Search results for "Variation"
showing 10 items of 2124 documents
Evaluation of the Complexity of Myocardial Activation During Ventricular Fibrillation. An Experimental Study
2013
A B S T R A C T Introduction and objectives: An experimental model is used to analyze the characteristics of ventricular fibrillation in situations of variable complexity, establishing relationships among the data produced by different methods for analyzing the arrhythmia. Methods: In 27 isolated rabbit heart preparations studied under the action of drugs (propranolol and KB-R7943) or physical procedures (stretching) that produce different degrees of change in the complexity of myocardial activation during ventricular fibrillation, use was made of spectral, morphological, and mapping techniques to process the recordings obtained with epicardial multielectrodes. Results: The complexity of ve…
Molecular analysis suggests that recent Citrus tristeza virus outbreaks in Italy were originated by at least two independent introductions
2005
Citrus tristeza virus (CTV) is the causal agent of the most important virus disease of citrus. Numerous CTV isolates differing in biological and molecular characteristics have been reported worldwide. Recently, CTV was detected in Italy in several citrus crops from three separate areas: (1) Cassibile, province of Syracuse; (2) Massafra, province of Taranto; and (3) Belpasso, province of Catania. CTV isolates from Massafra and Cassibile were mild, whereas isolates from Belpasso induced severe symptoms. To study the genetic variation of CTV populations of these areas, 150 samples per area were examined by single strand conformation polymorphism (SSCP) and nucleotide sequence analysis of CTV g…
Reproducibility and Daytime-Dependent Changes of Corneal Epithelial Thickness and Whole Corneal Thickness Measured With Fourier Domain Optical Cohere…
2016
To evaluate the reproducibility of Fourier domain anterior segment optical coherence tomography (RTVue) based on repeated measurements of corneal thickness (CT) and epithelial thickness (ET) and to test daytime-dependent changes of these parameters.Twenty-three eyes from 23 healthy volunteers were included in this prospective study. Three clinical observers performed 3 consecutive measurements each of CT and ET in 3 sessions using RTVue, resulting in 9 measurements per session. Session 1 was performed at 9 AM ± 1 hour, session 2 at 4 PM ± 1 hour on the same day, and session 3 at 9 AM ± 1 hour 2 days later. CT and ET were assessed in 9 areas: corneal vertex, 4 paracentral zones, and 4 periph…
Sampling and repeatability in the evaluation of hepatitis C virus genetic variability.
2003
Among the experimental techniques available to study the genetic variability of RNA virus populations, the most informative involve reverse transcription (RT), amplification, cloning and sequencing. The effects of several aspects of these techniques on the estimation of genetic variability in a virus population were analysed. Hepatitis C virus populations from four patients were examined. For each patient, ten series of data derived from independent PCR amplifications of a single RT reaction were obtained. The sample size of each data set was 10 sequences (in nine series) and 100 sequences (in one series). An additional data set derived from an independent RT reaction (about 10 sequences) p…
Early motor development and later language and reading skills in children at risk of familial dyslexia.
2005
Relationships between early motor development and language and reading skills were studied in 154 children, of whom 75 had familial risk of dyslexia (37 females, 38 males; at-risk group) and 79 constituted a control group (32 females, 47 males). Motor development was assessed by a structured parental questionnaire during the child's first year of life. Vocabulary and inflectional morphology skills were used as early indicators of language skills at 3 years 6 months and 5 years or 5 years 6 months of age, and reading speed was used as a later indicator of reading skills at 7 years of age. The same subgroups as in our earlier study (in which the cluster analysis was described) were used in th…
THE EFFECTS OF MATING SYSTEM AND GENETIC VARIABILITY ON SUSCEPTIBILITY TO TREMATODE PARASITES IN A FRESHWATER SNAIL, LYMNAEA STAGNALIS
2004
The amount and distribution of genetic variability in host populations can have significant effects on the outcome of host-parasite interactions. We studied the effect of mating system and genetic variability on susceptibility of Lymnaea stagnalis snails to trematode parasites. Mating system of snails from eight populations differing in the amount of genetic variability was manipulated, and self- and cross-fertilized offspring were exposed to naturally occurring trematode parasites in a controlled lake experiment. Susceptibility of snails varied between populations, but mating-system treatment did not have a significant effect. Heterozygosity of snails was negatively correlated with the pro…
A new approach to register variation : the missing link
2006
El objetivo del presente artículo es dirigir la atención de los especialistas hacia la noción de registro lingüístico con el fin de promover nuevos métodos de analizar los registros actuales. A pesar de la falta de claridad en su definición y la frecuente confusión con otros tipos de variación lingüística, el movimiento a través de toda la gama de registros es uno de los instrumentos comunicativos más efectivos y de uso más frecuente que posee una lengua para adaptarse a los diversos entornos privados, sociales y profesionales. Sin embargo, este movimiento es uno de los mecanismos más difíciles de percibir, aprender y utilizar correctamente, sobre todo en el caso de hablantes extranjeros y …
On State Constrained Optimal Shape Design Problems
1987
This paper is concerned with the following optimal design problem with constraints both on the state and on the control: $$MinimizeJ(y,u)$$ (P) subject to $$A\left( u \right)y + \partial \varphi \left( y \right) \mathrel\backepsilon Bu + f,$$ (1.1) $$y \in K,$$ (1.2) $$u \in {U_{ad}}.$$ (1.3)
Genetic risk profiles for Alzheimer's disease: Integration of APOE genotype and variants that up-regulate inflammation
2007
BACKGROUND: A number of studies associate Alzheimer's disease with APOE polymorphism and alleles which favor the increased expression of immunological mediators such as cytokines or acute phase proteins. We integrated this information to better define risk and determine the relative importance of APOE and immunological mediators. METHODS: We investigated functional gene variants for APOE, IL-10 (3 loci), ACT (2 loci), HMGCR, IL-1alpha, IL-1beta, TNF-alpha, IFN-gamma, and IL-6 found for 260 AD patients and 190 controls enrolled in Northern Italy. A fuzzy latent classification approach, namely grade-of-membership analysis (GoM), was taken to identify extreme pure type risk sets, or profiles. …
Population history in social spiders repeated: colony structure and lineage evolution inStegodyphus mimosarum(Eresidae)
2009
Social cooperative spiders from diverse taxonomic families share life-history and demographic traits, including highly inbred colony structure. The combination of traits suggests constrained pathways for social evolution in spiders. The genus Stegodyphus has three independently evolved social species, which can be used as replicate samples to analyse population constraints in evolutionary time. We tested colony structure and population history of the social S. mimosarum from South and East Africa using mitochondrial DNA variation, and we compared the results to published data for the independently evolved social congener S. dumicola. S. mimosarum had many and diverse haplotypes (5-7% sequen…