A deep dive into NGC 604 with Gemini/NIRI imaging

The giant HII region NGC 604 constitutes a complex and rich population to studying detail many aspects of massive star formation, such as their environments and physical conditions, the evolutionary processes involved, the initial mass function for massive stars and star-formation rates, among many others. Here, we present our first results of a near-infrared study of NGC 604 performed with NIRI images obtained with Gemini North. Based on deep JHK photometry, 164 sources showing infrared excess were detected, pointing to the places where we should look for star-formation processes currently taking place. In addition, the color-color diagram reveals a great number of objects that could be giant/supergiant stars or unresolved, small, tight clusters. A extinction map obtained based on narrow-band images is also shown.Comment: 4 pages, 4 figures. To appear in the proceedings of IAU Symposium 266, Star Clusters: Basic Galactic Building Blocks Throughout Time and Space, eds. R. de Grijs and J. Lepin

Individualizando la nueva generación estelar en NGC 604: estudio fotométrico infrarrojo con Gemini-NIRI

El estudio realizado en la presente Tesis de Doctorado se focaliza en la detección y primera caracterización de los objetos individuales que constituyen la nueva generación de estrellas de gran masa de la región Hii gigante, NGC 604. NGC 604 se encuentra ubicada en la galaxia M33 a 840 kpc de distancia, y es la segunda región Hii gigante más luminosa del Grupo Local, después de 30 Doradus. El cúmulo central ionizante contiene, al menos, 200 estrellas de tipos espectrales OB y presenta una estructura conocida como “Scale OB Association”, caracterizada por una distribución de objetos muy extendida, sin un núcleo central definido. En la población estelar de NGC 604 también se han identificado estrellas tipo Wolf-Rayet, una gigante roja confirmada y varias candidatas y una estrella en la fase de ‘Luminous Blue Variable’. La edad estimada para el cúmulo central es 2.5-5 millones de años. En cuanto al medio interestelar de la región, se observa que presenta una estructura muy compleja: regiones con distinto grado de excitación conformando cavidades interconectadas, filamentos y cáscaras en expansión cuya cinemática refleja dicha complejidad. Las nubes moleculares rodean al cúmulo central por la parte sur extendiéndose en esa dirección.Facultad de Ciencias Astronómicas y Geofísica

La figura del fusilado según las categorías de Héroe/Personaje del Bajtín

En el presente trabajo, a partir de una lectura en clave comparada de los textos Operación Masacre (1957), de Rodolfo Walsh y Soldados de Salamina (2001), de Javier Cercas, nos proponemos indagar sobre la figura del fusilado, a partir del marco teórico metodológico de Mijaíl Bajtín. La elección de este tema surge luego del cursado de la materia Literatura Española III, donde se trabajó con la lectura y análisis de Soldados de Salamina, cuya estructura, género y argumento nos resultaron sumamente interesantes; además, durante el dictado de clases de Lengua y Literatura para el Ciclo de Especialización, se desarrolló la temática de la no ficción y el análisis de la obra de Rodolfo Walsh, específicamente Operación Masacre, por lo que nos resultó pertinente hacer algunas analogías y establecer relaciones entre las dos obras, para profundizar sobre la composición novelesca y sus relaciones con la dimensión socia

Unveiling the new generation of stars in NGC604 with Gemini-NIRI

We present a near-infrared study focused on the detection and characterization of the youngest stellar component of the NGC604 giant star-forming region in the Triangulum galaxy (M33). By means of color-color diagrams derived from the photometry of JHKs images taken with the Gemini Near Infrared Imaging and Spectrometer (NIRI), we have found 68 candidate massive young stellar objects. The spatial distribution of these sources matches the areas where previous studies suggested that star formation might be taking place, and the high spatial resolution of our deep NIRI imaging allows us to pinpoint the star-forming knots. An analysis of the fraction of objects that show infrared excess suggests that the star formation is still active, supporting the presence of a second generation of stars being born, although the evidence for or against sequential star formation does not seem to be conclusive.Facultad de Ciencias Astronómicas y Geofísica

A deep dive into NGC604 with Gemini/NIRI imaging

The giant HII region NGC 604 constitutes a complex and rich population to study in detail many aspects of massive star formation, such as their environments and physical conditions, the evolutionary processes involved, the initial mass function for massive stars and starformation rates, among many others. Here, we present our first results of a near-infrared study of NGC 604 performed with NIRI images obtained with Gemini North. Based on deep JHK photometry, 164 sources showing infrared excess were detected, pointing to the places where we should look for star-formation processes currently taking place. In addition, the color-color diagram reveals a great number of objects that could be giant/supergiant stars or unresolved, small, tight clusters. An extinction map obtained based on narrow-band images is also shown.Facultad de Ciencias Astronómicas y Geofísica

A charge-coupled device photometric study of south hemispheric contact binary ae phoenicis

The complete charge-coupled device light curves in B, V, R, and I bands of the short-period binary system, AE Phe, are presented. It is found that the light curves of AE Phe belong to typical EW-type light variation. Photometric solutions were derived by using the 2003 version of the Wilson-Devinney code. It showed that AE Phe is a W-subtype shallow-contact system (f = 14.6%(0.5%)) with a mass ratio of q = 2.5491(0.0092). The temperature difference between the two components is 227 K. Analysis of the O - C curve suggests that the period of AE Phe shows a long-term continuous increase at a rate of dP/dt = +6.17(0.44) × 10-8 days year-1. The long-term period increase, the marginal-contact configuration, and the astrophysical parameters of the binary system, all suggest that it is a shallow-contact binary undergoing a thermal relaxation oscillation evolving into a detached binary.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plat

A charge-coupled device photometric study of south hemispheric contact binary AE Phoenicis

The complete charge-coupled device light curves in B, V, R, and I bands of the short-period binary system, AE Phe, are presented. It is found that the light curves of AE Phe belong to typical EW-type light variation. Photometric solutions were derived by using the 2003 version of the Wilson–Devinney code. It showed that AE Phe is a Wsubtype shallow-contact system (f = 14.6%(±0.5%)) with a mass ratio of q = 2.5491(±0.0092). The temperature difference between the two components is 227 K. Analysis of the O − C curve suggests that the period of AE Phe shows a long-term continuous increase at a rate of dP /dt = +6.17(±0.44) × 10−8 days year−1. The longterm period increase, the marginal-contact configuration, and the astrophysical parameters of the binary system, all suggest that it is a shallow-contact binary undergoing a thermal relaxation oscillation evolving into a detached binary.Fil: He, J. J.. Chinese Academy of Sciences; República de ChinaFil: Qian, S. B.. Chinese Academy of Sciences; República de ChinaFil: Fernandez Lajus, Eduardo Eusebio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; ArgentinaFil: Fariña, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentin

Aspergillus terreusstrain improvement for enhanced lovastatin production

Cholesterol plays a vital role in body metabolism and membrane transport, and acts as precursor for the synthesis of several key biomolecules. Nevertheless, changes in cholesterol level lead to cardiovascular disorders, like atherosclerosis and hypercholesterolemia, which are currently the maincauses of death. This is why controlling cholesterol by inhibition of its biosynthesis is a promising approach. Cholesterol is synthetized from acetyl-CoA through a complex pathway, where the rate-limiting step is the conversion of HMG-CoA to mevalonate, catalyzed by HMG-CoA reductase.This key enzyme is selectively and competitively inhibited by lovastatin, a fungal secondary metaboliteused as a hypocholesterolemic which can therefore reduce the risk of cardiovascular diseases.Fil: Babot, Jaime Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Caro, Florencia Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Delgado, Osvaldo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Catamarca. Universidad Nacional de Catamarca. Centro de Investigaciones y Transferencia de Catamarca; Argentina. Universidad Nacional de Catamarca. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Fariña, Julia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaXI Congreso Argentino de Microbiología GeneralCórdobaArgentinaSociedad Argentina de Microbiología Genera

Adapted and optimized colorimetric method for the rapid on-line quantification of scleroglucan during a submerged fermentation process

Scleroglucan is an extracellular neutral b-1,3-b-1,6-glucan frequently produced by Sclerotium fungal species during submerged fermentation processes. Due to its physicochemical, rheological and biological properties, scleroglucan became particularly attractive for diverse food, agro industrial, biomedical and oil recovery applications. Currently, the most widely used technique for polymer quantification consists in its purification from culture broths and dry weightdetermination. This method has the inconvenience of being poorly sensitive at low concentrations and time-consuming, therefore, being not suitable for real-time monitoring. Recently, Jörg Nitschke et al. (Food Chemistry, 2011. 127: 791?796) developed a colorimetric Congo red-based method to quantify b-1,3-glucans in mycelia and fruiting bodies from edible mushrooms. Congo red would incorporate into the b-1,3-b-1,6-glucans triple helix thus leading to a bathochromic shift that can be used for colorimetric quantification. Based on this previous report, this work is aimed at adapting and optimizing this novel technique in order to on-line quantify scleroglucan production during submerged fermentation. For this purpose, several dye (0.6-1 g/L Congo red) and NaOH (80-200 μL of NaOH 1 or 1.2 N) concentrations were tested to achieve the greater bathochromic shift when using commercial scleroglucan (LSCL) as standard. Reproducibility of bathochromic shift was also evaluated with lab-scale produced scleroglucans. A scleroglucan calibration curve (0.1-0.9 g/L) could be satisfactorily constructed. Linearity, sensitivity and specificity within this working range were assessed at different wavelengths and time points (0, 30 min, 1, 3, 5, 8 and 24 h post reaction). Finally, to validate the methodology, a fermentation process with Sclerotium rolfsii ATCC 201126 was performed, and scleroglucan quantification was simultaneously accomplished by conventional (dry weight) and Congo red methods. Selected conditions allowed the reliable and sensitive scleroglucan Congo red quantification during fermentation. Both commercial and lab-scale produced scleroglucans could be successfully used for the standard curve preparation. This novel methodology proved to be highly effective and sensitive for the on-line quantification throughout scleroglucan production, and the obtained results were comparable to those from the conventional technique (dry weight). The method optimized for scleroglucan measurement showed to be inexpensive, practical, reliable, specific and time-effective, being also potentially useful for other triple-helical b-glucans. Additionally, on-line monitoring of scleroglucan production represents a critical tool for taking real-time appropriate decisions during fermentation process, particularly when working at large scaleFil: Castillo, Natalia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Montes de Oca, Cecilia Estefania. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Valdez, Alejandra Leonor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Fariña, Julia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaIX Congreso Argentino de Microbiología GeneralSanta FeArgentinaSociedad Argentina de Microbiología Genera

Spectroscopic study of the N159/N160 complex in the Large Magellanic Cloud

We present a spectroscopic study of the N159/N160 massive star-forming region south of 30 Doradus in the Large Magellanic Cloud, classifying a total of 189 stars in the field of the complex. Most of them belong to O and early B spectral classes; we have also found some uncommon and very interesting spectra, including members of the Onfp class, a Be PCygni star, and some possible multiple systems. Using spectral types as broad indicators of evolutionary stages, we considered the evolutionary status of the region as a whole. We infer that massive stars at different evolutionary stages are present throughout the region, favoring the idea of a common time for the origin of recent star formation in the N159/N160 complex as a whole, while sequential star formation at different rates is probably present in several subregions.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plat