Effect of the steady flow on spatial damping of small-amplitude prominence oscillations

Aims. Taking account of steady flow in solar prominences, we study its effects on spatial damping of small-amplitude non-adiabatic magnetoacoustic waves in a homogeneous, isothermal, and unbounded prominence plasma. Methods. We model the typical feature of observed damped oscillatory motion in prominences, removing the adiabaticity assumption through thermal conduction, radiation and heating. Invoking steady flow in MHD equations, we linearise them under small-amplitude approximation and obtain a new general dispersion relation for linear non-adiabatic magnetoacoustic waves in prominences Results. The presence of steady flow breaks the symmetry of forward and backward propagating MHD wave modes in prominences. The steady flow has dramatic influence on the propagation and damping of magnetoacoustic and thermal waves. Depending upon the direction and strength of flow the magnetoacoustic and thermal modes can show both the features of wave amplification and damping. At the wave period of 5 min where the photospheric power is maximum, the slow mode shows wave amplification. However, in the absence of steady flow the slow mode wave shows damping. Conclusions. For the wave period between 5 min and 15 min, the amplification length for slow mode, in the case of prominence regime 1.1, varies between 3.4*10^11 m to 2*10^12 m. Dramatic influence of steady flow on small-amplitude prominence oscillations is likely to play an important role in both wave detection and prominence seismology

A note on the culture of Chanos chanos (Forskal) at Brackishwater Fish Farm, Kaninada

The culture of Chanos chanos to marketable size within a three months period, is described. Procedures involved include phased manuring coupled with proper water management to keep up enhanced primary productivity. Results show that, under monoculture, with low-input technology it is possible to produce 3,000 kg fish per hectare per year

A study on the trend of sports fishery of Mafia Island (Tanzania) along the East African coast from 1961-1972

Mafia waters in the western Indian Ocean on the east coast of Africa is a natural attractive area for fishing. It has extensive coral beds which harbour good fish life and attracts sport fishery in the area. About 12 commercially important fishes listed are caught by sports fishermen. The data indicates that this area can become an attractive centre for sports fishery almost throughout the year with peak season from November to February. Long-term planning of the fishery is necessary. The conservation measures should be evolved and gan fishing, dynamiting or any other kind of distructive fishing should be prohibited. This area has natural potential to become a sports fishing centre in the future and a great attraction for tourists and anglers

What Makes the Sun Shine?

23-27How does the Sun shine? How does it produce the vast amount of energy that makes life possible on Earth? These questions have posed a challenge to scientists since the nineteenth century

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Not AvailableThe ravine areas are most fragile ecosystem and subjected to various kinds of natural resource losses and threat to biodiversity. Due to unregulated and over exploitation, the forest area under ravines are facing severe threats of losing biodiversity. In this context, a study was conducted to assess the tree diversity of ravine areas in different parts of Bundelkhand viz., Orai, Banda and Datia. In each study site, quadrats of 20 m × 20 m were randomly laid out and the tree diversity were documented. The species diversity, richness and evenness were studied using different indices like Shannon, Simpson, Margalef and Berger-Parker. The relative density and relative frequency were also calculated. In the present study, the Shannon diversity was highest in ravines of Datia (1.887) followed by Banda (1.871) and Orai (1.259). Whereas the Shannon equitability index was found higher in Banda (0.899) followed by Datia (0.859) and Orai (0.782). The lowest value of Simpson diversity was reported in Banda (0.183) followed by Datia (0.194) and Orai (0.333). In Datia (9 species) maximum number of species were recorded, followed by Banda (8 species) and Orai (5 species). The Inverted Berger-Parker dominance was highest in Banda (3.296) followed by Datia (2.804) and Orai (2.500). Hence it indicates that, ravine areas of Banda and Datia are more diverse and healthier than Orai. Further analysis revealed that, the relative density of Anogeissus pendula was highest in Orai (40.16%) and Datia (38.18%), whereas Holoptelea integrifolia (27.72%) and Balanites aegyptiaca (21.85%) population was higher in Banda. The overall diversity of all the three sites was found low. The survey also reported high biotic interferences, which escalates ravine degradation. However, crop cultivation in these lands is not desirable as it leads to accelerated erosion, thus adding to their fast degradation. The best scientific land use of these lands is to place them under permanent vegetation through agroforestry interventions involving forest and fruit trees along with the grasses. The planting and management of indigenous tree species like Anogeissus pendula, Acacia leucophloea, A. nilotica, Ziziphus spp., Carissa carandas and Capparis decidua will pave the way towards sustaining ravine ecosystem and livelihood of the people.Not Availabl