Characterization of open cluster remnants

Despite progress in the theoretical knowledge of open cluster remnants and the growing search for observational identifications in recent years, open questions still remain. The methods used to analyze open cluster remnants and criteria to define them as physical systems are not homogeneous. In this work we present a systematic method for studying these objects that provides a view of their properties and allows their characterization. Eighteen remnant candidates are analyzed by means of photometric and proper motion data. These data provide information on objects and their fields. We establish criteria for characterizing open cluster remnants, taking observational uncertainties into account. 2MASS J and H photometry is employed (i) to study structural properties of the objects by means of radial stellar density profiles, (ii) to test for any similarity between objects and fields with a statistical comparison method applied to the distributions of stars in the CMDs, and (iii) to obtain ages, reddening values, and distances from the CMD, taking an index of isochrone fit into account. The UCAC2 proper motions allowed an objective comparison between objects and large solid angle offset fields. The objective analysis based on the present methods indicates 13 open-cluster remnants in the sample. Evidence of the presence of binary stars is found, as expected for dynamically evolved systems. Finally, we infer possible evolutionary stages among remnants from the structure, proper motion, and CMD distributions. The low stellar statistics for individual objects is overcome by means of the construction of composite proper motion and CMD diagrams. The distributions of remnants in the composite diagrams resemble the single-star and unresolved binary star distributions of open clusters.Comment: 16 pages, 15 figures, A&A accepte

Some practical points on organizing ETD consortia

Electronic Thesis and Dissertation (ETD) digital libraries are being developed worldwide. Higher education organizations commonly collaborate in these efforts by forming consortia. Some of the existing consortia are at the national level while others are at regional levels. NDLTD (Networked Digital Library for Thesis and Dissertations) is an initiative that is creating an international consortium which includes organizations or other ETD consortia in various countries. Consortia are important because they create an opportunity to collaborate, to share experiences, and to establish or adopt standards that guarantee interoperability among participant ETD digital libraries. However, developing consortia is challenging since it requires a strong degree of coordination while at the same time preserving existing organizational identities and functions. this makes the role of consortium coordinator complex. Implementation and operation of information services that integrate the participants\u27 initiatives are the ultimate goal of a consortium. These services are of paramount importance and need to be clearly established in order to operate effectively. This paper addresses some of the issues mentioned above including solutions that have been implemented. It also points to problems that might occur during the organization and operation of consortia

Open Cluster Characterization via Cross-Correlation with Spectral Library

We present a characterization method based on spectral cross-correlation to obtain the physical parameters of the controversial stellar aggregate ESO442-SC04. The data used was obtained with GMOS at Gemini-South telescope including 17 stars in the central region of the ob ject and 6 standard-stars. FXCOR was used in an iterative process to obtain self-consistent radial velocities for the standard-stars and averaged radial velocities for the science spectra. Spectral types, effective temperature, suface gravity and metallicities parameters were determined using FXCOR to correlate cluster spectra with ELODIE spectral library and selecting the best correlation matches using the Tonry and Davis Ratio (TDR). Analysis of the results suggests that the stars in ESO442-SC04 are not bound and therefore they do not constitute a physical system.Comment: 4-page paper from IAU symposium 266. Contains 3 eps figures and IAU document class file 'iau.cls

NGC2180: a disrupting open cluster

The spatial dependence of luminosity and mass functions of evolved open clusters is discussed in this work using J and H 2MASS photometry. The target objects are the overlooked open cluster NGC2180 and the intermediate-age open cluster NGC3680. We conclude that, although in an advanced dynamical state (mass segregated), NGC3680 does not present strong signs of dissolution. On the other hand, NGC2180 presents flat, eroded LFs throughout its structure, indicating that in addition to mass segregation, Galactic tidal stripping has been effective in depleting this cluster of stars. Accordingly, NGC2180 may be the missing link between evolved open clusters and remnants. We study both clusters in the context of dynamical states estimated from diagnostic-diagrams involving photometric and structural parameters. Both clusters are dynamically evolved systems. In particular, NGC2180 is closer to open cluster remnants than NGC3680.Comment: 9 pages, 8 figure

A model of multilingual digital library

Este trabalho aborda o problema de bibliotecas digitais multilíngües. A motiviação para tal biblioteca digital decorre da diversidade de línguas dos usuários da Internet, bem como da diversidade dos autores do conteúdo, de autores de livros eletrônicos para elaboradores de cursos. São discutidas as definições básicas de tal sistema, as especificações de sua funcionalidade e a identificação dos itens que ele comporta. Apresenta-se o impacto do multilingüismo em cada um dos aspectos anteriores. Um estudo de caso de uma biblioteca digital multilíngüe – no Sistema Maxwell, na PUC-Rio – é descrito nas últimas seções. Suas principais características são descritas e é mostrado o status atual de sua biblioteca digital

Qualitative and quantitative phytochemical screening and in vitro anti oxidant and anti microbial activities of Elephantopus scaber Linn.

Preliminary phytochemical analysis and quantification of total phenols, In-vitro antioxidant and anti microbial activities of the different fractions (hydro alcoholic, hexane, ethyl acetate and methanol) of Elephantopus scaber were carried out against five selected pathogenic bacteria and three fungal species. The plant fraction possesses steroids, triterpinoids, saponins, flavonoides, carbohydrates, glycosides and oils. For total phenolic content gallic acid was taken as a standard, the ethyl acetate fraction contains rich phenolic content than other fractions and the methanol fraction shows more DPPH, superoxide and hydroxyl radical scavenging activity. In Anti-microbial activity study all fractions showed good inhibition zone against three organisms i.e., Escherichia coli, Staphylococcus aureus Klebsiella pneumonia among the other test organisms along with Candida spp (fungal organism)

SYNTHESIS AND BIOLOGICAL EVALUATION OF SOME NOVEL HETEROCYCLIC MANNICH BASES

Various novel heterocyclic mannich bases were prepared by using Mannich reaction. Acetanilide was treated with substituted benzaldehyde and morpholine / methyl amine to give corresponding titled compounds in good yields. The synthesized compounds were characterized by physical properties and spectral studies (IR, 1H-NMR) and tested for antimicrobial activity against Escherichia coli, Bacillus subtilis by using cup plate method with reference to the standard Streptomycin. All the titled compounds show good antimicrobial activity

Different Uses for Remote Labs in Electrical Engineering Education: Initial Conclusions of an Ongoing Experience

Laboratories are a fundamental part of engineering education due to the very nature of the engineering profession. This is a characteristic of all en-gineering courses, though it may vary from one curriculum to the other and even in the same curriculum. This paper is dedicated to the analysis of different applications of a remote lab in an Electrical Engineering curriculum. If the types of experiments it offers are concerned, it is classified as an Electric and Electronic Circuits lab; one in a set that also has Digital Electronics, Analog Electronics, Electrical Machines, Control Systems, etc. But it is not a traditional lab – it is a remote lab, with traditional components remotely accessed over the Internet. This work presents the preliminary results of the deployment of VISIR – a remote lab for Electric and Electronic Circuits in some courses. It discusses the different course contexts and how the use of VISIR was adapted to each one. Results of students’ opinions are presented and discussed.N/