Diffuse Ionized Gas in the Dwarf Irregular Galaxy DDO 53

The spectral characteristics throughout the dwarf irregular galaxy DDO 53 are studied. The results are very similar to those for other irregular galaxies: high excitation and low values of the [SII]/Halpha ratio. The most likely ionization source is photon leakage from the classical HII regions, without any other source, although the interstellar medium of the galaxy is quite perturbed. Moreover, the physical conditions throughout the galaxy do not change very much because both the photon leakage percentage and the ionization temperature are very similar. In addition, the determined metal content for two HII regions indicates that DDO 53 is a low-metallicity galaxy.Comment: 32 pages, 9 figures, 7 tables. AJ, in pres

The Local Group dwarf Leo T: HI on the brink of star formation

We present Giant Meterwave Radio Telescope (GMRT) and Westerbork ynthesis Radio Telescope (WSRT) observations of the recently discovered Local Group dwarf galaxy, Leo T. The peak HI column density is measured to be 7x10^20 cm^-2, and the total HI mass is 2.8Xx10^5 Msun, based on a distance of 420 kpc. Leo T has both cold (~ 500 K) and warm (~ 6000 K) HI at its core, with a global velocity dispersion of 6.9 km/s, from which we derive a dynamical mass within the HI radius of 3.3x10^6 Msun, and a mass-to-light ratio of greater than 50. We calculate the Jeans mass from the radial profiles of the HI column density and velocity dispersion, and predict that the gas should be globally stable against star formation. This finding is inconsistent with the half light radius of Leo T, which extends to 170 pc, and indicates that local conditions must determine where star formation takes place. Leo T is not only the lowest luminosity galaxy with on-going star formation discovered to date, it is also the most dark matter dominated, gas-rich dwarf in the Local Group.Comment: 6 pages, 7 figures, accepted for publication in MNRAS on November 15th 2007, full resolution version at: http://www.ast.cam.ac.uk/~eryan/leot.pdf . Typographical error in sound speed equation has led to a new Figure 6 and minor changes to the tex

Trophoblast-induced changes in C-x-C motif chemokine 10 expression contribute to vascular smooth muscle cell dedifferentiation during spiral artery remodeling.

Objective- During pregnancy, fetal trophoblast disrupt endothelial cell and vascular smooth muscle cell (VSMC) interactions in spiral arteries of the maternal decidua to enable increased nutritional and oxygen delivery to the fetus. Little is known regarding this transformation because of difficulties of studying human pregnancy in vivo. This study investigated how trophoblast-secreted factors affect the interactions of vascular cells and the differentiation status of VSMC during spiral arteries remodeling using 3-dimensional vascular spheroid coculture. Methods and Results— Endothelial cell and VSMC were cocultured in hanging droplets to form spheroids representing an inverted vessel lumen. Control or conditioned media from an extravillous trophoblast (EVT) cell line was incubated with vascular spheroids for 24 hours. Spheroid RNA was then analyzed by Illumina Sentrix BeadChip array. Spheroids incubated with EVT conditioned medium showed significant up/downregulation of 101 genes (>1.5-fold; P<0.05), including an upregulation of C-X-C motif chemokine 10 (IP-10). C-X-C motif chemokine 10 expression was confirmed by qualitative real-time PCR and Western blot analysis of spheroids, and immunohistochemistry of first trimester decidua and ex vivo dissected nonplacental bed spiral arteries. EVT conditioned medium reduced VSMC expression of differentiation markers, and both EVT conditioned medium and C-X-C motif chemokine 10 increased motility of VSMC indicating dedifferentiation of VSMC. Conclusion— EVT-induced C-X-C motif chemokine 10 expression may contribute to spiral arteries remodeling during pregnancy by altering the motility and differentiation status of the VSMC in the vessel

Responses of Cyprinus carpio var. communis to Cyhalothrin, a pyrethroid insecticide

Haematological and biochemical profiles in a freshwater teleost, Cyprinus carpio var. communis, exposed to sub-lethal toxicity of the insecticide cyhalothrin were studied. During the treatment, erythrocyte count, haemoglobin content and protein content decreased, whereas leucocyte count and glucose level increased. The data are discussed in relation to the significance of haematological and biochemical changes as non-specific biomarkers against anthropogenic stress

NGC 602 Environment, Kinematics and Origins

The young star cluster NGC 602 and its associated HII region, N90, formed in a relatively isolated and diffuse environment in the Wing of the Small Magellanic Cloud. Its isolation from other regions of massive star formation and the relatively simple surrounding HI shell structure allows us to constrain the processes that may have led to its formation and to study conditions leading to massive star formation. We use images from Hubble Space Telescope and high resolution echelle spectrographic data from the Anglo-Australian Telescope along with 21-cm neutral hydrogen (HI) spectrum survey data and the shell catalogue derived from it to establish a likely evolutionary scenario leading to the formation of NGC 602. We identify a distinct HI cloud component that is likely the progenitor cloud of the cluster and HII region which probably formed in blister fashion from the cloud's periphery. We also find that the past interaction of HI shells can explain the current location and radial velocity of the nebula. The surrounding Interstellar Medium is diffuse and dust-poor as demonstrated by a low visual optical depth throughout the nebula and an average HI density of the progenitor cloud estimated at 1 cm^-3. These conditions suggest that the NGC 602 star formation event was produced by compression and turbulence associated with HI shell interactions. It therefore represents a single star forming event in a low gas density region.Comment: Accepted for publication in PASP. 25 pages, 10 figure

Study of genetic variation of some eggplant cultivars through RAPD-PCR molecular markers and its relatedness to phomopsis blight disease reaction

Disease susceptibility and genetic variability in 10 eggplant genotypes were studied after inoculating Phomopsis vexans under confined field conditions. Random amplified polymorphic DNA (RAPD) markers were used to assess genetic variation and relationships among eggplant genotypes. The disease index of leaves ranged 0.208-13.79%, while fruit infection ranged 2.15-42.76%. Two varieties, Dohazari G and Laffa S, were found to be susceptible, 6 were moderately resistant, 1 was moderately susceptible, and BAU Begun-1 was resistant to P. vexans. Amplification of genomic DNA by using 3 RAPD primers produced 20 bands: 14 (70%) were polymorphic and 6 (30%) were monomorphic. The highest intra-variety similarity indices values were found in ISD 006, Ishurdi L, Jessore L, and BAU Begun-1 (100%), while the lowest was in Dohazari G (90%). The lowest genetic distance (0.0513) and the highest genetic identity (0.9500) were observed between the ISD 006 and Ishurdi L combinations. A comparatively higher genetic distance (0.3724) and the lowest genetic identity (0.6891) were observed between the ISD 006 and Dohazari G combinations. A dendogram was constructed based on Nei’s genetic distance, which produced 2 main clusters of the genotypes - Cluster I: ISD 006, Ishurdi L, Marich begun L, BAU Begun-1, Marich begun S, and Chega and Cluster 2: Laffa S, Dohazari G, Jessore L, and Singhnath. Genetic variation and its relationship with disease susceptibility were assessed using RAPD markers, to develop disease-resistant varieties and improve eggplant crops

Binary Galaxies in the Local Supercluster and Its Neighborhood

We report a catalog of 509 pairs identified among 10403 nearby galaxies with line-of-sight velocities V_LG < 3500 km/s.We selected binary systems in accordance with two criteria (bounding and temporal), which require the physical pair of galaxies to have negative total energy and its components to be located inside the zero-velocity surface. We assume that individual galaxy masses are proportional to their total K-band luminosities, M = L_K x 6M/L. The catalog gives the magnitudes and morphological types of galaxies and also the projected (orbital) masses and pair isolation indices. The component line-of-sight velocity differences and projected distances of the binary systems considered have power-law distributions with the median values of 35 km/s and 123 kpc, respectively. The median mass-to-K-band luminosity ratio is equal to 11 M/L, and its uncertainty is mostly due to the errors of measured velocities. Our sample of binary systems has a typical density contrast of d ro/ro_c ~ 500 and a median crossing time of about 3.5 Gyr. We point out the substantial fraction of binary systems consisting of late-type dwarf galaxies, where the luminosities of both components are lower than that of the Small Magellanic Cloud. The median projected distance for 41 such pairs is only 30 kpc, and the median difference of their line-of-sight velocities is equal to 14 km/s which is smaller than the typical error for radial-velocity (30 km/s). This specific population of gas-rich dwarf binary galaxies such as I Zw 18 may be at the stage immediately before merging of its components. Such objects, which are usually lost in flux-limited (and not distance-limited) samples deserve a thorough study in the HI radio line with high spatial and velocity resolution.Comment: published in Astrophysical Bulletin, 2008, Vol. 63, No. 4, pp. 299-34