Pairs-Production of Higgs in Association with Bottom Quarks Pairs at e+e−e^+e^- Colliders

In a previous paper, we studied the Higgs pair production in the standard model with the reaction $e^{+}e^{-}\to t \bar t HH$. Based on this, we study the Higgs pair production via $e^{+}e^{-}\to b \bar b HH$. We evaluate the total cross section of $b\bar bHH$ and calculate the number total of events considering the complete set of Feynman diagrams at tree-level, and compare this process with the process $e^{+}e^{-}\to t \bar t HH$. The numerical computation is done for the energy which is expected to be available at a possible Next Linear $e^{+}e^{-}$ Collider with a center-of-mass energy $800, 1000, 1600$ $GeV$ and luminosity 1000 $fb^{-1}$.Comment: 12 pages, 6 figure

Hurst Coefficient in long time series of population size: Model for two plant populations with different reproductive strategies

Can the fractal dimension of fluctuations in population size be used to estimate extinction risk? The problem with estimating this fractal dimension is that the lengths of the time series are usually too short for conclusive results. This study answered this question with long time series data obtained from an iterative competition model. This model produces competitive extinction at different perturbation intensities for two different germination strategies: germination of all seeds vs. dormancy in half the seeds. This provided long time series of 900 years and different extinction risks. The results support the hypothesis for the effectiveness of the Hurst coefficient for estimating extinction risk

Evaluación educativa de la implementación de un programa interactivo para la adquisición de conocimientos medioambientales

Para conocer la calidad docente dentro de nuevas metodologías de aprendizaje es importante prestar especial atención a la evaluación, sus pautas, los diseños realizados y el proceso en sí, que junto con los resultados obtenidos nos indican los criterios susceptibles de mejora, así como las áreas fuertes y débiles a considerar para futuras experiencias dentro de la docencia. La evaluación se ha realizado dentro del proyecto“Propuesta metodológica para el aprendizaje autónomo de conceptos medioambientales en la formación de maestros”, que nace con la intención de adecuar la metodología de la asignatura obligatoria Fundamentos científicos medioambientales, por su adaptación en su manera de desarrollo a través de entornos virtuales

Aplicabilidad del test MABC en escolares con síndrome de down

El presente estudio analiza la aplicabilidad de tests de coordinación y habilidad motriz, diseñados para la población infantil general, en escolares de Educación Física Especial. Para el estudio se selecciona una muestra de niños y niñas con síndrome de Down, de 9 y 10 años, del colegio de educación especial ¿María Corredentora¿ de Madrid. Se utilizan las pruebas del Test MABC para el tramo de 4 a 6 años de edad (con algunas adaptaciones) y la escala de observación ECOMI tomada como criterio de validez. Resultados y conclusiones: El módulo de 4 a 6 años del test MABC es aplicable, con ligeras modificaciones, para evaluar las habilidades motrices fundamentales de niños y niñas con síndrome de Down. El conjunto de las pruebas muestra coeficientes de fiabilidad y validez adecuados. El grado de desarrollo motor de estos niños (9 y 10 años), mediante la comparación con el baremo de MABC, es inferior al promedio de la población española de escolares de 4 a 6 años

Limits on the Dipole Moments of the τ\tau-Lepton via the Process $e^{+}e^{-}\to \tau^+ \tau^- \gamma in a Left-Right Symmetric Model

Limits on the anomalous magnetic moment and the electric dipole moment of the $\tau$ lepton are calculated through the reaction $e^{+}e^{-}\to \tau^+ \tau^- \gamma$ at the $Z_1$-pole and in the framework of a left-right symmetric model. The results are based on the recent data reported by the L3 Collaboration at CERN LEP. Due to the stringent limit of the model mixing angle $\phi$, the effect of this angle on the dipole moments is quite small.Comment: 15 pages, 3 figure

Limits on the Electromagnetic and Weak Dipole Moments of the Tau-Lepton in E_6 Superstring Models

We obtain limits on the electromagnetic and weak dipole moments of the tau-lepton in the framework of a Left-Right symmetric model (LRSM) and a class of $E_6$ inspired models with an additional neutral vector boson $Z_\theta$. Using as an input the data obtained by the L3 and OPAL Collaborations for the reaction $e^+e^-\to \tau^+\tau^-\gamma$, we get a stringent limit on the LRSM mixing angle $\phi$, $-1.66\times 10^{-3}< \phi<1.22\times 10^{-3}$, which in turn induces bounds on the tau weak dipole moments which are consistent with the bounds obtained recently by the DELPHI and ALEPH Collaborations from the reaction $e^+e^-\to \tau^+\tau^-$. We also get similar bounds for the weak dipole moments of the tau lepton in the framework of $E_6$ superstring models.Comment: 18 pages, 5 figure

Identification of bioactive compounds in diabetes and infertility models of C. elegans

Polycystic ovary syndrome (POS) is a complex and heterogeneous endocrine disease characterized by hyperandrogenism, oligo-anovulation and metabolic disorders, including insulin resistance, obesity and type II diabetes. Additionally, POS causes infertility in childbearing age women, making of great interest the search of new treatments and compounds for the improvement of the symptoms of this chronic disease. Despite the definitive pathological mechanism of POS is still unknown, as mentioned before there is a strong relation between the syndrome and different alterations in the insulin signaling pathway. This pathway is evolutionary conserved and it has a homologue pathway in the organism Caenorhabditis elegans. Mutations in the insulin receptor homologue daf-2 gene or in the phosphatidylinositol 3-kinase (PI3K) homologue age-1, result in reduction of fertility, being the decrease in progeny sharper in the allele age-1(mg305) mutant, in addition to a less pleiotropic effect. We consider this mutant of C. elegans a good model to study the insulin pathway, and specifically POS, due to the high degree of conservation of the pathway and the similarities between the phenotype caused by the mutation and the human symptoms

Estimación de las relaciones genéticas entre razas caprinas españolas y criollas utilizando microsatélites

We have analyzed three Creole goat populations from Peru, Mexico and Chile using microsatellite markers. We have also analyzed the genetic relationship between them and Murciano-Granadina and Malagueña Spanish goat breeds. The average number of alleles per locus was similar in all populations (7.3) except the Chilean Creole (5.1). This Creole goat population has presented the lowest value of observed (Ho) (0.53) and expected (He) heterozygosis (0.59). The Peruvian Creole has presented the highest values of Ho (0.70) and He (0.71). We have found a scarce level of genetic differentiation between goat populations (FST= 0.069) being more important the individual genetic differences due to crossbreed with several breeds. The Peruvian Creole was closed to analyzed Spanish breeds, followed by Mexican Creole. Finally the Chilean Creole was the most distant to the others populations

Reversion of late progeny in mutants with reduced fertility in Caenorhabditis elegans.

The detailed study of fertility is an eminent objective due to its involvement in the human population. Interestingly, research in relation to dietary restriction in different species have related this circumstance to an increase in longevity and delay in fertility. The evolutionarily conserved insulin / insulin-like growth factor-1 pathway is directly related to this phenomenon. Caenorhabditis elegans is an animal model widely used for the study of, for which, and in relation to this pathway, the transcription factor DAF-16 (homologous to human FOXO) plays an especially important role. Mutants for the insulin pathway, which in some extent mimic a dietary restriction situation, have also shown to have reduced fertility. Based on this, previous studies corroborated that suppression by interfering RNA (iRNA) of DAF-16 in mutants with impaired fertility reverses this phenotype.The phenomenon of late progeny is that individuals appear to have offspring later in life than wild-type ones, not being described solidly in the literature; that is why the purposes of this project consist of its evaluation and the verification of a possible reversion. Two thermosensitive mutants of C. elegans have been selected for study, for which a reduction in fertility was observed: mutant daf-2 (e1370), receptor tyrosine kinase, and mutant age-1 (mg305), subunit of the PI3 Kinase. There is not much data regarding this second mutant.First, it has been necessary to establish a parameter to discern between what will be considered late progeny or not. To carry it out, its laying behavior has been observed after being incubated at different temperatures in its fertile period. The obtained results corroborate that the late progeny is a real and measurable phenomenon, reflecting a significant difference of the mutants with respect to the wild ones at a temperature of 22.5ºC; having established the fifth day of the fertile period as a margin to differentiate its existence. Subsequently, experiments are planned to observe a possible reversal of the condition through the administration of 4-5 iRNA for specific genes that have been previously identified through genetic screening, and that seem to intervene in some way in this route by suppressing the reduced fertility phenotype. If this is the case, these genes would be described as being involved in the phenomenon of late progeny, establishing a mechanical correlation between reduction of fertility and the phenomenon of late progeny