appressorium formation in M. oryzae. Taken all together, our study shows that orfamides produced by P protegens and related species have potential in biological control of a broad spectrum of fungal plant pathogens
Beeswax organogels: Influence of gelator concentration and oil type in the gelation process
This work focused on how different types of oil phase, MCT (medium chain triglycerides) and LCT (long chain triglycerides), exert influence on the gelation process of beeswax and thus properties of the organogel produced thereof. Organogels were produced at different temperatures and qualitative phase diagrams were constructed to identify and classify the type of structure formed at various compositions. The microstructure of gelator crystals was studied by polarized light microscopy. Melting and crystallization were characterized by differential scanning calorimetry and rheology (flow and small amplitude oscillatory measurements) to understand organogels' behaviour under different mechanical and thermal conditions. FTIR analysis was employed for a further understanding of oil-gelator chemical interactions. Results showed that the increase of beeswax concentration led to higher values of storage and loss moduli (G, G) and complex modulus (G*) of organogels, which is associated to the strong network formed between the crystalline gelator structure and the oil phase. Crystallization occurred in two steps (well evidenced for higher concentrations of gelator) during temperature decreasing. Thermal analysis showed the occurrence of hysteresis between melting and crystallization. Small angle X-ray scattering (SAXS) analysis allowed a better understanding in terms of how crystal conformations were disposed for each type of organogel. The structuring process supported by medium or long-chain triglycerides oils was an important exploit to apprehend the impact of different carbon chain-size on the gelation process and on gels' properties.The authors thank the Brazilian Synchrotron Light Laboratory (LNLS,
Campinas, SP, Brazil) for the opportunity to carry out SAXS measurements.
The author Miguel A. Cerqueira is recipient of a fellowship (SFRH/BPD/72753/2010) supported by Fundação para a Ciência e a Tecnologia, POPH-QREN and FSE (FCT, Portugal). The financial support
of CAPES/FCT Project “Nanotechnological systems based in biocompatible ingredients: characterization, controlled release and in vitro digestion” (CAPES/FCT no. 348/13) and CNPq (Universal 479459/2012-6)
are gratefully acknowledged. This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684) and the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462)
Doping dependence of charge dynamics in electron-doped cuprates
Within the t-t'-J model, the doping dependence of charge dynamics in
electron-doped cuprates is studied. The conductivity spectrum shows a pseudogap
structure with a low-energy peak appearing at and an rather
sharp midinfrared peak appearing around , and the
resistivity exhibits a crossover from the high temperature metallic-like to low
temperature insulating-like behavior in the relatively low doped regime, and a
metallic-like behavior in the relatively high doped regime, in qualitative
agreement with experiments. Our results also show that these unusual behaviors
of the charge dynamics is intriguingly related to the magnetic correlation in
the system.Comment: 5 pages, 3 figures, discussions are added, accepted for publication
in Phys. Lett.
Treatment of Bouveret Syndrome With Electrohydraulic Lithotripsy
info:eu-repo/semantics/publishedVersio
On the Hamiltonian structure of normal forms at elliptic equilibria of reversible vector fields in R^4
This paper addresses the question whether normal forms of smooth reversible vector fields in R4 at an elliptic equilibrium possess a formal Hamiltonian structure. In the non-resonant case we establish a formal conjugacy between re-versible and Hamiltonian normal forms. In the case of non-semi-simple 1 : 1 resonance and p:q resonance with p+q >2 we establish a weaker form of equivalence, namely that of a formal orbital equivalence to a Hamiltonian normal formthat involves an additional time-reparametrization of orbits. Moreover, in case p+q >3 we show that no formal conjugacy to a Hamiltonian normal form exists
Imaging and controlling electron transport inside a quantum ring
Traditionally, the understanding of quantum transport, coherent and
ballistic1, relies on the measurement of macroscopic properties such as the
conductance. While powerful when coupled to statistical theories, this approach
cannot provide a detailed image of "how electrons behave down there". Ideally,
understanding transport at the nanoscale would require tracking each electron
inside the nano-device. Significant progress towards this goal was obtained by
combining Scanning Probe Microscopy (SPM) with transport measurements2-7. Some
studies even showed signatures of quantum transport in the surrounding of
nanostructures4-6. Here, SPM is used to probe electron propagation inside an
open quantum ring exhibiting the archetype of electron wave interference
phenomena: the Aharonov-Bohm effect8. Conductance maps recorded while scanning
the biased tip of a cryogenic atomic force microscope above the quantum ring
show that the propagation of electrons, both coherent and ballistic, can be
investigated in situ, and even be controlled by tuning the tip potential.Comment: 11 text pages + 3 figure
Neutrophil apoptosis, phagocytosis and oxidative metabolism in septic patients
Sepse denota a continuidade de um processo de injuria tecidual onde a disfuncao organica multipla representa sua expressao mais grave. Trata-se de uma condicao patologica associada a altas taxas de mortalidade. Diferentes linhagens celulares estao relacionadas a sua fisiopatogenia. Neutrofilos, por exemplo, sao as primeiras celulas da linha de defesa a migrarem para os sitios de inflamacao e/ou infeccao. Suas funcoes primarias incluem fagocitose de bacterias, elaboracao de enzimas oxidativas e nao oxidativas de degradacao, e formacao de fatores quimiotaticos para recrutar outras celulas inflamatorias. O objetivo desse estudo foi avaliar os efeitos da sepse grave e do choque septico na apoptose e na funcao de neutrofilos, sendo esta analisada pela capacidade fagocitica e pelo metabolismo oxidativo. Para tanto, foram incluidos 10 pacientes com quadro clinico e laboratorial de sepse grave ou choque septico com menos de 48 horas de evolucao, classificados de acordo com as definicoes do consenso de 1992 do American College of Chest Physicians / Society of Critical Care Medicine Consensus Conference, internados em Unidade de Terapia Intensiva do Hospital São Paulo, e 10 individuos sadios, maiores de 18 anos, que nao se encontravam em uso de nenhum medicamento, considerados controles. De cada paciente ou voluntario sadio foram coletadas amostras de 10 ml de sangue arterial ou venoso periferico em tubos estereis com 100 U de heparina para realizacao dos ensaios de apoptose, fagocitose e metabolismo oxidativo, utilizando citometria de fluxo...(au)BV UNIFESP: Teses e dissertaçõe
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