3,945 research outputs found
Consensus and polarization in competing complex contagion processes
Vasconcelos, V. V., Levin, S. A., & Pinheiro, F. L. (2019). Consensus and polarization in competing complex contagion processes. Journal of The Royal Society Interface, 16(155), [20190196]. https://doi.org/10.1098/rsif.2019.0196The rate of adoption of new information depends on reinforcement from multiple sources in a way that often cannot be described by simple contagion processes. In such cases, contagion is said to be complex. Complex contagion happens in the diffusion of human behaviours, innovations and knowledge. Based on that evidence, we propose a model that considers multiple, potentially asymmetric and competing contagion processes and analyse its respective population-wide dynamics, bringing together ideas from complex contagion, opinion dynamics, evolutionary game theory and language competition by shifting the focus from individuals to the properties of the diffusing processes. We show that our model spans a dynamical space in which the population exhibits patterns of consensus, dominance, and, importantly, different types of polarization, a more diverse dynamical environment that contrasts with single simple contagion processes. We show how these patterns emerge and how different population structures modify them through a natural development of spatial correlations: structured interactions increase the range of the dominance regime by reducing that of dynamic polarization, tight modular structures can generate structural polarization, depending on the interplay between fundamental properties of the processes and the modularity of the interaction network.authorsversionpublishersversionpublishe
SĂndrome de Churg-Strauss - Vasculite CutĂąnea como Forma de Apresentação ClĂnica
A sĂndrome de Churg-Strauss (SCS) ou angeĂte granulomatosa
alérgica é uma doença rara caracterizada
pela presença de asma, eosinofilia e vasculite
dos pequenos e, por vezes, dos médios vasos. O
pulmão, coração, pele e nervos periféricos são frequentemente
atingidos.
Os autores descrevem o caso clĂnico de uma
doente do sexo feminino de 47 anos de idade, internada
por lesĂ”es purpĂșricas dolorosas com uma
semana de evolução, localizadas nas superfĂcies extensoras
dos membros inferiores. Nos antecedentes
pessoais destacava-se asma brĂŽnquica com
7 anos de evolução, rinite alérgica e sinusite. A
avaliação laboratorial revelou leucocitose com eosinofilia
e elevação dos parùmetros de inflamação.
Os anticorpos citoplasmĂĄticos anti-neutrĂłfilos
eram negativos. A avaliação neurológica e o estudo
electroneuromiogrĂĄfico mostraram uma polineuropatia
periférica assimétrica. A biopsia cutùnea
revelou uma vasculite necrotizante com infiltrado
perivascular rico em eosinĂłfilos. O diagnĂłstico
de SCS foi apoiado pelos achados clĂnicos
e histopatolĂłgicos, pelo que se iniciou corticoterapia
sistĂ©mica que resultou numa melhoria clĂnica
marcada.
As manifestaçÔes cutùneas podem ser uma forma
de apresentação clĂnica do SCS, sendo o seu reconhecimento
essencial para a instituição precoce
de terapĂȘutica e para a prevenção de lesĂ”es irreversĂveis
em ĂłrgĂŁos vitais
Benzyl N-(2-hyÂdroxy-1-{NâČ-[(1E)-2-hyÂdroxyÂbenzylÂidene]hydrazinecarbonÂyl}ethÂyl)carbamate
The molÂecule of the title compound, C18H19N3O5, adopts a curved arrangement with the terminal benzene rings lying to the same side. The hydroxylÂbenzene ring is close to coplanar with the adjacent hydrazine residue [dihedral angle = 11.14â
(12)°], an observation which correlates with the presence of an intraÂmolecular OâHâŻN hydrogen bond. The benzyl ring forms a dihedral angle of 50.84â
(13)° with the adjacent carbamate group. A twist in the molÂecule, at the chiral C atom, is reflected in the dihedral angle of 80.21â
(12)° formed between the amide residues. In the crystal, two-dimensional arrays in the ac plane are mediated by OâHâŻO and NâHâŻO hydrogen bonds
Benzyl N-(1-{NâČ-[(E)-2-chloroÂbenzylÂidene]hydrazinecarbonÂyl}-2-hyÂdroxyÂethÂyl)carbamate
The molÂecule of the title compound, C18H18ClN3O4, is twisted about the chiral C atom with the dihedral angle between the two amide residues being 87.8â
(5)°, but, overall, it can be described as curved, with the benzene rings lying on the same side of the molÂecule [dihedral angle = 62.8â
(4)°]. The conformation about the imine bond [1.294â
(7)â
Ă
] is E. In the crystal, a two-dimensional array in the ab plane is mediated by OâHâŻO and NâHâŻO hydrogen bonds as well as CâHâŻCl interÂactions. The layers stack along the c-axis direction, being connected by CâHâŻ.Ï contacts
Influence of the SSBI mitigation on the in-band crosstalk tolerance of virtual carrier-assisted DD multi-band OFDM metro networks
In this work, the tolerance to in-band crosstalk of virtual carrier (VC)-assisted direct detection (DD) multi-band orthogonal frequency division multiplexing (MB-OFDM) metro networks, with and without signal-to-signal beat interference (SSBI) mitigation, is compared numerically for 4-ary, 16-ary and 64-ary quadrature amplitude modulation (QAM) formats in the OFDM subcarriers. Our results show that the tolerance to in-band crosstalk is improved for lower modulation format orders. The tolerance to in-band crosstalk of DD OFDM receivers considering 4-QAM modulation format at the DD OFDM subcarriers is above 14 dB higher than the one obtained for the 64-QAM modulation format, regardless the receiver configuration. We have also shown that, the tolerance to in-band crosstalk for a given modulation format order depends on the difference between the virtual carrier-to-band power ratio (VBPR) of the selected and interfering signals, as interferers with same VBPR as the selected signal leads to equal tolerance to in-band crosstalk, independently from the DD OFDM receiver configuration and the subcarrier modulation format order considered.info:eu-repo/semantics/acceptedVersio
Tolerance to in-band crosstalk of virtual carrier-assisted direct detection multi-band OFDM system
The tolerance to in-band crosstalk of virtual carrier (VC)-assisted direct detection (DD) multi-band orthogonal frequency division multiplexing (MB-OFDM) system is assessed numerically through Monte-Carlo simulation and considering a single interferer. The influence of the virtual carrier-to-band power ratio (VBPR) and the virtual carrier-to-band gap (VBG) of the interferer on the in-band tolerance is also studied. We show that, for interferers with the same VBG as the selected signal, the increase of the VBPR of the interferer leads to lower optical signal-to-noise ratio (OSNR) penalties. The increase of the VBG of the interferer with central frequency different from the selected signal also leads to lower OSNR penalties. When the central frequencies of the interferer and selected bands are the same, the variation VBG of the interferer can lead to 11 dB less tolerance to in-band crosstalk of the VC-assisted DD OFDM system.info:eu-repo/semantics/acceptedVersio
Different hydrogen-bonded chains in the crystal structures of three alkyl N-[(E )-1-(2-benzylidene-1-methylhydrazinyl)-3- hydroxy-1-oxopropan-2-yl]carbamates
Peer reviewedPublisher PD
Both Palatable And Unpalatable Butterflies Use Bright Colors To Signal Difficulty Of Capture To Predators
Conselho Nacional de Desenvolvimento CientĂfico e TecnolĂłgico (CNPq)Conselho Nacional de Desenvolvimento CientĂfico e TecnolĂłgico (CNPq)Fundação de Amparo Ă Pesquisa do Estado de SĂŁo Paulo (FAPESP)Birds are able to recognize and learn to avoid attacking unpalatable, chemically defended butterflies after unpleasant experiences with them. It has also been suggested that birds learn to avoid prey that are efficient at escaping. This, however, remains poorly documented. Here, we argue that butterflies may utilize a variety of escape tactics against insectivorous birds and review evidence that birds avoid attacking butterflies that are hard to catch. We suggest that signaling difficulty of capture to predators is a widespread phenomenon in butterflies, and this ability may not be limited to palatable butterflies. The possibility that both palatable and unpalatable species signal difficulty of capture has not been fully explored, but helps explain the existence of aposematic coloration and escape mimicry in butterflies lacking defensive chemicals. This possibility may also change the role that putative Mullerian and Batesian mimics play in a variety of classical mimicry rings, thus opening new perspectives in the evolution of mimicry in butterflies.452107113FAPDF/CNPq/Pronex [563/2009]Brazilian Research Council [302585/2011-7]Brazilian Research Council (SISBIOTA-Brasil/CNPq) [563332/2010-7]National Science Foundation [DEB-1256742]FAPESP (BIOTA-FAPESP Program) [2011/50225-3]Conselho Nacional de Desenvolvimento CientĂfico e TecnolĂłgico (CNPq)Conselho Nacional de Desenvolvimento CientĂfico e TecnolĂłgico (CNPq)Fundação de Amparo Ă Pesquisa do Estado de SĂŁo Paulo (FAPESP
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