1,721,061 research outputs found
EPIGENETIC INVESTIGATION ON CYCLIC ONSET OF REPRODUCTIVE ACTIVITY IN DAIRY GOATS
Get PDFAt our latitude and under natural conditions, goats show autumn heats with calvings in spring. Individual variability in the onset of puberty and reproductive activity could hide a genetic and epigenetic variability that can allow a selection of goats more prone to deseasonalization. As a consequence, breeders could easily spread milk production throughout the year. The aim of the project was to analyze epigenetic profiles responsible for the reproductive seasonality in goat species. Considering the lack of information in literature for the species, we decided, first of all, to focus our effort on the characterization of the epigenetic profile (involving DNA methylation and microRNA) of two key organ in reproduction performances: hypothalamus and ovary. This basic research gave a first picture of the epigenome of goat species, representing a starting point for future researches in this field. In the three year of my PhD we gathered biological samples of interest for the project and we set up a pipeline for the epigenetic analysis (for DNA methylation and smallRNA) of the data produced. We saw different DNA methylation patterns across the goat genome between two organs, hypothalamus and ovary, and even a marked difference in the same organ (hypothalamus) between two physiological stages, before and after reaching puberty. In particular, the comparison between transcriptome and methylome in hypothalamus and ovary showed that a higher level of methylation is not accompanied by a higher gene suppression. We discovered interesting differences in the expression of microRNA in hypothalamus and ovary. We confirmed microRNAs already known on databases and we discovered some new, through structure homology with other related species. A selection of differentially expressed miRNAs was identified among hypothalamus, pituitary and ovary. In addition, 44, 55, and 69 miRNAs identified in pituitary, hypothalamus and ovary respectively, were specifically up-regulated in only one organ. Then we focused our efforts on the characterization of the epigenetic factors that could drive to puberty in the species. Genome wide DNA methylation analysis revealed 664 Differentially Methylated Genes (DMGs) among pubertal goats and their control. The crossing of DMGs and Differentially Expressed Genes (DEGs) among pubescent goats and their control, revealed new 8 genes, as potential marker for puberty onset. Among these, ATG16L1 (autophagy related 16 like 1), LRP5 (low-density lipoprotein receptor-related protein 5) and MERTK (proto-oncogene tyrosine-protein kinase MER) are suitable examples of puberty-related genes. According to False Discovery Rate threshold, it seems that miRNA population does not play a crucial role in the reaching of puberty in goat species in the organ analyzed.
Furthermore, we conducted a SNP discovery on three key genes for photoperiod response (Melatonin Receptor 1 - MTNR1A, type 2 Deiodinase Gene - DIO2, Thyroid Stimulating Hormone beta subunit -
TSHB), confirming and identifying new genetic polymorphisms. We found a novel non-synonymous polymorphism in the caprine DIO2 gene and we confirmed the high variability of the MTNR1A gene, discovering a new SNP bringing to a silent mutation.
The first genome-wide comparison among organs of DNA methylation in Capra hircus has been generated. The DNA methylome in the hypothalamus and ovary of goat offers a valid base for studying the involvement of epigenetic modifications in goat reproduction performances. By confirming that the neuroendocrine control of female puberty entail mechanisms subjected to epigenetic regulation, our results provide insight into genes and pathways involved in the system used by the hypothalamus to control the initiation of mammalian puberty. As such, they are consistent with the concept that the pubertal process depends not only on genetic determinants, but also on developmentally regulated changes in epigenetic information
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
Almond oxynitrilase.catalyzed transformation of substituted aldehydes. Part 2
No full textDifferent α- and β-alkyl substituted aldehydes (1-5) have been submitted to the catalytic action of almond oxynitrilase, in order to explore the influence of a stereocenter already present in the substrate molecule on the selectivity of this enzyme. The results indicate that substituents in α- position to the aldehyde group significantly influence the stereochemical outcome of the AON-catalyzed transformation, especially when they are of different size. On the other hand, the presence of a β-substituent seems to have little effect on AON selectivity
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
Influence of operating parameters on the emission of pollutants from fixed-roof storage tanks
No full textBeyond pedigree and towards applied genomics
No full textIn the past two centuries, breeding practices led to more than 400 modern dog breeds showing high genetic drift, small population size without admixing events, increased between-breeds differentiation and inbreeding depression. Inbreeding depression and reduced population sizes are major drawbacks of human-driven selection in the dog species. Therefore, increasing the breed genetic basis is extremely important for their welfare and biodiversity. The availability of efficient and affordable genomic techniques such as dense SNPs arrays, together with the effort of the scientific community, allowed the production of massive genomic data of purebred dogs (Parker et al., 2017; Talenti et al., 2018). However, the 75% of the 1 billion living dogs are free-ranging and breeding (Pilot et al., 2015), with largely unknown ancestry. Genomic tools could be useful in this, in improving welfare and possibly enlarging the genetic basis of small dog populations. In this study, we evaluate a combined approach to assign the ancestors of different admixed and purebred dogs, sampled by saliva swab following European rules and genotyped by the 230K SNP chip. We compared three admixed individuals with 183 breeds and populations, including wild canids and wolves from Talenti et al., 2018. A combination of ranked supervised admixture and haplotype sharing (Beagle 4; Browning & Browning, 2013), allowed us to guess the most likely populations of three different admixed dogs. Results diverged in the three cases. We confirmed the supposed ancestry of one dog, partially confirmed the second dog and defined the third dog as a true mongrel, with 5 different breeds found as top ancestry scores comparable in size and morphology. These results suggest usefulness of genomic metrics in define the make-up even for admixed dogs. The genomic era in this species reached the maturity and this information deserves to be included for a better management of single dog and breeds facing for example health and longevity challenges
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
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