De Sastres académicos : los estudios culturales como moda-lidad sin objeto

En el presente artículo analizamos las condiciones de aparición y los postulados fundamentales de esta escuela, a partir de las rupturas teóricas y políticas que tuvieron lugar en el seno del marxismo inglés por la década de fines de los años cincuenta. Además, nos preguntamos si podemos olvidar la herencia de la teoría crítica de la cultura a partir de la hegemonía de unos estudios culturales que cada vez se alejan más de una perspectiva de sospecha sobre el sistema social para adoptar una actitud académica complaciente y conservadora.

Effect of Prosopis flexuosa on understory species and its importance to pastoral management in woodlands of the Central Monte Desert

In the Monte Biogeographic Province, located in the arid region of Argentina, the presence of Prosopis flexuosa DC. produces spatial heterogeneity through edaphic modifications and microclimate changes. This results in vegetation patches differing in species composition and abundance. However, this interaction can be modified by the occurrence of gradients of biotic stress or disturbance intensity. In particular, grazing has been observed to enhance or reduce vegetation heterogeneity. Such complex of interactions could determine forage availability for cattle in one of the driest areas of the Monte Desert. We assessed the effect of Prosopis on understory species and analyzed whether the outcomes of this interaction differed with distance to watering points, as a proxy of grazing intensity, in the Northeast of Mendoza Province, Argentina. We used a two-way factorial design including the following factors: 1) microsite (under the cover of P. flexuosa trees and in intercanopy microsites) and 2) distance to watering points ("near the watering point", 500-700 m away, and "far from the watering point", 3-4 km away). Cover of each species, total cover, bare soil, and litter were recorded, and plant diversity, richness, and evenness were estimated with the modified Point Quadrat method. Results showed that P. flexuosa cover, distance from watering points, and the interaction between them determined species composition, abundance and spatial distribution of understory species, and were, consequently, a determining factor for forage availability. The presence of P. flexuosa enhances carrying capacity by supporting higher abundance of grasses under its canopy. Near watering points, high grazing intensity appears to disrupt the patches formed under P. flexuosa canopies, reducing the differences between microsites.

Conidial germination of Botryosphaeria dothidea Mough.: Fr (Ces. & De Not.) and histological alterations on stems of pitahaya (Hylocereus undatus H.) (Haworth) Britton & Rose

Conidial germination of Botryosphaeria dothidea (anamorph: Fusicoccum) in sterile distilled water and 1% sterile dextrose solution was evaluated at 4, 6, 12, 24 and 36 h after incubation. Also, it was described the anatomical changes on pitahaya stems induced by this fungus, collected in the field and artificially inoculated in the laboratory. Conidial germination was less than 30% in water and it was improved when 1% dextrose was added to the water. In 1% dextrose solution the germination was 90% after 4h of incubation and 100% at 6 h. Pathogen germ tubes had entered through wounds and sometimes through stomata and hyphae colonized intra and intercellularly in the parenchyma-chlorenchyma tissues. On naturally and artificially diseased stems the main alterations were: destruction of cuticle, hyperplasia of epidermal and collenchymatous hypodermal cells and conform the advance of the pathogen a layer of lignified periderm was formed surrounding the damaged tissues; however, it couldn't stop the advance of the pathogen and the cells that surrounded the lesion suffered necrosis.

Evaluation of the attack rates and level of damages by the fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), affecting corn-crops in the northeast of Argentina

The fall armyworm (FAW) is the most important threat to corn crops in Argentina, and there exists very little up-to-date information on its actual pest status because the available literature was published more than 20 years ago. Therefore, field surveys were carried out in the northeast of Argentina, in order to establish the attack rates and injury levels of the pest in relation to the crop phenology. The study was carried out at two localities: Colonia Benítez, an agricultural region, and Tapenagá, a cattle-raising area. At each site two 1-ha plots were sown either with a Bt-corn expressing Cry 1F protein or with an untransformed corn germplasm. Optimal and late sowing was assayed and FAW larval abundance, relative age composition, attack rates and level of damage to corn were recorded. At the moment of the field experiments, Bt-corn was not affected by FAW larvae. However, untransformed germplasms were severely affected by FAW larvae, with an average of attacked plants of 18% or more. In contrast to data obtained 30 years ago, higher values of FAW density were registered. Levels of damage to corn plants were higher after the V4 stage. It was found that the sowing date affected the infestation levels and early seeding avoided high armyworm densities that develop later in the season; in northern Argentina, this was only relevant in agricultural areas.

Genetic diversity among alfalfa genotypes (Medicago sativa L.) of non-dormant cultivars using SSR markers and agronomic traits

The aim of this study was to assess genetic diversity among 40 alfalfa (Medicago sativa L.) genotypes of different non-dormant (FD=8) cultivars. Biomass yield, regrowth speed and reaction to spring black stem, lepto leaf spot, and rust were evaluated. Analyses of variances were performed using a mixed model to examine the agronomic variation among individuals. A principal component analysis on standardized agronomic data was performed. Agronomic data were also used to calculate Gower's distance and UPGMA algorithm. For the molecular analysis, six SSR markers were evaluated and 84 alleles were identified. The genetic distance was estimated using standard Nei's distance. Average standard genetic diversity was 0.843, indicating a high degree of variability among genotypes. Finally, a generalized procrustes analysis was performed to calculate the correlation between molecular and agronomic distance, indicating a 65.4% of consensus. This value is likely related to the low number of individuals included in the study, which might have underestimated the real phenotypic variability among genotypes. Despite the low number of individuals and SSR markers analyzed, this study provides a baseline for future diversity studies to identify genetically distant alfalfa individuals or cultivars.

Consumer preferences towards beef cattle in Chile : Importance of country of origin, cut, packaging, brand and price

A study was carried out to evaluate preferences for two cuts, four countries of origin, two forms of presentation, brand and different prices of beef cattle among supermarket buyers in southern Chile, and to distinguish the existence of different market segments, through a survey of 800 people. Using a fractional factorial design for conjoint analysis, it was determined overall that the origin was more important (44.5%) than price (20.8%), form of presentation (12.2%), cut (12.0%) and brand (10.5%), with preference for Chilean and Argentinean striploin, packaged on trays, with no brand at medium price. Using a cluster analysis, three market segments were distinguished. The largest (52.3%) placed great importance on origin and preferred the highest price. The second (27.5%) also valued origin with the greatest preference for Argentinean beef, and it was the only group that preferred the ribeye as the cut. The third (20.5%) placed the greatest importance on price, and was the only group that preferred Paraguayan meat. The segments differed in the importance of eating meat for their personal well-being. The low importance of packaging and brand indicates poorly developed marketing of this product. In order to properly insert brand beef in the Chilean market, communication strategies must be implemented that identify the product with superior quality and that position the brand in the consumer's mind.

Effect of compost and slow-release fertilizers addition on soil biochemistry and yield of maize (Zea mays L.) in Oaxaca, Mexico

The effect of Bokashi (B, a fermented compost), slow-release fertilizers (SRFs) and their combined application on mycorrhizal colonization (MC), soil invertase, cellulase, acid (AcP) and alkaline (AlP) phosphatases activities and maize (Zea mays L.) yield was investigated in terrace (TS) and valley (VS) soils in Oaxaca, Mexico. A complete randomized design, seven fertilizer treatments and four replications were used: unamended control (C); conventional fertilization (90-46-00 NPK) (CF); B; SRF1 (Multigro 6®, 21-14-10 NPK); SRF2 (Multigro 3®, 24-05-14 NPK); B+SRF1; B+SRF2. Highest root colonization percentage: CF in VS, and SRF2 in TS. Highest extraradical mycelium length: B, B+SRF1, CF in VS, and B+SRF1 in TS. In both soils, B increased the spore number. Highest AcP activity: B, SRF2 in VS, and B+SRF1, B+SRF2 in TS. Highest AlP activity: B+SRF1, CF in VS, and C in TS. Highest invertase activity: B+SRF1, SRF2, CF in VS, and B in TS. Grain yield only increased with B in VS. The significant interaction soil type × fertilizer treatment for the majority of the biological soil properties analyzed suggests that MC and soil enzyme activity response to fertilization was influenced by soil type. Bokashi, alone or combined with SRFs improves biological soil fertility in maize fields.

A dispute in the world of the dead : René Descartes and Andreas Rüdiger

En 1731 un autor alemán anónimo publicó un diálogo del muerto continuando la tradición comenzada en la Grecia antigua por Luciano de Samosata. Hoy sobrevive una única copia del texto, publicada sin referencia del lugar de publicación o impresor y se encuentra ahora en el Evangelisches Predigerseminar Bibliothek en Wittenberg. Los protagonistas son el filósofo y físico Andreas Rüdiger (1673-1731) y René Descartes, quien representa en el diálogo a un tipo muy diverso de filósofo de la figura “histórica" que trascendió hasta nosotros en sus obras. Este artículo se propone reconstruir la composición de este texto raro y enigmático y contextualizar la perspectiva ideológica del autor en las controversias que animaban el trasfondo filosófico de las universidades alemanas de los comienzos del siglo XVIII.

El modo gótico y una literatura sin fronteras

El propósito de estas páginas es demostrar que el modo gótico ingresa a la literatura argentina para poner en evidencia la inestabilidad de la estructura de género y consecuentemente provocar una revisión del sistema literario. En segundo lugar se establecen las afiliaciones del gótico con lo fantástico cuya característica particular en la literatura argentina es que no abandona la referencia a lo real. Como ejemplo se propondrá una lectura de la obra Ganarse la muerte, de Griselda Gambaro.