Sentidos de la comunicación e interactividad entre los espacios educativos presenciales y la Red Social de Amigos hi5

La presente tesis aborda el proceso comunicativo en la red social de amigos hi5, desde un enfoque sociocultural. Su contenido propone una ruptura con los enfoques tradicionales y comprende a la comunicación como una construcción de sentido(s), a fin de explorar un tipo de comunicación específica, la de tipo virtual. Esto, conlleva la descripción de ciertas formas de interacción y relacionalidad social en el mundo moderno, las cuales están siendo transformadas desde la conformación de comunidades virtuales, a partir de contacto digital y uso de las Nuevas Tecnologías de la Información y la Comunicación (NTIC). La investigación se realiza en el año 2011, con un grupo femenino de jóvenes de cuarto curso del Colegio Nacional Experimental María Angélica Idrobo del Distrito Metropolitano de Quito. Se describe el proceso de interrelación presencial en dicha institución; para, seguidamente, observar la entrada, el accionar y, las razones y motivaciones que las llevan a sumarse y luego abandonar la red social hi5. Con ello, el presente estudio se enmarca en el análisis de la comunicación desde el proceso de movilidad interactiva que pasa por una red social virtual de amigos.

Voladoras: la red invisible del relato

Al interior de la tradición oral de muchas culturas del mundo, las brujas han sido personajes ligados a lo sobrenatural, mujeres con poderes excepcionales encarnadas de múltiples maneras a través de leyendas, historias, relatos e ilustraciones. Este estudio se ocupa de los relatos orales acerca de las brujas voladoras del pueblo de Mira, en la provincia del Carchi. La voladora es una beldad, ataviada de blancas vestiduras, que se precipita y suspende en el aire con la principal función de transportar noticias entre los pueblos circundantes. Cuando alza el vuelo, su cuerpo sutil abandona la piel de la esposa, la vecina, la madre, rompe los lazos de lo real y se proyecta hacia lo insondable. La autora hace uso de herramientas etnográficas y narratológicas para reflexionar en torno a la memoria oral, entendida como relato en permanente construcción y representación colectiva del pasado. Mediante la tradición oral es posible leer la historia de este pueblo de la Sierra norte del Ecuador. En la construcción permanente y dinámica de estas narraciones y sus personajes, las voladoras, se advierten metáforas cargadas de simbolismo, tanto en el texto revelado y su textura discursiva como en los vacíos y misterios que lo rodean. Los relatos orales de las voladoras son multivocales, polifónicos y creadores de sentido. En ellos se identifican símbolos, representaciones y elementos narrativos, se entablan interrelaciones y se interpreta su dinámica, otorgando valor a los elementos que entran en juego en la narrativa oral. Finalmente, se observa el papel que juega el lector que va desde el habitante de Mira hasta el viajero, el investigador o el detective que descifra el relato.

Las implicaciones políticas de la relación China-América Latina: el Consenso Asiático como red de poder global y el caso brasileño (Tema Central)

This paper analyzes the People’s Republic of China economic and political ascendance in the 21st century, focusing on the evolution of its sui géneris economic development model and its significance for the relationship between China and the developing countries of the peripheral ‘Global South.’ The objective of this article is to analyze the relationship between China and Latin America in the 21st century, characterizing it as a new Center-periphery global power network based on trade and investment, which is often referred to as the ‘Asian Consensus’. The article will give special attention to the Brazilian case.

Can the frequency of blocking be described by a red noise process?

The frequency of persistent atmospheric blocking events in the 40-yr ECMWF Re-Analysis (ERA-40) is compared with the blocking frequency produced by a simple first-order Markov model designed to predict the time evolution of a blocking index [defined by the meridional contrast of potential temperature on the 2-PVU surface (1 PVU ≡ 1 × 10−6 K m2 kg−1 s−1)]. With the observed spatial coherence built into the model, it is able to reproduce the main regions of blocking occurrence and the frequencies of sector blocking very well. This underlines the importance of the climatological background flow in determining the locations of high blocking occurrence as being the regions where the mean midlatitude meridional potential vorticity (PV) gradient is weak. However, when only persistent blocking episodes are considered, the model is unable to simulate the observed frequencies. It is proposed that this persistence beyond that given by a red noise model is due to the self-sustaining nature of the blocking phenomenon.

Modelling the movement and survival of the root-feeding clover weevil, Sitona lepidus, in the root-zone of white clover

White clover (Trifolium repens) is an important pasture legume but is often difficult to sustain in a mixed sward because, among other things, of the damage to roots caused by the soil-dwelling larval stages of S. lepidus. Locating the root nodules on the white clover roots is crucial for the survival of the newly hatched larvae. This paper presents a numerical model to simulate the movement of newly hatched S. lepidus larvae towards the root nodules, guided by a chemical signal released by the nodules. The model is based on the diffusion-chemotaxis equation. Experimental observations showed that the average speed of the larvae remained approximately constant, so the diffusion-chernotaxis model was modified so that the larvae respond only to the gradient direction of the chemical signal but not its magnitude. An individual-based lattice Boltzmann method was used to simulate the movement of individual larvae, and the parameters required for the model were estimated from the measurement of larval movement towards nodules in soil scanned using X-ray microtomography. The model was used to investigate the effects of nodule density, the rate of release of chemical signal, the sensitivity of the larvae to the signal, and the random foraging of the larvae on the movement and subsequent survival of the larvae. The simulations showed that the most significant factors for larval survival were nodule density and the sensitivity of the larvae to the signal. The dependence of larval survival rate on nodule density was well fitted by the Michealis-Menten kinetics. (c) 2005 Elsevier B.V All rights reserved.

Response of organically managed grassland to available phosphorus and potassium in the soil and supplementary fertilization: field trials using grass-clover leys cut for silage

Effective use and recycling of manures together with occasional and judicious use of supplementary fertilizing materials forms the basis for management of phosphorus (P) and potassium (K) within organic farming systems. Replicated field trials were established at three sites across the UK to compare the supply of P and K to grass-clover swards cut for silage from a range of fertilizing materials, and to assess the usefulness of routine soil tests for P and K in organic farming systems. None of the fertilizing materials (farmyard manure, rock phosphate, Kali vinasse, volcanic tuff) significantly increased silage yields, nor was P offtake increased. However, farmyard manure and Kali vinasse proved effective sources of K to grass and clover in the short to medium term. Available P (measured as Olsen-P) showed no clear relationship with crop P offtake in these trials. In contrast, available K (measured by ammonium nitrate extraction) proved a useful measurement to predict K availability to crops and support K management decisions.

Uptake Pathways of Polycyclic Aromatic Hydrocarbons in White Clover

An understanding of the primary pathways of plant uptake of organic pollutants is important to enable the risks from crops grown on contaminated soils to be assessed. A series of experiments were undertaken to quantify the importance of the pathways of contamination and the Subsequent transport within the plant using white clover plants grown in solution culture. Root uptake was primarily an absorption process, but a component of the contamination was a result of the transpiration flux to the shoot for higher Solubility compounds. The root contamination can be easily predicted using a simple relationship with K-OW, although if a composition model was used based on lipid content, a significant under prediction of the contamination was observed. Shoot uptake was driven by the transpiration stream flux which was related to the solubility of the individual PAH rather than the K-OW. However, the experiment was over a short duration, 6 days, and models based on K-OW may be better for crops grown in the field where the vegetation will approach equilibrium and transpiration cannot easily be measured, A significant fraction of the shoot contamination resulted from aerial deposition derived from volatilized PAH. This pathway was more significant for compounds approaching log K-OA > 9 and log K-AW < -3. The shoot uptake pathways need further investigation to enable them to be modeled separately, There was no evidence of significant systemic transport of the PAR so transfer outside the transpiration stream is likely to be limited.

Host plant recognition by the root feeding clover weevil, Sitona lepidus (Coleoptera : Curculionidae)

This study investigated the ability of neonatal larvae of the root-feeding weevil, Sitona lepidus Gyllenhal, to locate white clover Trifolium repens L. (Fabaceae) roots growing in soil and to distinguish them from the roots of other species of clover and a co-occurring grass species. Choice experiments used a combination of invasive techniques and the novel technique of high resolution X-ray microtomography to non-invasively track larval movement in the soil towards plant roots. Burrowing distances towards roots of different plant species were also examined. Newly hatched S. lepidus recognized T. repens roots and moved preferentially towards them when given a choice of roots of subterranean clover, Trifolium subterraneum L. (Fabaceae), strawberry clover Trifolium fragiferum L. (Fabaceae), or perennial ryegrass Lolium perenne L. (Poaceae). Larvae recognized T. repens roots, whether released in groups of five or singly, when released 25 mm (meso-scale recognition) or 60 mm (macro-scale recognition) away from plant roots. There was no statistically significant difference in movement rates of larvae.

Effects of carbon dioxide on the searching behaviour of the root-feeding clover weevil Sitona lepidus (Coleoptera : Curculionidae)

The respiratory emission of CO2 from roots is frequently proposed as an attractant that allows soil-dwelling insects to locate host plant roots, but this role has recently become less certain. CO2 is emitted from many sources other than roots, so does not necessarily indicate the presence of host plants, and because of the high density of roots in the upper soil layers, spatial gradients may not always be perceptible by soil-dwelling insects. The role of CO2 in host location was investigated using the clover root weevil Sitona lepidus Gyllenhall and its host plant white clover (Trifolium repens L.) as a model system. Rhizochamber experiments showed that CO2 concentrations were approximately 1000 ppm around the roots of white clover, but significantly decreased with increasing distance from roots. In behavioural experiments, no evidence was found for any attraction by S. lepidus larvae to point emissions of CO2, regardless of emission rates. Fewer than 15% of larvae were attracted to point emissions of CO2, compared with a control response of 17%. However, fractal analysis of movement paths in constant CO2 concentrations demonstrated that searching by S. lepidus larvae significantly intensified when they experienced CO2 concentrations similar to those found around the roots of white clover (i.e. 1000 ppm). It is suggested that respiratory emissions of CO2 may act as a 'search trigger' for S. lepidus, whereby it induces larvae to search a smaller area more intensively, in order to detect location cues that are more specific to their host plant.

Analysis of red and yellow ochre samples from Clearwell Caves and Catalhoyuk by vibrational spectroscopy and other techniques

Ochre samples excavated from the neolithic site at Qatalhoyuk, Turkey have been compared with "native" ochres from Clearwell Caves, UK using infrared spectroscopy backed up by Raman spectroscopy, scanning electron microscopy (with energy-dispersive X-rays (EDX) analysis), powder X-ray diffraction, diffuse reflection UV-Vis and atomic absorption spectroscopies. For the Clearwell Caves ochres, which range in colour from yellow-orange to red-brown, it is shown that the colour is related to the nature of the chromophore present and not to any differences in particle size. The darker red ochres contain predominantly haematite while the yellow ochre contains only goethite. The ochres from Qatalhoyuk contain only about one-twentieth of the levels of iron found in the Clearwell Caves ochres. The iron oxide pigment (haematite in all cases studied here) has been mixed with a soft lime plaster which also contains calcite and silicate (clay) minerals. (C) 2003 Elsevier B.V. All rights reserved.