Search results for "Dendrogram"
showing 10 items of 20 documents
Evaluation of morphological and genetic diversity of loquat accessions grown in sicily
2015
In this study 20 accessions of loquat (Eriobotrya japonica Lindl.) that originated from Sicily and other countries were characterized phenotypically and genotyped using seven microsatellite markers. The microsatellites clearly distinguished 14 accessions; three pairs of local accessions were not differentiated, and three accessions from abroad can be considered bud sport mutations of the main Spanish cultivar âAlgerieâ. The mean alleles per locus was four, ranging from two with the marker EJ075 and five with EJ012 and EJ271; the mean Polymorphic Information Content was 0.53; the average expected and observed heterozygosities resulted 0.62 and 0.59, respectively. These values revealed a …
A molecular approach to the taxonomy and biogeography of African parrots
2000
Random amplified polymorphic DNA analysis of blood samples from eight African parrot species was performed to study the genetic relationship within the genus Poicephalus and among Poi-cephalus and the two other main African parrot genuses, Agapornis and Psittacus. To this end, DNA from six Poicephalus species, one species, of the Agapornis group and the single Psittacus species was analysed. The amplification pattern was then converted into a binary matrix and scored by the unweighted pair-group method algorithm. The resulting dendrogram showed a neat separation of all the Poicephalus on one side, from Psittacus-Agapornis on the other side. Among the six analysed species of Poicephalus, two…
A general strategy to determine the congruence between a hierarchical and a non-hierarchical classification
2007
This article is available from: http://www.biomedcentral.com/1471-2105/8/442
A voltammetric e-tongue tool for the emulation of the sensorial analysis and the discrimination of vegetal milks
2018
[EN] The relevance of plant-based food alternatives to dairy products, such as vegetable milks, has been growing in recent decades, and the development of systems capable of classifying and predicting the sensorial profile of such products is interesting. In this context, a methodology to perform the sensorial analysis of vegetable milks (oat, soya, rice, almond and tiger nut), based on 12 parameters, was validated. An electronic tongue based on the combination of eight metals with pulse voltammetry was also tested. The current intensity profiles are characteristic for each non-dairy milk type. Data were processed with qualitative (PCA, dendrogram) and quantitative (PLS) tools. The PCA stat…
Comparative statistical studies on the physical anthropology of the late Medieval period (A.D. 1000–1500)
1984
Continuing previous studies on preceding temporal periods, a total of 162 skeletal series from the late Medieval period are analysed. The dendrogram reveals an east cluster as in the other periods but a west cluster is not evident possibly because western Europe is represented by very few series. Moreover, we find a Scandinavian and a Turk cluster. Regional or ethnic pooling of the original series gives an affinity structure which is more influenced by geographic proximity than by ethnic relation. This structure predominantly reflects differentiations of skull width and length and to a lesser degree of facial height. The diachronic trend appears again, but in this period there is only a sli…
Hierarchical and non-hierarchical clustering methods to study students algebraic thinking in solving an open-ended questionnaire
2017
The problem of taking a data set and separating it into subgroups, where the members of each subgroup are more similar to each other than they are to members outside the subgroup, has been extensively studied in science and mathematics education research. Student responses to written questions and multiple-choice tests have been characterised and studied using several qualitative and/or quantitative analysis methods. However, there are inherent difficulties in the categorisation of student responses in the case of open-ended questionnaires. Very often, researcher bias means that the categories picked out tend to find the groups of students that the researcher is seeking out. In our contribu…
Euryhaline Brachionus strains (Rotifera) from tropical habitats: morphology and allozyme patterns
2006
The euryhaline rotifer Brachionus is a complex of sibling species. Although many investigations have been carried out in the past, the relationships among the Spanish species, the tropical SS strains and the clusters previously described, remained unknown. In this study, allozyme data for five populations from the tropics and two from Spanish lagoons — one of them B. ibericus and the other B. rotundiformis — were combined with data from the previous studies. Cluster analysis based on genetic distance allowed the 74 strains to be divided into two major groups. One group was associated with B. plicatilis-like strains, and the other group was associated with B. rotundiformis and B. ibericus. T…
Phylogeny of snapdragon species (Antirrhinum; Scrophulariaceae) using non-coding cpDNA sequences
2005
Antirrhinum is an Old World genus of up to 25 perennial taxa, mainly located in the western Mediterranean basin. A molecular analysis of 24 taxa of Antirrhinum was undertaken using cpDNA sequences from the trnT (UGU)-trnL (UAA) 5' exon region. The Kimura two-parameter model was chosen to calculate pairwise nucleotide divergence values between cpDNA sequences, and a bootstrapped neighbor-joining dendrogram was constructed from the nucleotide divergence distance matrix. Eighteen sites were variable across the studied samples and the position of 7 indels, ranging from 1 to 7 bp, was inferred from the sequence alignment. Several trnT-trnL sequences are identical in: some members of subsection K…
Genetic diversity in theCentaurea cinerariagroup (Compositae) in Sicily using isozymes
2006
Abstract The genetic diversity of seven taxa endemic to Sicily, C. cineraria, C. busambarensis, C. ucriae subsp. ucriae, C. ucriae subsp. umbrosa, C. todari, C. erycina and C. saccensis, from 11 localities was investigated using isozymes. Eight loci from five enzyme systems (IDH, MDH, PGD, PGM and PGI) were examined. A total of 19 alleles were identified, some rare and two of them exclusive to different populations. The allelic frequencies and the genetic variability values for each population were calculated. On the whole, the genetic diversity, i.e., average polymorphism (P) = 0.41, average number of alleles per locus (A) = 1.75, Nei's gene diversity (H) = 0.18, is moderate, with the high…
SparseHC: A Memory-efficient Online Hierarchical Clustering Algorithm
2014
Computing a hierarchical clustering of objects from a pairwise distance matrix is an important algorithmic kernel in computational science. Since the storage of this matrix requires quadratic space with respect to the number of objects, the design of memory-efficient approaches is of high importance to this research area. In this paper, we address this problem by presenting a memory-efficient online hierarchical clustering algorithm called SparseHC. SparseHC scans a sorted and possibly sparse distance matrix chunk-by-chunk. Meanwhile, a dendrogram is built by merging cluster pairs as and when the distance between them is determined to be the smallest among all remaining cluster pairs. The k…