3,045 research outputs found
Continuations of the nonlinear Schr\"odinger equation beyond the singularity
We present four continuations of the critical nonlinear \schro equation (NLS)
beyond the singularity: 1) a sub-threshold power continuation, 2) a
shrinking-hole continuation for ring-type solutions, 3) a vanishing
nonlinear-damping continuation, and 4) a complex Ginzburg-Landau (CGL)
continuation. Using asymptotic analysis, we explicitly calculate the limiting
solutions beyond the singularity. These calculations show that for generic
initial data that leads to a loglog collapse, the sub-threshold power limit is
a Bourgain-Wang solution, both before and after the singularity, and the
vanishing nonlinear-damping and CGL limits are a loglog solution before the
singularity, and have an infinite-velocity{\rev{expanding core}} after the
singularity. Our results suggest that all NLS continuations share the universal
feature that after the singularity time , the phase of the singular core
is only determined up to multiplication by . As a result,
interactions between post-collapse beams (filaments) become chaotic. We also
show that when the continuation model leads to a point singularity and
preserves the NLS invariance under the transformation and
, the singular core of the weak solution is symmetric
with respect to . Therefore, the sub-threshold power and
the{\rev{shrinking}}-hole continuations are symmetric with respect to ,
but continuations which are based on perturbations of the NLS equation are
generically asymmetric
CORRELATION OF N-TERMINAL PRO B-TYPE NATRIURETIC PEPTIDE AND SPECKLE TRACKING DERIVED LONGITUDINAL STRAIN IN SEVERE ASYMPTOMATIC AORTIC STENOSIS
In silico identification and experimental validation of hits active against KPC-2 \u3b2-lactamase
Bacterial resistance has become a worldwide concern, particularly after the emergence of resistant strains overproducing carbapenemases. Among these, the KPC-2 carbapenemase represents a significant clinical challenge, being characterized by a broad substrate spectrum that includes aminothiazoleoxime and cephalosporins such as cefotaxime. Moreover, strains harboring KPC-type \u3b2-lactamases are often reported as resistant to available \u3b2-lactamase inhibitors (clavulanic acid, tazobactam and sulbactam). Therefore, the identification of novel non \u3b2-lactam KPC-2 inhibitors is strongly necessary to maintain treatment options. This study explored novel, non-covalent inhibitors active against KPC-2, as putative hit candidates. We performed a structure-based in silico screening of commercially available compounds for non-\u3b2-lactam KPC-2 inhibitors. Thirty-two commercially available high-scoring, fragment-like hits were selected for in vitro validation and their activity and mechanism of action vs the target was experimentally evaluated using recombinant KPC-2. N-(3-(1H-tetrazol-5-yl)phenyl)-3-fluorobenzamide (11a), in light of its ligand efficiency (LE = 0.28 kcal/mol/non-hydrogen atom) and chemistry, was selected as hit to be directed to chemical optimization to improve potency vs the enzyme and explore structural requirement for inhibition in KPC-2 binding site. Further, the compounds were evaluated against clinical strains overexpressing KPC-2 and the most promising compound reduced the MIC of the \u3b2-lactam antibiotic meropenem by four fold
Cone beam computed tomography in the diagnosis of Stafne bone cavity: Report of seven cases and review of the open-access literature.
Stafne bone cavity (SBC) is a rare entity to find on panoramic radiography and on cone beam computed tomography. We reviewed in a systematic way the open-access literature from PubMed and DOAJ. We also proposed a new methodology consisting of collaboration with private practitioners, application of participative science approach, and open science practices, and using social media tool to obtain and describe seven different cases of SBC. We finally propose a new matrix table for classification of anatomical types of SBC already described and those yet to be described in open-access literature.Stafne bone cavity (SBC) is a rare entity to find on panoramic radiography and on cone beam computed tomography. We reviewed in a systematic way the open-access literature from PubMed and DOAJ. We also proposed a new methodology consisting of collaboration with private practitioners, application of participative science approach, and open science practices, and using social media tool to obtain and describe seven different cases of SBC. We finally propose a new matrix table for classification of anatomical types of SBC already described and those yet to be described in open-access literature
Seeing the Whole Picture. Towards a Multi-perspective Approach to News Content Diversity based on Liberal and Deliberative Models of Democracy
By providing diverse news content, news media are key for a well-functioning public sphere. However, agreement on how to measure news content diversity is lacking. Research often refers to democratic theory as normative reference point, but different models of democracy understand news content diversity differently. Our study makes a unique, innovative contribution to this field: (1) We develop a methodological framework for measuring news content diversity, that is a set of comprehensive measuring instruments that derive different operationalizations of topic and actor diversity each from liberal and deliberative democratic theories. (2) Considering that a good public discourse requires more than diversity, we analyze news content diversity in the context of four other journalistic standards: neutrality, rationality, discursivity, and civility. (3) We prove the applicability of our measuring instruments by means of a standardized content analysis of six German news media as a case study. The different quality profiles of these outlets our analysis reveals are explained by their different functions in the media system. Our study shows how important a multi-perspectival normative approach to news content diversity is, both empirically and theoretically. Future studies on news content diversity should make their normative foundations transparent and derive their indicators purposefully therefrom
Reassessment of the geology of the southeastern Tapajós Gold Province, Amazonian Craton, Brazil, based on field, petrographic, and airborne geophysical data
The Tapajós Gold Province, central portion of the Amazonian Craton, is one of the main metallogenic provinces in Brazil, but lack geological studies at an appropriate scale in its southeastern portion. Fieldwork, petrography, and high-resolution airborne geophysics (magnetometry and gamma spectrometry) allowed us to produce a new map at the 1:100,000 scale. In this study, we identified two new geological units: (1) the volcanic and pyroclastic rocks of the Vila Riozinho Formation, previously attributed to the Iriri Group, including a newly described facies of this formation, which comprises a group of rocks with the highest magnetic contents of the study area, and (2) the Serra Alkali Feldspar Granite, which intruded into the Vila Riozinho Formation. Based on available geochronological information these units can be associated to a volcano-plutonic event that occurred in the Orosirian period, at about 1.98 Ga. In addition, our work allowed us to define better the areas of occurrence of other units. The Parauari Intrusive Suite and Iriri Group areas were strongly reduced, whereas the areas of the Creporizão Intrusive Suite and of the Novo Progresso Formation were increased
An Experimental Toolbox for Structure-Based Hit Discovery for P. aeruginosa FabF, a Promising Target for Antibiotics
FabF (3-oxoacyl-[acyl-carrier-protein] synthase 2), which catalyses the rate limiting condensation reaction in the fatty acid synthesis II pathway, is an attractive target for new antibiotics. Here, we focus on FabF from P. aeruginosa (PaFabF) as antibiotics against this pathogen are urgently needed. To facilitate exploration of this target we have set up an experimental toolbox consisting of binding assays using bio-layer interferometry (BLI) as well as saturation transfer difference (STD) and WaterLOGSY NMR in addition to robust conditions for structure determination. The suitability of the toolbox to support structure-based design of FabF inhibitors was demonstrated through the validation of hits obtained from virtual screening. Screening a library of almost 5 million compounds resulted in 6 compounds for which binding into the malonyl-binding site of FabF was shown. For one of the hits, the crystal structure in complex with PaFabF was determined. Based on the obtained binding mode, analogues were designed and synthesised, but affinity could not be improved. This work has laid the foundation for structure-based exploration of PaFabF.publishedVersio
Caracterização Morfológica e Hidrodinâmica de Praias do Estado de Santa Catarina com Vista à Avaliação de Perigo ao Banhista
O objetivo deste trabalho foi avaliar o grau de perigo aos banhistas de 14 praias do litoral de Santa Catarina. Para isso foi utilizada a metodologia aplicada nos planos de segurança nas praias australianos. O método consiste em calcular o grau de perigo com base no estágio morfodinâmico e na altura de quebra da praia. As praias a serem avaliadas foram escolhidas com base no número de ocorrências apontado no registro do corpo de bombeiros do estado. A classificação do estágio morfodinâmico das praias foi realizada com fotografia aérea e imagens de satélite. Os dados de altura de onda foram obtidos da base de dados do projeto SMC Brasil. Dentre as praias analisadas houve o predomínio do estágio intermediário com apenas uma praia refletiva e nenhuma praia dissipativa. Os graus de risco variaram de baixo a moderado nas praias verificadas
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