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11.
V. K. Sehgal C. V. S. Sastri N. Kalra V. K. Dadhwal 《Journal of the Indian Society of Remote Sensing》2005,33(1):131-136
A study aimed at generating wheat yield maps of farmer’s fields by using remote sensing (RS) inputs was undertaken during
the rabi season of 1998-99 in six villages of Alipur Block of Delhi State. RS derived leaf area index (LAI) were linked to
wheat simulation model WTGROWS by adopting a strategy christened “Modified Corrective Approach”. This essentially uses an
empirical relation of grain yield and LAI, which was derived from WTGROWS simulation model by running model for a combination
of input resources, management practices and soil types occurring in the area. This biometric relationship was applied to
all the wheat fields of the study area for which the LAI was derived from single acquisition of IRS LISS-III data (Jan 27,
99). The LAI-NDVI relation adopted was logarithmic in nature (R2=0.83) and was based on ground measurements of LAI in farmer’s fields in the same area. A comparison of predicted grain yield
by the modified corrective approach and actual observed yield for the 22 farmer’s fields showed high correlation coefficient
of 0.8 and a root mean square error (RMSE) of 597 kg ha-1 which was 17% of the observed mean yield. Thus linking of RS information and crop simulation model provides an alternative
for mapping and forecasting crop yield under highly variable cropping environment of Indian farms, which is a pre-requisite
for implementing Precision Crop Management (PCM). 相似文献
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Water-borne infections are the most common causes of infectious diseases in developing countries, often resulting from the
lack of a protected water supply, a faulty water-supply system or improper sewage disposal. A recent study of 107 samples
from bore wells of Mysore city has revealed that 51 samples (47.66%) contain Nitrate greater than 45 ppm, an indication that
the water would be harmful for drinking. Out of 51 samples tested for faecal pollution, using a H2S-strip test, 37 samples turned black and these were subjected to microbial identification. Out of these 37 samples, 63 H2S producing strains were isolated and the H2S producing organisms are Klebsiella ozaene;Klebsiella pneumoniae;Proteus mirabilis;Proteus vulgaris;Salmonella sp. and Citrobacter freundi.
The frequency of occurrence of the above-mentioned six micro-organism strains are as follows: Proteus mirabilis (19);Proteus vulgaris (14);Citrobacter freundi (13);Salmonella sp. (8);Klebsiella pneumoniae (5); and Klebsiella ozaene (4). Klebsiella and Proteus are known to cause urinary infection and Salmonella intestional infection.
Received: 7 September 1998 · Accepted: 10 November 1998 相似文献
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J. Hanumath Sastri 《Solar physics》1987,111(2):429-437
The correlations between the plasma characteristics of the solar wind flow in the vicinity (± 12 hr) of stream-free sector boundaries near Earth are examined using the composite data base of interplanetary plasma for the period 1965–1980. We confirm the result of Lopez et al. (1986) of an inverse relationship of the proton temperature (T
p) with the momentum flux density (NV
2) in the low speed wind at 1 AU. The coefficients of lines of best fit to the T
pvs NV
2(as well as T
pvs V) distribution in our sample are, however, significantly different from those of the undifferentiated sample of low speed wind considered by Lopez et al. such that T
pis, in general, lower than expected. We find further that the proton number density (N) varies as the inverse cube of the flow speed (V) indicating an invariance of the kinetic energy flux density (NV
3) relative to velocity structure in the plasma flow around stream-free boundaries. These average relationships, which are unaffected by interplanetary dynamical processes, are suggested to be due to sub-sonic addition of momentum and energy to the solar wind flow from the source structures, namely coronal streamers. 相似文献
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Jean-éric Tremblay Dominique Robert Diana E. Varela Connie Lovejoy Gérald Darnis R. John Nelson Akash R. Sastri 《Climatic change》2012,115(1):161-178
During the International Polar Year (IPY), large international research programs provided a unique opportunity for assessing the current state and trends in major components of arctic marine ecosystems at an exceptionally wide spatio-temporal scale: sampling covered most regions of the Canadian Arctic (IPY-Canada??s Three Oceans project), and the coastal and offshore areas of the southeastern Beaufort Sea were monitored over almost a full year (IPY-Circumpolar Flaw Lead project). The general goal of these projects was to improve our understanding of how the response of arctic marine ecosystems to climate warming will alter the productivity and structure of the food web and the ecosystem services it provides to Northerners. The present paper summarizes and discusses six key findings related to primary production (PP), which determines the amount of food available to consumers. (1) Offshore, the warming and freshening of the surface layer is leading to the displacement of large nanophytoplankton species by small picophytoplankton cells, with potentially profound bottom-up effects within the marine food web. (2) In coastal areas, PP increases as favourable winds and the deeper seaward retreat of ice promote upwelling. (3) Multiple upwelling events repeatedly provide food to herbivores throughout the growth season. (4) A substantial amount of pelagic PP occurs under thinning ice and cannot be detected by orbiting sensors. (5) Early PP in the spring does not imply a trophic mismatch with key herbivores. (6) The epipelagic ecosystem is very efficient at retaining carbon in surface waters and preventing its sedimentation to the benthos. While enhanced PP could result in increased fish and marine mammal harvests for Northerners, it will most likely be insufficient for sustainable large-scale commercial fisheries in the Canadian Arctic. 相似文献
15.
Geomagnetic crochets (sfe) observed at Kodaikanal over the period 1966–71 have been studied in relation to solar X-ray bursts observed by NRL satellite (SOLRAD-9) in the 0.5–3 Å, 1–8 Å and 8–20 Å bands and radio bursts observed in the frequency range 1000–17000 MHz. The amplitude of sfe is linearly correlated with the peak intensities of X-ray bursts in the 1–8 Å and 8–20 Å bands. The single frequency correlation of sfe with radio bursts is a flat maximum in the frequency range 2000–3750 MHz. Following the spectral classification of AFCRL for microwave bursts, it is noticed that sfe are mostly associated with the A type burst spectra and are very poorly correlated with bursts with the G, C and M type spectra. These features differ from those of other SID's reported earlier. 相似文献
16.
We present the characteristics of the response of equatorial ionospheric zonal electric field and F-region plasma density to the asymmetric ring current intensifications that occurred in succession on 16 December 1991, corresponding to the STEP/EITS-2 campaign period. The study is based on high-time-resolution (1-min) data of asymmetic ring current indices, ASY(H/D) and F-region vertical plasma drift, Vz measurements at Kodaikanal (10.25°N; 77.5°E; dip 4°), India and quarter-hourly ionosonde data of For-taleza (4°S; 322°E; dip -9°), Brazil. It is shown that short-lived disturbances in F-layer vertical plasma drift, Vz and height (hF/hpF2) indicative of westward and eastward electric fields prevail simultaneously in the dusk (18–21 LT) and predawn (02–05 LT) sectors, respectively, in association with the decay phase of asymmetic ring current events. Electric fields of opposite polarity do also seem to manifest at these local times, particularly in the early-morning sector in conjunction with the intensification of the asymmetric ring current. At a given location, electric field disturbances associated with individual asymmetric ring current events are thus bipolar in nature, with fields of opposite polarity during the growth and decay phases. The nature and polarity structure of the observed electric field disturbances are in agreement with the theoretical/model predictions of prompt penetration of high-latitude electric fields to the equatorial region.On sabbatical leave from Indian Institute of Astrophysics, Bangalore, India 相似文献
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The Tertiary geosynclinal sediments of the Surma Valley and Tripura State range in age from Eocene to Mio-Pliocene. They are classified into those of the Disang, Barail, Surma and Tipam groups which respectively represent sediments belonging to geosynclinal, flysch, early molasse and late molasse stages. These sediments are devoid of diagnostic and persistent faunal and palynological assemblages. Frequent lithofacial variations render lithologic criteria unsuitable for regional correlation. Heavy-mineral suites, however, appear diagnostic and they, along with lithologic criteria, can be utilised for local and regional correlations.The mode of evolution of the heavy-mineral suites is discussed. Appearance of marker heavy minerals in successively younger sequences is concluded to be a reflection of successive cycles of positive tectonism in the provenance. The study brings out that the bulk of the sediments were derived from the Shillong Plateau. Contributions from older sedimentaries are also concluded. 相似文献