Gemini/GMOS search of massive binaries in the ionizing cluster of 30 Dor

If binaries are common among massive stars, it will have important consequences for the derivation of fundamental properties like the cluster age, IMF and dynamical mass. Making use of the multiplexing facilities of Gemini Multi Object Spectrograph (GMOS) we were able to investigate the presence of binary stars within the ionising cluster of 30 Doradus. From a seven epochs observing campaign at Gemini South we detect a binary candidate rate of about 50%, which is consistent with an intrinsic 100% binary rate among massive stars. We find that single epoch determinations of the velocity dispersion give values around 30 km/s . After correcting the global velocity dispersion for the binary orbital motions, the true cluster velocity dispersion is 8.3 km/s. This value implies a virial mass of about 4.5E5 Msun or 8 percent of the mass calculated using the single epoch value. The binary corrected virial mass estimate is consistent with photometric mass determinations thus suggesting that NGC 2070 is a firm candidate for a future globular cluster.Comment: 9 pages, accepted at Astronomical Journa

La carta comercial publicitaria y su entramado textual

El presente estudio responde a un tipo de texto: la carta comercial publicitaria. Como texto publicitario la carta es persuasiva, tiene un fin práctico e interesado puesto que se requiere del receptor que adquiera la oferta o servicio que se anuncia en la carta de una forma explícita o implícita. El estudio se plantea en dos partes. En la primera, estudiamos la superestructura del texto epistolar, que cuenta con unas funciones comunicativas precisas con formulismos y apelaciones. En la segunda parte, analizamos un ejemplo representativo observando los mecanismos lingüísticos retóricos y persuasivos que definen a este tipo de texto epistolar persuasivo.The present study deals with effective ways of promoting sales through direct advertising. The main function of the sales letter is persuasive, so it is the seller s interest to capture the attention of the potential customer so as to achieve the desired communicative outcome: the purchase of the offer. The paper falls into two sections. In the first section the sales letter is studied within a genre-based approach (promotional business genre-based) as a communicative event with a communicative purpose. In the second section a representative sample is analysed with respect to the layout, stylistic features, text-structure, emotional appeal and other persuasive features. The insight gained from this kind of analysis can ultimately be of use for pedagogical [email protected]

Gemini/GMOS search for massive binaries in the ionizing cluster of 30 DOR

If binaries are common among massive stars, it will have important consequences for the derivation of fundamental properties such as the cluster age, initial mass function, and dynamical mass. Making use of the multiplexing facilities of the Gemini Multi-Object Spectrograph, we were able to investigate the presence of binary stars within the ionizing cluster of 30 Doradus. From a seven-epoch observing campaign at Gemini South we detect a binary candidate rate of about 50%, which is consistent with an intrinsic 100% binary rate among massive stars. We find that single-epoch determinations of the velocity dispersion give values around 30 kms-1. After correcting the global velocity dispersion for the binary orbital motions, the "true" cluster velocity dispersion is 8.3 kms-1. This value implies a virial mass of about 4.5 × 105 M or 8% of the mass calculated using the single-epoch value. The binary corrected virial mass estimate is consistent with photometric mass determinations, thus suggesting that NGC2070 is a firm candidate for a future globular cluster.Facultad de Ciencias Astronómicas y Geofísica

Implications of the kinematical structure of circumnuclear star-forming regions on their derived properties

[Abbreviated] We review the results of high dispersion spectroscopy of 17 circumnuclear starforming regions (CNSFRs) in 3 nearby early spiral galaxies, NGC2903, NGC3310 and NGC3351. We find that single Gaussian fitting to the H$\beta$ and [OIII]5007A line profiles results in velocity dispersions around 32km/s and 52km/s, respectively, while the IR CaII triplet cross-correlation technique provides stellar velocity dispersion values close to 50km/s. Even though multiple kinematical components are present, the relation between gas velocity dispersion and Balmer emission line luminosity (L-sigma relation) reproduces the correlation for disk giant HII regions albeit with a larger scatter. The scatter in the L-sigma relation is considerably reduced when theoretical evolutionary corrections are applied suggesting that an age range is present in the sample of CNSFRs. To analyse the observed complex profiles, we performed multiple Gaussian component fits to the Hbeta and [OIII]?5007A lines obtaining optimal fits with two Gaussians of different width. These best fits indicate that the narrower component has average velocity dispersion close to 23km/s while the broader component shows average values in the range 50-60km/s for both lines, close to the observed stellar velocity dispersions. The fluxes of the broad and narrow Hbeta components are similar. This is not the case for [OIII]5007A for which the broad components have higher fluxes than the narrow ones, thus producing a clear segregation in their [OIII]/Hbeta ratios. We suggest a possible scenario for understanding the behaviour of CNSFRs in the L-sigma and sigma_gas-sigma_star diagrams involving an inner gaseous disk responsible for the narrow component of the emission lines.Comment: 14 pages, 10 figures, accepted by MNRA

Gemini/GMOS detection of stellar velocity variations in the ionising cluster of 30 Dor

We have analysed spectra obtained with the Gemini Multi Object Spectrograph (GMOS) for more than 50 stars in the ionising cluster of 30Doradus during a seven epochs observing campaign at Gemini South. We derive a binary candidate rate of about 50%, which is however consistent with an intrinsic 100% binary rate among massive stars. After decontaminating the sample from the stars that show binary orbital motions, we were able to calculate the "true" cluster velocity dispersion and found it to be about 8 km s-1. This value implies a virial mass of about 4.5 × 10M⊙ which is consistent with previous photometric mass determinations therefore suggesting that NGC 2070 is a firm candidate for a future globular cluster.Facultad de Ciencias Astronómicas y Geofísica

Gemini/GMOS detection of stellar velocity variations in the ionising cluster of 30 Dor

We have analysed spectra obtained with the Gemini Multi Object Spectrograph (GMOS) for more than 50 stars in the ionising cluster of 30Doradus during a seven epochs observing campaign at Gemini South. We derive a binary candidate rate of about 50%, which is however consistent with an intrinsic 100% binary rate among massive stars. After decontaminating the sample from the stars that show binary orbital motions, we were able to calculate the "true" cluster velocity dispersion and found it to be about 8 km s-1. This value implies a virial mass of about 4.5 × 10M⊙ which is consistent with previous photometric mass determinations therefore suggesting that NGC 2070 is a firm candidate for a future globular cluster.Facultad de Ciencias Astronómicas y Geofísica

Relationship between the sea surface temperature of different oceans and the maize yields in the Argentine Pampa region

La temperatura superficial del mar (TSM) guarda estrecha relación con algunas variables climáticas como la precipitación en el sudeste de Sudamérica y en particular con algunos cultivos en la Pampa Húmeda. El objetivo de este trabajo es analizar la relación entre la TSM de los océanos Pacífico, Atlántico e Indico y los rendimientos del cultivo de maíz en dicha región. Se comprobó que los rendimientos de maíz responden en mayor o menor medida a las fluctuaciones de las TSM en los diferentes océanos, exceptuando parte del sur y el sudoeste de la región de estudio, coincidente con el sur de la provincia de Buenos Aires y este de La Pampa, donde la relación es muy débil o inexistente. Para el resto de la región de estudio se observó una significativa influencia del océano Pacífico subtropical y ecuatorial en la región del ENOS, el océano Indico en presencia del dipolo (DOI) y del océano Atlántico tropical y subtropical occidental principalmente durante la primavera y en algunos casos en el otoño.The sea surface temperature anomalies (SST) are closely related to the precipitation anomalies in central and eastern Argentina and therefore they are related to some crops in the Argentine Pampa region as well. The objective of this paper is to analyze the relationship between SST in the Pacific, Atlantic and Indian Oceans and maize yields in the Pampa region. It is found that maize yields respond in different ways to the SST variability, except for the south, southeast and west of Buenos Aires province and the east of the La Pampa province, where the signal is either weak or nonexistent. It is also found that some oceanic regions have a significant influence over the rest of the Pampa region, in particular the subtropical Pacific Ocean, the equatorial Pacific Ocean ENSO region, the Indian Ocean dipole (IOD) and the tropical and subtropical western Atlantic Ocean mainly in the spring and in some cases in the fall.Fil: Muller, Gabriela Viviana. Provincia de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Universidad Autónoma de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; ArgentinaFil: Fernández Long, María Elena. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Bosch, Ezequiel. Universidad de Buenos Aires. Facultad de Agronomía; Argentin

Complint una intuïció de Darwin: genètica humana i llengües

Les similituds entre la manera com s'hereten i evolucionen els gens i les llengües han promogut l'interès en l'anàlisi conjunta d'ambdós camps. La correlació entre gens i llengües va ser demostrada per primer cop per Cavalli-Sforza i col·laboradors en comparar un arbre construït amb marcadors genètics clàssics amb un arbre lingüístic de les llengües. S'han formulat diverses crítiques a aquest mètode, i se n'han descrit nombroses excepcions. S'ha demostrat que el factor més important que determina la correlació de gens i llengües és la geografia. Nogensmenys, la informació proporcionada per la genètica i la lingüística, ensems amb la proporcionada per altres disciplines, ens permetrà reconstruir la història de la humanitat.The similarities between the mode of inheritance and evolution of genes and languages have fostered interest in the joint analysis of both disciplines. The correlation between genes and languages was firstly demonstrated by Cavalli-Sforza and collaborators comparing a tree build from ‘classical’ genetic markers to a linguistic tree of languages. Several criticisms to this correlation have been raised and a large number of exceptions have been described. It has been shown that the most plausible factor that influences in the correlation of genes and languages is geography. However, the information provided by genetics and linguistics, as well as the one provided by other disciplines, will allow us to reconstruct the history of humankind