DoS protection for a Pragmatic Multiservice Network Based on Programmable Networks

Proceedings of First International IFIP TC6 Conference, AN 2006, Paris, France, September 27-29, 2006.We propose a scenario of a multiservice network, based on pragmatic ideas of programmable networks. Active routers are capable of processing both active and legacy packets. This scenario is vulnerable to a Denial of Service attack, which consists in inserting false legacy packets into active routers. We propose a mechanism for detecting the injection of fake legacy packets into active routers. This mechanism consists in exchanging accounting information on the traffic between neighboring active routers. The exchange of accounting information must be carried out in a secure way using secure active packets. The proposed mechanism is sensitive to the loss of packets. To deal with this problem some improvements in the mechanism has been proposed. An important issue is the procedure for discharging packets when an attack has been detected. We propose an easy and efficient mechanism that would be improved in future work.Publicad

Evolution of Perturbations in Flow Field Mechanics

This project explores the stability analysis of a given flow field. Specifically, where the peak disturbance occurs in a flow as this is the disturbance that is most likely to occur. In rocket combustion, it is important to understand where the maximum disturbance occurs so that the mixing of fuel can be stabilized. The instabilities are the results of frequencies in the area surrounding the flow field. The linear stability governing equations are employed to better understand the disturbance. The governing equations for continuity and momentum in the x and y directions are used to form an equation for the second derivative of the transverse complex velocity disturbance amplitude (the transverse perturbation) in terms of y. This research uses the shooting method and Euler’s method of numerical integration to find a frequency (ω) that affects the flow field of a given velocity profile. The shooting method involves making an educated guess for ω, numerically integrating the second derivative of the transverse perturbation across the flow field to find the transverse perturbation, and comparing the final value with the expected asymptotic solution. Euler’s method of numerical integration and the computing language Python are used to find a method to predict the frequencies (ω) that cause disturbances for a given velocity profile

A simple and efficient method to allocate costs and benefits in energy communities

Purpose: Define a simple and efficient method to allocate costs and benefits in energy communities, and characterize some of its key properties. Design/methodology/approach: The approach is theoretical. We define an algorithm to allocate costs and benefits in energy communities, and derive some of its formal properties using mathematical reasoning. We also compare the proposed algorithm with several alternatives. Findings: The proposed algorithm is simple and it ensures that the resulting distribution of costs and benefits is (i) beneficial for every member of the community, (ii) efficient, (iii) fair (in a formally defined sense), (iv) smooth (small changes in the consumption or in the generation of energy cannot lead to big changes in the allocation of costs and benefits), and (v) environmentally friendly in the sense that the individual allocated cost is a strictly increasing function of individual consumption. Research limitations/implications: The properties of the proposed algorithm are satisfied for a specific type of energy community that is defined in the manuscript.    Practical implications: The algorithm is easy to implement in any energy community. Social implications: The algorithm is highly relevant for any community of prosumers who are willing to exchange energy internally. It guarantees a number of desirable properties that are formally defined in the paper. Originality/value: We prove that a simple algorithm to allocate costs and benefits in energy communities guarantees the fulfilment of several desirable properties

Diversidade de psilídeos (Hemiptera: Psylloidea) em Sorriso, MT.

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EVALUATION OF EMPIRICAL NUSSELT CORRELATIONS FOR NUMERICAL PREDICTION OF FROST THICKNESS GROWTH OVER A COLD CYLINDER

This paper evaluates numerically some of the parameters involved in modeling the process of frost formation over a cold cylinder surface subject to the flow of humid air. The model employs one-dimensional transient formulation based upon the local volume averaging technique. Was utilized for numerical predictions the empirical Nusselt correlation from the literature, obtained in experimental studies on frost formation phenomena of frost grow over a cold cylinder surface. To predict frosting process a numerical solution was utilized, and a new correlation for Nusselt number based on the experimental correlation of Kim was estimated. For the new Nusselt correlation an optimization method that adjusts the numerical solution of modeling the frost formation process with experimental results of the frost layer thickness was used. The calculation procedure allows the estimation of the parameter K of equation. The modeling process was validated by comparison with available experimental data

Ocorrência de Isogonoceraia divergipennis White & Hodkinson (1980) associado a Caesalpinia pluviosa (Fabaceae) em Mato Grosso, Brasil.

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Introdução ao dossiê «Juventudes, decolonialidades e estéticas insurgentes»

Os diálogos culturais gerados entre África, Américas e Europa têm sido férteis na difusão de novas narrativas sonoras, corporais e plásticas, globalizadas em ritmo acelerado através das migrações internacionais e de plataformas comunicacionais na era/geração digital (Feixa, 2014). Do funk carioca ao rap crioulo, da arte performativa às linguagens audiovisuais, as intervenções estéticas protagonizadas por jovens de áreas socialmente periféricas – seja nas margens do sistema-mundo capitalista, seja nas margens dos países imperiais – têm conquistado espaço na Internet, televisão e rádio, bem como em exposições de arte e pistas de dança de ambos os lados do Atlântico (Kabir, 2014; Aderaldo e Raposo, 2016; Marcon et al., 2018). Esses processos de globalização têm seguido uma lógica contra-hegemônica, constituindo o que Thussu (2007) denomina “contrafluxos” (ver Jiménez, 2019 para o caso da kizomba). Muitas dessas intervenções estéticas, por outro lado, têm a capacidade de inserir pautas incômodas ao poder público, dando visibilidade a uma política de representação que busca cidadania social e cultural entre aqueles que ocupam posições marginais e periféricas na atual ordem neoliberal (Raposo, 2016).info:eu-repo/semantics/publishedVersio

Er/Yb co-doped LiYF4 transparent oxyfluoride glass-ceramics with up-conversion optical properties

Transparent oxyfluoride glass-ceramics doped with rare earth ions (RE3+) are promising materials for photoluminescence up- and down-conversion. In this study, glass compositions within the system 40SiO2–25Al2O3–18Li2O–7LiF–10YF3 (mol.%) doped with ErF3 and codoped with ErF3/YbF3 were prepared by melt-quenching method and subjected to thermal treatment at temperatures above glass transition (Tg + 35 °C) for long dwell times to obtain the corresponding glass-ceramics. The formation of LiYF4 and LiAlSiO4 nanocrystals was confirmed by XRD analysis after thermal treatment at 540 °C for 20 h. The increase in the treatment time up to 80 h resulted in the enhancement of the UC luminescence yield and the decrease of the Red to Green ratio (R/G) emission intensity. Due to the nano-sized crystals, the glass-ceramic products were transparent (%T) in near-infrared (NIR) and visible spectral region with %T remaining approximately 85% and 75%, respectively, after 20 h treatment. However, the visible window transparency reduced, with %T dropping to around 50% after 80 h due to the increase in crystal size and crystalline fraction. The influence of Yb3+ co-doping on the up-conversion (UC) luminescence has been investigated in the glass-ceramics and compared to the parent glasses, confirming that Yb3+ ions were also a key factor for facilitating up-conversion via energy transfer (ET), leading to a greater luminescence yield than for Er3+ single doped glass-ceramics and tuning of R/G intensities.This work was supported by a part of the European Union’s Horizon 2020 research and innovation program [grant number 739566]; the MICINN [grant number PID2020-115419GBC-21/C-22/AEI/10.13039/501100011033]; and the project VEGA 1/0476/22

The Impact of Charcoal Production on Forest Degradation: a Case Study in Tete, Mozambique

Charcoal production for urban energy consumption is a main driver of forest degradation in sub-Saharan Africa. Urban growth projections for the continent suggest that the relevance of this process will increase in the coming decades. Forest degradation associated to charcoal production is difficult to monitor and commonly overlooked and underrepresented in forest cover change and carbon emission estimates. We use a multi-temporal dataset of very high-resolution remote sensing images to map kiln locations in a representative study area of tropical woodlands in central Mozambique. The resulting maps provided a characterization of the spatial extent and temporal dynamics of charcoal production. Using an indirect approach we combine kiln maps and field information on charcoal making to describe the magnitude and intensity of forest degradation linked to charcoal production, including aboveground biomass and carbon emissions. Our findings reveal that forest degradation associated to charcoal production in the study area is largely independent from deforestation driven by agricultural expansion and that its impact on forest cover change is in the same order of magnitude as deforestation. Our work illustrates the feasibility of using estimates of urban charcoal consumption to establish a link between urban energy demands and forest degradation. This kind of approach has potential to reduce uncertainties in forest cover change and carbon emission assessments in sub-Saharan Africa

Detección fenotípica de mecanismos de resistencia antimicrobiana de Escherichia coli aisladas de infecciones entéricas de porcinos provenientes de granjas de producción tecnificada

The aim of this study was to detect the antimicrobial resistance mechanisms of 36 Escherichia coli isolates to beta-lactams, quinolones and aminoglycosides using the Kirby-Bauer technique. Thirty-six E. coli isolates from pigs of technified production farms obtained during the 2010-2015 period were used. Fifteen antimicrobials of importance in human and veterinary medicine were tested. The isolates showed resistance mainly to nalidixic acid (89%, 32/36), cloxacillin (83%, 30/36) and amoxicillin-clavulanic acid (69%, 25/36). Only 3% (1/36) were AmpC producers, 42% (15/36) showed a possible mutation in gyrA and 14% (5/36) at least two possible mutations in gyrA or gyrA+parC. In addition, 33% (12/36) showed high probabilities of presence of qnr genes. The enzymes associated to aminoglycoside resistance mechanism were positive in 39% (14/36) to AAC (6’), 28% (10/36) to ANT (2") and 11% (4/36) to AAC (3) IV.El objetivo del estudio fue detectar fenotípicamente los mecanismos de resistencia antimicrobiana de 36 aislados de Escherichia coli a betalactámicos, quinolonas y aminoglucósidos mediante la técnica de Kirby-Bauer. Se utilizaron 36 aislados de E. coli procedentes de porcinos de granjas tecnificadas, obtenidos durante el periodo 2010- 2015. Se utilizaron 15 antimicrobianos de importancia en medicina humana y veterinaria. Se detectó resistencia principalmente al ácido nalidíxico (89%, 32/36), cloxacilina (83%, 30/36) y amoxicilina-ácido clavulánico (69%, 25/36). Solo un 3% (1/36) presentó AmpC inducible, 42% (15/36) evidenció una posible mutación en gyrA y el 14% (5/36) al menos dos posibles mutaciones en gyrA o gyrA+parC. Además, el 33% (12/36) evidenció altas probabilidades de presencia de genes qnr. Las enzimas del mecanismo de resistencia a aminoglucósidos fueron positivas en un 39% (14/36) de AAC (6’), 28% (10/36) ANT (2") y 11% (4/36) de AAC (3) IV