1,720,965 research outputs found
Supporting Data for: Allochrony in Atlantic lumpfish: genomic and otolith shape divergence between spring and autumn spawners
No full textThis data set contains two datasets. Firstly, the Single Nucleotide Polymorphism (SNP) genotypes for the Atlantic lumpfish (Cyclopterus lumpus) used in the population genomics study. Samples are collected from fjords around Norway (Sørøya and Namdal). The genotypes are called using whole genome shotgun sequencing approach. Second data is 4th wavelet data for otoliths. From each contour, a total of 512 Cartesian coordinates on each orthogonal projection of the otolith were extracted using the wavelet representation routines developed in MATLAB® language and implemented in the AFORO v-1.1.2 (‘Anàlisi de FORmes d'Otòlits’) web page (http://aforo.cmima.csic.es/index.jsp). The 4th (medium-small detail) wavelet was selected for further analyses, as it is recommended to capture the optimal level of detail for identification of intra-specific populations or morphotypes
Investigating population genomic structure of salmon lice (Lepeophtheirus salmonis) in northern Norway
Full text linkSalmon louse (Lepeophtheirus salmonis) is a parasitic copepod that causes significant damage to Atlantic salmon (Salmo salar) and incurs significant costs to the salmonid aquaculture industry. In Norway, the industry has been coping with salmon lice issues with various methods such as chemical treatments, but it has resulted in an acquisition of resistance in salmon lice towards the existing delousing treatments. In order to maximize the effectiveness of the treatments, it is important to understand population structuring of salmon lice, and factors that are driving the structure, since recent studies suggested that several Atlantic salmon lice populations are sharing genetic materials coding for resistance toward delousing treatments. The objective of this study was to investigate whether salmon lice in northern Norway display population structure and differentiation at small geographical scales. We identified 25,795 robustly supported SNPs among salmon lice from 8 different locations in northern Norway. While only very weak structure was observed based on the full SNP dataset (25,795 SNPs), relatively weak, but highly significant, population structure was observed using 303 important SNPs identified using a random forest classification approach. No significant correlation between genetic differentiation and geographical distance was observed. To our knowledge, it was the first study to reveal the significant population structure of salmon lice at such small spatial scales. Our results suggested that the observed population structure was a result of dispersal and mixing of salmon lice, as well as selective pressure such as delousing treatments and local environment. Our results are potentially helpful to make population specific delousing treatments, where the treatments are designed depending on the genetic characteristics of the targeted salmon lice population
Speciation reversal in sympatric eco-morphs of European whitefish (Coregonus lavaretus. L) – phenotypic and genomic consequences
Full text linkAnthropogenic activities, such as introduction of non-native species, is considered as one of the most significant causes for declining biodiversity, since such introduction may destabilise ecological barriers to gene flow between native populations. In the 1960s a salmonid fish, vendace, was introduced to the upper parts of Pasvik watercourse and during the early 1990s it invaded the entire watercourse, including the lakes studied in this project/thesis. These lakes harbour an eco-morph pair of European whitefish that has diverged in sympatry in post-glacial times. The vendace, being a competitively superior planktivore to the densely rakered eco-morph, relegated this eco-morph from its native pelagic habitat into the non-native littoral habitat, which is mainly occupied by the large sparsely rakered eco-morph. These observations have inspired this PhD thesis to study the phenotypic, genetic, and genomic consequences of the vendace invasion on native sympatric European whitefish eco-morphs. Using neutral microsatellite markers, the study documented that the introduction and invasion of vendace have induced speciation reversal in the eco-morph pair. The comparison of the number of gill rakers from the pre- and post-invasion periods revealed merging of two peaks of distribution of number of gill rakers following the invasion suggesting reduction in discreteness of phenotypes. Population genomic analyses, using genome-wide coverage of SNP markers obtained by sequencing of restriction site associated DNA libraries (RADseq), revealed an unpredicted outcome of speciation reversal at the genomic and functional phenotypic levels. This was attributed to a change in the selective forces during speciation reversal. The introgression patterns at genomic regions of adaptive importance, showed that speciation reversal have unpredictable consequences on introgression. Overall, this PhD study concludes that anthropogenic activities have wide-ranging and stochastic effects for species undergoing speciation reversal
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
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
Genomic characterization and insights of local adaptation in Norwegian juvenile lumpfish populations
Full text linkThe lumpfish (Cyclopterus lumpus Linnaeus, 1758) has for many years been an attractive target for the roe fisheries in Norway and has more recently become an important cleanerfish in the salmonid farming industry for the control of salmon lice (Copepoda: Caligidae). Despite this, there is a lack of knowledge about several life aspects of the species and studies on its genetic structure have been inconsistent. It is therefore uncertain how scenarios involving, for instance, overfishing or escaping of lumpfish from the fish farms might affect the natural stocks genetically and biologically. To initiate the investigations of how human activities might affect lumpfish in nature, this project aimed to clarify the genetic structure and reveal potential signatures of local adaptation in juvenile lumpfish in Norway. Whole genome sequencing was performed for 30 individuals from three different locations and a set of 607,663 SNPs were selected for downstream genetic structure analyses. Significant genetic differentiation was detected between the northern and southern parts of Norway, with further discrimination of two populations within one location in the north. Lumpfish separated by long geographical distances showed greater differentiation than those collected at locations more proximate to each other, but no significant correlation was detected. Loci putatively under selection were identified and revealed population structure at smaller geographical scales. These findings suggest that multiple driving forces may have contributed to population structuring in lumpfish. The study presents evidence for genetic structuring of Norwegian juvenile lumpfish and discriminate at least three populations, and further studies should therefore contribute to establishing sustainable management practices for the species.
Keywords: Lumpfish, Cyclopterus lumpus, population genetics, whole genome sequencing, SNPs, genetic structur
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
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