1,720,984 research outputs found
Characterization of eyes, photoreceptors and opsins in developmental stages of the arrow worm Spadella cephaloptera (Chaetognatha)
No full textThe phylogenetic position of chaetognaths, or arrow worms, has been debated for decades, however recently they have been grouped into the Gnathifera, a sister clade to all other Spiralia. Chaetognath photoreceptor cells are anatomically unique by exhibiting a highly modified cilium and are arranged differently in the eyes of the various species. Studies investigating eye development and underlying gene regulatory networks are so far missing. To gain insights into the development and the molecular toolkit of chaetognath photoreceptors and eyes a new transcriptome of the epibenthic species Spadella cephaloptera was searched for opsins. Our screen revealed two copies of xenopsin and a single copy of peropsin. Gene expression analyses demonstrated that only xenopsin1 is expressed in photoreceptor cells of the developing lateral eyes. Adults likewise exhibit two xenopsin1+ photoreceptor cells in each of their lateral eyes. Beyond that, a single cryptochrome gene was uncovered and found to be expressed in photoreceptor cells of the lateral developing eye. In addition, cryptochrome is also expressed in the cerebral ganglia in a region in which also peropsin expression was observed. This condition is reminiscent of a non-visual photoreceptive zone in the apical nervous system of the annelid Platynereis dumerilii that performs circadian entrainment and melatonin release. Cryptochrome is also expressed in cells of the corona ciliata, an organ in the posterior dorsal head region, indicating a role in circadian entrainment. Our study highlights the importance of the Gnathifera for unraveling the evolution of photoreceptors and eyes in Spiralia and Bilateria.A summary of all parameters related to sequencing and assembly of the transcriptome is added (see metadata spreadsheet Wollesen.xlsx
Octopod Hox genes and cephalopod plesiomorphies
No full text<p>2 assembled transcriptomes and the respective raw reads</p>
<p>“Ovu1”: mRNA of almost hatched individuals (stage XX)</p>
<p>“Ovu2”: pooled mRNA of developmental stages VIII, XI, XV, XVIII</p>
<p>RNA-seq libraries were constructed with a Lexogen SENSE mRNA-Seq Library Prep Kit V2 and sequenced with an Illumina Hi-Seq 2500 generating paired-end, stranded 125 bp libraries resulting in 53,523,481 (ovu1) and 63,328,653 (ovu2) paired end reads. The overall transcriptome assembly follows the procedure performed by De Oliveira et al. (2016) [42]. The short‐read libraries were preprocessed using Trimmomatic v. 0.36 (ref. [43]) to remove known specific Illumina adapters from the paired‐end libraries (Illumina universal adapter). Filtering by quality and length was performed with a SLIDINGWINDOW:4:15 MINLEN:36. First and last nucleotides from reads with low quality score were clipped and the library file was converted into FASTA format using fq2fa from SeqKit version 0.11.0 (ref. [44]). Quality of the initial and filtered library was assessed with the software FastQC v.0.11.8 (ref. [45]) considering quality score of the bases, GC‐content, and read length. 13.33% (ovu1) and 16,23% (ovu2) of reads were excluded during the preprocessing procedure resulting in a total of 46,386,109 (ovu1) and 53,052,713 (ovu2) reads. The assemblies and all downstream analyses were conducted with a high‐quality and clean library. The filtered transcriptome was assembled into contiguous cDNA sequences with IDBA_tran v1.1.3 software (ref. [46]) using the default settings (except: −mink20 −maxk 80 −step5). The resulting assembly was assessed using the tool QUAST (available at: http://quast.bioinf.spbau.ru [47]). The number of contigs was 16,723 sequences (ovu1) and 18,551 (ovu2).</p>
<p>For information on references see publication/ more info on request</p>
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
- …
