17 research outputs found
Towards service integration in electronic government implementations
Service integration is one of the most critical issues
affecting electronic government implementations all over the
world. Providing integrated services to citizens, businesses, and all other stakeholders involved in electronic government activities at "one stop portal" is considered to be a big opportunity for governments to improve their services’ efficiency and effectiveness. This paper aims to provide a general background and theoretical foundation towards understanding the role of
service integration and its importance in electronic government implementations in order to achieve the main aims and objectives of electronic government programs all over the globe by conducting a comprehensive literature review on electronic government, in general, and the issue of service integration in particular. The paper has shed a new light on the main concepts,definitions, characteristics, interactions, models, objectives,
benefits, challenges and analytical bases for the topic. As a result, a model that is suggesting a set of key factors to accomplish service integration in electronic government implementations and clarifying the importance of service integration in electronic government implementations is proposed. The main contribution of the paper is to build a good understanding of the nature and role of service integration in electronic government implementations and to establish a foundation for further research in this domain.
Keywords : E-government implementation; Service
integration; Maturity models; One stop portal; Pillars; Critical factor
Searching for Multiple Populations in the Integrated Light of the Young and Extremely Massive Clusters in the Merger Remnant NGC~7252
Recent work has shown that the properties of multiple populations within massive stellar clusters (i.e., in the extent of their abundance variations as well as the fraction of stars that show the anomalous chemistry) depend on the mass as well as the age of the host cluster. Such correlations are largely unexpected in current models for the formation of multiple populations and hence provide essential insight into their origin. Here we extend or previous study into the presence or absence of multiple populations using integrated light spectroscopy of the ~Myr, massive (~\msun) clusters, W3 and W30, in the galactic merger remnant, NGC 7252. Due to the extreme mass of both clusters, the expectation is that they should host rather extreme abundance spreads, manifested through, e.g., high mean [Na/Fe] abundances. However, we do not find evidence for a strong [Na/Fe] enhancement, with the observations being consistent with the solar value. This suggests that age is playing a key role, or alternatively that multiple populations only manifest below a certain stellar mass, as the integrated light at all ages above ~Myr is dominated by stars near or above the main sequence turn-off
Multiple Populations in integrated light spectroscopy of intermediate - age clusters
The presence of star-to-star light-element abundance variations (a.k.a. multiple populations, MPs) appears to be ubiquitous within old and massive clusters in the Milky Way and all studied nearby galaxies. Most previous studies have focussed on resolved images or spectroscopy of individual stars, although there has been significant effort in the past few years to look for multiple population signatures in integrated light spectroscopy. If proven feasible, integrated light studies offer a potential way to vastly open parameter space, as clusters out to tens of Mpc can be studied. We use the NaD lines in the integrated spectra of two clusters with similar ages ( Gyr) but very different masses, NGC 1978 ( Msun) in the LMC and G114 ( Msun) in NGC 1316. For NGC 1978, our findings agree with resolved studies of individual stars which did not find evidence for Na spreads. However, for G114, we find clear evidence for the presence of multiple populations. The fact that the same anomalous abundance patterns are found in both the intermediate age and ancient GCs lends further support to the notion that young massive clusters are effectively the same as the ancient globular clusters, only separated in age
An Investigation of the Use of Synthetic Spectra to Find the Ages of Stellar Clusters
The utility of stellar cluster aging methods based on integrated spectra is clearly demonstrated by its extensive use by researchers for decades. However, few studies have determined the accuracy of such methods using a significant sample of age-calibrated stellar clusters with recent models. We have amassed a sample of 27 stellar clusters, 20 with new spectra we obtained with the SOAR and Blanco 4-m Telescopes, with previously determined ages using color-magnitude diagrams (CMDs). We compared the CMD ages to ages obtained from the clusters’ integrated spectra. We find that the integrated spectra in the wavelength range 3626–6230 Ã…, when compared with high resolution computational models, provide very good age predictions. In particular, the spectral method is more robust in resolving the age-extinction degeneracy that plagues broad-band photometric aging methods. We observe no significant difference in the ability of the synthetic spectra to fit and properly age stellar clusters based on the intrinsic mass of the stellar clusters in our sample.Fil: Asa'd, Randa S.. American University of Sharjah; Emiratos Arabes Unidos. University Of Cincinnati; Estados UnidosFil: Hanson, M. M.. University Of Cincinnati; Estados UnidosFil: Ahumada, Andrea Veronica. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; Argentin
Can the Full Spectrum Fitting Technique correctly detect Age Spreads in Young Star Clusters?
elastic scattering at 30 GeV/c incident momentum in the momentum trasfer range 0.5<−t<5.8(GeV/c)2
Analysis of Red Supergiants in VDBH 222
Recent surveys uncovered new young massive clusters (YMCs) that host dozens of red supergiants (RSGs) in the inner Milky Way. These clusters are ideal for studying the most recent and violent star formation events in the inner Galaxy. However, due to the high extinction that affects the Galactic plane, they need to be studied through infrared (IR) spectroscopy. IR spectra of RSGs have proven to be powerful tools for obtaining chemical abundances. We present the first [Fe/H] measurement (-0.07 \ub1 0.02) for the YMC VdBH 222 through analysis of its RSGs using Very Large Telescope/X-shooter spectra. We find no evidence for multiple stellar populations in this YMC, contrary to what is routinely observed in older massive clusters