Evaluación y calidad: análisis de un modelo

Este artículo se centra en el análisis de un modelo sistémico de la educación en la perspectiva de su evaluación con referencia a criterios de valor y mérito integrados en un concepto preciso de calidad operacionalmente definido. A partir del modelo, se justifica y legitima el establecimiento de criterios de calidad educativa en sus dimensiones básicas (funcionalidad, eficacia y eficiencia) mediante la derivación, de acuerdo con unas reglas, de indicadores relevantes y utilizables para la evaluación de la educación. Tras unas precisiones sobre el concepto de evaluación y su función crítica como instrumento de optimización de los sistemas sociales artificiales, se presenta el modelo lógico de calidad de la educación, como un modelo sistémico, y se apunta a las condiciones para la derivación de indicadores

Detection and linkage to mobile genetic elements of tetracycline resistance gene tet(M) in Escherichia coli isolates from pigs

BACKGROUND: In Escherichia coli the genes involved in the acquisition of tetracycline resistance are mainly tet(A) and tet(B). In addition, tet(M) is the most common tetracycline resistance determinant in enterococci and it is associated with conjugative transposons and plasmids. Although tet(M) has been identified in E. coli, to our knowledge, there are no previous reports studying the linkage of the tet(M) gene in E. coli to different mobile genetic elements. The aim of this study was to determine the occurrence of tet(A), tet(B), and tet(M) genes in doxycycline-resistant E. coli isolates from pigs, as well as the detection of mobile genetic elements linked to tet(M) in E. coli and its possible transfer from enterococci. RESULTS: tet(A) was the most frequently detected gene (87.9%) in doxycycline-resistant isolates. tet(M) was found in 13.1% E. coli isolates. The tet(M) gene was detected in relation with conjugative transposons in 10 out of 36 enterococci isolates analyzed but not in any of E. coli isolates positive for tet(M). Southern blot showed that in E. coli and in most of the enterococci isolates the tet(M) gene was carried on a plasmid. According to the phylogenetic analysis, E. coli contained a new tet(M) allele grouping separately. Mating experiments revealed that tet(M) was carried on a mobile element successfully transferred between enterococci and between enterococci and E. coli. CONCLUSIONS: The detection of tet(M) in E. coli isolates from pigs was higher than expected. In our study, tet(M) detected in E. coli seems not to have been transferred from enterococci, although it can not be ruled out that the horizontal transfer of this gene occurred from other intestinal tract bacteria

Restoring catalase activity in Staphylococcus aureus subsp. anaerobius leads to loss of pathogenicity for lambs

Staphylococcus aureus subsp. anaerobius, a microaerophilic and catalase-negative bacterium, is the etiological agent of abscess disease, a specific chronic condition of sheep and goats, which is characterized by formation of necrotic lesions that are located typically in superficial lymph nodes. We constructed an isogenic mutant of S. aureus subsp. anaerobius (RDKA84) that carried a repaired and functional catalase gene from S. aureus ATCC 12600, to investigate whether the lack of catalase in S. aureus subsp. anaerobius plays a role in its physiological and pathogenic characteristics. The catalase activity had no apparent influence on the in vitro growth characteristics of RDKA84, which, like the wild-type, did not grow on aerobically incubated agar plates. Restoration of catalase activity in RDKA84 substantially increased resistance to H2O2 when analyzed in a death assay. The intracellular survival rates of the catalase-positive mutant RDKA84 in polymorphonuclear neutrophils (PMN) isolated from adult sheep were significantly higher than those of the wild-type, while no differences were found with PMN isolated from lambs. RDKA84 showed significantly lower survival rates in murine macrophages (J774A.1 cells) than the wild-type strains did, whereas, in bovine mammary epithelial cells (MAC-T), no differences in intracellular survival were observed. Interestingly, the virulence for lambs, the natural host for abscess disease, of the catalase-positive mutant RDKA84 was reduced dramatically in comparison with wild-type S. aureus subsp. anaerobius in two experimental models of infection

Diseño y desarrollo de una aplicación de escritorio como soporte para la toma de decisiones de zonas de control en la asignación de las ayudas agrarias

El control de las ayudas agrarias es imprescindible dentro del contexto normativo de la agricultura europea. Los procesos de control que realizan las administraciones públicas se basan, en gran medida, en visitas de campo a zonas concretas que varían anualmente en función de factores definidos para cada campaña. Esta metodología origina una movilización importante de personal y equipos que redunda en altos costes económicos y temporales, lo que implica que las zonas elegidas para el control sean las más óptimas posibles para rentabilizar al máximo el trabajo. Esta necesidad de optimización pone de manifiesto la necesidad de automatizar la selección de las zonas, tal que los criterios que intervengan en el proceso sean valorados de forma objetiva e imparcial atendiendo a parámetros que aparecen regulados en la normativa vigente. Este marco planteado es idóneo para el desarrollo y empleo de un SIG que permita de manera automática, sistemática y objetiva la selección de dichas zonas mediante una evaluación multicriterio. El objetivo de este trabajo es el desarrollo de una aplicación de escritorio adaptada a unas necesidades particulares, empleando librerías de código libre para determinar las zonas de control mediante una evaluación multicriterio.The control of agricultural aid is essential in the context of European agricultural policy. The control processes carried out by the government are based on field visits to specific areas, such areas change annually depending on factors for each campaign. This methodology results in a significant mobilization of personnel and equipement causing high economic costs and time, which means that the areas chosen for the control must be the most optimal possible to maximize the job. The need for optimization emphasizes the need to automate the selection of areas, such that the criteria involved in the process must be evaluated objectively and impartially on the basis of parameters present in the regulations. The framework proposed is suitable for the development and use of a GIS to automatically enable, the systematic and objective selection of these areas through a multi-criteria evaluation. The aim of this study is to develop a desktop application adapted to some particular needs, using open source libraries to identify areas of control via a multicriteria evaluation

Control de campo de ayudas agrarias basado en telefonía móvil

Hoy día, la mayoría de los datos que se manejan llevan asociados una componente geográfica. Bajo este contexto asistimos a un acercamiento de tecnologías empleadas por usuarios expertos hacia usuarios genéricos. En este marco se plantea la integración de las nuevas tecnologías en el control de las ayudas agrarias. Actualmente, los procesos de control de ayudas agrarias se basan fundamentalmente en visitas de campo con objeto de certificar el uso del suelo. Esta metodología de control origina una movilización importante de personal y equipos, empleando simultáneamente dispositivos como cámara fotográfica, tablet-PC, GPS, etc. El objetivo de este proyecto ha sido el desarrollo de una aplicación para telefonía móvil aprovechando los distintos sensores que se encuentran integrados en él, utilizando terminales que añaden nuevas funcionalidades, asegurando la integridad de la información, mejorando su correcta interpretación así como estableciendo diferentes canales de difusión. El proyecto se ha desarrollado bajo Android, empleando librerías de código abierto y de ejecución independiente al fabricante del dispositivo telefónico. El resultado es un software que integra información de diferentes sensores, presentando el terminal móvil apto para los trabajos de control de campo, reduciendo el material a emplear y mejorando la integridad de la información.Today, most data we use is associated with a geographic component. In this context we are witnessing a convergence in technologies used by expert users to generic users. In this framework we look at the integration of new technologies in the control of agricultural aid. Currently, control processes agricultural subsidies are fundamentally based on field visits in order to certify the land use. This control methodology results in a significant mobilization of personnel and equipment, using devices like a camera, tablet PC, GPS, etc. The objective of this project has been to develop a mobile application taking advantage of the different sensors that are integrated into it, using terminals that add new functionality, ensuring data integrity, improving its correct interpretation as well as establishing different channels diffusion. The project has been developed under Android, using open source libraries independent to the device manufacturer. The result is software that integrates information from different sensors, introducing the mobile terminal suitable for the work of field control, reducing the material to be used and improved data integrity

Necrotoxigenic Escherichia coli from sheep and goats produce a new type of cytotoxic necrotizing factor (CNF3) associated with the eae and ehxA genes

Fecal samples from sheep and goats were screened by tissue-culture assays and PCR for the presence of necrotoxigenic Escherichia coli (NTEC) producing cytotoxic necrotizing factors (CNFs). Of the 18 NTEC strains assayed, four were positive for the cnf1 gene while 14 strains were negative for the cnf1 and cnf2 genes. All of the NTEC strains had the eae gene and most of them also carried the ehxA gene. Moreover, all the cnf1– cnf2– NTEC strains were negative for several virulence markers associated with CNF1+ or CNF2+ strains. The cnf gene present in one of these strains was sequenced and analysis of the gene product revealed a new type of CNF, which was named CNF3 (and the coding gene cnf3). Oligonucleotide primers were designed to PCR-amplify a fragment of cnf3. The results showed that all strains examined in this study, except one cnf1+strain, were cnf3+. The association of cnf3 with eae and ehxA suggests that cnf3+ NTEC strains might be pathogenic for humans. [Int Microbiol 2007; 10(1):47-55

Automatic generation of models for abdominal aortic aneurysms and intraluminal thrombus based on hexahedral meshes

To propose an automated patient-specific algorithm for the creation of accurate and smooth meshes of the aortic anatomy, to be used for evaluating rupture risk factors of abdominal aortic aneurysms (AAA). Finite element (FE) analyses and simulations require meshes to be smooth and anatomically accurate, capturing both the artery wall and the intraluminal thrombus (ILT). The two main difficulties are the modeling of the arterial bifurcations, and of the ILT, which has an arbitrary shape that is conforming to the aortic wall

Effects of Aging and Different Mechanical Recycling Processes on the Structure and Properties of Poly(lactic acid)-clay Nanocomposites

The growing use of poly(lactic acid) (PLA) and PLA-based nanocomposites in packaging has raised the interest of studying the mechanical recycling of the wastes and the properties of the recycled materials. The main objective of this work was to study the effect of two different mechanical recycling processes on the structure and properties of a PLA-montmorillonite nanocomposite. The two recycling processes included accelerated thermal and photochemical aging steps to simulate the degradation experienced by post-consumer plastics during their service life. One of them also included a demanding washing process prior to the reprocessing. A decrease in the molecular weight of PLA was observed in the recycled materials, especially in those subjected to the washing step, which explained the small decrease in microhardness and the increased water uptake at long immersion times. Water absorption at short immersion times was similar in virgin and recycled materials and was accurately described using a Fickian model. The recycled materials showed increased thermal, optical and gas barrier properties due to the improved clay dispersion that was observed by XRD and TEM analysis. The results suggest that recycled PLA-clay nanocomposites can be used in demanding applications

Neumoperitoneo tras megacolon tóxico. ¿Es posible un manejo conservador?

Paciente de 83 años con antecedentes de hipotiroidismo, deterioro cognitivo severo, Parkinson. Ingresa en el Servicio de Medicina Interna por cuadro diarreico, filiado clínica y radiológicamente de megacolon tóxico (Figura 1). Se instaura tratamiento médico conservador: metronidazol intravenoso, dieta absoluta y fluidoterapia. Se realiza colonoscopia descompresiva/diagnóstica que informa de inflamación compatible con colitis isquémica. Las biopsias confirmaron el diagnóstico de ulceraciones con intensa respuesta inflamatoria superficial y profunda y angiogénesis, con inmunohistoquímica positiva para citomegalovirus. Seis días después, en un control radiológico, se objetiva importante neumoperitoneo (Figura 2), sin identificar zona de posible perforación. La paciente se mantiene estable hemodinámicamente y asintomática (no dolor, ni peritonismo) a excepción de la distensión abdominal presente al ingreso, que persiste. Dada la situación general, se desestima intervención quirúrgica y se opta por evacuación del neumoperitoneo mediante punción percutánea en región infraumbilical con Abbocath® N° 14 (Figura 3). Fue necesario repetir el procedimiento en dos ocasiones en un intervalo de 6 días. Durante ese período la paciente se mantuvo bajo cobertura antibiótica, nutrición parenteral periférica y dieta absoluta. El cultivo del mínimo exudado recogido en la segunda punción fue positivo para E. coli y Candida albicans. La paciente falleció 6 días después de la última punción

Antigenic and molecular characterisation of Border disease virus associated with high mortality in lambs in Spain

Border disease virus (BDV) causes congenital disorders in sheep and results in severe, but underestimated, economic losses worldwide. However, information about BDV strains affecting several ruminants worldwide is scarce. Therefore, antigenic and genetic classification of isolates from different geographical regions is important to enhance the knowledge of the epidemiology of BDV. Five pestiviruses isolated from lambs in an epidemic outbreak with an unusually high mortality in Spain in 1997 were characterised antigenically with a panel of monoclonal antibodies and genetically by sequencing within the 50 untranslated (50UTR) region of the genome. All the isolates were classified as BDV and showed a high homology with the Aveyron strain (Av), which was associated with an epidemic reported in sheep from the Aveyron region of France in 1984. Classification of the isolates from this study provides valuable information on the molecular epidemiology of BDV