Characteristics of certain surface meteorological parameters in relation to the interannual variability of Indian summer monsoon

With an objective to understand the influence of surface marine meteorological parameters in relation to the extreme monsoon activity over the Indian sub-continent leading to flood/drought, a detailed analysis of the sea level pressure over the Southern Hemisphere and various surface meteorological parameters over the Indian seas is carried out. The present study using the long term data sets (Southern Hemispheric Sea Level Pressure Analysis; Comprehensive Ocean Atmospheric Data Set over the Indian Seas; Surface Station Climatology Data) clearly indicates that the sea surface temperature changes over the south eastern Pacific (El Ninõ/La Niña) have only a moderate impact (not exceeding 50% reliability) on the Indian summer monsoon activity. On the other hand, the sea level pressure anomaly (SOI) over Australia and the south Pacific has a reasonably high degree of significance (more than 70%) with the monsoon activity over India. However, these two parameters (SLP and SST) do not show any significant variability over the Indian seas in relation to the summer monsoon activity. Over the Indian seas, the parameters which are mainly associated with the convective activity such as cloud cover, relative humidity and the surface wind were found to have a strong association with the extreme monsoon activity (flood/drought) and thus the net oceanic heat loss over the Indian seas provides a strong positive feed-back for the monsoon activity over India.     

Leisure in the daily lives of South African economically active single mothers

This paper represents a contribution to the emerging field of the geography of gender in South Africa. The focus of attention is leisure participation and leisure spaces of economically active single mothers in South Africa. Findings are presented from a survey on the nature, frequency and constraints affecting this group of women in Greater Pretoria. It is shown that economically active single mothers confront a host of constraints which impact upon patterns of leisure participation. A key finding is that the home is the essential leisure space for this sub-group of women. Certain clear divides exist between the leisure worlds daily experienced by white and black South African women.     

Anomalous behaviour of uranium isotopes in coastal marine environment of the west coast of India

During the last few years, a remarkable anomaly between ²³⁸U and ²³⁴U activities has been observed in the top layers of the coastal sediments along the western region of the Indian sub-continent. Sediment samples from Bombay (19°N, 73°E) to Kottilppad (8°N, 77°E) were leached with saturated ammonium carbonate solution to extract uranium isotopes from the surface layers of the sediment particles without attacking the mineral cores. The ²³⁴U/²³⁸U activity ratios in these leachates are in the range of 1.12–1.14 while ²³⁵U/²³⁸U activity ratio is 0.046 which is the same as for other natural uranium.

The surface organic matter from the sediment particles was removed by treatment with hydrogen peroxide in presence of 0.05 M hydrochloric acid. ²³⁴U/²³⁸U and ²³⁵u/²³⁸U activity ratios in the extract and the residues were determined.

It is observed that disequilibrium between ²³⁸U and ²³⁴U exists only on the surface of sediment particles. ²³⁴U/²³⁸U on the surface of the sediment particles is the same as in the ambient water and as the surface organic matter is removed from the particle surface, the cores show equilibrium activities.     

Radioactive heat generation and heat flow in the Indian shield

Using a laboratory gamma-ray spectrometer, 160 rock samples from different heat flow sites in India have been analysed for their U, Th and K contents. Heat generation has been estimated for the significant rock types. Of the six regions covered by this study, correction due to heat generation contrast and geologic structure was found necessary and has been applied in two regions. Heat flow/heat generation plots for two regions in the southernmost part of the shield follow the line characteristic of a normal continental heat flow province. The plots for the other four regions indicate a heat flow province with an intercept of 0.92 HFU and a slope of 14.8 km. From data available at present, these parameters are higher compared to those from the other shields. The higher parameters imply a higher temperature and heat flow at the Moho, indicating a region of “hotter” upper mantle in the Indian shield.     

Visual interpretation of landsat-1 imagery of central and southern districts of Haryana state,India

LANDSAT-MSS data in the form of a false colour composite image at a scale of 1:250,000 has been used to produce terrain unit maps of parts of north west India. The area of study consisted of central and southern districts of Haryana State. It has been possible to obtain a qualitative assessment of land use patterns and surface hydrology by means of visual Interpretation. The boundaries between differeat terrain units and moisture regimes were clearly discernible It is felt that comparative studies of false colour infrared imagery over a period of time can provide valuable Information for those engaged in reclamation schemes. In particular, the data can be used to plan reclamation of salt affected and waterlogged lands in semi-arid zones of states like Haryana.     

Spawning of major carps in the lower Halda River,Bangladesh

Spawning biology and spawn fishery of three valuable species of Indian major carps,Catla catla, Labeo rohita andCirrhinus mrigala, in the lower Halda River, Bangladesh, were studied in 1978. The major carps spawned only in the Sonairchar oxbow-bend from April to June on or near the dates of the full moon and the new moon. The tide was then at its highest level, and there was heavy flood water runoff from the hill region with sharp increases in water level, turbidity and current velocity, as well as decreases in water temperature, dissolved oxygen, and hydrogen ion concentration. These three heterogeneric species, as a result of parallelism or convergence in evolution, overlap in their environmental requirements for spawning. The nursery ground of the major carp fry spawned in the Halda River was found to be in the Bay of Bengal. The brood stock origin is suspected to be at the Shankha River, 40 miles south of the Karnafuli River. The spawn fishery in the Halda River was intensive but inefficient. Engineering works and water management schemes are threatening the spawning habitat.     

Rb-Sr dating of the impact melt from East Clearwater,Quebec

The Rb-Sr composition of eight melt rock and three basement samples from the East Clearwater impact structure, Quebec, and two basement samples from the West Clearwater structure has been determined. The whole rock ⁸⁷Sr/⁸⁶Sr ratios of the melt samples, 0.7167–0.7253, are within the range of the basement samples, 0.7054–0.7322, and provide further evidence that the melt rocks represent shock-melted basement. A mineral isochron obtained from a relatively coarse grained melt rock gives an age of 287±26 Ma for the crystallization age of the melt. This is equivalent to K-Ar whole-rock ages of 285±30 Ma and 300±30 Ma and a Rb-Sr age of 266±15 Ma obtained on melt rocks from West Clearwater and confirms the previously generally held assumption that the East and West Clearwater structures resulted from the simultaneous impact of two bodies at 285–300 Ma ago.Contribution from the Earth Physics Branch No. 909     

Cooxidation of Carcinogenic Benzo(a) Pyrene and Phenols by Horseradish Peroxidase (Armoracia lapathifolia)

The catalytic activity of horseradish (Armoracia lapathifolia) peroxidase in the oxidation reactions of benzo(a)pyrene (BP) and phenols, separately and in admixture, has been studied. Experiments were carried out with model phenols from industrial sewage (phenol, m-, p-cresols, catechol, hydroquinone, resorcinol, orcinol), keeping to the real concentration ratio of reagents, 0.5 mM for phenols, 0.1 nM for benzo(a)pyrene. The total oxidation process for all reagents tested is described by the second-order formal kinetic equation up to 60 … 90% of their conversion. Addition of peroxidase increases the rate of oxidation of benzo(a)pyrene and phenols 2 … 6 times as compared with the control test (with hydrogen peroxide), whereas a linear dependence of the rate of benzo(a)pyrene oxidation on the enzyme concentration is observed. By cooxidation a mutual inhibition of benzo(a)pyrene and phenols is established whose degree depends on the phenol-chemical structure and varies in the range of 23 … 58% for BP under the influence of phenols and 35 … 80% for phenols under the influence of benzo(a)pyrene. The results obtained permit a supposition that peroxidase containing plants are capable of simultaneously transforming carcinogenic benzo(a)pyrene and toxic phenols in water reservoirs and in the soil, thus promoting the detoxication of environment.     

Geomorphology and landuse of Pasighat-Jonai bazar area-A photo based study in a part of Dihang river basin,Arunachal pradesh and Assam

Photo-interpretation coupled with systematic field checks over an area of about 1500 sq. km has led to the identification of various landform units and their characteristic landuse pattern in part of the submontaneous tract of Arunachal Pradesh and Assam in the Dihang river basin. Four major geomorphic units have been mapped and their respective lithounits are studied in detail. Present landuse and the land’s capability inrespect of each of the major geomorphic units have been noted. Suggestions have been made for better utilisation of land.     

Multiphase reverse vertical tectonic displacement across major faults in northern Israel

Geological investigations in northern Israel, supported by recent seismic interpretation of offshore data, indicate that the major fault systems there have undergone several tectonic phases since the Mesozoic. It is suggested that the vertical displacements related to the younger phase of Neogene to Recent age are in a reverse direction to those of the Mesozoic and older phases.