Search results for " Variation"
showing 10 items of 1712 documents
Mechanically-based approach to non-local elasticity: Variational principles
2010
Abstract The mechanically-based approach to non-local elastic continuum, will be captured through variational calculus, based on the assumptions that non-adjacent elements of the solid may exchange central body forces, monotonically decreasing with their interdistance, depending on the relative displacement, and on the volume products. Such a mechanical model is investigated introducing primarily the dual state variables by means of the virtual work principle. The constitutive relations between dual variables are introduced defining a proper, convex, potential energy. It is proved that the solution of the elastic problem corresponds to a global minimum of the potential energy functional. Mo…
An initial comparative map of copy number variations in the goat (Capra hircus) genome
2010
Abstract Background The goat (Capra hircus) represents one of the most important farm animal species. It is reared in all continents with an estimated world population of about 800 million of animals. Despite its importance, studies on the goat genome are still in their infancy compared to those in other farm animal species. Comparative mapping between cattle and goat showed only a few rearrangements in agreement with the similarity of chromosome banding. We carried out a cross species cattle-goat array comparative genome hybridization (aCGH) experiment in order to identify copy number variations (CNVs) in the goat genome analysing animals of different breeds (Saanen, Camosciata delle Alpi,…
Seasonal variation in total phenolic content of Dictyopteris polypodioides (Dictyotaceae) and Cystoseira amentacea (Sargassaceae) from the Sicilian c…
2014
This study focuses on the differences in total phenolic content and its seasonal variations in two temperate brown algae, Cystoseira amentacea (C. Agardh) Bory and Dictyopteris polypodioides (A.P. De Candolle) J.V. Lamouroux, inhabiting respectively the infralittoral fringe and the upper infralittoral zone. Phenolic compounds are secondary metabolites, found in almost all brown algal orders, that function as defense against grazers, epiphytes and UV radiation. Total phenolic content was determined colorimetrically with the Folin-Ciocalteu reagent. Results showed significant differences in total phenol content between D. polypodioides and C. amentacea with higher values observed in the first…
Comparative analysis of variation and selection in the HCV genome
2016
AbstractGenotype 1 of the hepatitis C virus (HCV) is the most prevalent of the variants of this virus. Its two main subtypes, HCV-1a and HCV-1b, are associated to differences in epidemic features and risk groups, despite sharing similar features in most biological properties. We have analyzed the impact of positive selection on the evolution of these variants using complete genome coding regions, and compared the levels of genetic variability and the distribution of positively selected sites. We have also compared the distributions of positively selected and conserved sites considering different factors such as RNA secondary structure, the presence of different epitopes (antibody, CD4 and C…
Assigning Elephant Ivory with Stable Isotopes
2016
The international ivory trade remains one of the world’s most controversial wildlife trade issues. One of the main arguments for the trade prohibition is the fact that it is very difficult to distinguish legal from illegal ivory in the markets, so that the legal ivory trade would provide a perfect cover for smuggling. The purpose of this study was to analyze the variability of isotope ratios in ivory samples from Appendix I and II elephant populations in Africa to validate their potential for forensic purposes more quantitatively. We selected a subset of 293 data of ivory samples from the www.ivoryid.org database that stores isotopic ratios of δ13C, δ15N, δ18O, δ2H, and δ34S from more than …
Genetic variation and evolutionary analysis of Cucumber mosaic virus in medicinal, aromatic and ornamental plants from Northern Italy
2011
The genetic variation and evolution of Cucumber mosaic virus (CMV) (1) infecting aromatic, medicinal and ornamental plants in Northern Italy were studied by sequence analysis of the movement protein gene and comparison with equivalent sequences of isolates from other countries. Comparison of nonsynonymous and synonymous substitutions at each codon suggested that 30% of amino acid sites were under negative selection and only one was under positive selection. Phylogenetic inference, nucleotide diversity estimation, neutrality tests and genetic differentiation analysis revealed a high nucleotide diversity of CMV in Northern Italy with respect to areas of other countries [1,2] and suggested tha…
Intronic Variant in CNTNAP2 Gene in a Boy With Remarkable Conduct Disorder, Minor Facial Features, Mild Intellectual Disability, and Seizures
2020
Introduction: Mutations in the contactin-associated protein-like 2 (CNTNAP2) gene (MIM#604569) encoding for CASPR2, a cell adhesion protein of the neurexin family, are known to be associated with autism, intellectual disability, and other neuropsychiatric disorders. A set of intronic deletions of CNTNAP2 gene has also been suggested to have a causative role in individuals with a wide phenotypic spectrum, including Pitt-Hopkins syndrome, cortical dysplasia–focal epilepsy syndrome, Tourette syndrome, language dysfunction, and abnormal behavioral manifestations. Case presentation: A 10-years-old boy was referred to the hospital with mild intellectual disability and language impairment. Moreove…
A Comparative Analysis of Copy Number Variation of the Sheep and Goat Genomes
2010
Recent studies have shown that copy number variants (CNVs) are important sources of variability of mammalian genomes. We applied a cross species array comparative genome hybridization (aCGH) experiment using as reference the cattle genome to investigate, for the first time, variability in the sheep and goat genomes derived from copy number variation and identified 431 and 358 CNVs, respectively. A comparison of these results to those obtained in other mammals for similar experiments is reported. The identified CNVs could be important in determining phenotypic and production differences between and within breeds. Further studies will be carried out to evaluate the identified CNVs from both f…
Diurnal Variation of Non-Arboreal Pollen in the Air in Finland
1981
Abstract This study was carried out in Jyvaskyla and Turku, in central and southern Finland, with Burkard spore traps. The average diurnal variation of all non-arboreal pollen types found in sufficient quantities is presented. A high concentration of Artemisia pollen lasting 4–8 hours was found mainly in the morning. The highest concentrations of Brassicaceae, Calluna, Cyperaceae and Rosaceae occurred during the daylight hours, often with no definite peaks. The peak occurrence of Chenopodiaceae, Compositae and Plantago pollen was around 12.00 and of Rumex from 06.00 to 10.00. The diurnal variation of Poaceae pollen varies considerably depending on the species flowering at the time. Peaks oc…
Evidence for cryptic glacial refugia from North American mountain sheep mitochondrial DNA
2006
The separation of populations by ice sheets into large refugia can account for much of the genetic diversity found in present day populations. The evolutionary implications of small glacial refugia have not been as thoroughly explored. To examine refugial origins of North American mountain sheep Ovis spp., we analyzed a 604 bp portion of the mitochondrial DNA (mtDNA) control region from 223 O. dalli and O. canadensis. Major refugia were identified in eastern Beringia and southern North America, and we found evidence for two smaller refugia situated between the Laurentide and Cordilleran glaciers. Our results are the first to demonstrate support for survival of any organism in the latter two…