Escarda selectiva, una nueva estrategia para el control de las malas hierbas

Este artículo presenta los resultados de un TFC (Trabajo Final de Carrera) desarrollado en la Faculty of Life Science, de Copenhague. El propósito de este proyecto es describir una nueva estrategia para el control de la flora arvense, basado en la selección y tratamiento de las malas hierbas "dañinas" presentes en el campo, manteniendo la biodiversidad. Esta nueva estrategia se denomina escarda selectiva, mediante procedimientos de visión artificial, de identificación de áreas de trabajo, de tratamiento de escarda y su mapeado

India in the victorian popular fiction, analysis of Arthur Conan Doyle's The sign of four

Colonialist ideologies, the effects of colonization and the colonial relations between two countries may be apparently hidden in a literary work. Nevertheless, the contrapuntal and post-colonial reading of a literary work can reveal all these matters. Arthur Conan Doyle’s novella The Sign of Four includes colonialist ideologies and the colonial process of India in the second half of the nineteenth century. This novel acted as a double mechanism that diffused a colonialist ideology to the British population and, at the same time, reflected an India that was not entirely ‘real’. This happens through Orientalism, a discourse of the construction of the ‘other’, a form of authority and a phenomenon constructed by intellectuals, artists and writers, among others, constructed by the naturalizing of a wide range of Orientalist assumptions and stereotypes.Las ideologías coloniales, los efectos de la colonización y las relaciones coloniales entre dos países pueden estar aparentemente ocultas en una obra literaria. Sin embargo, la lectura contrapuntual y post-colonial de una obra literaria nos permite revelar estas cuestiones. El Signo de los Cuatro de Arthur Conan Doyle tiene presente el imperialismo y el proceso colonial británico en la India en la segunda mitad del siglo XIX. Esta novela actuó como un doble mecanismo que difundía una ideología colonialista a la población británica, y al mismo tiempo reflejaba una India que no era del todo ‘real’. Esto ocurre a través del orientalismo, el cual es un discurso de construcción de ‘lo otro’, una forma de autoridad y un fenómeno que es construido por intelectuales, artistas y escritores, entre otros, por la naturalización de un conjunto de suposiciones y estereotipos orientalistas.Departamento de Filología InglesaGrado en Estudios Inglese

Validation of a qualitative method of Listeria monocytogenes detection in a food matrix according to ISO 17025 and ISO 11290-1

Motivation: Listeria monocytogenes is a bacterium that is mainly transmitted through contaminated water and food. It can cause listeriosis in susceptible populations such as pregnant women, neonates, the elderly and immunosuppressed individuals.In recent years, there has been an increase in the incidence of this disease, so, to safeguard public health, it is very important to have a fast and secure method of detection and identification of L. monocytogenes in contaminated products [1].Therefore, the main objective of this study is to perform a secondary validation of a qualitative method of L. monocytogenes detection on five food matrices.Methods: As a general rule for the cultures preparation, it will be used the European and International Standard method for detection and enumeration of Listeria monocytogenes (EN ISO 11290-1) [2], with the use of a chromogenic agar, the "Agar Listeria according to Ottaviani and Agosti" (ALOA) [3]. In addition, it will be used the UNE-EN ISO 17025 Standard.A commercial strain of L. monocytogenes will be used.In order to determine the detection limit of the validation method, some chicken samples will be inoculated with L. monocytogenes at different concentrations.Having calculated this parameter, it will be chosen the concentration to inoculate the samples of each matrix. In addition, it will be done negative controls with Staphylococcus aureus contaminated samples.The artificially contaminated samples will be cultured in ALOA medium and incubated at 37 °C for 24 hours.The L. monocytogenes growth in each plate, will be ratified with confirmatory tests.Finally, it will be calculated the next parameters: sensitivity, specificity, false negatives, false positives and efficiency.Results: The parameters calculated were: detection limit of <10 ufc/25 g, 94% sensitivity, 98% specificity, 2% false positives, 5,7% false negative and 96% efficiency.Conclusions: It is concluded that the analytical technique has been applied properly in the laboratory, obtaining high efficiency values. Therefore, this method of L. monocytogenes detection would successfully validated for its use in this laboratory

Manejo de poblaciones de malezas resistentes a herbicidas. 100 preguntas sobre resistencias

Publishe

Problemática de las malas hierbas en el cultivo del azafrán en el valle del Jiloca (Teruel)

Proyecto INIA PET 2007-14-C05-0

Suelos volcanicos endurecidos

In Mexico, there is very few informations about the soil surface crusting in relation to the rain. When creating a new soil from a indurated volcanic tuff, it is important to study the behaviour and dynamics of the new structure under the action of rain and cultivation practices. We followed 6 terraces during 3 years on different kinds of soil and tepetate, as well as different kinds of soil tillage and crops. We used the rugosimeter and a crop covermeter of 2 m2 with a precision of 10 cm2 for each mesure. We measured the humidity and thecrusting of the soil after every runoff-producing event and the vegetation covering once a week. At the same time, we followed the state of the row and their ruptures along every terrace. This study confirms and details the 4 different kinds of crusting of this new soil. They are following this dynamic: 1) a structure crust with predominance of plasma is formed; 2) then come the erosion crust; 3) then the runoff crust and nearly in the same time; 4) the deposit crust. To pass from the phase 1 to 2, the cumulated energy of the rain must be higher than 560 MJ/h. In the case of the beginning of destruction of the row, this energy is nearly the same: 530 for the tepetate and 580 MJ/ha for the soil (phoeozem). Laboratory tests and the following of agregates bigger than 5 cm show that in the case of terraces with manure, the strucutre of the soil is more stable. But in the fields, there is not such a clear difference with the other treatments. The protection of the soil by vegetation is clearly better with the other treatments. It does not only protect the aggregates but also the row. In effect, corn produces a stem flow which destrys the row at the foot of the plant, while the association of corn and string bean limitsthis influence by the captation of the rain by the string bean. In the case of barley, the erosion is laminar and diffuse but, at the base of the terrace, it is possible to notice a clear runoff concentration. In the case of corn, water is concentrated inside the row and under certain conditions occurs a movement from one row to the other one due to their rupture. Erosion is more visible but really less intense than with barley because there is runoff only during strong and exceptional rains, while with barley runoff occurs during quite all rains over 3 mm. Cleaning of the fields during the rainy season could have catastrophic results. Under this climate, we recommend rows with little rain catchment and with an association of corn and string bean to limit destruction of the furrows and soil erosion. (Résumé d'auteur)