1,720,991 research outputs found
La problemática del piscardo (Phoxinus sp.) en los lagos de alta montaña del Pirineo
Full text linkAquest document conté originàriament altre material i/o programari només consultable a la Biblioteca de Ciència i Tecnologia.Los ecosistemas de alta montaña son considerados espacios naturales en buen estado de conservación, dado su aislamiento de los núcleos urbanos. Sin embargo, la realidad es que se encuentran amenazados por diversos factores, entre ellos las especies invasoras. Este trabajo se centra en el impacto que un ciprínido, el piscado (Phoxinus sp.), produce en los lagos de alta montaña del Pirineo, afectando tanto al Parque Nacional de Aigüestortes i Estany de Sant Maurici como al Parque Natural de l'Alt Pirineu. Además, se analiza el conocimiento de la población, tanto residente como visitante, sobre la problemática que este pez ocasiona en el medio y las afectaciones que produce en la población y en las administraciones. Mediante el estudio de la dieta del piscardo en tres lagos de alta montaña, se concluye que su presencia en estos ambientes los altera negativamente; se produce un efecto en cascada en la cadena trófica, disminuyendo la diversidad de especies, aumentando la población algas y llegando a eutrofizarlos. Gracias a la realización de encuestas y entrevistas se sabe que exista una falta de conocimiento de los ecosistemas lacustres de alta montaña, dado que un 85,6% de encuestados ubican los peces como organismos clave para la diversidad del medio. Por lo tanto, esta problemática es poco conocida por la población en general, haciendo énfasis en los visitantes a los parques. Asimismo, de la población local que conoce la problemática, un 9,4% está en contra de la acción de extracción de individuos, una iniciativa de mejora del ecosistema impulsada por la administración. Existe una contradicción entre la legislación que regula la pesca deportiva y la conservación y protección del medio natural, por lo que es vital un diálogo entre los gestores encargados de estos espacios para compatibilizar ambas actividades.Alpine ecosystems are considered natural areas in good conditions, given their isolation from urban areas. However, the reality is that they are threatened by several factors, including alies species. This paper focuses on the impact of a cyprinid, the minnow (Phoxinus sp.), present in the Pyrenees alpine lakes, which is affecting both Aigüestortes i Estany de Sant Maurici National Park and Alt Pirineu Natural Park. In addition, knowledge of the population (both residents and visitors) of the problems caused by this fish and how the authorities manage this issue, are analysed in. Through the study of the minnow's diet in three alpine lakes, it is concluded that their presence in these environments alters them negatively; a cascade effect is produced in the lake's food chain, which decreases the biodiversity of them, this effect increases algae population, coming to the eutrophication. Thanks to the carrying out of surveys and interviews, it is said that 85,6% of respondents place the fish as a key point for the diversity of alpine lakes. Therefore, this problem is little known by the population, with emphasis on visitors to the parks. However, 9,4% of locals who know the problem are against to the removing actions of these fishes, an initiative for the improvement of these ecosystems done by the public administration. There is a contradiction between fishing law and preservation of this type of ecosystem. Consequently, it is vital to reach an agreement to combine both activities
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Genetic variability of minnows and loaches in rivers and high mountain lakes from the Pyrenees and Italian Alps
Full text link[eng] The invasion of alien species is a major global threat to ecosystems, with significant impacts, especially on freshwater ecosystems. The species diversity in freshwater ecosystems has significantly declined worldwide, and in Europe, freshwater fish represent one of the animal groups with the highest number of invasive species. Due to human activities, restrictions on geographical distribution have disappeared, and fish are being introduced into new and distant areas for recreational and other economic benefits. The purpose of this thesis was to identify and assess the distribution of two invasive fish introduced by human activities, infer the spread process and introduction pathways. Through the use of various genetic analysis techniques, we aimed to characterize introduced individuals across a broad area and, beyond species identification, obtain information about inter-species hybridization and intra-species admixture.
The first chapter aimed to accurately identify the species and assess the distribution of the genus Phoxinus in high-altitude lakes in the Pyrenees and the Italian Alps. The goal was to understand the introduction pathways of these species in order to shed light on their presence and distribution. Mitochondrial DNA (COI and Cytb; mtDNA) was sequenced in 201 individuals sampled from 53 sites including alpine lakes and adjacent water bodies. This data was utilized for species identification through phylogenetic tree analysis and for inferring introduction pathways using haplotype networks. P. dragarum has been discovered in its native habitat, including the Garonne basin, and in lakes to the east of the Pyrenees, and rivers in Catalonia. P. bigerri was primarily found in its native range, the Adour basin, and lakes to the west of the Pyrenees, suggesting it has been introduced. Lower species diversity of genus Phoxinus was observed in areas where fishing is prohibited, indicating that most introductions are associated with the use of live bait by anglers. The regulation of fishing has been confirmed as an effective measure to prevent the introduction of invasive species.
The second chapter involved a more detailed using a total of 890 individuals from 62 locations, and nuclear DNA (microsatellite) sequencing was conducted. With the analyses of microsatellites (nuclear DNA; nDNA) we identified various lineages, including information on interspecies and intraspecies hybridization.
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The nDNA results generally aligned with mtDNA, but some differences were noted. Individuals from Catalonia identified as P. septimaniae based on mtDNA were identified as P. dragarum or P. bigerri based on nDNA, suggesting that the individuals known as P. septimaniae in Catalonia are hybrids. Contrary to the assumption that there would be a high rate of intraspecies hybridization in isolated lake environments, a low rate was observed. An interesting observation was the recording of nuclear and mitochondrial three-way hybrids of P. septemaniae (mtDNA) and P. dragarum x P. bigerri (nDNA) in the River Tenes.
The third chapter focused on the introduced species of loaches in the Catalonia, particularly in lowland rivers with greater human activity and accessibility. Individuals of Barbatula, Cobitis, and Misgurnus/Paramisgurnus were collected from 21 locations and were sequenced for COI and RAG-1. These data were utilized for species identification through phylogenetic tree analysis and introduction pathway inference using haplotype networks. We identified at least five non-native fish species (C. bilineata, M. anguillicaudatus, M, bipartitus, P. dabryanus, and an undescribed Barbatula species) in the Catalonia, and most of them were spreading in their distribution. The characteristics of invasive species were evolving over time after introduction, and the established invasive species in Catalonia shifted from being large and long-lived fish species used for culture or game fishing to small, benthic fish species used as live bait or for ornamental purposes
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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