The AGN and Gas Disk in the Low Surface Brightness Galaxy PGC045080

We present radio observations and optical spectroscopy of the giant low surface brightness (LSB) galaxy PGC 045080 (or 1300+0144). PGC 045080 is a moderately distant galaxy having a highly inclined optical disk and massive HI gas content. Radio continuum observations of the galaxy were carried out at 320 MHz, 610 MHz and 1.4 GHz. Continuum emission was detected and mapped in the galaxy. The emission appears extended over the inner disk at all three frequencies. At 1.4 GHz and 610 MHz it appears to have two distinct lobes. We also did optical spectroscopy of the galaxy nucleus; the spectrum did not show any strong emission lines associated with AGN activity but the presence of a weak AGN cannot be ruled out. Furthermore, comparison of the H$\alpha$ flux and radio continuum at 1.4 GHz suggests that a significant fraction of the emission is non-thermal in nature. Hence we conclude that a weak or hidden AGN may be present in PGC 045080. The extended radio emission represents lobes/jets from the AGN. These observations show that although LSB galaxies are metal poor and have very little star formation, their centers can host significant AGN activity. We also mapped the HI gas disk and velocity field in PGC 045080. The HI disk extends well beyond the optical disk and appears warped. In the HI intensity maps, the disk appears distinctly lopsided. The velocity field is disturbed on the lopsided side of the disk but is fairly uniform in the other half. We derived the HI rotation curve for the galaxy from the velocity field. The rotation curve has a flat rotation speed of ~ 190 km/s.Comment: Paper contains 14 figures and 4 tables. Figures 8, 10 (color) and 13 supplied separately. Accepted for publication in MNRA

On feature reduction with application to electroencephalograms

Random process model and feature reduction of spontaneous and alpha frequency electroencephalogram

Interplanetary Consequences of a Large CME

We analyze a coronal mass ejection (CME) which resulted from an intense flare in active region AR486 on November 4, 2003. The CME propagation and speed are studied with interplanetary scintillation images, near-Earth space mission data, and Ulysses measurements. Together, these diverse diagnostics suggest that the internal magnetic energy of the CME determines its interplanetary consequences.Comment: 5 pages, 9 figures, To appear in "Magnetic Coupling between the Interior and the Atmosphere of the Sun", eds. S.S. Hasan and R.J. Rutten, Astrophysics and Space Science Proceedings, Springer-Verlag, Heidelberg, Berlin, 200

Night sky at the Indian Astronomical Observatory during 2000-2008

We present an analysis of the optical night sky brightness and extinction coefficient measurements in UBVRI at the Indian Astronomical Observatory (IAO), Hanle, during the period 2003-2008. They are obtained from an analysis of CCD images acquired at the 2 m Himalayan Chandra Telescope at IAO. Night sky brightness was estimated using 210 HFOSC images obtained on 47 nights and covering the declining phase of solar activity cycle-23. The zenith corrected values of the moonless night sky brightness in mag/square arcsecs are 22.14(U), 22.42(B), 21.28(V), 20.54(R) and 18.86(I) band. This shows that IAO is a dark site for optical observations. No clear dependency of sky brightness with solar activity is found. Extinction values at IAO are derived from an analysis of 1325 images over 58 nights. They are found to be 0.36 in U-band, 0.21 in B-band, 0.12 in V-band, 0.09 in R-band and 0.05 in I-band. On average, extinction during the summer months is slightly larger than that during the winter months. No clear evidence for a correlation between extinction in all bands and the average night time wind speed is found. Also presented here is the low resolution moonless optical night sky spectrum for IAO covering the wavelength range 3000-9300 \AA. Hanle region thus has the required characteristics of a good astronomical site in terms of night sky brightness and extinction, and could be a natural candidate site for any future large aperture Indian optical-infrared telescope(s).Comment: 18 pages, 7 figures, uses basi.cls, accepted for publication in Bulletin of the Astronomical Society of Indi

Aplicação de silicato de cálcio na cultura do arroz.

Na Embrapa Arroz e Feijão, as pesquisa sobre utilização de silicato de cálcio em arroz foram iniciadas em 1995. Apesar de recentes, as pesquisas tem obtido resultados extremamente interessantes do efeito do silicato de cálcio, tanto no aumento de rendimento de grãos e incidência de doenças, quanto na melhoria da fertilidade do solo e como condicionador de condições quimicamente favoráveis ao desenvolvimento das plantas.bitstream/CNPAF/19678/1/circ_51.pd

Review Study on Larvicidal and Mosquito Repellent Activity of Volatile Oils Isolated from Medicinal Plants

Mosquito is a vector for serious human diseases like dengue fever, hemaorrhagic dengue fever and chikungunya, .yellow fever, malaria, filaria and encephalitis among these dengue, hemaorrhagic dengue and chikungunya are highly endemic diseases in Southeast Asian and African countries, causing millions of deaths each and every year. Mosquito repellents thus play a major role in preventing man-mosquito contact and there by minimize the chance of infections and its adverse effects. The development of resistance to chemical insecticides, results rebounding vectorial capacity. Synthetic repellents are chemicals which used worldwide for protection against mosquito-borne diseases and it adversely affects the environment by contaminating water, soil and air. There is an urgent need to find alternatives to the synthetic insecticides. Plants are rich source of alternative agents for control of mosquitoes and its vectors. Extracts and isolated compounds from different plant families have been evaluated for their promising larvicidal and mosquito repellent activities. Literature has documented that essential oils and extracts have been traditionally used as effective repellents. The essential oils whose repellent activities have been demonstrated, as well as the importance of the synergistic effects among their components are the main focus of this review study. Essential oils are volatile mixtures of hydrocarbons with a diversity of functional groups, and their repellent activity has been linked to the presence of monoterpenes and sesquiterpenes. The present review study focused the larvicidal potential and mosquito repellent activity of different volatile oils of medicinal plants. From an economical point of view synthetic chemical is still more frequently used as repellents than essential oils; these essential oils have the potential to provide efficient and can be used as a cheap, eco-friendly, safer for humans and the environment and also efficient alternative to the chemical larvicides

Aplicação de silicato de cálcio na cultura do arroz.

Características desejáveis das fontes de silício; Resultados de pesquisa; Perspectivas.bitstream/CPAF-AC-2009-09/20799/1/circ_51.pd

Optical Photometry of the GRB 010222 Afterglow

The optical afterglow of GRB 010222 was observed using the recently installed 2-m telescope at the Indian Astronomical Observatory, Hanle, and the telescopes at the Vainu Bappu Observatory, Kavalur, beginning ~ 0.6 day after the detection of the event. The results based on these photometric observations combined with others reported in the literature are presented in this paper. The R band light curve shows an initial decline of intensities proportional to t^{-0.542} which steepens, after 10.3 hours, to t^{-1.263}. Following the model of collimated outflow, the early break in the light curve implies a very narrow beam angle (~ 2-3 deg). The two decay rates are consistent with the standard jet model in a uniform density ambient medium, but require a hard spectrum of electron power density with p ~ 1.5. The R band light between 14 and 17 hours since outburst departs from the power law fit by 0.1 mag and shows some evidence for fluctuations over timescales of an hour in the observer's frame. Such deviations are expected due to density inhomogeneities if the ambient medium is similar to the local interstellar medium. GRB 010222 is thus an example of a highly collimated outflow with a hard spectrum of electron energy distribution in normal interstellar environment.Comment: 15 pages, Latex, including 2 postscript figures, to appear in the Bull. astro. Soc. India, September 2001 issu

Pharmacognostic and Phytochemical Analysis of Asystasia Variabilis Trim. - An Extrapharmacopoeal Ayurvedic Medicinal Plant

Background - Asystasia Variabilis Trim. also known as Maithaala Kaddi by traditional practitioners of Udupi. Belonging to the family Acanthaceae. Is a semi-scandent herb, and effectively used by the Folklore practitioners for the management of Amlapitta (acid peptic disorder), worm infestations and rheumatism. Aim - To explore the pharmacognostical and preliminary phytochemical parameters of plant to standardize the drug. Materials and Methods - whole mature plant of A.variabilis was collected from Udupi district. Macroscopic, microscopic physico-chemical standards, HPTLC and secondary metabolites screening were scientifically recorded. Results - The pharmacognostical leaf study has shown single layered epidermis throughout midrib and lamina. Anatomical features of stem exhibit single layer of epidermis covered with trichomes. Inner to this, densely arranged collenchyma cells are present. In transverse section of root showed epidermal layer is surrounded by root hairs which are abundant. Powder microscopy characteristics showed the presence of starch in parenchyma region, mesophyll cells with stomata and sclerides were present. The standard out print of the drug is represented by physicochemical standards and HPTLC. Preliminary Phytochemical study shows that it contains Alkaloids, Carbohydrates, Steroids, Tannins and Phenol. Conclusion - Pharmacognostical study carried out on A.variabilis showed quality standards of the drug, with respect to its macroscopy, microscopy, physico-chemical standards and HPTLC