410 research outputs found
Secuenciación dinámica de sistemas de fabricación flexible mediante aprendizaje automático: análisis de los principales sistemas de secuenciación existentes
Una forma habitual de secuenciar de modo dinámico los trabajos en los sistemas de fabricación es mediante el empleo de reglas de secuenciación. Sin embargo, el problema que presenta este método es que el comportamiento del sistema de fabricación dependerá de su estado, y no existe una regla que supere a las demás en todos los posibles estados que puede presentar el sistema de fabricación. Por lo tanto, sería interesante usar en cada momento la regla más adecuada. Para lograr este objetivo, se pueden utilizar sistemas de secuenciación que emplean aprendizaje automático que permiten, analizando el comportamiento previo del sistema de fabricación (ejemplos de entrenamiento), obtener el conocimiento necesario para determinar la regla de secuenciación más apropiada en cada instante. En el presente trabajo se realiza una revisión de los principales sistemas de secuenciación existentes en la literatura que utilizan aprendizaje automático para variar de forma dinámica la regla de secuenciación empleada en cada momento
Identification and characterization of Rhipicephalus (Boophilus) microplus candidate protective antigens for the control of cattle tick infestations
The cattle ticks, Rhipicephalus (Boophilus) spp., affect cattle production in tropical and subtropical regions of the world. Tick vaccines constitute a cost-effective and environmentally friendly alternative to tick control. The recombinant Rhipicephalus microplus Bm86 antigen has been shown to protect cattle against tick infestations. However, variable efficacy of Bm86-based vaccines against geographic tick strains has encouraged the research for additional tick-protective antigens. Herein, we describe the analysis of R. microplus glutathione-S transferase, ubiquitin (UBQ), selenoprotein W, elongation factor-1 alpha, and subolesin (SUB) complementary DNAs (cDNAs) by RNA interference (RNAi) in R. microplus and Rhipicephalus annulatus. Candidate protective antigens were selected for vaccination experiments based on the effect of gene knockdown on tick mortality, feeding, and fertility. Two cDNA clones encoding for UBQ and SUB were used for cattle vaccination and infestation with R. microplus and R. annulatus. Control groups were immunized with recombinant Bm86 or adjuvant/saline. The highest vaccine efficacy for the control of tick infestations was obtained for Bm86. Although with low immunogenic response, the results with the SUB vaccine encourage further investigations on the use of recombinant subolesin alone or in combination with other antigens for the control of cattle tick infestations. The UBQ peptide showed low immunogenicity, and the results of the vaccination trial were inconclusive to assess the protective efficacy of this antigen. These experiments showed that RNAi could be used for the selection of candidate tick-protective antigens. However, vaccination trials are necessary to evaluate the effect of recombinant antigens in the control of tick infestations, a process that requires efficient recombinant protein production and formulation systems
Aplicación de redes neuronales artificiales a la previsión de series temporales no estacionarias o no invertibles
En los últimos tiempos se ha comprobado un aumento del interés en la aplicación de las Redes Neuronales Artificiales a la previsión de series temporales, intentando explotar las indudables ventajas de estas herramientas. En este artículo se calculan previsiones de series no estacionarias o no invertibles, que presentan dificultades cuando se intentan pronosticar utilizando la metodología ARIMA de Box-Jenkins. Las ventajas de la aplicación de redes neuronales se aprecian con más claridad, cuando se trata de pronosticar sistemas multivariantes no estacionarios
A Comparative study for some semi-recursive methods on real-time multibody vehicle dynamics model
Some topological formulations in terms of semi-recursive fashion have been proposed recently to improve computational efficiency in complex multibody systems (MBS). An improved semi-recursive method has been developed by García de Jalón, Kim has introduced a subsystem synthesis method, and Bae has implemented an implicit generalized semi-recursive method. These semi-recursive methods, in which the system topology is used to obtain velocities recursively in an open-loop MBS, are efficient for solving the equations of motion of large-scale multibody models. A numerical comparative study among the aforesaid methods is carried out based on theory, accuracy and efficiency
Creación de un Laboratorio de Análisis Socio-Político de América Latina (AMELAT -LAB)
El objetivo principal de este proyecto era crear un espacio de colaboración entre estudiantes, investigadores y profesores para el análisis y comprensión de problemáticas y fenómenos sociales y politicos actuales en América Latina
Simultaneous Surface Plasmon Resonance and X-ray Absorption Spectroscopy
We present here an experimental set-up to perform simultaneously measurements
of surface plasmon resonance (SPR) and X-ray absorption spectroscopy (XAS) in a
synchrotron beamline. The system allows measuring in situ and in real time the
effect of X-ray irradiation on the SPR curves to explore the interaction of
X-rays with matter. It is also possible to record XAS spectra while exciting
SPR in order to detect the changes in the electronic configuration of thin
films induced by the excitation of surface plasmons. Combined experiments
recording simultaneously SPR and XAS curves while scanning different parameters
can be carried out. The relative variations in the SPR and XAS spectra that can
be detected with this set-up ranges from 10-3 to 10-5, depending on the
particular experiment
Comparison of polydrug use prevalences and typologies between men who have sex with men and general population men, in madrid and barcelona
Altres ajuts: Delegación del Gobierno para el Plan Nacional sobre Drogas (2019-017)This study compares the prevalence of drug use and the typologies of polydrug use (PDU) in men who have sex with men (MSM) and general population men (GPM). Participants were men aged 16-64, living in the provinces of Madrid and Barcelona: 1720 were recruited in a GPM survey, and 2658 were HIV-negative MSM from HIV/STIs diagnosis services. Lifetime and last-year prevalence of drug use and prevalence ratios (PRs) of MSM to GPM for the different drugs were calculated using Poisson regression. Latent class analysis (LCA) was performed to identify typologies of PDU. Lifetime use of the drugs considered was higher in MSM, and even higher for drug use in the last-year: PRs for cannabis, hallucinogens and cocaine ranged from 2-5; for amphetamine, ecstasy and methamphetamine 12-16; and above 60 for ketamine, GHB/GBL, inhalants and mephedrone. In the LCA for lifetime PDU four classes arose from the GPM (No-PDU (79.6%); Conventional PDU (13.8%); Intensive conventional PDU (4.9%); Heavy PDU (1.8%)) and four among MSM (No-PDU (57.7%); Conventional PDU plus poppers (18.8%); PDU preferring chemsex drugs (6.4%); Heavy PDU (17.2%)). For PDU during the last-year, three classes arose in the GPM: No-PDU (94.7%); Conventional PDU (4.3%); Heavy PDU (0.9%). For MSM, we identified four classes: No-PDU (64.7%); Conventional PDU plus poppers (15.6%); PDU preferring chemsex drugs (6.2%); Heavy PDU (13.5%). MSM should be considered a priority group for the prevention of the use of all drugs but the heterogeneity of PDU typologies regarding users' preference towards conventional and/or sexualised drugs needs to be taken into account
Self-assembled hyaluronan nanocapsules for the intracellular delivery of anticancer drugs
Preparation of sophisticated delivery systems for nanomedicine applications generally involve multi-step procedures using organic solvents. In this study, we have developed a simple self-assembling process to prepare docetaxel-loaded hyaluronic acid (HA) nanocapsules by using a self-emulsification process without the need of organic solvents, heat or high shear forces. These nanocapsules, which comprise an oily core and a shell consisting of an assembly of surfactants and hydrophobically modified HA, have a mean size of 130 nm, a zeta potential of −20 mV, and exhibit high docetaxel encapsulation efficiency. The nanocapsules exhibited an adequate stability in plasma. Furthermore, in vitro studies performed using A549 lung cancer cells, showed effective intracellular delivery of docetaxel. On the other hand, blank nanocapsules showed very low cytotoxicity. Overall, these results highlight the potential of self-emulsifying HA nanocapsules for intracellular drug delivery
Transcellular diapedesis is initiated by invasive podosomes
Producción CientíficaDiapedesis is critical for immune system function and inflammatory responses. This occurs by migration of blood leukocytes either directly through individual microvascular endothelial cells (the “transcellular” route) or between them (the “paracellular” route). Mechanisms for transcellular pore formation in endothelium remain unknown. Here we demonstrate that lymphocytes used podosomes and extended “invasive podosomes” to palpate the surface of, and ultimately form transcellular pores through, the endothelium. In lymphocytes, these structures were dependent on Src kinase and the actin regulatory protein WASP; inhibition of podosome formation selectively blocked the transcellular route of diapedesis. In endothelium, membrane fusion events dependent on the SNARE-containing membrane fusion complex and intracellular calcium were required for efficient transcellular pore formation in response to podosomes. These findings provide insights into basic mechanisms for leukocyte trafficking and the functions of podosomes
Calculation of the efficacy of vaccines against tick infestations on cattle
Articles in International JournalsCattle ticks are responsible for great economic losses in cattle farming worldwide, and their main control method,
chemicals, has been showing problems, whether resulting from the development of resistant strains of ticks or
environmental contamination. Research studies directed toward developing vaccines against ticks are emerging. One
way to evaluate those vaccines is to calculate the percentage of efficacy. The aim of this study was to analyze scientific
publications archived in PubMed that used this method of assessment and discuss the main factors that may affect its
calculation. Thus, 25 articles addressing this subject were selected. The percentage of efficacy was usually calculated
in one of two ways, with one considering the reduced fertility of eggs and the other not. The latter method may
underestimate the vaccine efficacy, and the most complete formula for calculating the efficacy reflects how much the
vaccine actually affects the infestation. In our view, the use of the complete formula for calculating the percentage of
efficacy is broader and more representative of the vaccine effect on the tick population.RESUMO - Carrapatos de bovinos são responsáveis por grandes perdas econômicas para a pecuária bovina mundial e seu principal
método de controle, o químico, vem apresentando problemas, seja pelo desenvolvimento de amostras de carrapatos
resistentes ou pela contaminação ambiental. Na tentativa de diminuir a utilização dos acaricidas, surgem pesquisas
direcionadas ao desenvolvimento de vacinas contra carrapatos. Uma maneira de avaliar essas vacinas é pelo cálculo de
percentagem de eficácia. O objetivo deste trabalho foi analisar as publicações científicas indexadas no PubMed que
utilizaram este método de avaliação e discutir os principais fatores que podem interferir no seu cálculo. Dessa maneira,
selecionaram-se 25 artigos que tratavam desse assunto. A percentagem de eficácia apareceu sendo calculada de duas
formas, uma considerando a redução da fertilidade dos ovos e a outra não. Essa última pode subestimar a eficiência da
vacina, e a fórmula de cálculo da eficácia mais completa representa o quanto da infestação a vacina realmente reduziu.
Em nosso entendimento, a utilização da fórmula completa para o cálculo da percentagem de eficácia é mais abrangente
e representativa do efeito da vacina na população de carrapatos
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