497 research outputs found
Oligodendroglioma anaplásico en el nervio óptico de un perro
Los gliomas son tumores no neuronales del tejido nervioso. En el Sistema Nervioso Central (SNC) dependiendo de su origen se clasifican en astrocitomas, oligodendrogliomas, tumores mixtos (oligoastrocitomas), ependimomas y papilomas de plexos coroideos. La retina y el nervio óptico pertenecen al SNC. Aunque las neoplasias primarias de la retina y el nervio óptico son bastante infrecuentes, son los meningiomas los tumores primarios más comunes siendo los gliomas más raros
WALDIM: A code for the dimensionality analysis of magnetotelluric data using the Rotational Invariants of the Magnetotelluric Tensor
In the magnetotelluric (MT) method, the analysis of geoelectric dimensionality has acquired special importance in the last years, because numerical codes have made it possible to model and invert data using either one-dimensional (1D), two-dimensional (2D) or three-dimensional (3D) approaches. We present a FORTRAN code termed WALDIM to perform the dimensionality analysis of a set of MT data, according to the WAL rotational invariants criteria. These criteria are based on the possible annulment of the invariants of the MT tensor, which allow retrieval of as much information as possible from this tensor, without taking any a priori dimensionality assumption. When determining the dimensionality of real and therefore noisy data, two problems arise. The first is due to the data errors, which propagate into the invariants values, and therefore, to the determination of the dimensionality. The second is the fact that the invariants are rarely precisely zero, and the definition of a threshold is necessary. To solve these problems, WALDIM takes into account the data errors. Additionally, the dimensionality results can be grouped into frequency bands. Thus, we provide a software utility that allows providing a robust description of the dimensionality, and the parameters necessary for data correction prior to modeling. Given its completeness at analyzing the MT tensor for both individual and bands of frequencies, this code is meant to be a practical tool for MT data analysis
Mapping quantitative trait loci for kernel composition in almond
Background
Almond breeding is increasingly taking into account kernel quality as a breeding objective. Information on the parameters to be considered in evaluating almond quality, such as protein and oil content, as well as oleic acid and tocopherol concentration, has been recently compiled. The genetic control of these traits has not yet been studied in almond, although this information would improve the efficiency of almond breeding programs.
Results
A map with 56 simple sequence repeat or microsatellite (SSR) markers was constructed for an almond population showing a wide range of variability for the chemical components of the almond kernel. A total of 12 putative quantitative trait loci (QTL) controlling these chemical traits have been detected in this analysis, corresponding to seven genomic regions of the eight almond linkage groups (LG). Some QTL were clustered in the same region or shared the same molecular markers, according to the correlations already found between the chemical traits. The logarithm of the odds (LOD) values for any given trait ranged from 2.12 to 4.87, explaining from 11.0 to 33.1 % of the phenotypic variance of the trait.
Conclusions
The results produced in the study offer the opportunity to include the new genetic information in almond breeding programs. Increases in the positive traits of kernel quality may be looked for simultaneously whenever they are genetically independent, even if they are negatively correlated. We have provided the first genetic framework for the chemical components of the almond kernel, with twelve QTL in agreement with the large number of genes controlling their metabolism
Dimensionality imprint of electrical anisotropy in magnetotelluric responses.
Dimensionality analysis of magnetotelluric data is a common procedure for inferring the main properties of the geoelectric structures of the subsurface such as the strike direction or the presence of superficial distorting bodies, and enables the most appropriate modeling approach (1D, 2D or 3D) to be determined. Most of the methods currently used assume that the electrical conductivity of individual parts of a structure is isotropic, although some traces of anisotropy in data responses can be recognized. In this paper we investigate the imprints of anisotropic media responses in dimensionality analysis using rotational invariants of the magnetotelluric tensor. We show results for responses generated from 2D synthetic anisotropic models and for field data that have been interpreted as showing the effects of electrical anisotropy in parts of the subsurface structure. As a result of this study we extend the WAL dimensionality criteria to include extra conditions that allow anisotropic media to be distinguished from 2D isotropic ones. The new conditions require the analysis of the strike directions obtained and take into account the overall behavior of different sites in a survey
Improving Bahr's invariant parameters using the WAL approach.
In the magnetotelluric technique, several methods exist to perform dimensionality analysis of the measured data using rotational invariants of the impedance tensor. Among these methods there is some dilemma on the different criteria established, which sometimes lead to non-equivalent interpretation
Association mapping for kernel phytosterol content in almond
Almond kernels are a rich source of phytosterols, which are important compounds for human nutrition. The genetic control of phytosterol content has not yet been documented in almond. Association mapping (AM), also known as linkage disequilibrium (LD), was applied to an almond germplasm collection in order to provide new insight into the genetic control of total and individual sterol contents in kernels. Population structure analysis grouped the accessions into two principal groups, the Mediterranean and the non-Mediterranean. There was a strong subpopulation structure with LD decaying with increasing genetic distance, resulting in lower levels of LD between more distant markers. A significant impact of population structure on LD in the almond cultivar groups was observed. The mean r2-value for all intra-chromosomal loci pairs was 0.040, whereas, the r2 for the inter-chromosomal loci pairs was 0.036. For analysis of association between the markers and phenotypic traits five models were tested. The mixed linear model (MLM) approach using co-ancestry values from population structure and kinship estimates (K model) as covariates identified a maximum of 13 significant associations. Most of the associations found appeared to map within the interval where many candidate genes involved in the sterol biosynthesis pathway are predicted in the peach genome. These findings provide a valuable foundation for quality gene identification and molecular marker assisted breeding in almond.Publishe
Identificación de regiones genómicas de almendro en progenies de hÃbridos interespecÃficos (abstract)
La mejora genética de portainjertos tiene por objetivo obtener diferentes hÃbridos interespecÃficos
y combinar la tolerancia a estreses abióticos. Distintos cruzamientos entre almendro, melocotonero
y ciruelo se están estudiado para su adaptación a un amplio rango de condiciones
edafoclimáticas. En este estudio analizamos 49 individuos de cuatro progenies de hÃbridos interespccÃficos
de tres especies y sus parentales (dos ciruelos mirobolanes: 'P.2175' y 'P.2980'; los
hÃbridos almendro x melocotonero 'Garnem' y 'Felinem'; el almendro 'Garfi'; y el melocotonero
'Nemared'). Se analizaron 48 SSRs polimórficos en los parentales a lo largo de los 8 grupos de
ligamiento a partir de varios mapas de referencia de Prunus. El dendrograma UPGMA generado
con la variabilidad genética observada, clasificó los genotipos en 5 grupos, permitiéndonos diferenciar
en nuestras progenies las regiones genómicas del almendro entre las regiones del melocotonero
y el ciruelo. En estas regiones se va a llevar a cabo el estudio de distintos genes implicados
en la tolerancia a la sequÃa, puesto que el almendro es más tolerante que las otras dos especies,
melocotonero y cirueloPublishe
Identification of almond genomic regions in four 3-way interspecific hybrid progenies (abstract)
Publishe
Self-compatibility in Prunus species : diversity of mutations
Self-compatibility (SC) is an interesting horticultural trait. Molecular approaches
have been recently applied to the elucidation of the interacting pollen-pistil mechanism
and to the identification of the genes involved in pistil-pollen recognition. Both
mutations of the pistil S-RNases and the pollen SFBs have been reported to explain the
changes in the S allele expression. Stylar-part mutations have revealed that ribonuclease
activity of the S-RNases is required to inhibit pollen growth. A defective function of the
pollen may also give rise to SC. Breakdown of SI has also been associated with
mutations affecting modifier loci unlinked to the S-locus. Additionally, a double
phenotypic expression of the same genotype has been observed. The nature of these
different mutations has only been identified in a few cases, including deletions,
insertions, shift mutations and, more recently, epigenetic changes.EUCARPIA. European Association for Research on Plant Breedin
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