HI and OH absorption at z=0.89

We report on WSRT observations of HI and OH absorption at z=0.885 towards the radio lens PKS 1830-21, mm wave transitions of several molecular species have already been observed at this redshift. At mm wavelengths the source structure is dominated by two extremely compact components, the northeast (NE) and southwest (SW) components. At lower frequencies the continuum emission is much more extended and there is also a broad Einstein ring connecting the NE and SW components. This means that the HI and OH spectra sample a much larger region of the absorber than the mm wave spectra. The HI spectrum that we obtain is asymmetric, with a peak at -147 km/s with respect to the main molecular line redshift of z=0.88582. Weak mm wave molecular absorption has also been detected towards the NE component at this same velocity. The HI absorption, however, covers a total velocity width of 300 km/sec, i.e. including velocities well to the red of molecular features suggesting that it is spatially widespread. In OH we detect both the 1667 and the 1665 MHz transitions. The OH spectrum has a velocity width comparable to that of the HI spectrum, suggesting that it too is widespread in the absorber. The lack of a prominent HI peak in the spectrum at the velocity corresponding to the SW component, suggests that the galaxy responsible for the absorption at z=0.885 has a central molecular disk many kpc in size, and that HI is deficient in this central region. Our observations are sensitive to the large scale kinematics of the absorber, and to first order the implied dynamical mass is consistent with the lens models of Nair et. al. (1993).Comment: 4 pages, 3 figure

Indian summer monsoon experiments

Eight major field experiments have been carried out so far addressing the Indian summer monsoon. While these experiments were international and the impetus was external till 1980, India's own monsoon programmes evolved since then. In this article, objectives and outcomes from some of these experiments are described. It is shown that monsoon experiments have contributed in several ways. Each experiment enhanced the infrastructure facilities in the country, brought together scientists from different organizations to a common platform and also injected new people in this field. A large amount of data have been generated and their analysis has led to better understanding of the summer monsoon and discovery of new phenomena

On The Center Sets and Center Numbers of Some Graph Classes

For a set $S$ of vertices and the vertex $v$ in a connected graph $G$, $\displaystyle\max_{x \in S}d(x,v)$ is called the $S$-eccentricity of $v$ in $G$. The set of vertices with minimum $S$-eccentricity is called the $S$-center of $G$. Any set $A$ of vertices of $G$ such that $A$ is an $S$-center for some set $S$ of vertices of $G$ is called a center set. We identify the center sets of certain classes of graphs namely, Block graphs, $K_{m,n}$, $K_n-e$, wheel graphs, odd cycles and symmetric even graphs and enumerate them for many of these graph classes. We also introduce the concept of center number which is defined as the number of distinct center sets of a graph and determine the center number of some graph classes

Novel heat-flux scaling for convection at low winds

An analysis of atmospheric observational data indicates that the conventionally defined drag and heat transfer coefficients increase rapidly as wind speed falls. It is shown here that, at low winds, (i) there is a linear increase of drag with wind speed and (ii) the observed heat flux is independent of wind speed. These findings are not consistent with the so-called free-convection limit of Monin-Obukhov theory. They are instead best seen as the result of a new regime of 'weakly forced convection', in which the heat flux is determined solely by temperature differentials as in free convection, and the momentum flux by a perturbation linear in wind on free convection. This regime is governed by a new velocity scale determined by the heat flux (rather than by the friction velocity as in classical turbulent boundary layer theory). Novel definitions of the drag and heat exchange coefficients, based on appropriate heat-flux velocity scales, are found to be independent of wind speed at low winds. The height of the capping inversion in this regime is proportional to the surface heat flux, and is determined by a simple argument balancing energy supply at surface to rate of work done to lift air parcels to inversion height

Amoxicillin induced toxic epidermal necrolysis

Toxic epidermal necrolysis (TEN) is a rare life-threatening adverse drug reaction associated with mucocutaneous eruptions and peeling of skin (sloughing) mostly caused by drugs like sulphonamides, beta lactams, carbamazepine and non-steroidal anti-inflammatory drugs (NSAIDs). Amoxicillin is a broad spectrum, bactericidal, Beta-lactam antibiotic used in treatment of various infections. Here by we have reported the case of amoxicillin induced severe toxic epidermal necrolysis. A Patient admitted in the hospital with the symptoms of epidermal sloughing that resulted in bare dermis as he received Amoxicillin drug for his diagnosis of fever. After clear examination TEN was confirmed and suspected with the cause due to Amoxicillin. The drug was stopped and patient was treated with other drugs for symptomatic cure. The patient was recovered from his condition and improved significantly