indices of similarity
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2020 ◽  
Vol 200 (3) ◽  
pp. 767-788
Author(s):  
A. A. Dulenin

Dominant species are identified at infracenotic level for aquatic vegetation in the sublittoral zone of the northwestern Tatar Strait (Japan Sea) on the data collected in 2010–2019. Seven different methods of the identifying are considered based both on visual qualitative and quantitative assessments and on instrumental estimations of abundance for 44 macrophyte species. Depending on applied method, 19–25 species (7–22 % of total number of species) are identified as the dominants, including 10 species identified by all methods. List of these 10 species is defined as the core of vegetation that determines its general properties and the species are determined as unconditional dominants, in opposite to other ones identified by at least one method — conditional dominants. All macrophyte species in areas of low abundance do not meet the dominance criteria. All lists of dominants, including those based on visual estimates of projective cover and its physiognomy, are statistically indistinguishable (p = 0.55–0.92, by pairs of lists) and highly similar (Bray-Curtis index 0.80–0.95, Jacquard index 0.65–0.87), with one exception for the list identified by the method of ranking for the average projective cover (indices of similarity with other lists: 0.68–0.71 by Bray-Curtis, 0.46–0.56 by Jacquard). This visual method of projective cover assessment is combined with the procedure of species dividing to dominant and non-dominant groups. Quantitative criteria of projective cover and biomass, by species (thresholds 0.2 and 1.0 kg/m3, respectively) are used for dividing on cenotic and landscape levels and ranking with Brotskaya-Zenkevich index and its modification for projective cover is used for dividing on regional level. Visual methods are available for verification, but the lists of dominants based on visual and instrumental assessments should be mutually verified.


2020 ◽  
pp. 35-46
Author(s):  
Hugo Cabral

Although there are many studies that analyse and describe the distribution patterns of diverse organisms in South America at different scales, Paraguay has been poorly assessed from a biogeographic point of view. Some of the available contributions on the biogeography of Paraguay are based on different taxonomic groups, such as mammals, birds, reptiles, and plants, describing relationships between species and their habitats by using indices of similarity and cluster analysis. The main objective of this contribution is to identify areas of endemism based on the distribution of the 87 amphibian species known from Paraguay, and to compare the results with the three schemes of ecoregion proposed for the country. Eight areas of endemism were identified at different size of grids/scales, congruent with Dry Chaco, Atlantic Forest, Cerrado, Grasslands of Mesopotamia, Ñeembucú, and the Great American Chaco ecoregions.


2019 ◽  
Vol 32 (6) ◽  
pp. 956-964 ◽  
Author(s):  
Martina Riberto ◽  
Gorana Pobric ◽  
Deborah Talmi

AbstractEmotional similarity refers to the tendency to group stimuli together because they evoke the same feelings in us. The majority of research on similarity perception that has been conducted to date has focused on non-emotional stimuli. Different models have been proposed to explain how we represent semantic concepts, and judge the similarity among them. They are supported from behavioural and neural evidence, often combined by using Multivariate Pattern Analyses. By contrast, less is known about the cognitive and neural mechanisms underlying the judgement of similarity between real-life emotional experiences. This review summarizes the major findings, debates and limitations in the semantic similarity literature. They will serve as background to the emotional facet of similarity that will be the focus of this review. A multi-modal and overarching approach, which relates different levels of neuroscientific explanation (i.e., computational, algorithmic and implementation), would be the key to further unveil what makes emotional experiences similar to each other.


2013 ◽  
Vol 59 (5) ◽  
pp. 591-599
Author(s):  
I.V. Fedyushkina ◽  
I.V. Romero Reyes ◽  
A.A. Lagunin ◽  
V.S. Skvortsov

The several predictive models based on two well-known methods PASS and SIMCA were created. These models predict a type of physiological response of steroid compounds binding to nuclear receptors of steroid hormones. We considered 10 variants: the agonists and the antagonists of estrogen, progesterone, androgen, glucocorticoid and mineralocorticoid receptors respectively. Two different sets of descriptors were used during SIMCA (the Dragon descriptors and indices of similarity). The results of discriminant analysis are good enough with average accuracy of 80-85%.


2012 ◽  
Vol 54 (2) ◽  
pp. 189-198
Author(s):  
Ahmed N. Albatineh ◽  
Hafiz M.R. Khan ◽  
Magdalena Niewiadomska-Bugaj

2012 ◽  
Vol 64 (4) ◽  
pp. 1523-1531 ◽  
Author(s):  
Snezana Pesic

Artificial stagnant aquatic ecosystems such as reservoirs, are suitable for monitoring the succession of biocenoses because they are usually formed by rearrangement of the former current river ecosystems. The weevil assembly, as part of such a dynamic biocenose, develops following host macrophytes. In the frame of weevil fauna studies realized during 2001 and 2002 in wet habitats beside four artificial lakes in Central Serbia (Gruza, Grosnica, Sumarice and Bubanj), the aquatic adults from 13 species, divided into two families, Eryrhinidae (Tanysphyrus lemnae and Notaris scirpi) and Curculionidae (Bagous bagdatensis, B. collignensis, B. lutulentus, Pelenomus canaliculatus, P. comari, P. waltoni, Phytobius leucogaster, Rhinoncus castor, R. inconspectus, R. pericarpius and R. perpendicularis), were collected. The quantitative and qualitative picture of the studied aquatic weevil assemblies, as well as indices of similarity among them, are given and related to the dimensions and ecological characteristics of studied aquatic systems (particularly the level of eutrophication).


2010 ◽  
Vol 3 (2) ◽  
pp. 34-37 ◽  
Author(s):  
Marco Jacometto Marchi ◽  
Gerson Azulim Müller ◽  
Carlos Brisola Marcondes

Foram coletadas espécies de mosquitos antropofílicas em duas áreas de Mata Atlântica onde será implantada uma Unidade de Conservação no município de Itapema-SC. O objetivo desse estudo foi analisar o nível de preservação de duas áreas da Mata Atlântica através da composição da fauna de Culicidae. A diversidade de espécies mostrou-se semelhante nos dois locais de amostragem (Dm=4,02 na Praia Grossa e Dm = 4,04 em São Paulinho). O índice de similaridade entre as duas áreas foi: CCs = 0,57 e CMH = 0,07. O índice de dominância de Simpson foi de 0,63 para a Praia Grossa e 0,31 para São Paulinho. A maior abundância de Anopheles cruzii Dyar & Knabe Culex (Microculex) (táxons relacionados a áreas preservadas) em São Paulinho e de Ochlerotatus scapularis (Rondani) e Psorophora ferox (Humboldt) (táxons relacionados a áreas degradadas) na Praia Grossa sugere que a primeira área é mais preservada do que a segunda. Mosquitoes (Diptera: Culicidae) of a Future Conservation Unit in the Area of Atlantic Forest in Southern Brazil. Abstract. Anthropophilic mosquitoes were collected in two areas of the Atlantic Forest wich will constitute a Conservation Unit in the municipality of Itapema-SC. The aim of this study was to analyze the level of preservation of two areas of Atlantic Forest trough the composition of the Culicidae fauna. Species diversity was similar in both sampling sites (Dm = 4.02 in Praia Grossa and Dm = 4.04 in São Paulinho). Indices of similarity between the two areas were: CCs = 0.57 and CMH = 0.07. The Simpson’s dominance index was 0.63 in Praia Grossa and 0.31 in São Paulinho. The higher abundance of Anopheles cruzii Dyar & Knaband Culex (Microculex) (taxa related to preserved area) in São Paulinho and Ochlerotatus scapularis (Rondani) and Psorophora ferox (Humboldt) (taxa related to degraded area) in Praia Grossa suggests that the first area is more preserved than the last.


2005 ◽  
Vol 360 (1462) ◽  
pp. 1825-1834 ◽  
Author(s):  
M. Alex Smith ◽  
Brian L Fisher ◽  
Paul D.N Hebert

The role of DNA barcoding as a tool to accelerate the inventory and analysis of diversity for hyperdiverse arthropods is tested using ants in Madagascar. We demonstrate how DNA barcoding helps address the failure of current inventory methods to rapidly respond to pressing biodiversity needs, specifically in the assessment of richness and turnover across landscapes with hyperdiverse taxa. In a comparison of inventories at four localities in northern Madagascar, patterns of richness were not significantly different when richness was determined using morphological taxonomy (morphospecies) or sequence divergence thresholds (Molecular Operational Taxonomic Unit(s); MOTU). However, sequence-based methods tended to yield greater richness and significantly lower indices of similarity than morphological taxonomy. MOTU determined using our molecular technique were a remarkably local phenomenon—indicative of highly restricted dispersal and/or long-term isolation. In cases where molecular and morphological methods differed in their assignment of individuals to categories, the morphological estimate was always more conservative than the molecular estimate. In those cases where morphospecies descriptions collapsed distinct molecular groups, sequence divergences of 16% (on average) were contained within the same morphospecies. Such high divergences highlight taxa for further detailed genetic, morphological, life history, and behavioral studies.


1974 ◽  
Vol 11 (01) ◽  
pp. 32-42 ◽  
Author(s):  
Annette J. Dobson

It is common to represent taxonomic hierarchies of related objects (such as similar plant or animal species or languages of the same family) by rooted trees with labelled terminal vertices which represent the objects. The multivariate data comparing numerous characteristics of the objects is first reduced to indices of similarity (or more often of dissimilarity) between each pair of objects. These are used to classify the objects into groups which are then depicted on a tree. This paper shows that an unrooted tree with labelled terminal vertices may provide a better representation of the relationships between the objects because the similarity indices are required to conform to fewer restrictions. Also for a given number of terminal vertices, there are fewer unrooted than rooted trees so that studies using probability distributions of trees or seeking the most suitable tree to represent the data are more practicable.


1974 ◽  
Vol 11 (1) ◽  
pp. 32-42 ◽  
Author(s):  
Annette J. Dobson

It is common to represent taxonomic hierarchies of related objects (such as similar plant or animal species or languages of the same family) by rooted trees with labelled terminal vertices which represent the objects. The multivariate data comparing numerous characteristics of the objects is first reduced to indices of similarity (or more often of dissimilarity) between each pair of objects. These are used to classify the objects into groups which are then depicted on a tree.This paper shows that an unrooted tree with labelled terminal vertices may provide a better representation of the relationships between the objects because the similarity indices are required to conform to fewer restrictions. Also for a given number of terminal vertices, there are fewer unrooted than rooted trees so that studies using probability distributions of trees or seeking the most suitable tree to represent the data are more practicable.


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