7,036 research outputs found
Characteristics of gravity waves generated in a convective and a non-convective environment revealed from hourly radiosonde observation under CPEA-II campaign
Analyses of hourly radiosonde data of temperature, wind, and relative
humidity during four days (two with convection and two with no convection)
as a part of an intensive observation period in CPEA-2 campaign over Koto
Tabang (100.32° E, 0.20° S), Indonesia, are presented.
Characteristics of gravity waves in terms of dominant wave frequencies at
different heights and their vertical wavelengths are shown in the lower
stratosphere during a convective and non-convective period. Gravity waves with
periods ~10 h and ~4–5 h were found dominant near
tropopause (a region of high stability) on all days of
observation. Vertical propagation of gravity waves were seen modified near
heights of the three identified strong wind shears (at ~16, 20, and
25 km heights) due to wave-mean flow interaction. Between 17 and 21 km
heights, meridional wind fluctuations dominated over zonal wind, whereas from
22 to 30 km heights, wave fluctuations with periods ~3–5 h and
~8–10 h in zonal wind and temperature were highly associated,
suggesting zonal orientation of wave propagation. Gravity waves from
tropopause region to 30 km heights were analyzed. In general, vertical
wavelength of 2–5 km dominated in all the mean-removed (~ weekly mean)
wind and temperature hourly profiles. Computed vertical wavelength spectra
are similar, in most of the cases, to the source spectra (1–16 km height)
except that of zonal wind spectra, which is broad during active convection.
Interestingly, during and after convection, gravity waves with short
vertical wavelength (~2 km) and short period (~2–3 h)
emerged, which were confined in the close vicinity of tropopause, and were
not identified on non-convective days, suggesting convection to be the source
for them. Some wave features near strong wind shear (at 25 km height) were
also observed with short vertical wavelengths in both convective and
non-convective days, suggesting wind shear to be the sole cause of generation
and seemingly not associated with deep convection below. A drop in the
temperature up to ~4–5 K (after removal of diurnal component) was
observed at ~16 km height near a strong wind shear (~45–55 m s<sup>−1</sup> km<sup>−1</sup>) during active period of convection
Current Status of Radioisotope Applications in Defence
Reviews the current status of radioisotope applications in Defence- R&D Establishments, Defence Inspectorates, Ordnance Factories, Public Sector Undertakings under the Defence Ministry, Army, Navy and Air Force Establishments and Military Hospitals. It also lists the users of film badge service in Defence. Training programmes in radioisotope applications in Defence conducted by DRDO organisations have also been highlighted
Iodization status of common salt in districts of western Uttar Pradesh
Research Problem: What is the amount of iodine in common salt samples. Objective: To estimate theamountof iodine in common salt samples. Study Design: Population based cross - sectional study. Setting: Randomly selected six districts of western U.P. Sample: Two salt samples randomly collected from house holds of each block area of the district. Sample Size: 152 salt samples. Study Variables: Iodine content in salt samples. Statistical Analysis: By chi - square test. Result: Unsatisfactory level of iodine was found in 52% of the salt samples. Crystal salt samples were more poorly iodized (70.9%) than powder salt samples (41.2%). Recommendations: Strict enforcement of ban on the sale of non-iodised salt
Rapid, accurate and routine HPLC method for large-scale screening of pro-vitamin A carotenoids in oilseeds
Plant carotenoids, the precursors of vitamin A display several important biological functions as antioxidants and anti-carcinogens. The oilseed crops, owing to their high oil content, form a good matrix for the bioavailability of β-carotene, thereby providing potential targets for biofortification to combat vitamin A deficiency (VAD). However, the screening and characterization of these crops, that otherwise contain very low levels of pro-vitamin A carotenoids has been difficult owing to their poor recovery and strong binding to the oil matrix. Here, we report a rapid method for high volume HPLC analysis involving the extraction and determination of β-carotene in four oilseed crops (peanut, soybean, sunflower and mustard). This included a comprehensive study of the factors that potentially influence the qualitative and quantitative yields of β-carotene in these crops. This is the first crop-independent HPLC method for the quantification of pro-vitamin A carotenoids that shows excellent recovery and reproducibility (>90 percentage recovery in oil) using small tissue sample and is capable of processing up to 30 samples per day. The protocol is sensitive, and enables better detection and separation of individual carotenoids by reducing artefacts during extraction, purification and chromatography that can be used for routine screening of oilseeds
Crop biofortification through genetic engineering : present status and future directions
Global food system is failing to deliver adequate quantities of healthy, nutritionally balanced food, especially to the resource-poor underprivileged people leading to micronutrient malnutrition. The malnutrition of minerals (Fe, Zn) and vitamin A are major food-related primary health problem among populations of the developing world including India where there is a heavy dependence on cereal-based diets and limited access to meat, fruits and vegetables. Vitamin A deficiency (VAD) alone is significant from the public health point of view resulting in over 330,000 child deaths every year, and about 57% of preschoolers and their mothers having subclinical VAD leading to increased morbidity and risk of mortality. While therapeutic supplementation of vitamin A is currently being addressed through sponsored nutrition programmes, they are not sufficient in covering the affected populations.
Biofortification of important crop plants through biotechnological applications is a cost-effective and sustainable solution for alleviating VAD. Genetic engineering is the obvious alternative to enhance the β-carotene levels in crop plants. The development of the ‘golden rice’ proved that, it is possible to redirect a complete biosynthetic pathway of carotenoids by genetic engineering of multiple genes encoding key enzymes of the pathway. Recently, there have been several reports on the development of transgenic crops for enhanced levels provitamin A content in crops like maize, tomato, cassava, potato and mustered. At ICRISAT, transgenic events of groundnut and pigeonpea carrying either a single maize phytoene synthase 1 (psy1) gene or both psy1 and tomato β-lycopene cyclase (β-lyc) have been developed through Agrobacterium-mediated genetic transformation. Preliminary results showed a significant increase in the total carotenoids and β-carotene levels in the transgenic events. Provitamin A enrichment of these crops could have a significant impact on the nourishment and nutrient interactions by playing a major role in the bioavailability and metabolic efficiency in the affected population
Transgenic approaches for abiotic stress tolerance in plants: and prospects
Abiotic stresses including drought are serious threats to the sustainability of crop yields accounting for more crop productivity losses than any other factor in rainfed agriculture. Success in breeding for better adapted varieties to abiotic stresses depend upon the concerted efforts by various research domains including plant and cell physiology, molecular biology, genetics, and breeding. Use of modern molecular biology tools for elucidating the control mechanisms of abiotic stress tolerance, and for engineering stress tolerant crops is based on the expression of specific stress-related genes. Hence, genetic engineering for developing stress tolerant plants, based on the introgression of genes that are known to be involved in stress response and putative tolerance, might prove to be a faster track towards improving crop varieties. Far beyond the initial attempts to insert "single-action" genes, engineering of the regulatory machinery involving transcription factors has emerged as a new tool now for controlling the expression of many stress-responsive genes. Nevertheless, the task of generating transgenic cultivars is not only limited to the success in the transformation process, but also proper incorporation of the stress tolerance. Evaluation of the transgenic plants under stress conditions, and understanding the physiological effect of the inserted genes at the whole plant level remain as major challenges to overcome. This review focuses on the recent progress in using transgenic technology for the improvement of abiotic stress tolerance in plants. This includes discussion on the evaluation of abiotic stress response and the protocols for testing the transgenic plants for their tolerance under close-to-field conditions
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