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Spatio-temporal evolution of soil moisture is a complex process and controlled by several factors including hydro-meteorological forcings. This study borrows a recently developed concept of temporal networks to capture the time-varying association between hydro-meteorological forcings and spatio-temporal evolution of soil moisture. Climate change and dynamic terrestrial environment cause slow but continuous change in the characteristics of hydro-meteorological forcings leading to variation in spatio-temporal distribution of soil moisture. Keeping this in the focus of the study, temporal networks based time-varying modelling framework is adapted for one-month to one-season (three-months) in advance prediction of monthly soil moisture for entire Indian mainland. Results indicate that the association among the hydro-meteorological forcings varies with both space and time. With the increase in prediction lead-time, the strength of association with the variables, such as pressure, wind and temperature, decreases and that with the variables like leaf area index remains informative. Among different seasons, the model shows superior performance for the monsoon and post monsoon periods. Next, the soil moisture based extremes are assessed by utilizing two deficit indices and two wetness indices. The model performance is highly satisfactory but varies over space and seasons, with a marginally better performance for the wetness indices. Overall, given the vast spatial extent of the Indian mainland, the proposed model performs robustly for almost all the climatic regions and may be promising for other parts of the world as well. [ABSTRACT FROM AUTHOR]

Background: The issue of HIV/AIDS and women's health can be viewed in the context of (1) the unravelling epidemic, (2) the screening of women for HIV and provision of ongoing surveillance, and (3) hope for the future, even though the battle against HIV has not won. Estimating the seroprevalence of HIV in a low risk population such as pregnant women provides essential information for an effective implementation of AIDS control programs, and also for the monitoring of HIV spread within a country. This study was conducted to establish the prevalence rate of HIV amongst pregnant women attending antenatal clinic. Methods: Blood samples from pregnant women attending antenatal clinics in Sola Civil Hospital and G.M.E.R.S. Medical College, Ahmedabad, were collected after informed consent and pre test counselling. The samples were tested for HIV antibodies as per the WHO guidelines. Data was collected and analyzed for a period of 1 year from 1st April 2010 to 31st March 2011. Results: Of the 3101 pregnant women tested in one year 11(0.35%) women were found to be HIV seroreactive. Conclusion: The economic and demographic consequences of the spread of HIV/AIDS are inexorable and awesome. The prevalence rate recorded in this study suggests that HIV screening of pregnant women should be an on- going exercise. Development of programs with an integrated approach to inducing behavioural change, promotion of use of condoms and controlling Sexually Transmitted Diseases(STD)'s may reduce the infectivity of HIV transmitters and susceptibility of HIV exposed persons. [ABSTRACT FROM AUTHOR]

The paper gives a broad overview of the work carried out by the Indian Institute of Technology Bombay (IITB) in determining the post-seismic effect of the December 26, 2004 Sumatra-Andaman earthquake on the Indian plate, using space-based technology, the GPS. A GPS network established by the IITB along the western coast of the Indian peninsular was considered for this purpose, observed and analyzed thoroughly, in order to investigate the potential of GPS technology in studying Earth dynamics. To understand the pattern of movement of the Earth's surface to the effect of the large Sumatra-Andaman earthquake, the magnitude and, most importantly, the direction of deformation of the GPS network were estimated. The GPS-estimated deformations were thereby used as indicators to identify any change in the Earth surface movement due to the large external force caused by the 2004 earthquake. [ABSTRACT FROM AUTHOR]

Timely and accurate information about various habitats of a wetland ecosystem is necessary for the assessment, monitoring and management of a wetland. In this article, the state-of-the-art Polarimetric Synthetic Aperture Radar (PolSAR) data have been analysed to characterize various components of a wetland ecosystem. SAR polarimetry has received negligible attention in India, mostly owing to lack of data over the Indian sub-continent. With a recent DLR-ESAR (Experimental-SAR) flight over India, it was possible to conduct a detailed, planned experiment to explore the potentials of SAR polarimetry. This study has been carried out using fully polarimetric, multi-frequency DLR-ESAR data over parts of a world heritage and Ramsar site, the Keoladeo National Park, Bharatpur, India. Scattering models based on physical principles have been applied to characterize the wetland targets like open-water habitat, various types of aquatic vegetation with or without standing water, along with various species of forested areas. Entropy, alpha angle and anisotropy have been derived by performing eigen vector-based target decomposition on L- and P-bands fully polarimetric SAR data, enabling us to understand the differences in wetland targets in terms of their scattering behaviour at the L- and P-bands. A significant outcome of this study is that it explores and demonstrates the potential of the state-of-the-art technique of PolSAR for characterizing scattering behaviour of various components of a wetland ecosystem, which is a less explored application of SAR, particularly in the Asian countries. [ABSTRACT FROM AUTHOR]

The sensitivity of synthetic aperture radar (SAR) backscatter to soil moisture has been adequately established. However, monitoring of soil moisture over large agricultural areas is still difficult because SAR backseatter is also sensitive to other target properties like surface roughness, crop cover, and soil texture (soil type), along with its strong sensitivity to soil moisture. Hence, to develop a methodology for large-area soil moisture estimation using SAR, it is necessary to incorporate the effects of surface roughness, crop cover, and soil texture in the soil moisture retrieval model. In this paper, a methodology for soil moisture estimation over a large area is developed using a pair of low- and high-incidence-angle RADARSAT-1 SAR data over parts of Agra, Mathura, and Bharatpur districts, India, during March 1999. The methodology requires acquisition of synthetic aperture radar data at low and high incidence angles, such that the soil moisture changes are negligible between the two acquisitions. In order to demonstrate the applicability of the developed methodology, the same was validated over a different area (parts of Saharanpur and Haridwar district.s, India) during March 2005. Both test sites provided the variety of agricultural heterogeneity required for development and validation of the methodology for large-area soil moisture estimation. The proposed methodology offers an approach to incorporate the effects of surface roughness, crop cover, and soil texture in the soil moisture retrieval model from the space platform, without making any assumptions on the distributions of these parameters or without knowing the actual values of these parameters on ground. [ABSTRACT FROM AUTHOR]