Computational linguistics : a brief introduction

Computationai Linguistics is an interdisciplinary field of study that encornpasses knowledge rnainly from three areas: Linguistics, Computer Science and Logic. This article is an introduction to the anai~sis of language frorn a Computational Linguistics approach, to the first questions linguists face when &ey need to make natural language fit into structures that computers can manipulate. Easy examples illustrate current existing approaches to the morphology, syntax and meaning of language, presenting sorne of the dificulties and challenges faced in this field. A list of basic introductory readings is provided in the last section

Progressive structures of English and Catalan

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Complementarity between microhistological analysis and PCR-capillary electrophoresis in diet analysis of goats and cattle using faecal samples

Altres ajuts: project Life Montserrat (LIFE13 BIO/ES/000094). Javier Pareja was supported by the National Fund for Scientific, Technological Development and Technological Innovation (FONDECYT), the funding branch of the National Council for Science, Technology and Technological Innovation (CONCYTEC) Peru (Grant contract number N° 236-2015-FONDECYT).An evaluation is made of the complementarity between two non-invasive techniques, cuticle microhistological analysis (CMA) and PCR-capillary electrophoresis (PCR-CE) DNA-based analysis, for the determination of herbivore diet composition from faecal samples. Cuticle microhistological analysis is based on the different microanatomical characteristics of the epidermal fragments remaining in the faeces. The PCR-CE technique combines PCR amplification of a trnL(UAA) genomic DNA region with amplicon length determination by CE, with this length being characteristic for each species or taxon. A total of 37 fresh stool samples were analyzed, including 16 from feral goats (Capra hircus) from the Tramuntana mountain range (Mallorca, Baleares) and 11 from Bruna dels Pirineus cattle breed (Bos taurus) from the surrounding Montserrat mountain range (Barcelona, Spain). All the animals were in a free grazing Mediterranean pine habitat, dominated by Aleppo pine (Pinus halepensis). The results showed that both techniques detected a similar number of plant components in the faeces of goats and cows. In the case of goats, a positive correlation was obtained between the percentage of samples in which a particular taxon is detected by CMA and the percentage of samples in which that taxon is detected by PCR-CE. This correlation was not observed in the case of cows. It is concluded that PCR-CE is a fast and reliable method to detect the different plant components in the faeces of herbivores. However, it cannot be considered as an alternative to CMA, but as a complementary method, since both techniques can detect some taxa that are not detected by the other technique. In addition, CMA detected the presence of the different taxa in a greater number of samples, and at the same time, it enables quantitative data to be obtained for plant diet composition. The species of herbivore also seems to influence the results obtained by PCR-CE, so more studies are required to address this aspect

Comparing the accuracy of PCR-capillary electrophoresis and cuticle microhistological analysis for assessing diet composition in ungulates : a case study with Pyrenean chamois

The study of diet composition is required to understand the interactions between animal and plant ecosystems. Different non-invasive techniques applied on faecal samples have commonly been used for such purposes, with cuticle microhistological analysis (CMA) and emerging DNA-based methods being the most relevant. In this work, we refined and optimized a qualitative DNA-based approach combining PCR amplification of long trnL(UAA) and ITS2 fragments and capillary electrophoresis (PCR-CE), instead of short trnL(UAA) fragments and massive sequencing technologies commonly reported. To do so, we develope a controlled diet assay using a stabled Pyrenean chamois specimen (Rupicapra pirenaica pyrenaica), which included representative herbaceous and shrubby plant species. We also assessed the impact of sample freshness on the diet determination of this mountain caprinae by exposing faecal samples to the outdoor environment for three weeks. Faecal samples from both experiments were analysed by qualitative PCR-CE and semi-quantitative CMA in order to compare the pros and cons of both approaches. Our results show that all of the offered plant species were detected by both methodologies although CMA overdetected shrubs compared to herbaceous species. At the same time, sample degradation due to sustained climate exposure is a limiting factor for molecular analysis, but not for CMA. Taken all together, our results suggest that the qualitative information obtained by CMA and PCR-CE can be interchangeable when faecal samples are fresh (less than one week after deposition) but, afterwards, molecular analysis underestimates diet composition probably due to DNA degradation. CMA, however, can accurately be used at least three weeks after defecation. Moreover, by combining the results of simultaneous PCR amplification of two complementary genes, this optimized PCR-CE methodology provides a reliable, feasible and more affordable alternative for multiple and routine analyses of complex samples. Neither CMA nor PCR-CE seems to solve comprehensively the quatification of herbivore diets and thus further research needs to be done

Efecto de la simulación de ramoneo en parámetros estructurales de tres especies de matorral mallorquín

La herviboría por la cabra salvaje mallorquina y la cabra doméstica asilvestrada puede ser uno de los factores que determinen la regresión en que se encuentran las poblaciones de tres especies anteriormente abundantes y actualmente raras del matorral mallorquín: boj balear (Buxus balearica), canadillo (Ephedra fragilis) y enebro rojo (Juniperus oxycedrus). Para determinar esta afectación analizamos la respuesta de estas especies en condiciones de invernadero, a las que se les realizó una simulación de ramoneo cortando el 80% de sus brotes terminales y se les midió la variación en los parámetros estructurales de crecimiento y capacidad de generar brotes nuevos. La simulación de ramoneo produjo respuestas morfológicas diferentes en las tres especies estudiadas. Mientras en las tres especies aumenta la producción de brotes, el crecimiento en diámetro no aumenta de manera significativa en B. balerica ni en E. fragilis, y en J. oxycedrus se ve afectado negativamente. Por lo que respecta al crecimiento en altura, el ramoneo tiene un efecto positivo en B. balearica y J. oxycedrus y es indiferente en E. fragilis. El hecho de que B .balearica sea actualmente una especie poco ramoneada contribuiría a explicar su regresión