Genetic diversity studies using the RAPD technique were carried out in a set of 103 olive cultivars from the World Germplasm Bank of the Centro de Investigación y Formación Agraria (CIFA) "Alameda ...del Obispo" in Cordoba (Spain). A total of 126 polymorphisms (6.0 polymorphic markers per primer) out of 135 reproducible products (6.4 fragments per primer) were obtained from the 21 primers used. The number of bands per primer ranged from 4 to 11, whereas the number of polymorphic bands ranged from 3 to 10, corresponding to 83% of the amplification products. The dendrogram based on unweighted pair-group cluster analysis using Jaccard's index includes three major groups according to their origin: (1) cultivars from the Eastern and Central Mediterranean areas, (2) some Italian and Spanish cultivars, and (3) cultivars from the Western Mediterranean zone. The pattern of genetic variation among olive cultivars from three different Mediterranean zones (West, Centre and East) was analysed by means of the analysis of molecular variance (AMOVA). Although most of the genetic diversity was attributable to differences of cultivars within Mediterranean zones (96.86%) significant phi-values among zones (phi(st) = 0.031; p < 0.001) suggested the existence of phenotypic differentiation. Furthermore, the AMOVA analysis was used to partition the phenotypic variation of Spain, Italy (Western region), Greece and Turkey (Eastern region) into four categories: among regions, among countries (within regions), within countries, and among and within countries of each region. Most of the genetic diversity was attributable to differences among genotypes within a country. These results are consistent with the predominantly allogamous nature of Olea europaea L. species. This paper indicates the importance of the study of the amount and distribution of genetic diversity for a better exploration of olive genetic resources and the design of plant breeding programmes.
Abstract
The development and integration of an electroencephalographic signal acquisition and stimulation system is proposed to support the detection of pathologies related to the optic nerve. It is ...based on the extraction and analysis of a characteristic waveform called Visual Evoked Potential immersed in the electroencephalographic register. Some parameters of this potential, as latency and amplitude, are affected by the optic nerve pathologies, and measurement of changes from its normal states can be used as indicators of abnormal visual functionality of a patient. The proposed stimulation system can generate Visual Evoked Potential and multifocal Visual Evoked Potential which can help to locate pathologies in different areas of the visual field.
This paper addresses some questions which have arisen from the use of the Sérsic r1/n law in modelling the luminosity profiles of early-type galaxies. The first issue deals with the trend between the ...half-light radius and the structural parameter n. We show that the correlation between these two parameters is not only real, but also a natural consequence from the previous relations found to exist between the model-independent parameters: total luminosity, effective radius and effective surface brightness. We also define a new galaxy concentration index which is largely independent of the image exposure depth, and is shown to be monotonically related with n. The second question concerns the curious coincidence between the form of the Fundamental Plane and the coupling between 〈I〉e and re when modelling a light profile. We explain, through a mathematical analysis of the Sérsic law, why the quantity re〈I〉e0.7 appears almost constant for an individual galaxy, regardless of the value of n (over a large range) adopted in the fit to the light profile. Consequently, Fundamental Planes of the form re〈I〉e0.7∝σ0x (for any x, and where σ0 is the central galaxy velocity dispersion) are insensitive to galaxy structure. Finally, we address the problematic issue of the use of model-dependent galaxy light-profile parameters versus model-independent quantities for the half-light radii, mean surface brightness and total galaxy magnitude. The former implicitly assume that the light-profile model can be extrapolated to infinity, while the latter quantities, in general, are derived from a signal-to-noise ratio truncated profile. We quantify (mathematically) how these parameters change as one reduces the outer radius of an r1/n profile, and reveal how these can vary substantially when n≥4.
Satellites around massive galaxies since z∼ 2 Mármol-Queraltó, E; Trujillo, I; Pérez-González, P. G ...
Monthly notices of the Royal Astronomical Society,
20/May , Letnik:
422, Številka:
3
Journal Article
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The accretion of minor satellites has been postulated as the most likely mechanism to explain the significant size evolution of massive galaxies over cosmic time. Using a sample of 629 massive (M
...star∼ 1011 M⊙) galaxies from the near-infrared Palomar/DEEP-2 survey, we explore what fraction of these objects have satellites with 0.01 < M
sat/M
central < 1 (1:100) up to z= 1 and what fraction have satellites with 0.1 < M
sat/M
central < 1 (1:10) up to z= 2 within a projected radial distance of 100 kpc. We find that the fraction of massive galaxies with satellites, after background correction, remains basically constant and close to 30 per cent for satellites with a mass ratio down to 1:100 up to z= 1, and close to 15 per cent for satellites with a 1:10 mass ratio up to z= 2. The family of spheroid-like massive galaxies presents a 2-3 times larger fraction of objects with satellites than the group of disc-like massive galaxies. A crude estimation of the number of 1:3 mergers a massive spheroid-like galaxy has experienced since z∼ 2 is around 2. For a disc-like galaxy this number decreases to ∼1.
Swietenia macrophylla is a tropical timber species of ecological and economic importance. However, its slow vegetative growth and root development in nurseries strongly limit its production. This ...study evaluated the effect of 10 rhizobacteria strains during the early stages of production of S. macrophylla. Superficially disinfected seeds were inoculated with rhizobacteria under commercial nursery conditions. Inoculation was complemented by initial fertilization without growth regulators, fungicides, or bactericides. The results indicate that the rhizobacteria strains induce different responses in plants. Significant differences in plant biomass and root architecture were found. Treatments inoculated with Bacillus sp., Bacillus polyfermenticus, and Bacillus siamensis strains; showed an increase of up to 41% (dry weight). Plants increased root biomass by 30% when inoculated with S. siamensis. All inoculated strains were identified as members of the genus Bacillus spp., and their presence three months after inoculation was assessed by 16S rRNA gene-based amplicon massive sequencing. We found that Bacillus sp. genus was only present in inoculated treatments, suggesting that inoculated bacteria could establish themselves successfully as part of the microbiota. These results support the advantages of using PGPRs in commercial tropical tree production.
We characterize the kinematics, morphology, stellar populations and star formation histories of a sample of massive compact galaxies in the nearby Universe, which might provide a closer look at the ...nature of their high-redshift (z >rsim 1.0) massive counterparts. We find that nearby compact massive objects show elongated morphologies and are fast rotators. New high-quality long-slit spectra show that they have young mean luminosity-weighted ages (
2 Gyr) and metallicities solar or above (Z/H >rsim 0.0). No significant stellar population gradients are found. The analysis of their star formation histories suggests that these objects have experienced recently enormous bursts which, in some cases, represent unprecedented large fractions of their total stellar mass. These galaxies seem to be truly unique, as they do not follow the characteristic kinematical and stellar population patterns of present-day massive ellipticals, spirals or even dwarfs.
Twelve simple sequence repeat (SSR) loci were used to differentiate among 118 cultivars sampled in several countries of the Mediterranean basin and to analyze the genetic structure of olive cultivar ...gene pools. The markers were found to have high discrimination power. On average, with a single assay it was possible to discriminate 96% of the pairwise comparisons and, with a combination of 3 loci, virtually all cultivars were distinguished. The SSR markers were also tested for their ability to assign cultivars to their geographic population of origin. A selection of 6 loci was found to maximize assignment accuracy, correctly reallocating up to 75.4% of cultivars to their population of origin. Because of the confusion surrounding the origin of most olive cultivars, their molecular identification and ascertainment of origin will be extremely useful for germplasm management and breeding.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Dengue fever is an increasing health problem in tropical and subtropical regions. During 2010 in Medellin, the younger population presented a particularly high dengue incidence rate. This study ...estimated dengue virus (DENV) transmission in schoolchildren (aged 5–19 years) in Medellin from 2010 to 2012. A longitudinal serological survey (IgG) and spatial analysis were conducted to determine the distribution of DENV seroprevalence. A total of 4,385 schoolchildren participated for at least one year. Dengue seroprevalence significantly increased during the studied period (53.8% to 64.6%; p<0.001). A significantly higher seroconversion rate was observed in 2010-2011 (16.8%) compared to 2011-2012 (7.8%). Multivariate regression analysis showed that the main factor associated with the seroprevalence was the aging. Furthermore, in 2010, patients with high socioeconomic status presented a lower risk. Predominant multitypic and DENV4 monotypic antibody responses were demonstrated. Geostatistical analysis evidenced a temporal clustering distribution of DENV seroprevalence in 2010. Population density and Ae. aegypti House Index were significantly correlated with the observed pattern. This study revealed high DENV transmission in schoolchildren determined as “sentinel population.” High DENV risk was found in districts with combined poorly socioeconomic conditions and densest human and mosquito populations. These findings may allow to target population for effective prevention and vaccination campaigns.
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