FSG

This work focuses on the analysis of uncertain neutral time-delay systems, which involve delays in both the state and its derivatives. Our study aims to investigate the stability and observability of transmission lines under both certain and uncertain conditions. To achieve this, we employ the Lyapunov-Krasovskii functional as a key analytical tool. By solving linear matrix inequalities (LMI) and applying optimization theory, we derive new criteria for ensuring stability and observability. These criteria are then validated through simulation results, demon-strating the practical applicability of our theoretical findings. Our approach not only enhances the understanding of transmission line dynamics but also provides robust methodologies for ensuring system reliability and performance.

Introdução: O estresse ocupacional, as mudanças de rotina e emoções negativas são alguns dos fatores que podem ter sofrido influencia pelo isolamento causado pela pandemia de COVID-19 e, além disso, são aspectos que podem conduzir às mudanças no consumo alimentar. Objetivo: Avaliar o consumo de alimentos marcadores de alimentação saudável e não saudável e os fatores associados em trabalhadores de uma Instituição de Ensino Superior privada do Sul do Brasil, durante o período inicial de isolamento ocasionado pela pandemia de COVID-19. Metodologia: Estudo observacional transversal, realizado por um questionário eletrônico autoaplicável (julho/agosto de 2020). Investigou-se aspectos sociodemográficos, nutricionais, psicossociais, de comportamentos de risco à saúde e consumo alimentar (consumo regular de marcadores de alimentação saudável e não saudável). Realizou-se análise estatística pelo teste Qui-Quadrado e pela regressão de Poisson, considerando um intervalo de confiança em 95%. Resultados: Dos 170 trabalhadores, 25,3% e 26,2% apresentavam consumo regular de marcadores de alimentação saudável e não saudável, respectivamente. Identificou-se que indivíduos com sintomas depressivos apresentavam menor probabilidade de ter um consumo regular de marcadores de alimentação saudável (RP: 0,37; p=0,007) e maior possibilidade de consumir marcadores de alimentação não saudável (RP: 1,89; p=0,027). Também, observou-se que os participantes do sexo masculino (RP: 2,60; p≤0,001) e os indivíduos com idade <37 anos (RP: 1,80; p=0,036) apresentavam maior probabilidade de apresentar consumo regular de marcadores de alimentação não saudável. Conclusão: Aspectos psicológicos e demográficos podem influenciar no consumo alimentar dos trabalhadores investigados, enfatizando a importância de medidas que promovam a educação alimentar e nutricional.

We study algebraic structures on the free commutative twisted algebra generated by a positive operad $\mathbf q$, in the framework of vector species. Given a nonunital commutative twisted algebra structure $\mu$ on $\mathbf q$, we introduce the notion of $\mu$-compatible operad structure, leading to a nonunital operad structure on $\mathbf E \circ \mathbf q$, where $\mathbf E$ stands for the exponential species. Next, we define nested pre-Lie operads (NPL-operads), a weak form of the notion of operad, in which the nested associativity axiom is weakened down to a nested pre-Lie condition. This structure is new up to our knowledge. Several constructions of NPL-operads are presented. Finally, we define algebras over a NPL-operad, based on the notion of polynomial functions.

The Advanced Very High Resolution Radiometer (AVHRR) sensors onboard The National Oceanic and Atmospheric Administration (NOAA) polar-orbiting satellites have been measuring electromagnetic radiation emitted by the Earth in the visible (VIS), Near-Infrared (NIR) and Infrared (IR) portions of the electromagnetic spectrum for nearly 30 years. The Global Vegetation Index Vegetation Health product (GVI-x VH) developed from the AVHRR dataset includes the Brightness Temperature (BT) variable calculated from the IR channels, which in turn is used to estimate other environmental variables such as Sea Surface Temperature (SST), Land Surface Temperature (LST), Temperature Condition Index (TCI), and Vegetation Health Index (VTI) among others. However, the satellite measured IR radiances need to be corrected with sufficient accuracy to minimize the uncertainty introduced by a host of sources such as the atmosphere, stratospheric aerosols, and satellite orbital drift before being input into any algorithm to generate remotely sensed products. In this research we have applied a statistical technique based on Empirical Distribution Functions (EDF) to normalize the NOAA GVI-x BT records for the combined effect of the sources of uncertainty mentioned above, avoiding the need for physics based corrections. The normalized results are tested to verify that the normalization improves the data.

To study the three-dimensional (3D) magnetic field topology and its long-term evolution associated with the X3.4 flare of 2006 December 13, we investigate the coronal relative magnetic helicity in the flaring active region (AR) NOAA 10930 during the time period of December 8-14. The coronal helicity is calculated based on the 3D nonlinear force-free magnetic fields reconstructed by the weighted optimization method of Wiegelmann, and is compared with the amount of helicity injected through the photospheric surface of the AR. The helicity injection is determined from the magnetic helicity flux density proposed by Pariat et al. using Solar and Heliospheric Observatory/Michelson Doppler Imager magnetograms. The major findings of this study are the following. (1) The time profile of the coronal helicity shows a good correlation with that of the helicity accumulation by injection through the surface. (2) The coronal helicity of the AR is estimated to be -4.3$\times$10$^{43}$ Mx$^{2}$ just before the X3.4 flare. (3) This flare is preceded not only by a large increase of negative helicity, -3.2$\times$10$^{43}$ Mx$^{2}$, in the corona over ~1.5 days but also by noticeable injections of positive helicity though the photospheric surface around the flaring magnetic polarity inversion line during the time period of the channel structure development. We conjecture that the occurrence of the X3.4 flare is involved with the positive helicity injection into an existing system of negative helicity.