Una generalización de los procesos estocásticos log-normal y de Gompertz como procesos de Itô

Estudiamos una ecuación diferencial estocástica de Itô que es una generalización de los modelos estocásticos logarítmico-normal y de Gomperz. Reducimos la ecuación mediante una transformación de cambio de estado a otra que resulta una generalización de la ecuación de Langevin, que rige el proceso de Uhlenbeck-Ornstein. A partir de la expresión analítica de las soluciones de ésta y de la original estudiamos las características estadísticas de ambos procesos solución, en particular los momentos de las distribuciones finito dimensionales, sus funciones de densidad de transición, las distribuciones límite y las condiciones de estacionariedad, obteniendo que la expresada generalización del proceso de U-O es el único proceso Gaussiano, Markoviano y estacionario no centrado en tiempo continuo. Por otra parte, se establece que las potencias del proceso lognormal-Gompertz generalizado satisfacen una E.D.E. del mismo tipo

Differences in muscle enzyme profile and metabolic response to fighting in bulls from one to three years old

The metabolic response to exercise is partially linked to muscle enzyme profile, and both factors might be influenced by ageing. This research aims: 1) To analyze the differences in muscle characteristics of fighting bulls of different ages; and 2) To assess whether the muscle enzyme profile is affected by ageing in the same way it affects other bovine breeds. Muscle biopsies from gluteus medius and semitendinosus muscles were withdrawn immediately after bullfighting, at depths of 3 and 5 cm, from a total of 24 animals, belonging to three age groups: A (1-year-olds; n=6), B (2-year-olds; n=6) and C (3-year-olds; n=12). Muscle concentrations of glycogen, lactate, adenosin triphosphate and glucose-6-P were determined. In addition, activities of citrate synthase, 3-OH-acyl-dehydrogenase, glycogen phosphorylase, lactate dehydrogenase and hexokinase were measured. No significant differences were found between the two analyzed muscles and neither between depths for any of the muscle parameters. Group A showed lower muscle lactate accumulation, with positive correlations between oxidative and glycolytic enzymes, reflecting a balance between both metabolic pathways. Group B was the most oxidative, whereas group C was the most glycolytic. Therefore, muscle oxidative potential achieved its maximum at 2 years of age, whereas the glycolytic capacity increased progressively with ageing. These results are different from those showed by other bovine breeds, with a progressive reduction in oxidative potential from birth. In conclusion, age significantly influences metabolic response to fighting as well as muscle enzyme profile in bulls

An integrative model for media literacy and digital competence in Primary Education

Tras un amplio estudio acercadela formación sobre y con los medios en el marco regulatorio español vigente, se estima oportuno incorporar un modelo integrador, TPACK, para facilitar el desarrollo de actividades para la mejora de la alfabetización mediática con los medios en la Educación Primaria. Para llevar a cabo este trabajo, se optó por un método bajo un enfoque exploratorio y concluyente con metodología cuasi-experimental, realizándose cuestionarios pretest y postest, tras la implementación de los campos de conocimiento que se incluyen en las matrices trabajadas y que dan lugar al desarrollo de actividades de competencia digital, en función del contexto o ecosistema educativo digital, de entre los reconocidos por la UNESCO. Los resultados sobre la valoración didáctica y pedagógica de los profesores, acerca de la confección de los materiales didácticos digitales resultantes, concluyó en la conveniencia y validez de dichas matrices tanto a nivel disciplinar, pedagógico, como en el aprovechamiento tecnológico.After an extensive study on media training in the current Spanish regulatory framework, it is considered appropriate to incorporate an integrative model, TPACK, to facilitate the development of activities for the improvement of media literacy in Primary Education. To carry out this research, a quasi-experimental methodology was chosen and an exploratory and conclusive approach adopted Pre-test and post-test questionnaires were administered after the implementation of the fields of knowledge included in the matrices. These help develop activities to improve students’ digital competence in the different digital education ecosystems recognized by UNESCO. The results regarding teachers’ assessment of the digital teaching materials created point to the validity and suitability of the matrices used, both at the pedagogical and the technological level

Linkage disequilibrium at the APA insecticidal seed protein locus of common bean (Phaseolus vulgaris L.)

Background: An interesting seed protein family with a role in preventing insect herbivory is the multi-gene, APA family encoding the ?-amylase inhibitor, phytohemagglutinin and arcelin proteins of common bean (Phaseolus vulgaris). Variability for this gene family exists and has been exploited to breed for insect resistance. For example, the arcelin locus has been successfully transferred from wild to cultivated common bean genotypes to provide resistance against the bruchid species Zabrotes subfasciatus although the process has been hampered by a lack of genetic tools for and understanding about the locus. In this study, we analyzed linkage disequilibrium (LD) between microsatellite markers at the APA locus and bruchid resistance in a germplasm survey of 105 resistant and susceptible genotypes and compared this with LD in other parts of the genome. Results: Microsatellite allele diversity was found to vary with each of the eight APA-linked markers analyzed, and two markers within the APA locus were found to be diagnostic for bruchid resistance or susceptibility and for the different arcelin alleles inherited from the wild accessions. Arc1 was found to provide higher levels of resistance than Arc5 and the markers in the APA locus were highly associated with resistance showing that introgression of this gene-family from wild beans provides resistance in cultivated beans. LD around the APA locus was found to be intermediate compared to other regions of the genome and the highest LD was found within the APA locus itself for example between the markers PV-atct001 and PV-ag004. Conclusions: We found the APA locus to be an important genetic determinant of bruchid resistance and also found that LD existed mostly within the APA locus but not beyond it. Moderate LD was also found for some other regions of the genome perhaps related to domestication genes. The LD pattern may reflect the introgression of arcelin from the wild into the cultivated background through breeding. LD and association studies for the arcelin gene, linked genes and other members of the APA family are essential for breaking linkage drag while maintaining high levels of bruchid resistance in common bean

Projected multicluster model with Jastrow and linear state dependent correlations for 12≤A≤1612 \leq A \leq 16 nuclei

Variational wave functions based on a Margenau-Brink cluster model with short range and state dependent correlations, and angular momentum projection are obtained for some nuclei with $12 \leq A \leq 16$. The calculations have been carried out starting from the nucleon-nucleon interaction by using the Variational Monte Carlo method. The configuration used consists of three alpha clusters located at the apexes of an equilateral triangle, and an additional cluster, not necessarily of alpha type, forming a tetrahedron. This cluster is located at the top of its height. Short-range and state dependent correlations are included by means of a central Jastrow factor and a linear operatorial correlation factor respectively. Angular momentum projection is performed by using the Peierls-Yoccoz operators. Optimal structures are obtained for all the nuclei studied. Some aspects of our methodology have been tested by comparing with previous calculations carried out without short range correlations. The binding energy, the root mean square radius, and the one- and two-body densities are reported. The effects of correlations on both the energy and the nucleon distribution are analyzed systematically.Comment: 19 pages, 6 figure

Evaluación cuantitativa del riesgo de entrada del virus de la gripe aviar altamente patógeno en la comunidad valenciana por importación de aves vivas

The Region of Valencia has had many imports of live poultry from different countries that have had several outbreaks of Highly Pathogenic Bird flu during their history. The aim of this paper is to do a quantitative assessment of the risk of entry of HPAI in the Region of Valencia and its provinces due to the importation of live poultry, and identify the countries which entail a higher risk. The results indicate that Alicante is the province with more risk and Italy is the country that represents the greatest proportion of risk due to his imports. The probability to introduce the HPAI virus to the Region of Valencia due to life poultry imports is low.En la Comunidad Valenciana (CV) se importa cantidades altas de aves vivas desde países que han sufrido algún brote de influenza aviar altamente patógena (HPAI) a lo largo de su historia. El objetivo de este trabajo es realizar una evaluación cuantitativa del riesgo que hay de que el virus HPAI entre en la CV y sus provincias por importación de aves vivas, e identificar los países desde los que es más probable introducirlo. Los resultados obtenidos muestran a Alicante como la provincia con más probabilidad de sufrir la entrada del virus y a Italia, el país desde donde hay más probabilidad que entre. La probabilidad de introducir el virus HPAI en la CV mediante importaciones de aves vivas es baja

Resistance mechanism to Notch inhibition and combination therapy in human T-cell acute lymphoblastic leukemia.

Gain-of-function mutations in NOTCH1 are among the most frequent genetic alterations in T-cell acute lymphoblastic leukemia (T-ALL), highlighting the Notch signaling pathway as a promising therapeutic target for personalized medicine. Yet, a major limitation for long-term success of targeted therapy is relapse due to tumor heterogeneity or acquired resistance. Thus, we performed a genome-wide CRISPR-Cas9 screen to identify prospective resistance mechanisms to pharmacological NOTCH inhibitors and novel targeted combination therapies to efficiently combat T-ALL. Mutational loss of phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1) causes resistance to Notch inhibition. PIK3R1 deficiency leads to increased PI3K/AKT signaling, which regulates cell cycle and the spliceosome machinery, both at the transcriptional and posttranslational level. Moreover, several therapeutic combinations have been identified, in which simultaneous targeting of the cyclin-dependent kinases 4 and 6 (CDK4/6) and NOTCH proved to be the most efficacious in T-ALL xenotransplantation models

Genetic mapping of microsatellite markers around the arcelin bruchid resistance locus in common bean

The deployment in common beans (Phaseolus vulgaris L.) of arcelin-based bruchid resistance could help reduce post-harvest storage losses to the Mexican bean weevil [(Zabrotes subfasciatus (Boheman)]. Arcelin is a member of the arcelin-phytohemagglutinin-α-amylase inhibitor (APA) family of seed proteins, which has been extensively studied but not widely used in bean breeding programs. The purpose of this study was to evaluate microsatellite markers for genetic analysis of arcelin-based bruchid resistance and to determine the orientation of markers and the rate of recombination around the APA locus. A total of 10 previously developed microsatellites and 22 newly developed markers based on a sequenced BAC from the APA locus were screened for polymorphism and of these 15 were mapped with an F(2) population of 157 individuals resulting from a susceptible × resistant cross of SEQ1006 × RAZ106 that segregated for both the arcelin 1 allele and resistance to the bruchid, Z. subfasciatus. Microsatellites derived from APA gene sequences were linked within 0.8 cM of each other and were placed relative to the rest of the b04 linkage group. In a comparison of genetic to physical distance on the BAC sequence, recombination was found to be moderate with a ratio of 125 kb/cM, but repressed within the APA locus itself. Several markers were predicted to be very effective for genetic studies or marker-assisted selection, based on their significant associations with bruchid resistance and on low adult insect emergence and positions flanking the arcelin and phytohemagglutinin genes

Response of a catalytic reaction to periodic variation of the CO pressure: Increased CO_2 production and dynamic phase transition

We present a kinetic Monte Carlo study of the dynamical response of a Ziff-Gulari-Barshad model for CO oxidation with CO desorption to periodic variation of the CO presure. We use a square-wave periodic pressure variation with parameters that can be tuned to enhance the catalytic activity. We produce evidence that, below a critical value of the desorption rate, the driven system undergoes a dynamic phase transition between a CO_2 productive phase and a nonproductive one at a critical value of the period of the pressure oscillation. At the dynamic phase transition the period-averged CO_2 production rate is significantly increased and can be used as a dynamic order parameter. We perform a finite-size scaling analysis that indicates the existence of power-law singularities for the order parameter and its fluctuations, yielding estimated critical exponent ratios $\beta/\nu \approx 0.12$ and $\gamma/\nu \approx 1.77$. These exponent ratios, together with theoretical symmetry arguments and numerical data for the fourth-order cumulant associated with the transition, give reasonable support for the hypothesis that the observed nonequilibrium dynamic phase transition is in the same universality class as the two-dimensional equilibrium Ising model.Comment: 18 pages, 10 figures, accepted in Physical Review

Magnetic Behavior of a Mixed Ising Ferrimagnetic Model in an Oscillating Magnetic Field

The magnetic behavior of a mixed Ising ferrimagnetic system on a square lattice, in which the two interpenetrating square sublattices have spins +- 1/2 and spins +-1,0, in the presence of an oscillating magnetic field has been studied with Monte Carlo techniques. The model includes nearest and next-nearest neighbor interactions, a crystal field and the oscillating external field. By studying the hysteretic response of this model to an oscillating field we found that it qualitatively reproduces the increasing of the coercive field at the compensation temperature observed in real ferrimagnets, a crucial feature for magneto-optical applications. This behavior is basically independent of the frequency of the field and the size of the system. The magnetic response of the system is related to a dynamical transition from a paramagnetic to a ferromagnetic phase and to the different temperature dependence of the relaxation times of both sublattices.Comment: 10 figures. To be published in Phys.Rev