On the bar pattern speed determination of NGC 3367

An important dynamic parameter of barred galaxies is the bar pattern speed. Among several methods that are used for the determination of the pattern speed the Tremaine-Weinberg method has the advantage of model independency and accuracy. In this work we apply the method to a simulated bar including gas dynamics and study the effect of 2D spectroscopy data quality on robustness of the method. We added a white noise and a Gaussian random field to the data and measured the corresponding errors in the pattern speed. We found that a signal to noise ratio in surface density ~5 introduces errors of ~20% for the Gaussian noise, while for the white noise the corresponding errors reach ~50%. At the same time the velocity field is less sensitive to contamination. On the basis of the performed study we applied the method to the NGC 3367 spiral galaxy using H{\alpha} Fabry-Perot interferometry data. We found for the pattern speed 43 \pm 6 km/s/kpc for this galaxy.Comment: Accepted for publication in ApJ. 16 pages, 16 figure

Evidence of chaotic modes in the analysis of four delta Scuti stars

Since CoRoT observations unveiled the very low amplitude modes that form a flat plateau in the power spectrum structure of delta Scuti stars, the nature of this phenomenon, including the possibility of spurious signals due to the light curve analysis, has been a matter of long-standing scientific debate. We contribute to this debate by finding the structural parameters of a sample of four delta Scuti stars, CID 546, CID 3619, CID 8669, and KIC 5892969, and looking for a possible relation between these stars' structural parameters and their power spectrum structure. For the purposes of characterization, we developed a method of studying and analysing the power spectrum with high precision and have applied it to both CoRoT and Kepler light curves. We obtain the best estimates to date of these stars' structural parameters. Moreover, we observe that the power spectrum structure depends on the inclination, oblateness, and convective efficiency of each star. Our results suggest that the power spectrum structure is real and is possibly formed by 2-period island modes and chaotic modes

Genetic control of purothionins in wheat: problems of the aneuploid analysis when searching for regulatory genes

The study of the genetic control of purothionins in wheat endosperm illustrates some of the problems and pitfalls faced in aneuploid analysis of regulatory effects. Biochemical and genetic evidence is presented indicating that the possible regulatory effect of genes located in group 5 chromosomes on the expression of the purothionin structural genes located in group 1 chromosomes is not actually operating "in vivo"

Contrastación de un modelo de ciberconsumo

El consumo de productos y servicios en Internet se ha estudiado a partir de dos hipótesis, según las cuales los usuarios compran productos o contratan servicios en la medida en que la información se percibe como útil o riesgosa. Por consiguiente, la utilidad percibida supone que los protocolos de in - formación digitales tienen mayores beneficios que costos, o bien, en comparación con otros modos de comercio, Internet resulta más compatible con estilos de vida implicados en dispositivos electrónicos. Sin embargo, la percepción de riesgo es un factor que no solo inhibe las transferencias electrónicas, sino que además hace más selectiva la búsqueda y compra de bienes de consumo o la contratación de servi - cios. Precisamente, el objetivo del presente trabajo fue establecer las dimensiones de la selectividad en torno al consumo electrónico. Para tal fin, se realizó una selección no probabilística de 188 internautas a los que se aplicó un cuestionario de ciberconsumo, el cual obtuvo una consistencia interna adecuada. A partir de un modelo estructural, se estimó la validez reflectiva de cuatro indicadores del consumo en Internet. Los resultados se discuten a partir del estado actual del conocimiento

The Kramer sampling theorem revisited

The classical Kramer sampling theorem provides a method for obtaining orthogonal sampling formulas. Besides, it has been the cornerstone for a significant mathematical literature on the topic of sampling theorems associated with differential and difference problems. In this work we provide, in an unified way, new and old generalizations of this result corresponding to various different settings; all these generalizations are illustrated with examples. All the different situations along the paper share a basic approach: the functions to be sampled are obtaining by duality in a separable Hilbert space H through an H -valued kernel K defined on an appropriate domain

Sampling associated with resolvent-type kernels and lagrange-type interpolation series

In this paper a new class of Kramer kernels is introduced, motivated by the resolvent of a symmetric operator with compact resolvent. The article gives a necessary and sufficient condition to ensure that the associ- ated sampling formula can be expressed as a Lagrange-type interpolation series. Finally, an illustrative example, taken from the Hamburger moment problem theory, is included

IDENTIFICACIÓN DE CONGLOMERADOS PARA IMPULSAR LAS CADENAS PRODUCTIVAS DE CARNE EN MÉXICO

El objetivo del presente trabajo fue realizar un análisis de correlación espacial regional de la producción de carne en canal por especie en México