The VirS/VirR two-component system regulates the anaerobic cytotoxicity, intestinal pathogenicity, and enterotoxemic lethality of Clostridium perfringens type C isolate CN3685.

Clostridium perfringens vegetative cells cause both histotoxic infections (e.g., gas gangrene) and diseases originating in the intestines (e.g., hemorrhagic necrotizing enteritis or lethal enterotoxemia). Despite their medical and veterinary importance, the molecular pathogenicity of C. perfringens vegetative cells causing diseases of intestinal origin remains poorly understood. However, C. perfringens beta toxin (CPB) was recently shown to be important when vegetative cells of C. perfringens type C strain CN3685 induce hemorrhagic necrotizing enteritis and lethal enterotoxemia. Additionally, the VirS/VirR two-component regulatory system was found to control CPB production by CN3685 vegetative cells during aerobic infection of cultured enterocyte-like Caco-2 cells. Using an isogenic virR null mutant, the current study now reports that the VirS/VirR system also regulates CN3685 cytotoxicity during infection of Caco-2 cells under anaerobic conditions, as found in the intestines. More importantly, the virR mutant lost the ability to cause hemorrhagic necrotic enteritis in rabbit small intestinal loops. Western blot analyses demonstrated that the VirS/VirR system mediates necrotizing enteritis, at least in part, by controlling in vivo CPB production. In addition, vegetative cells of the isogenic virR null mutant were, relative to wild-type vegetative cells, strongly attenuated in their lethality in a mouse enterotoxemia model. Collectively, these results identify the first regulator of in vivo pathogenicity for C. perfringens vegetative cells causing disease originating in the complex intestinal environment. Since VirS/VirR also mediates histotoxic infections, this two-component regulatory system now assumes a global role in regulating a spectrum of infections caused by C. perfringens vegetative cells

Estudio de los conocimientos teóricos básicos de los alumnos de nuevo ingreso a ingeniería civil del instituto politécnico nacional

Se presenta un análisis estadístico de los conocimientos básicos en matemáticas de los alumnos de recién ingreso al nivel licenciatura en ingeniería civil del Instituto Politécnico Nacional. La información obtenida a través de la aplicación de un examen de conocimientos sobre temas de matemáticas que se adquirieron en el bachillerato técnico, se analiza con las técnicas del análisis estadístico multidimensional. Se determina el manejo que el alumno tiene en aritmética y álgebra del nivel secundaria, así como en los procesos de derivación e integración de funcio nes elementales. La estructura jerárquica que tienen los conocimientos básicos del alumno de nuevo ingreso muestra una particularidad muy especial: dos cortes con una discriminación casi perfecta entre conocimientos teóricos-prácticos y la ausencia de ellos

Game change in the Gulf of Guinea: three intertwined perspectives on Sino-Equatoguinean cooperation

The Republic of Equatorial Guinea (EG) joined the Forum for Economic and Trade Cooperation between China and Portuguese-speaking Countries (Forum Macao) in 2022, becoming the tenth member-state. This occurred during the 2022 Extraordinary Ministerial Conference, after it acceded to the Community of Portuguese-Speaking Countries (CPLP) in 2014. Since 2015, China and EG have been intensifying their bilateral cooperation after establishing a comprehensive cooperative partnership (Ministry of Foreign Affairs of the People’s Republic of China, 2015). In 2019, the two countries signed a Belt and Road Initiative (B&RI) MoU during the second Belt and Road Forum in Beijing, and initiated a strategic approach for bilateral cooperation. Consequently, considering the uniqueness of EG as a Portuguese-speaking Country (PSC) and as the newest member of Forum Macao, this paper poses and answers the following research question: What will be the impact of Sino-Equatoguinean cooperation in light of EG’s recent accession to FM? Methodologically, the research uses qualitative data supported by triangular referencing, including official and non-official sources, namely official statistics, academic papers, and media reports, to look into the bilateral Sino-Equatoguinean relations under the B&RI Lusophone framework, as well as the fact that EG is a CPLP member state. Accordingly, the methodologic rationale focuses on the uniqueness of EG as one of the Lusophone countries and relates it to the Chinese B&RI at three levels: domestic, regional and global. This paper is organized as follows: (1) Introduction; (2) The uniqueness of EG as a PSC; (3) The B&RI and the Lusophone Countries; (4) Cooperation between Equatorial Guinea and China; (5) Conclusion – The Future of Sino-Equatoguinean Cooperation.A República da Guiné Equatorial (GE) tornou-se membro do Fórum para a Cooperação Económica e Comercial entre a China e os Países de Língua Portuguesa (Fórum de Macau, doravante designado por FM) em 2022, tornando-se o décimo estado a fazê-lo. A integração oficial da GE, decorreu à margem da Reunião Extraordinária Ministerial do Fórum de Macau em 2022, após o país ter aderido à Comunidade dos Países de Língua Portuguesa (CPLP) em 2014. Desde 2015, a China e a GE têm vindo a intensificar a cooperação bilateral desde o estabelecimento das relações de parceria de cooperação abrangente (Ministério dos Negócios Estrangeiros da República Popular da China, 2015). Em 2019, os dois países assinaram o Memorando de Entendimento sobre a Iniciativa Uma Faixa Uma Rota (B&RI, em sigla inglesa) durante a segunda edição do Fórum Faixa e Rota em Pequim e iniciaram desde já uma abordagem estratégica na cooperação bilateral. Por conseguinte, tendo em consideração a singularidade da GE como País de Língua Portuguesa e o facto de ser o mais recente membro do FM, este artigo coloca e responde à seguinte questão central de investigação: Qual será o impacto da cooperação Sino-Equatoguineense à luz da recente adesão da GE ao FM? Metodologicamente, a investigação utiliza dados qualitativos sustentados por referências triangulares, incluindo relatórios oficiais e não oficiais, estatísticas oficiais, documentos académicos e notícias dos meios de comunicação social, para analisar as relações bilaterais Sino-Equatoguineenses no âmbito da B&RI nos países lusófonos. Desse modo, a fundamentação qualitativa metodológica centra-se na singularidade da GE como um dos países lusófonos que se envolve na B&RI Chinesa em três níveis: doméstico, regional e global. O presente artigo apresenta a seguinte estrutura: (1) Introdução; (2) A singularidade da GE como um dos PLP; (3) B&RI e os Países Lusófonos; (4) Cooperação entre a Guiné Equatorial e a China; (5) Conclusão - o Futuro da Cooperação Sino-Equatoguineense.info:eu-repo/semantics/publishedVersio

Accurate calculation of the complex eigenvalues of the Schr\"{o}dinger equation with an exponential potential

We show that the Riccati--Pad\'{e} method is suitable for the calculation of the complex eigenvalues of the Schr\"{o}dinger equation with a repulsive exponential potential. The accuracy of the results is remarkable for realistic potential parameters

Surface Chemistry of Copper Precursors in Connection with Atomic Layer Deposition (ALD) Processes

Chemistry and Chemical Biolog

A proof-of-concept superregenerative QPSK transceiver

In this paper we present a description and experimental verification of an HF-band proof-of-concept superregenerative transceiver for QPSK signals. We describe a simple implementation of an all-digital, FPGA-based, QPSK transmitter section. On the receiver side, the quench signal is generated in the same FPGA with a minimum of analog circuitry. As the main novelty, we present a simple synchronization scheme suitable for packetized transmissions.Peer ReviewedPostprint (author’s final draft

Descomposición de hojarasca de especies nativas y exóticas en un humedal boscoso de agua dulce de Chile

Decomposition of leaf litter is a fundamental process for the functioning of forested wetlands. The rapid increment of forest plantations has involved a greater contribution of leaf litter of exotic origin to these ecosystems. The decomposition rate between leaf litter of native and exotic origin in a forested wetland of the Mediterranean zone of Chile was compared, as well as the contribution of bacteria and macroinvertebrate to this process. It was determined that the decomposition rate of the leaf litter presented signifi cant differences (p < 0.05) between species, being faster in those of non-native origin. This could be due to differences in ecophysiological aspects of the leaves like the presence of chemical compounds such as waxes or oils. Both analyzed communities were relevant in the studied process. However, bacteria contributed mostly to the decomposition of both types of leaves. The implications of the physical and chemical characteristics of the leaves and the water on the processing of the foliar material are discussed.En los humedales boscosos, la descomposición de la hojarasca es un proceso fundamental para su funcionamiento. El rápido incremento de las plantaciones forestales ha implicado un mayor aporte de hojarasca de origen exótico a estos ecosistemas. Se comparó la tasa de descomposición entre hojarasca de origen nativo y exótico en un humedal boscoso de la zona Mediterránea de Chile, así como la contribución de las bacterias y macroinvertebrados a este proceso. Se determinó que la tasa de descomposición de la hojarasca presentó diferencias signifi cativas entre las diferentes especies (p < 0,05), siendo más rápido en especies de origen exótico. Esto podría ser dado por diferencias en algunos aspectos ecofi siológicos de las hojas como la presencia de compuestos químicos tales como ceras o aceites. Ambas comunidades analizadas fueron relevantes en el proceso estudiado. Sin embargo, las bacterias contribuyeron mayormente a la descomposición de ambos tipos de hojas. Se discuten las implicaciones de las características físicas y químicas de las hojas y el agua en el procesamiento del material foliar

Creació de materials docents per assignatures de telecomunicacions amb eines informàtiques de fàcil utilització

Seguint l’enfocament de l’Espai Europeu d’Educació Superior (EEES), on es valora l’aprenentatge cooperatiu i basat en projectes, es troba interessant disposar de materials docents, per al treball individual o col·lectiu, en dues de les assignatures de l’Enginyeria Tècnica de Telecomunicacions que s’ofereix a l’EPSEM. El treball realitzat es divideix en diverses fases. En primer lloc, s’ha preparat la informació que es desitja transmetre als alumnes, per agrupar-la després en blocs temàtics. Amb aquesta informació ja estructurada, s’han començat a entrar les dades. Un cop realitzats aquests passos, es pot crear, de manera fàcil, la presentació flash, ja que l’aplicació disposa d’una opció amb aquesta finalitat. Aquesta presentació es pot guardar i utilitzar en qualsevol moment i lloc. El principal resultat ha estat la obtenció de materials docents interactius, disponibles en suport informàtic, amb text i gràfics, pels quals es pot navegar fàcilment i còmoda, per a dues assignatures de la titulació de telecomunicacions.Peer ReviewedPostprint (published version

Una aproximación al reaseguro financiero en la modalidad de 'finite risk'

Si bien el reaseguro tradicional tiene como objeto exclusivo cubrir del riesgo de suscripción del asegurador cedente, en el Reasegur siniestros. G? parte o 1 Financiero Finite Risk esta cobertura se amplía al riesgo de que se produzcan variaciones en el tipo de interés al que están invertidas las 11 primas y al timingrisk o riesgo de anticipación de los pagos por En este trabajo planteamos un modelo actuarial basado en la simulación de MonteCarlo que cuantifica la prima del Reaseguro Finite Risk en un 11 contrato Cuota-Parte y en un contrato de Exceso de Pérdid