FIGGS: Faint Irregular Galaxies GMRT Survey

The Faint Irregular Galaxies GMRT Survey (FIGGS) is a large program aimed at providing a comprehensive and statistically robust characterisation of the neutral ISM properties of faint (M_B > -14.5), nearby, gas rich, dwarf irregular galaxies using the Giant Metrewave Radio Telescope (GMRT). Here we briefly describe the survey and discuss some of the science that we anticipate can be done with this data set.Comment: 4 Pages, 3 Figures. To be published in the proceedings of "Galaxies in the Local Volume", ed. B. Koribalski, H. Jerje

Small Bites: Star formation recipes in extreme dwarfs

We study the relationship between the gas column density (Sigma_HI) and the star formation rate surface density (Sigma_SFR) for a sample of extremely small (M_B ~ -13, Delta V_50 ~ 30 km/s) dwarf irregular galaxies. We find a clear stochasticity in the relation between the gas column density and star formation. All gas with Sigma_HI >~ 10 M_sun/pc^2 has some ongoing star formation, but the fraction of gas with ongoing star formation decreases as the gas column density decreases, and falls to about 50% at Sigma_HI ~ 3 M_sun/pc^2. Further, even for the most dense gas, the star formation efficiency is at least a factor of ~ 2 smaller than typical of star forming regions in spirals. We also find that the ratio of H-alpha emission to FUV emission increases with increasing gas column density. This is unlikely to be due to increasing dust extinction because the required dust to gas ratios are too high. We suggest instead that this correlation arises because massive (i.e. H-alpha producing) stars are formed preferentially in regions with high gas density.Comment: 5 pages, 5 figures, 1 table. Accepted for publication in MNRAS Letters. The definitive version is available at www.blackwell- synergy.co

Cold HI in faint dwarf galaxies

We present the results of a study of the amount and distribution of cold atomic gas, as well its correlation with recent star formation in a sample of extremely faint dwarf irregular galaxies. Our sample is drawn from the Faint Irregular Galaxy GMRT Survey (FIGGS) and its extension, FIGGS2. We use two different methods to identify cold atomic gas. In the first method, line-of-sight HI spectra were decomposed into multiple Gaussian components and narrow Gaussian components were identified as cold HI. In the second method, the brightness temperature (T_B) is used as a tracer of cold HI. We find that the amount of cold gas identified using the T_B method is significantly larger than the amount of gas identified using Gaussian decomposition. We also find that a large fraction of the cold gas identified using the T_B method is spatially coincident with regions of recent star formation, although the converse is not true. That is only a small fraction of the regions with recent star formation are also covered by cold gas. For regions where the star formation and the cold gas overlap, we study the relationship between the star formation rate density and the cold \HI column density. We find that the star formation rate density has a power law dependence on the HI column density, but that the slope of this power law is significantly flatter than that of the canonical Kennicutt-Schmidt relation.Comment: Accepted for publication in MNRA

Eco-friendly management of anthracnose of chilli caused by Colletotrichum capsici

The anthracnose of chilli caused by Colletotrichum capsici is a widespread problem limiting the profitable cultivation and seed production of chilli throughout the major chilli growing regions of India. Four isolates (SCC1, SCC2, SCC3 and SCC4) of C. capsici were collected from different chilli growing areas of West Bengal. An experiment on efficacy of four botanical oils viz., Garlic (Allium sativum), Neem (Azadirachta indica), Polyalthia (Polyalthia longifolia) and Citronella(Cymbopogon nardus) at concentrations of 0.05%, 0.1% and 0.2% and two isolates each of three biocontrol agents (Trichoderma harzianum, T. viride and Pseudomonas flourescens) were carried out against these isolates of C. capsici in vitro. The result revealed significant (5% level of significance) antifungal activities of these botanicals and biocontrol agents. Garlic gave cent per cent inhibition of mycelial growth of all the four isolates of C. capsici at all the concentrations tested. However, neem showed cent percent inhibition of mycelial growth of C. capsici at 0.1%. Citronella was least effective among the botanical oils. Among the biocontrol agents tested T. harzianum isolate Th-2 was found most effective giving 77.78%, 100%, 83.33 % and 88.89% inhibition on the mycelial growth of SCC1, SCC2, SCC3 and SCC4 respectively followed by T. harzianum isolate Th-1 inhibiting 74.00%, 78.9% 81.7% and 80.90% of the mycelial growth of SCC1, SCC2, SCC3 and SCC4 respectively. P. fluorescens was least effective. Thus, garlic, neem, polyalthia, T. harzianumand T. viride can be utilized for management of anthracnose of chilli

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

Methyl parathion induced regional alterations in the regulatory proteins during critical stage of central nervous system development in albino rat pups

Sublethal doses of methyl parathion (O,O-dimethyl-O-nitropbenyl-thiophosphate) injected intraperitoneally to IS and 21 day old rat pups induced regional alterations in the central nervous system (CNS) in the levels of total RNA, total proteins, modulatory protein Calmodulin (CaM), in the activity levels of memberane bound enzyme Cal•• ATPase and phospholipids. Levels of RNA and tOtal proteins increased considerably in IS days old methyl parathion treated (MPT) rat pups. Contrary to this the RNA lIIId total protein content exhibited remarkable decrease in 21 d.y old melthyl parathion treated animah. Calmodulin level showed an increase in cerebn.1 cortex and brain stern and decrease in cerebellum and spinal cord in IS day old methyl parathion treated rat pups. Whereas the level of Calmodulin decreased in cerebral cortex and cerebellum and increased in brain stem and spinal cord in 21 day ·old methyl parathion treated rat pups. Activity levels of calcium dependent ATPase showed significant inhibition in all the regions of Central Nervous System (CNS) of IS and 21 day old methyl parathion treated rat pups. Phospholipids showed a general increase in all the regions of Central Nervous System on methyl parathion exposure. In the light of these observations, it has been suggested that the molecular regulatory mechanisms involving Ca"/CaM are rendered inefficieilt due to toxic impact of methyl parathion

Nonparametric Bayesian Multiple Comparisons for Dependence Parameter in Bivariate Exponential Populations

A nonparametric Bayesian multiple comparisons problem (MCP) for dependence parameters in I bivariate exponential populations is studied. A simple method for pairwise comparisons of these parameters is also suggested. The methodology by Gopalan and Berry (1998) is extended using Dirichlet process priors, applied in the form of baseline prior and likelihood combination to provide the comparisons. Computation of the posterior probabilities of all possible hypotheses are carried out through a Markov Chain Monte Carlo, Gibbs sampling, due to the intractability of analytic evaluation. The process of MCP for the dependent parameters of bivariate exponential populations is illustrated with a numerical example