“Aquí vemos a Colón llegando a América”. Desarrollo cognitivo e interpretación de imágenes históricas

Resumen

Las lecturas de imágenes en el contexto de la enseñanza de la historia plantean interesantes problemas que hemos abordado desde la perspectiva de la psicología cognitiva. Hemos estudiado las interpretaciones que los sujetos generan en las lecturas de las imágenes. Para ello realizamos un estudio comparativo en el que sujetos de diferentes edades (12, 14, 16 años y adultos) y países de procedencia (Argentina, Chile y España) interpretaban un conocido grabado de T. de Bry (siglo XVII) sobre el Descubrimiento de América. Los resultados indican que los sujetos más jóvenes, en los tres países por igual, tienen dificultades para realizar una comprensión contextualizada de la imagen, como producto histórico y realizan lecturas simples y literales de la misma. En vista de estos resultados, se discute la necesidad de introducir claves que mejoren la interpretación de estas fuentes históricas, tanto en los libros de texto como en la intervención didáctica en el aula.     

基于免疫遗传演化的检测器生成算法

传统人工免疫方法中对自体的定义不是动态的,这并不符合真实的系统环境。因为随着时间的积累,有些正常与异常的区别会变小,甚至相互转化。所以,必须根据环境的变化动态调整自体集。另外,采用有限差异变异和基因重排机制产生初始检测器集,将遗传算法引入到成熟检测器的免疫进化过程中,由于遗传算法具有良好的全局寻优能力,可有效地提高优质成熟检测器的产生并缩短成熟时间。基于KDDcup数据集上的仿真实验结果证明了本方法在检测异常和入侵方面能表现出良好的性能。     

Immune algorithm for discretization of decision systems in rough set theory

INTRODUCTION As a new effective mathematical tool to deal with vagueness and uncertainty, the rough set theory was first proposed by Pawlak in 1982. Theoretical research on rough set theory is characterized by many achievements (Dai, 2004b; 2005; Dai et al., 2004). In recent years rough set theory has been successfully applied in many fields such as machine learning, pattern recognition, decision support and data mining. But rough set theory cannot deal with continuous attributes althoug…     

An immune-tabu hybrid algorithm for thermal unit commitment of electric power systems

This paper presents a new method based on an immune-tabu hybrid algorithm to solve the thermal unit commitment （TUC） problem in power plant optimization. The mathematical model of the TUC problem is established by analyzing the generating units in modem power plants. A novel immune-tabu hybrid algorithm is proposed to solve this complex problem. In the algorithm, the objective function of the TUC problem is considered as an antigen and the solutions are considered as antibodies, which are determined by the affinity computation. The code length of an antibody is shortened by encoding the continuous operating time, and the optimum searching speed is improved. Each feasible individual in the immune algorithm （IA） is used as the initial solution of the tabu search （TS） algorithm after certain generations of IA iteration. As examples, the proposed method has been applied to several thermal unit systems for a period of 24 h. The computation results demonstrate the good global optimum searching performance of the proposed immune-tabu hybrid algorithm. The presented algorithm can also be used to solve other optimization problems in fields such as the chemical industry and the power industry.     

Proteome changes in the plasma of Papilio xuthus (Lepidoptera:Papilionidae): effect of parasitization by the endoparasitic wasp Pteromalus puparum (Hymenoptera: Pteromalidae)

Although the biochemical dissection of parasitoid-host interactions is becoming well characterized, the molecular knowledge concerning them is minimal. In order to understand the molecular bases of the host immune response to parasitoid attack, we explored the response of Papilio xuthus parasitized by the endoparasitic wasp Pteromalus puparum using proteomic approach. By examining the differential expression of plasma proteins in the parasitized and unparasitized host pupae by two-dimensional (2D) electrophoresis, 16 proteins were found to vary in relation to parasitization compared with unparasitized control samples. All of them were submitted to identification by mass spectrometry coupled with a database search. The modulated proteins were found to fall into the following functional groups: humoral or cellular immunity, detoxification, energy metabolism,and others. This study contributes insights into the molecular mechanism of the relationships between parasitoids and their host insects.     

免疫不育控制下的种群动态分析

建立了以病毒为媒介的不育种群动力学模型,从理论上探讨各平衡点存在性,并通过构造Liapunov函数,Dulac函数等证明了各平衡点的全局稳定性。     

Establishment of a production process for a novel vaccine candidate against Lawsonia intracellularis

BackgroundLawsonia intracellularis remains a problem for the swine industry worldwide. Previously, we designed and obtained a vaccine candidate against this pathogen based on the chimeric proteins: OMP1c, OMP2c, and INVASc. These proteins formed inclusion bodies when expressed in E. coli, which induced humoral and cellular immune responses in vaccinated pigs. Also, protection was demonstrated after the challenge. In this study, we established a production process to increase the yields of the three antigens as a vaccine candidate.ResultsBatch and fed-batch fermentations were evaluated in different culture conditions using a 2 L bioreactor. A fed-batch culture with a modified Terrific broth medium containing glucose instead of glycerol, and induced with 0.75 mM IPTG at 8 h of culture (11 g/L of biomass) raised the volumetric yield to 627.1 mg/L. Under these culture conditions, plasmid-bearing cells increased by 10% at the induction time. High efficiency in cell disruption was obtained at passage six using a high-pressure homogenizer and a bead mill. The total antigen recovery was 64% (400 mg/L), with a purity degree of 70%. The antigens retained their immunogenicity in pigs, inducing high antibody titers.ConclusionsConsidering that the antigen production process allowed an increment of more than 70-fold, this methodology constitutes a crucial step in the production of this vaccine candidate against L. intracellularis.How to cite: Salazar S, Gutiérrez N, Sánchez O, et al. Establishment of a production process for a novel vaccine candidate against Lawsonia intracellularis. Electron J Biotechnol 2021.https://doi.org/10.1016/j.ejbt.2021.01.002     

鱼类MS刑基因的研究进展

肌肉生长抑制素（MSTN）属于转化生长因子超家族,是主要在骨骼肌中特异性表达且功能比较专一的肌肉发育负调控因子．鱼类的MSTN基因比较复杂,具有不同的同源基因．本文综述了鱼类MSTN基因的结构、种类、时空表达特征,MSTN的作用机理及生物学功能,鱼类MSTN基因多态性研究以及MSTN基因在鱼类生产中潜在的应用前景．