2,319 research outputs found

    Strategies for climate change impacts on irrigated crops in National Capital Region of India

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    Irrigation has helped in increasing food production and achieving food security in India. However, climate change is expected to affect the crop production in irrigated area particularly in groundwater irrigated areas. This study was undertaken for suggesting strategies to climate change impact on irrigated crops based on projected change in crop water requirement and groundwater availability for irrigation in the National Capital Territory of Delhi. Prevailing groundwater recharge in the study area during monsoon was 4.01 MCM (Million cubic meter). The same for various scenarios varied from -15.47 MCM to 5.08 MCM. It was revealed that groundwater recharge would increase if it is estimated based on the climate prediction done using local weather data. The impact of climate change on groundwater availability is evident in scenarios based on INCCA and IPCC predictions where it varied from -2.66 MCM to 1.02 MCM. Contrary to common perceptions, crop water requirement of prevailing cropping system would not increase in future if all the important climatic parameters are considered for its prediction. This may be due to the fact that effect of increase in temperature on crop water requirement may be compensated by decrease in other climatic parameters such wind speed and duration of daily sunshine hours. Results indicated that climate change may not have much impact on sustainability of prevailing cropping system as per the crop water requirement is concerned. Based on water requirement and groundwater availability under various climate change scenarios, appropriate strategies to cope up the climate change impact on irrigated crops have been suggested

    Environmental Control Measures in Sponge Iron Industry with Particualr Reference to Tata Sponge Iron Limited

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    Direct reduced iron or sponge iron technology was developed as an alternate route for steel making and is considered as a clean technology. The waste generation and gas emissi-ons from this route of steel making are far less when comp-ared to the conventional blast furnace route. The paper details the efforts of Tata Sponge Iron Limited to make the process a clean technology without affecting its surroundings and natural resources

    Linking healthcare associated norovirus outbreaks: a molecular epidemiologic method for investigating transmission.

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    BACKGROUND: Noroviruses are highly infectious pathogens that cause gastroenteritis in the community and in semi-closed institutions such as hospitals. During outbreaks, multiple units within a hospital are often affected, and a major question for control programs is: are the affected units part of the same outbreak or are they unrelated transmission events? In practice, investigators often assume a transmission link based on epidemiological observations, rather than a systematic approach to tracing transmission.Here, we present a combined molecular and statistical method for assessing:1) whether observed clusters provide evidence of local transmission and2) the probability that anecdotally|linked outbreaks truly shared a transmission event. METHODS: 76 healthcare associated outbreaks were observed in an active and prospective surveillance scheme of 15 hospitals in the county of Avon, England from April 2002 to March 2003. Viral RNA from 64 out of 76 specimens from distinct outbreaks was amplified by reverse transcription-PCR and was sequenced in the polymerase (ORF 1) and capsid (ORF 2) regions. The genetic diversity, at the nucleotide level, was analysed in relation to the epidemiological patterns. RESULTS: Two out of four genetic and epidemiological clusters of outbreaks were unlikely to have occurred by chance alone, thus suggesting local transmission. There was anecdotal epidemiological evidence of a transmission link among 5 outbreaks pairs. By combining this epidemiological observation with viral sequence data, the evidence of a link remained convincing in 3 of these pairs. These results are sensitive to prior beliefs of the strength of epidemiological evidence especially when the outbreak strains are common in the background population. CONCLUSION: The evidence suggests that transmission between hospitals units does occur. Using the proposed criteria, certain hypothesized transmission links between outbreaks were supported while others were refuted. The combined molecular/epidemiologic approach presented here could be applied to other viral populations and potentially to other pathogens for a more thorough view of transmission

    A Wave-function for Stringy Universes

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    We define a wave-function for string theory cosmological backgrounds. We give a prescription for computing its norm following an earlier analysis within general relativity. Under Euclidean continuation, the cosmologies we discuss in this paper are described in terms of compact parafermionic worldsheet systems. To define the wave-function we provide a T-fold description of the parafermionic conformal field theory, and of the corresponding string cosmology. In specific examples, we compute the norm of the wave-function and comment on its behavior as a function of moduli.Comment: 30 pages, 3 figures, v3: references adde

    Ferns: heavy metal guzzlers can replace expensive methods of controlling pollution

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    Now Indian ecotype of brake fern found in Kerala has been found to exhibit similar properties. A team of researchers from National Environmental Engineering Institute (NEERI) found that the fern could also help remove chromium from the soil and water. The study published in March 25 issue of Current Science says this particular ecotype of brake fern is found only in India. For most of the developing countries, including India, brake fern plantation could help in reducing the expenditure required on mitigating heavy metal pollution using modern technologies

    Cosmological stretching of perturbations on a cosmic string

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    We investigate the effects of cosmological expansion on the spectrum of small-scale structure on a cosmic string. We simulate the evolution of a string with two modes that differ in wavelength by one order of magnitude. Once the short mode is inside the horizon, we find that its physical amplitude remains unchanged, in spite of the fact that its comoving wavelength decreases as the longer mode enters the horizon. Thus the ratio of amplitude to wavelength for the short mode becomes larger than it would be in the absence of the long mode.Comment: 11 pages, 5 postscript figure

    A radiation-like era before inflation

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    We show that the semiclassical approximation to the Wheeler-DeWitt equation for the minisuperspace of a minimally coupled scalar field in the spatially flat de Sitter Universe prompts the existence of an initial power-law evolution driven by non-adiabatic terms from the gravitational wavefunction which act like radiation. This simple model hence describes the onset of inflation from a previous radiation-like expansion during which the cosmological constant is already present but subleading.Comment: LaTeX, 8 pages, no figures; final version to be published in JCA

    Cosmic String Cusps with Small-Scale Structure: Their Forms and Gravitational Waveforms

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    We present a method for the introduction of small-scale structure into strings constructed from products of rotation matrices. We use this method to illustrate a range of possibilities for the shape of cusps that depends on the properties of the small-scale structure. We further argue that the presence of structure at cusps under most circumstances leads to the formation of loops at the size of the smallest scales. On the other hand we show that the gravitational waveform of a cusp remains generally unchanged; the primary effect of small-scale structure is to smooth out the sharp waveform emitted in the direction of cusp motion.Comment: RevTeX, 8 pages. Replaced with version accepted for publication by PR
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