Epidemiology, detection, molecular typing and control of porcine colonic spirochaetosis (Brachyspira pilosicoli)

Brachyspira pilosicoli is a Gram negative anaerobic intestinal spirochaete which is the aetiological agent of porcine colonic spirochaetosis (PCS). PCS is prevalent in the United Kingdom and many other countries. This study aimed to determine risk factors associated with PCS, assess detection procedures, investigate the genetic variation among isolates from porcine colitis outbreaks and evaluate the efficacy of disinfectant-sanitisers against B. pilosicoli in vitro. An epidemiological study was carried out using data from pig farms with and without infectious colitis to determine possible risk factors. Categorical variables including a wide range of housing and management factors were analysed. The major factors associated with infectious colitis involving B. pilosicoli were: source of breeding stock replacements (p<0.045), presence of concurrent infection with Streptococcus suis on the farm (p<0.038), and bedded floors (p<0.007). Fully slatted floors were identified as a protective factor (p<0.007).The diagnostic potential of immunomagnetic separation (IMS) for detection of B. pilosicoli and B. hyodysenteriae from faecal samples was investigated. The sensitivities of the IMS (direct and indirect methods) using polyclonal antibodies (PAbs) and monoclonal antibodies (MAbs) were evaluated and compared with the standard diagnostic method namely direct culture, and polymerase chain reaction (PCR). IMS using PAbs did not improve the diagnostic sensitivity. IMS using MAbs did not increase diagnostic sensitivity when performed with the recommended washing steps. However, IMS performed without the washing steps improved the sensitivity for detection ofB. pilosicoli and had higher sensitivity than direct culture. PCR was more sensitive than the IMS using MAbs (performed with the recommended washing steps). IMS using MAbs shows potential to improve detection ofBrachyspira spp. but further work on a method that avoids significant loss of target cells during the washing steps is required.The genetic diversity of single and multiple isolates from pig farms, two dog isolates and one human isolate ofB. pilosicoli was investigated by arbitrarily primed PCR (AP-PCR). One isolate of the different species B. hyodysenteriae was included as an outgroup. AP-PCR was optimised using four primers individually. The generated data was subjected to analysis by distance method and parsimony method. The DNA banding patterns of B. hyodysenteriae and B. pilosicoli were clearly differentiated by each primer. Phylograms were generated from DNA fragment data for each primer and for pooled data (fragment data of the four primers) to give more robustness to the analysis. The high genetic variation shown by some of the multiple isolates from the same farm suggested that infections by B. pilosicoli in UK farms might not be caused by a single (clonal) genotype.Seven disinfectant-sanitisers were tested for their efficacy against six isolates ofB. pilosicoli. The products were commercially available and included four different chemical groups: quaternary ammonium group, tar-organic acid group, caustic soda group and peroxide group. Serial 10-fold dilutions ofthe products were prepared and challenged with an inoculum of 105 bacterial cells ofB. pilosicoli. To determine the importance of thorough cleaning of farm buildings in relation to the potential of efficacy of disinfectant agents, these products were tested with and without presence of organic matter (as sterile pig faeces). Contact times of 15, 30, 45 and 60 minutes between the disinfectant agents and B. pilosicoli were evaluated. No differences were observed between contact times or between isolates. In the absence of organic matter, the highest efficacies were obtained by DSC-1000 and Long Life with 64 and 50.0 % efficacy at 1:10000 dilution, followed by Ambicide with 43.0 % efficacy at the same dilution (1:10000). In the presence of organic matter the best results were achieved by DSC-1000 and Long Life both with 14.0 % efficacy at dilution 1:1000. The presence of organic matter had a negative effect on the efficacy of the products evaluated against B. pilosicoli (P<0.006), confirming the importance of thorough cleaning prior to disinfection. Heavy Duty and Virkon S were the most affected by the presence of organic matter with efficacies at the level of 7.0 and 0.0 %, respectively, at the 1:100 dilution. The chemical groups that showed the best performance in the presence of organic matter were the quaternary ammonium and tar-organic acids groups in particular the products DSC-100, Long Life, Ambicide and Farm Fluid

Property Rights as Human Rights in International Investment Arbitration: A Critical Approach

The treaty-based regime of investment protection is said to protect the property rights of foreign investors. Arbitral tribunals are usually tasked with settling investment disputes using principles of international law, some of which refer to the doctrine of protection of aliens. These features have led some commentators to compare the protection of foreign investment with the protection of property rights by human rights instruments and courts. This Essay provides a critical perspective on the relationship between these two systems. The Essay re-examines the widespread assumptions that underlie efforts to find parallels between human rights and foreign investment protection. The analysis reveals that even when investment tribunals protect property rights, they do so within the narrow confines of a monetary dispute. Substantive treaty provisions, as interpreted by arbitral tribunals, cannot be placed in the tradition of the protection of aliens, but rather in the efforts of developed countries to entrench the Hull formula. Furthermore, after examining the distinct approaches to the protection of property rights by arbitral tribunals and human rights courts, this Essay concludes that the narrow goals of international investment agreements are fundamentally different from those pursued by human rights instruments

Análisis de sensibilidad paramétrica para sistemas lineales semi-infinitos a través del método de relajación extendido

El presente trabajo tiene como objetivo principal el estudio paramétrico de sensibilidad a través del método de Relajación extendido (MRE) aplicable a Sistemas Semi-Infinitos Lineales (SLSI). Se parte de la idea de extender el Método de Relajación (MR), los cálculos numéricos en (MR) nos permitieron hallar el valor que mejor se aproxima a la región factible deseada, este análisis nos sirvió como preámbulo para la aplicación del MRE en el análisis paramétrico de sensibilidad, lo que consideramos nuestra mayor aportación en esta investigación. El desarrollo de este trabajo consideró las siguientes etapas: la primera consistió en seleccionar los problemas para su análisis, la segunda en desarrollar un algoritmo computacional para realizar el estudio de sensibilidad de los parámetros y la tercera en hacer todo el análisis de sensibilidad. Por ultimo se presentan los resultados de la implementación computacional

Enhancement of teacher talk based on the lesson study methodology and student feedback

82 páginas incluye diagramasEste estudio buscaba explorar la eficacia en la metodología de estudio por lección y la retroalimentación de los estudiantes para mejorar la claridad del profesor y aumentar la comprensión y la participación del alumnado en el aula ILE (Inglés como lengua extranjera). Esta metodología consta de varias clases que buscan mejorar la instrucción, en la que un grupo de profesores se reúnen con el fin de diseñar, discutir y perfeccionar una lección, un término acuñado por William Cerbin y Bryan Kopp. Esta investigación se realizó con 60 estudiantes de grado undécimo de 2 grupos diferentes en una escuela en Colombia por 2 meses en ocho sesiones. La metodología de investigación de acción análisis se llevó a cabo a partir de datos recogidos a través de 4 instrumentos. Para los datos cualitativos, se aplicaron 3 instrumentos: un formato de observación del profesor, un protocolo de lección evaluación y las transcripciones del vídeo. Para los datos cuantitativos solo se aplicó las encuestas de los estudiantes. Con base en la metodología de estudio por lección y la retroalimentación de los estudiantes, los resultados indicaron que claridad en el habla profesor no era una cuestión independiente que garantizaba la comprensión y participación de los estudiantes. Había otras variables como la cantidad, la calidad, la velocidad y el nivel de lenguaje que tenían un gran efecto en la claridad del habla del profesor, de acuerdo con las necesidades de los estudiantes. Los resultados también confirman que la metodología utilizada como práctica colaborativa y reflexiva permitió a los investigadores generar mejora progresiva de la intervención del profesor, lo que ayudó a los participantes a entender la instrucción mejor

Hypervelocity Impact Experiments on Epoxy/Ultra-high Molecular Weight Polyethylene Fiber Composites Reinforced with Single-walled Carbon Nanotubes

AbstractNanocomposites of ultra-high molecular weight polyethylene (UHMWPE) fabrics with single-walled carbon nanotubes (SWCNT) in epoxy matrix were prepared in order to study their hypervelocity impact (HVI) characteristics. These nanocomposites were assessed for their use as bumper shields and as rear walls in Whipple shield configurations at impact velocities in the 6.5-7km/s range. The HVI performances of the nanocomposites were compared against that of the epoxy/UHMWPE composites without nanotubes (or simply, neat composites) and aluminum (Al) sheets having areal density similar to both the composites. The results show that the nanocomposites and the neat composites perform better as rear walls than the Al sheets, but are lesser effective bumper shields. Comparatively, the two composites perform similarly to one another as rear walls and as bumper shields. For these epoxy/UHMWPE composite samples, the reinforcement with 0.5 wt% of SWCNT has no noticeable effect on their HVI response

¿Cómo se mueven los océanos y cómo influye esto en el clima?

Las corrientes oceánicas juegan un papel fundamental en el funcionamiento del sistema climático. Repasaremos en este artículo algunos conceptos básicos para entender dicho papel y cómo el estudio de los mares puede ayudarnos a comprender, tanto el clima del pasado, como su posible evolución futura

Paleoclimatología

La Paleoclimatología es la ciencia que se encarga de estudiar los climas del pasado. En este Trabajo de Fin de Grado se hace un recorrido cronológico de la historia de la Tierra. Se analizan los diferentes climas, las causas y consecuencias de los cambios climáticos a diferentes escalas temporales, las evidencias experimentales y las principales teorías sobre los cambiso climáticos. A pesar de haber un Sol con una menor luminosidad, la atmósfera primitiva estuvo compuesta por gases capaces de generar un efecto invernadero lo suficientemente grande como para mantener la Tierra con agua líquida. Tras la aparición de la vida, aumentó la concentración de oxígeno en la Tierra y se redujeron los gases de efecto invernadero. Esta reducción de gases de efecto invernadero y otros mecanismos iniciaron las primeras glaciaciones que se registraron en la Tierra. Algunas de ellas llegaron a cubrir tanto latitudes polares como tropicales. Las glaciaciones se fueron alternando con climas cálidos. Los climas cambiaron debido, principalmente, a cambios en las configuraciones de los continentes, la variaciones en las concentraciones de gases de efecto invernadero y cambios en los parámetros de insolación. También se registraron cambios climáticos en periodos de tiempos cortos que causaron la extinción de diversas especies de fauna y flora.Universidad de Sevilla. Grado en Físic

Control and eradication of Aujeszky's disease: an assessment of the scheme in Northern Ireland

Aujeszky's disease (AD) is an important disease affecting the swine industry in many countries. An eradication catnpaign was officially applied in September of 1994 in Northern Ireland. The current eradication scheme was investigated. Two main groups of herds were identified from an existing computed database and were classified as: group A, herds that changed their health status, and group B herds that did not change their health status. Herds within each group (A and B) were also classified according to their health status into two groups: a) Otliers, herds that were neither infected nor vaccinated and regarded as free of the disease, and b) PS's, herds that were either vaccinated and/or infected. The eradication scheme in Northern Ireland is making progress. The linear regressions on months were significantly for the number of herds (F=29.14, P<0.05), and the high health status OADF (F=91.5, P<0.01) and ADF(F= 167.8, P<0.001). More herds had higher health status in tl1an before. Infected herds decreased from 25 % to 10.7 % after two years. In addition the pig industry expanded with new herds being registered, although their disease status has yet to be assessed. The groups of herds were analysed by region, current status, herd type and pig population The main significant difference in the number of herds was found for the comparisons between the groups 1) Others and PS's (X²= 116.9, P<0.001), 2) PS1 +PS2 and PS3+PS4 (X²=3.73, P<0.05), and 3) PS1+PS3 and PS2+PS4 (X²=5.68, P<0.01) of group A and group B when compared together. It was identified that the most important regions in terms of number of infected herds, pig population and new herds awaiting classification of their health status were UK3 and UK4 where more than 50% of infected herds were found in these two regions that share borders

Uso de transfusiones sanguíneas y de hemocomponentes en el Hospital Daniel Alcides Carrión durante el año 2001

DESCRIPCIÓN DEL PROBLEMA: ¿Es justificado el uso de transfusiones sanguíneas y de hemocomponentes en los servicios de Emergencia y Hospitalización del Hospital Nacional “Daniel Alcides Carrión” durante el año 2001? JUSTIFICACIÓN DE LA INVESTIGACIÓN: La Ley 26454 creó el Programa Nacional de Hemoterapia y Bancos de Sangre (PRONAHEBAS) como órgano competente del Ministerio de Salud, dicha ley en su Capitulo V, de la Donación y Transfusión de Sangre, el Art. 18 dice: “La Transfusión de sangre humana, sus componentes y derivados con fines terapéuticos, constituye un acto médico que debe llevarse a cabo únicamente después de un estudio racional y especifico de la patología a tratar“, lo cual indica establecer los mecanismos adecuados para su uso debidamente justificado. OBJETIVOS: - Determinar el uso justificado o no de la transfusión de sangre y hemocomponentes en los Servicios de Emergencia y Hospitalización del Hospital “Daniel Alcides Carrión” durante el año 2001. - Determinar la causa del uso justificado o no de las transfusiones sanguíneas y de hemocomponentes en el Hospital “Daniel Alcides Carrión”. - Determinar cual es el hemocomponente transfundido de mayor uso injustificado en el Hospital “Daniel Alcides Carrión” durante el 2001. - Determinar cuales son las indicaciones principales por las cuales se transfunden sangre y hemocomponentes en el Hospital “Daniel Alcides Carrión”.Tesis de segunda especialida

Visión del alumnado de secundaria sobre la calidad docente en el ámbito de las ciencias. Una valoración mediante la escala SERVQUAL

La importancia de la calidad de servicio no solamente atañe al mundo empresarial. En los últimos años, también se ha convertido en uno de los objetivos prioritarios en el campo de la Educación. En este trabajo, se presentan los resultados de una investigación sobre la calidad docente en el ámbito de la enseñanza de las Ciencias en la ESO (12-16 años). El estudio se ha realizado mediante una adaptación apropiada de la escala SERVQUAL a dicho contexto educativo, y el análisis factorial de componentes principales no confirma las cinco dimensiones originales. Finalmente, se muestran aquellos aspectos donde los alumnos perciben una mayor calidad de servicio, y se estudia si existen diferencias en la calidad de servicio percibida, según el curso de la etapa educativa estudiada.The server quality is not alone important in the business area. In recent years, this field forms part of the priority objectives in all the levels of the Education. In this paper, we present the results of an investigation about teaching quality in the Science Education in Secondary School (12-16 years old). The investigation has been realized by means of an appropriate adaptation of the SERVQUAL scale for Secondary School. Exploratory factor analysis using principles component not confirms the five original dimensions. Finally, we show the aspects where the pupils perceive a great service quality, and we study if there are differences in the perceived service quality between different courses