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Search Results: 1 - 10 of 5253 matches for " Alfonso Trejo "
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On the Nature of the Non-Thermal Radio Source at the Center of the Orion Streamers
Trejo, Alfonso;Rodríguez, Luis F;
Revista mexicana de astronomía y astrofísica , 2010,
Abstract: we present vla continuum observations at 20 and 6 cm toward a non-thermal radio source located at the streamers region in orion. we compare 1991 archive observations with new ones taken by us in 2008. the radio source could be a young stellar source or an evolved object like a microquasar or even a jet from a radio galaxy. our analysis shows that there is no evidence of changes in the flux densities between both epochs at a level higher than 10%. also, we set an upper limit at a 3σ level of 23 mas year-1 for the proper motions. at the distance of orion this implies an upper limit to the velocity in the plane of the sky of 45 km s-1. at 6 cm, we detect linearly polarized emission at a level of ~ 5%, while at 20 cm we do not detect this emission above a level of ~ 2%. we conclude that the non-thermal radio source most probably is a radio galaxy aligned by chance with the line of sight to the streamers in orion.
Compact Radio Sources Apparently Associated with Extended Galactic Sources
Trejo, Alfonso;Rodríguez, Luis F;
Revista mexicana de astronomía y astrofísica , 2010,
Abstract: we report vla radio observations of the 21 cm hi line toward two compact radio sources that could be associated with extended galactic sources. in the case of the planetary nebula phr 1735-333 we observed hi absorption against a non-thermal radio source recently discovered in the region, which was proposed to be physically associated with the planetary nebula. however, from the analysis of the hi absorption spectrum, we suggest a larger distance for this non-thermal source. in the case of the supernova remnant candidate snr g3.8+0.3 we obtained hi absorption spectra towards it and towards a compact radio source located at its center. we conclude that snr g3.8+0.3 is more distant than the compact radio source and that they are not physically associated.
ON THE NATURE OF THE NON-THERMAL RADIO SOURCE AT THE CENTER OF THE ORION STREAMERS
Alfonso Trejo,Luis F. Rodru00EDguez
Revista mexicana de astronomía y astrofísica , 2010,
Abstract: Presentamos un análisis de observaciones del VLA en el continuo a 20 y 6 cm hacia una fuente de radio no térmica en la región de las Serpentinas (Streamers) en Orión. Comparamos observaciones de archivo de 1991 con nuevas observaciones hechas por nosotros en 2008. Dicha fuente puede ser un objeto estelar joven o un objeto evolucionado, como un microcuasar, o incluso un jet de una radiogalaxia. Nuestro análisis muestra que no hay evidencia de cambio en la densidad de flujo, entre ambas épocas, arriba del 10%, y que la morfología permanece constante dentro del ruido. Tampoco hay indicio de movimientos propios mayores que 23 msa a o-1, a un nivel de 3o, que a la distancia de Orión implican un límite superior a la velocidad en el plano del cielo de 45 km s-1. A 6 cm detectamos emisión polarizada linealmente con un nivel de ~5%, mientras que a 20 cm no se detecta esta emisión por encima de ~2%. Concluimos que esta fuente de radio no térmica es muy probablemente una radiogalaxia vista por mera casualidad en la línea de visión hacia el centro del sistema de las Serpentinas de Orión.
COMPACT RADIO SOURCES APPARENTLY ASSOCIATED WITH EXTENDED GALACTIC SOURCES
Alfonso Trejo,Luis F. Rodru00EDguez
Revista mexicana de astronomía y astrofísica , 2010,
Abstract: Reportamos observaciones hechas con el VLA de la línea de 21 cm del HI hacia dos fuentes compactas que podrían estar asociadas con fuentes galácticas extendidas. En el caso de la nebulosa planetaria PHR 1735-333 observamos HI en absorción hacia una fuente de radio no térmica recientemente descubierta en la región, la cual se propuso estaba físicamente asociada con la nebulosa planetaria. Sin embargo, el análisis del espectro de HI en absorción sugiere una distancia mayor para esta fuente no térmica. En el caso del candidato a remanente de supernova SNR G3.8+0.3 obtuvimos espectros de HI en absorción hacia ella y hacia la fuente compacta de radio localizada en su centro. Concluimos que SNR G3.8+0.3 es más distante que la fuente compacta y que por lo tanto no están asociadas físicamente.
ALMA 690 GHz observations of IRAS 16293-2422B: Infall in a highly optically-thick disk
Luis A. Zapata,Laurent Loinard,Luis F. Rodriguez,Vicente Hernandez-Hernandez,Satoko Takahashi,Alfonso Trejo,Berengere Parise
Physics , 2013, DOI: 10.1088/2041-8205/764/1/L14
Abstract: We present sensitive, high angular resolution ($\sim$ 0.2 arcsec) submillimeter continuum and line observations of IRAS 16293-2422B made with the Atacama Large Millimeter/Submillimeter Array (ALMA). The 0.45 mm continuum observations reveal a single and very compact source associated with IRAS 16293-2422B. This submillimeter source has a deconvolved angular size of about 400 {\it milli-arcseconds} (50 AU), and does not show any inner structure inside of this diameter. The H$^{13}$CN, HC$^{15}$N, and CH$_{3}$OH line emission regions are about twice as large as the continuum emission and reveal a pronounced inner depression or "hole" with a size comparable to that estimated for the submillimeter continuum. We suggest that the presence of this inner depression and the fact that we do not see inner structure (or a flat structure) in the continuum is produced by very optically thick dust located in the innermost parts of IRAS 16293-2422B. All three lines also show pronounced inverse P-Cygni profiles with infall and dispersion velocities larger than those recently reported from observations at lower frequencies, suggesting that we are detecting faster, and more turbulent gas located closer to the central object. Finally, we report a small east-west velocity gradient in IRAS 16293-2422B that suggests that its disk plane is likely located very close to the plane of the sky.
Identificación de especies y áreas prioritarias para el estudio de la reproducción de aves rapaces de Argentina
Trejo,Ana;
El hornero , 2007,
Abstract: ninety seven publications on raptor breeding biology in argentina (until 2006) were analyzed and classified according to species, year of publication, province, habitat associations, and subject. the amount of publications has increased, especially since 1970. almost all provinces are represented. there is no quantitative information for 33 species, 19 diurnal and 14 nocturnal. to determine priority areas for the study of reproduction, species richness, number of endemic or exclusive species, conservation status and degree of information on the species were considered for each life zone. on this basis, selva paranaense, yungas, chaco, and the andean-patagonian forests were established as the most important areas. analyzing the preferred habitat of the 33 species with no information, 85% are typical forest species. an evident disparity exists between the achieved knowledge and the necessity of conserving a vulnerable fauna (for its low habitat utilization flexibility and higher conservation risk). this is due to two fundamental factors: scarcity of researchers, and structural complexity of the habitat.
Bibliografía comentada sobre aves rapaces de Argentina
Trejo,Ana;
El hornero , 2007,
Abstract: a compilation of published literature on argentine diurnal and nocturnal raptors is presented, including papers until 2004. theses, technical reports and conference presentations were omitted. a total of 852 citations are presented. studied species, subjects of the study, and the provinces in which work was carried out are indicated for every paper.
Estatuto Provisional del Imperio Mexicano: su aplicación al gobierno departamental sonorense, 1865-1866
Trejo, Zulema;
Región y sociedad , 2007,
Abstract: the purpose of the present article is to compare legislation established in the provisional statute of the mexican empire, which governed imperial departments, and the way it was enacted in sonora.this article consists of six parts. the first three describe the establishment process of the second empire and clarify the meaning of a statute in general, and the provisional statute of the mexican empire in particular. in the fourth and fifth parts, we analyze title ix of the statute, which establishes the institutional framework for the departments. the sixth part contains conclusions.
Estatuto Provisional del Imperio Mexicano: su aplicación al gobierno departamental sonorense, 1865-1866
Zulema Trejo
Región y sociedad , 2007,
Abstract: El propósito de este artículo es comparar la legislación establecida en el Estatuto Provisional del Imperio Mexicano para gobernar los departamentos imperiales, y la forma de practicarlo en el de Sonora. Los tres primeros apartados están dedicados a describir el proceso de establecimiento del Segundo Imperio, así como a clarificar lo que es en general un estatuto, y en particular el Provisional del Imperio Mexicano. En el cuarto y quinto apartados se analiza el título IX del Estatuto, que establece el marco institucional departamental; y el sexto incluye las conclusiones.
Serum nucleosomes during neoadjuvant chemotherapy in patients with cervical cancer. Predictive and prognostic significance
Catalina Trejo-Becerril, Luis F O?ate-Oca?a, Lucía Taja-Chayeb, América Vanoye-Carlo, Lucely Cetina, Alfonso Duenas-Gonzalez
BMC Cancer , 2005, DOI: 10.1186/1471-2407-5-65
Abstract: From December 2000 to June 2001, 41 patients with cervical cancer staged as FIGO stages IB2-IIIB received three 21-day courses of carboplatin and paclitaxel, both administered at day 1; then, patients underwent radical hysterectomy. Nucleosomes were measured the day before (baseline), at day seven of the first course and day seven of the third course of chemotherapy. Values of nucleosomes were analyzed with regard to pathologic response and to time to progression-free and overall survival.All patients completed chemotherapy, were evaluable for pathologic response, and had nucleosome levels determined. At a mean follow-up of 23 months (range, 7–26 months), projected progression time and overall survival were 80.3 and 80.4%, respectively. Mean differential values of nucleosomes were lower in the third course as compared with the first course (p >0.001). The decrease in the third course correlated with pathologic response (p = 0.041). Survival analysis showed a statistically significant, better progression-free and survival time in patients who showed lower levels at the third course (p = 0.0243 and p = 0.0260, respectively). Cox regression analysis demonstrated that nucleosome increase in the third course increased risk of death to 6.86 (95% confidence interval [CI 95%], 0.84–56.0).Serum nucleosomes may have a predictive role for response and prognostic significance in patients with cervical cancer patients treated with neoadjuvant chemotherapy.The search for molecular markers to predict response to treatment and prognosis in patients with cancer has always occupied a major role in cancer research. To date, glycoproteins, polypeptides, or other macromolecules such as CEA, CAI5-3, AFP, βHGC, etc. – that are determined by biochemical methods – have a definitive, albeit modest, role for patient management in some tumor types [1,2].Knowledge of tumor biology and availability of molecular biology techniques have allowed testing of a vast array of potential molecular marker
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