Occultation of compact radio sources by the ion tail of Halley's Comet

Enhancements of scintillations of the compact radio sources PKS 2314+03 and 1827-360 were observed at 103 MHz and 408 MHz during 18-21 December 1985 and on 29 March 1986, respectively, when the plasma tail of Halley's Comet swept across them. At 103 MHz the RMS plasma density variation along the tail was 10 and 3.3/cu cm at 0.12 AU and 0.18 AU, respectively, as measured from the comet's position. At 408 MHz it was 1.9/cu cm at 0.036 AU. Comparison of results of these two sets of observations is presented

Microwave solar radiometer at 2800 MHz

A Dicke-type microwave radiometer has been developed for daily measurement of solar flux at 2800 MHz. The antenna system, consists of a 5 foot parabolic dish with horn feed, is equatorially mounted and is capable of tracking the sun for about 8 hours each day. The dynamic range of the radiometer is such that even strong solar bursts (flux = 10,000 × 10-22 Watts m-2 Hz-1) can be recorded by using the receiver in the AGC mode. The calibration procedure and the errors involved in the measurement of the solar flux are briefly discussed. Some sample records of solar bursts made by means of this equipment are presented

Seismic Effects in F2 Region Related to Electron Temperature

The effect of earthquakes in the ionospheric F2 range was studied using the Indian satellite SROSS-C2 data on the cosmic electron temperature around the Indian sector in the ranges 0-34 ° N and 40-100 ° E for the period 1995-1997. Five episodes of earthquakes were analyzed and the observed anomalies at an average electron temperature were 29 to 10% higher than in the preceding days, and 16 to 4% higher than on days after the earthquake, and a latitudinal variation of this temperature. It is shown that the increase in this temperature was the maximum on the day preceding the earthquake, and for several hours before and after it. The anomalies observed around (in the ± 2-degree latitude range) were the epicenter of the earthquake. They were probably observed due to electromagnetic radiation during the earthquake activity. The period from 1995 to 1997 for this study was taken as a period of quiet geomagnetic conditions

Multifrequency spectra of solar brightness temperature derived from eclipse observations

Changes in solar radio-brightness temperature were derived at 2.8,19.3 and 22.2 GHz from the observations of radio flux during the total eclipse of 1980 February 16. High-resolution MEM spectra of the brightness temperature fluctuations at the three frequencies showed periodicities ranging from 3.5 min to 128 min. Between 3.5 min and 14.6 min there are several periodicities of comparable significance common to the three operating frequencies. If the corresponding variations in brightness temperature are assumed to result from spatial variations in the solar radio emission, the observed periodicities imply scale sizes in the range 76000 km to 320000 km

Complementary bursts, coronal inhomogeneities and new microscopic spectral features of solar bursts in type IV bursts

Complementary bursts (C.B's) have been observed in the decametric range during noise storms and/or type IV activity. These bursts essentially consist of two components, each component having a duration ~ 1 second. The first component shows weak emission or emission gap over a certain frequency range. The second component is observed after a certain delay. If the bursts are assumed to be generated at the fundamental, and if the radiation corresponding to the gap propagates through an electron density irregularity located close to the source along the line of sight, whose cross-section is less than the linear extent of the source, then almost all properties of the C.B.'s can be explained. High sensitivity and high frequency and time resolution spectra of type IV bursts at 137 MHz revealed new microscopic spectral features displaying "wave- like" and "fork- like" shapes

Proposal for creating a centre for research in solar-terrestrial physics as an interdepartmental activity during IHY at Shivaji University, Kolhapur (16.40°N, 74.15°E)

This note describes teaching and R & D activities presently being carried out in the solar-terrestrial Physics at the Space Science laboratory, Department of Physics, Shivaji University, Kolhapur. A variety of solar and geophysical ground based experiments are available, which can be operated on a regular basis during IHY, with financial help from the government funding agencies in India. The main purpose of this note is to briefly describe our experimental research facilities of relevance to IHY

U-shaped type II solar radio bursts associated with the 1980 March 28 flare

Observations of the 1980 March 28, 2B flare in optical, radio microwave and metric and X-ray wavelengths are presented. In the dynamic radio spectrum, unusual and rare U-shaped type II radio bursts associated with this flare have been observed. The normal type II bursts display negative frequency drift, due to the flare-triggered shock wave travelling outwards in the solar corona. But in this case the type II emission first showed the usual negative frequency drift, and then after reaching a plateau level, showed a positive drift, thus giving the shape of an inverted "U". The authors propose a model for this type II emission.We suggest that the shock wave generated by the flare or the flare spray propagates through sucting and repeated reflections, which takes place within a large scale coronal loop or an arcade of loops, thus resulting in reverse frequency drift in type II emission

Multi-Frequency observations of radio sun during total solar eclipse of February 16, 1980

Measurements of radio flux of the Sun duirng the total solar eclipse on February 16, 1980 were made from the Japal-Rangapur Observatory near Hyderabad, at radio frequencies of 2.8, 10, 19 and 22.2 GHz. Observations for both ingress and egress are available. Residual fluxesat totality for 2.8, 10 and 19 GHz were 23, 3.5 and 3 per cent respectively. The minimum fluxes were observed from 2 to 7 minutes prior to the mid-eclipse

Association between tobacco use and body mass index in urban Indian population: implications for public health in India

BACKGROUND: Body mass index [BMI, weight (kg)/height (m(2))], a measure of relative weight, is a good overall indicator of nutritional status and predictor of overall health. As in many developing countries, the high prevalence of very low BMIs in India represents an important public health risk. Tobacco, smoked in the form of cigarettes or bidis (handmade by rolling a dried rectangular piece of temburni leaf with 0.15–0.25 g of tobacco) or chewed, is another important determinant of health. Tobacco use also may exert a strong influence on BMI. METHODS: The relationship between very low BMI (< 18.5 kg/m(2)) and tobacco use was examined using data from a representative cross-sectional survey of 99,598 adults (40,071 men and 59,527 women) carried out in the city of Mumbai (formerly known as Bombay) in western India. Participants were men and women aged ≥ 35 years who were residents of the main city of Mumbai. RESULTS: All forms of tobacco use were associated with low BMI. The prevalence of low BMI was highest in bidi-smokers (32% compared to 13% in non-users). For smokers, the adjusted odds ratio (OR) and 95% confidence interval (CI) were OR = 1.80(1.65 to 1.96) for men and OR = 1.59(1.09 to 2.32) for women, respectively, relative to non-users. For smokeless tobacco and mixed habits (smoking and smokeless tobacco), OR = 1.28(1.19 to 1.38) and OR = 1.83(1.67 to 2.00) for men and OR = 1.50(1.43 to 1.59) and OR = 2.19(1.90 to 3.41) for women, respectively. CONCLUSION: Tobacco use appears to be an independent risk factor for low BMI in this population. We conclude that in such populations tobacco control research and interventions will need to be conducted in concert with nutrition research and interventions in order to improve the overall health status of the population