The Mass-Size Relation from Clouds to Cores. I. A new Probe of Structure in Molecular Clouds

We use a new contour-based map analysis technique to measure the mass and size of molecular cloud fragments continuously over a wide range of spatial scales (0.05 < r / pc < 10), i.e., from the scale of dense cores to those of entire clouds. The present paper presents the method via a detailed exploration of the Perseus Molecular Cloud. Dust extinction and emission data are combined to yield reliable scale-dependent measurements of mass. This scale-independent analysis approach is useful for several reasons. First, it provides a more comprehensive characterization of a map (i.e., not biased towards a particular spatial scale). Such a lack of bias is extremely useful for the joint analysis of many data sets taken with different spatial resolution. This includes comparisons between different cloud complexes. Second, the multi-scale mass-size data constitutes a unique resource to derive slopes of mass-size laws (via power-law fits). Such slopes provide singular constraints on large-scale density gradients in clouds.Comment: accepted to ApJ; references updated in new versio

A Comparative Study Between Alcoholics of Koraga Community, Alcoholics of General Population and Healthy Controls for Antioxidant Markers and Liver Function Parameters

Objectives: It is well established that long-term alcohol consumption leads to liver cirrhosis and other related disorders. Sufficient work has been done on biochemical markers of liver damage and antioxidant status of chronic alcoholics in general population. In the current study chronic alcoholics from a community called Koraga are analysed for the same parameters in a view to assess the extent of liver damage as compared to healthy controls and other alcoholics. Methods: Serum and urine samples from Koraga alcoholics (n=28), general alcoholics (n=30) and healthy controls (n=31) were analysed for liver function parameters and antioxidant markers. Liver function parameters were determined by automated analyzer. Markers of antioxidant status were estimated spectrophotometrically. The data was analysed using SPSS version 16.0. Results: There was significant increase in serum AST, serum ALT, serum GST and urine GST in both general and Koraga alcoholics when compared to healthy controls (p<0.0001). Serum ALT, serum GST and urine GST activity was significantly higher in general alcoholics when compared to Koraga alcoholics (p<0.001). Serum and urine total thiol levels were significantly lower in general alcoholics when compared to healthy controls and Koraga alcoholics (p<0.0001). We have observed no difference in total thiols level between healthy controls and Koraga alcoholics, in fact, there was significant increase in urine total thiols level in Koraga alcoholics compared to healthy controls (p<0.001). On Pearson’s correlation serum AST, serum ALT correlated positively with serum and urine GST (p<0.0001) and negatively with serum total thiols (p<0.0001). Serum GST correlated negatively with serum total thiols (p<0.0001). Conclusion: Results of our study possibly indicate that the extent of alcohol induced liver damage in Koraga subjects is comparatively lower than general alcoholics, even though the alcohol consumption is found to be higher in them. There may be some mechanism that is rendering them resistant to alcoholic liver damage which needs to be explored through further studies at molecular level

Global Modeling of Spur Formation in Spiral Galaxies

We investigate the formation of substructure in spiral galaxies using global MHD simulations, including gas self-gravity. Our models extend previous local models by Kim and Ostriker (2002) by including the full effects of curvilinear coordinates, a realistic log-spiral perturbation, self-gravitational contribution from 5 radial wavelengths of the spiral shock, and variation of density and epicyclic frequency with radius. We show that with realistic Toomre Q values, self-gravity and galactic differential rotation produce filamentary gaseous structures with kpc-scale separations, regardless of the strength -- or even presence -- of a stellar spiral potential. However, the growth of sheared features distinctly associated with the spiral arms, described as spurs or feathers in optical and IR observations of many spiral galaxies, requires a sufficiently strong spiral potential in self gravitating models. Unlike independently-growing ''background'' filaments, the orientation of arm spurs depends on galactic location. Inside corotation, spurs emanate outward, on the convex side of the arm; outside corotation, spurs grow inward, on the concave side of the arm. Based on spacing, orientation, and the relation to arm clumps, it is possible to distinguish ''true spurs'' that originate as instabilities in the spiral arms from independently growing ''background'' filaments. Our models also suggest that magnetic fields are important in preserving grand design spiral structure when gas in the arms fragments via self-gravity into GMCs.Comment: 36 pages, 17 figures, Accepted for publication in ApJ. PDF version with high resolution figures available at http://www.astro.umd.edu/~shetty/Research

Accuracy of core mass estimates in simulated observations of dust emission

We study the reliability of mass estimates obtained for molecular cloud cores using sub-millimetre and infrared dust emission. We use magnetohydrodynamic simulations and radiative transfer to produce synthetic observations with spatial resolution and noise levels typical of Herschel surveys. We estimate dust colour temperatures using different pairs of intensities, calculate column densities and compare the estimated masses with the true values. We compare these results to the case when all five Herschel wavelengths are available. We investigate the effects of spatial variations of dust properties and the influence of embedded heating sources. Wrong assumptions of dust opacity and its spectral index beta can cause significant systematic errors in mass estimates. These are mainly multiplicative and leave the slope of the mass spectrum intact, unless cores with very high optical depth are included. Temperature variations bias colour temperature estimates and, in quiescent cores with optical depths higher than for normal stable cores, masses can be underestimated by up to one order of magnitude. When heated by internal radiation sources the observations recover the true mass spectra. The shape, although not the position, of the mass spectrum is reliable against observational errors and biases introduced in the analysis. This changes only if the cores have optical depths much higher than expected for basic hydrostatic equilibrium conditions. Observations underestimate the value of beta whenever there are temperature variations along the line of sight. A bias can also be observed when the true beta varies with wavelength. Internal heating sources produce an inverse correlation between colour temperature and beta that may be difficult to separate from any intrinsic beta(T) relation of the dust grains. This suggests caution when interpreting the observed mass spectra and the spectral indices.Comment: Revised version, 17 pages, 17 figures, submitted to A&

Silicon-induced changes in antifungal phenolic acids, flavonoids, and key phenylpropanoid pathway genes during the interaction between miniature roses and the biotrophic pathogen <em>Podosphaera pannosa</em>

Application of 3.6 mm silicon (Si+) to the rose (Rosa hybrida) cultivar Smart increased the concentration of antimicrobial phenolic acids and flavonoids in response to infection by rose powdery mildew (Podosphaera pannosa). Simultaneously, the expression of genes coding for key enzymes in the phenylpropanoid pathway (phenylalanine ammonia lyase, cinnamyl alcohol dehydrogenase, and chalcone synthase) was up-regulated. The increase in phenolic compounds correlated with a 46% reduction in disease severity compared with inoculated leaves without Si application (Si−). Furthermore, Si application without pathogen inoculation induced gene expression and primed the accumulation of several phenolics compared with the uninoculated Si− control. Chlorogenic acid was the phenolic acid detected in the highest concentration, with an increase of more than 80% in Si+ inoculated compared with Si− uninoculated plants. Among the quantified flavonoids, rutin and quercitrin were detected in the highest concentrations, and the rutin concentration increased more than 20-fold in Si+ inoculated compared with Si− uninoculated plants. Both rutin and chlorogenic acid had antimicrobial effects on P. pannosa, evidenced by reduced conidial germination and appressorium formation of the pathogen, both after spray application and infiltration into leaves. The application of rutin and chlorogenic acid reduced powdery mildew severity by 40% to 50%, and observation of an effect after leaf infiltration indicated that these two phenolics can be transported to the epidermal surface. In conclusion, we provide evidence that Si plays an active role in disease reduction in rose by inducing the production of antifungal phenolic metabolites as a response to powdery mildew infection

The Mass-Size Relation from Clouds to Cores. II. Solar Neighborhood Clouds

We measure the mass and size of cloud fragments in several molecular clouds continuously over a wide range of spatial scales (0.05 < r / pc < 3). Based on the recently developed "dendrogram-technique", this characterizes dense cores as well as the enveloping clouds. "Larson's 3rd Law" of constant column density, m(r) = C*r^2, is not well suited to describe the derived mass-size data. Solar neighborhood clouds not forming massive stars (< 10 M_sun; Pipe Nebula, Taurus, Perseus, and Ophiuchus) obey m(r) < 870 M_sun (r / pc)^1.33 . In contrast to this, clouds forming massive stars (Orion A, G10.15$-$0.34, G11.11$-$0.12) do exceed the aforementioned relation. Thus, this limiting mass-size relation may approximate a threshold for the formation of massive stars. Across all clouds, cluster-forming cloud fragments are found to be---at given radius---more massive than fragments devoid of clusters. The cluster-bearing fragments are found to roughly obey a mass-size law m = C*r^1.27 (where the exponent is highly uncertain in any given cloud, but is certainly smaller than 1.5).Comment: accepted to the Astrophysical Journa

Workplace Collaboration Using Remote Desktop

WORKPLACE COLLABORATION USING REMOTE DESKTOP refers to a software or Operating System feature that allows a PCs desktop environment (client) to be run remotely by another system (server). It is a set of platform for the project leaders and administrator to monitor the activities performed by their team in real time (live) and sends messages to keep constant interaction with the programmers. We aim to provide multiple features through a single platform. It helps to maintain the attendance record in an organization, provides a feature of monitoring all the live activities performed by the employee in real time and block the users from doing any inappropriate or unofficial task during their work hours and to provide communication between the employee within an organization through video chatting and text chatting features along with the file transfer activity as well .This facilitates the user to concentrate more on the project and less on the managing of these tasks. In particular, showing live actions on the Administrators desktop of a remote employee has great instructional value that must not be overlooked. Similarly, an employee can demonstrate skills and report about the status of the project from time to time that would otherwise need a physical presence in a meeting, rather than a virtual one