A high-sensitivity OH 5-cm line survey in late-type stars

We have undertaken a comprehensive search for 5-cm excited OH maser emission from evolved stars representative of various stages of late stellar evolution. Observed sources were selected from known 18-cm OH sources. This survey was conducted with the 100-m Effelsberg telescope to achieve high signal to noise ratio observations and a sensitivity limit of about 0.05 to 0.1 Jy. A total of 64 stellar sources were searched for both main line and satellite line emission. We confirm the previous detection of 5 cm OH in Vy 2-2, do not confirm emission from NML-Cyg and do not report any other new detection within the above sensitivity limit. Implications of these results on the pumping mechanism of the OH radical in circumstellar envelopes are briefly discussed.Comment: 8 pages, 5 figures, A&A in pres

Evaluation of micronutrient status of sandy clay loam as influenced by sulphur fertilization on blackgram

Secondary nutrient deficiency especially sulphur (S) in blackgram has imparted poor grain setting percentage and yield as well. Interest on S availability in soils has increased due to acute shortage production of quality blackgram. Therefore, an attempt was made to assess the three SO4-2- S sources (Gypsum, Ammonium sulphate and Potassium sulphate) and two S levels (10 and 20 kg S ha-1) under irrigated condition. This experimental trial was replicated three times along with randomized block design at farmer field of Thenamallur village, T. Kallikudi block, Madurai district. S treatments were also evaluated by two methods of fertilizer amendment such as, soil application (as basal dose) and foliar spray (0.5 % K2SO4) on 30th and 45th days after sowing and its combinations. Soil analysis is good method to assess the S nutritional status of soil under tropical areas. The results revealed that the S and micronutrient content was low in single soil application or foliar spray and irrespective of source and level. Foliar spray treatment plants recovered limited S concentration. We could found that the better higher S concentration among the combination treatments. Soil application of K2SO4 @ 20 kg ha-1 + foliar spray was increased the soil available S and DTPA - extractable Micronutrient (Zn, Fe, Mn and Cu) status. Our study explains that the treatment combinations had synergistic effect and it may be concluded that the combinations (soil + foliar spray) are increased soil available S and micronutrient status. Further, future studies are required to confirm the results of S fertilizers in alkaline soil

Astrometry of circumstellar masers

The circumstellar masers around evolved stars offer an interesting possibility to measure stellar parameters through VLBI astrometry. In this paper the application of this technique is discussed, including the accuracy and the uncertainties of the method. The different maser species (OH, H_2O, SiO) have slightly different characteristics and applications. This paper does not concern astrometry of maser spots to study the kinematics of the envelope, but concentrates on attempting to measure the motion of the underlying star.Comment: 8 pages, 2 figures, to appear in "Mass-losing Stars and their Circumstellar Matter", eds Y. Nakada & M. Honma, Kluwer ASSL serie

Outpatient prescription audit in a tertiary care hospital at Puducherry

Background: Rational use of medicines promotes good health practices and prevents inappropriate use of medicines, polypharmacy, unnecessary use of antimicrobials, injections, and also encourages use of medicines from essential medicine list and dispensing by generic names. The aim of the study was to analyze the outpatient prescriptions of a tertiary care centre by utilizing World Health Organization (WHO) core drug use prescribing indicators.Methods: A retrospective observational study was conducted in a tertiary care health setup at Puducherry, South India. Outpatient prescriptions from all the major clinical departments were analyzed using WHO prescribing indicators and they were compared with some similar studies.Results: The average number of drugs per prescription was 2.74. The percentage of prescriptions with antibiotics was 20.33% and the percentage of prescriptions with injections was 0.16%. The percentage of drugs prescribed by generic names and from essential medicine list was 83.13% and 87.9 respectively. Further antibiotic utilization was found to be higher in the department of ENT (56.67%), respiratory medicine (45%) and surgery (40%). Percentage of drugs prescribed by generic names in pediatrics and respiratory medicine were found to be 67.88% and 65.27% and percentage of drugs prescribed from essential medicine list in dermatology was 69.62%.Conclusions: Prescription pattern followed in our Institute almost adheres to the guidelines laid down by the WHO. Moreover, it is also implied that a routine audit of this type should be done in health care setups to ensure that they adhere to the WHO guidelines for better health care

Observations of the 6 Centimeter Lines of OH in Evolved (OH/IR) Stars

Recent observational and theoretical advances have called into question traditional OH maser pumping models in evolved (OH/IR) stars. The detection of excited-state OH lines would provide additional constraints to discriminate amongst these theoretical models. In this Letter, we report on VLA observations of the 4750 MHz and 4765 MHz lines of OH toward 45 sources, mostly evolved stars. We detect 4765 MHz emission in the star forming regions Mon R2 and LDN 1084, but we do not detect excited-state emission in any evolved stars. The flux density and velocity of the 4765 MHz detection in Mon R2 suggests that a new flaring event has begun.Comment: 4 pages, to appear in ApJ

Infrared Spectroscopy of U Equulei's Warm Circumstellar Gas

Medium and high resolution spectroscopy of U Equulei from 1 to 4 microns during 1997-2003 has revealed information about its unusual circumstellar envelope, observed previously at optical and radio wavelengths. Strong absorption bands of H2O and of CO dominate the 1-4um spectrum. The gas has a mean temperature of 600 K and 12C/13C =< 10. The CO 2-0 line profiles and velocities imply no net ejection or infall and indicate either rapid radial gas motions being seen along a narrow continuum beam, or absorption by orbiting gas that is nearly coincident with a highly extended continuum source. The gas could be located in a disk-like structure. The observed high column densities of warm CO and H2 normally would be associated with sufficient dust to completely obscure the star at optical wavelengths. The observations thus indicate either a highly abnormal gas-to-dust ratio, consistent with the earlier optical observation of abundant refractory metal oxides in the circumstellar gas, or peculiar geometry and/or illumination.Comment: 21 pages incl. 8 postscript figures and 1 table; typos correcte

Insight into the OH polarimetric structure of OH 26.5+0.6

We present the first view of the magnetic field structure in the OH shell of the extreme OH/IR star OH 26.5+0.6. MERLIN interferometric observations of this object were obtained in December 1993 in full polarisation, at 1612, 1665 and 1667 MHz. The maser spots show a spheroidal distribution both at 1612 and 1667 MHz, while at 1665 MHz emission from the blue-shifted maser peak is concentrated on the stellar position, and the red-shifted peak emission exhibits a filamentary structure oriented on a SE-NW axis. The linear polarisation in both main lines is rather faint, ranging from 9 to 20% at 1665 MHz and from 0 to 30% at 1667 MHz. At 1612 MHz most maser spots exhibit a similar range of linear polarisation although those in the outermost parts of the envelope reach values as high as 66%. This is particularly apparent in the southern part of the shell. The detailed distribution of the polarisation vectors could only be obtained at 1612 MHz. The polarisation vectors show a highly structured distribution indicative of a poloidal magnetic field inclined by 40-60$^\circ$ to the line of sight. The velocity distribution of the maser spots with respect to the radial distance is well explained by an isotropic outflow at constant velocity in the case of a prolate shaped spheroid envelope, also tilted about 45-65$^\circ$ to the line of sight.Comment: 20 pages, 16 figures, accepted for publication in MNRA

Polarization properties of OH masers in AGB and post-AGB stars

Context: Ground-state OH maser emission from late-type stars is usually polarized and remains a powerful probe of the magnetic field structure in the outer regions of circumstellar envelopes if observed with high angular and spectral resolutions. Observations in all four Stokes parameters are quite sparse and this is the most thorough, systematic study published to date. Aims: We aim to determine polarization properties of OH masers in an extensive sample of stars that show copious mass loss and search for candidate objects that are well-suited for high angular resolution studies. Methods: Full-polarization observations of the OH 1612 and 1667 MHz maser transitions were carried out for a sample of 117 AGB and post-AGB stars. Several targets were also observed in the 1665 MHz line. Results: Polarized features occur in more than 75% of the sources in the complete sample and there is no intrinsic difference in the occurrence of polarized emission between the three classes of objects of different infrared characteristics. The highest fractional polarization occurs for the post-AGB+PN and the Mira+SR classes at 1612 and 1667 MHz, respectively. Differences in the fractional polarization between the sources at different evolutionary stages appear to be related to depolarization caused by blending. The alignment of the polarization angles at the extreme sides of the shell implies a regular structure of the magnetic field of a strength of 0.3-2.3 mG. Conclusions: Polarized OH maser features are widespread in AGB and post-AGB stars. The relationship between the circular and linear fractional polarizations for a representative sample are consistent with the standard models of polarization for the Zeeman splitting higher than the Doppler line width, whereas the polarized features are the sigma components.Comment: Accepted for publication in Astronomy and Astrophysics. A version with appendices (Tab. A.1 and Fig. B.1) can be downloaded from http://paulo.astro.uni.torun.pl/~pw/arXiv_

Discrete Source Survey of 6 GHz OH emission from PNe & pPNe and first 6 GHz images of K 3-35

The aim of this study is to investigate the physical properties of molecular envelopes of planetary nebulae in their earliest stages of evolution. Using the 100m telescope at Effelsberg, we have undertaken a high sensitivity discrete source survey for the first excited state of OH maser emission (J=5/2, 2PI3/2 at 6GHz) in the direction of planetary and proto-planetary nebulae exhibiting 18cm OH emission (main and/or satellite lines), and we further validate our detections using the Nan\c{c}ay radio telescope at 1.6-1.7GHz and MERLIN interferometer at 1.6-1.7 and 6GHz. Two sources have been detected at 6035MHz (5cm), both of them are young (or very young) planetary nebulae. The first one is a confirmation of the detection of a weak 6035MHz line in Vy 2-2. The second one is a new detection, in K 3-35, which was already known to be an exceptional late type star because it exhibits 1720MHz OH emission. The detection of 6035MHz OH maser emission is confirmed by subsequent observations made with the MERLIN interferometer. These lines are very rarely found in evolved stars. The 1612MHz masers surround but are offset from the 1720 and 6035MHz masers which in turn lie close to a compact 22GHz continuum source embedded in the optical nebula.Comment: 9 pages, 7 figures, published in A&