66 research outputs found
Studies on Neutron, Photon (Bremsstrahlung) and Proton Induced Fission of Actinides and Pre-Actinides
We present the yields of various fission products determined in the reactor neutron, 3.7-18.1 MeV quasi-mono energetic neutron, 8-80 MeV bremsstrahlung and 20-45 MeV proton induced fission of 232Th and 238u using radiochemical and off-line beta or gamma ray counting. The yields of the fission products in the bremsstrahlung induced fission natPb and 209Bi with 50-70 MeV and 2.5 GeV based on off-line gamma ray spectrometric technique were also presented. From the yields of fission products, the mass chains yields were obtained using charge distribution correction. From the mass yield distribution, the peak-to-valley (P/V) ratio was obtained. The role of excitation energy on the peak-to-valley ratio and fine structure such as effect of shell closure proximity and even-odd effect of mass yield distribution were examined. The higher yields of the fission products around A=133-134, 138-140 and 143-144 and their complementary products explained from the nuclear structure effect and role of standard I and II mode of asymmetric fission. In the neutron, photon (bremsstrahlung) and proton induced fission, the asymmetric mass distribution for actinides (Th, u) and symmetric distribution for pre-actinides (Pb, Bi) were explained from different type of potential fission barrier
Land use and cropping effects on carbon in black soils of semi-arid tropical India
Soil organic carbon (SOC) and rainfall are generally
positively related, whereas a negative relationship
between soil inorganic carbon (SIC) and rainfall with
some exception is observed. Land use pattern in black
soil region (BSR) of the semi-arid tropical (SAT)
India, consists of 80% under agriculture, followed by
forest, horticulture, wasteland and permanent fallow.
For sustainable agriculture on these soils, there is a
concern about their low OC status, which warrants
fresh initiatives to enhance their OC status by suitable
management interventions. In the BSR region, cotton,
soybean and cereal-based systems dominate but it is
not yet clear as to which cropping system in the SAT
black soils is most suitable for higher OC sequestration.
Many short-term experiments on cotton or
cereal-based systems clearly suggest that cotton or
cereal-based cropping systems including leguminous
crops perform better in terms of SOC sequestration
whereas soybean–legume combination do not add any
substantial amount of OC. In sub-humid bioclimatic
zones (1053–1209 mm mean annual rainfall), soybean is
grown successfully with wheat or fallowing, and SOC
concentration is maintained at 0.75% in the 0.30 m soil
layer under integrated nutrient management. In view of
enhancement and maintenance of OC in many shortterm
experiments conducted in various agro-climate
zones of SAT, it is realized that OC accumulation in
soils of the semi-arid ecosystem with suitable cropping
and management practices could be substantial especially
in cotton–pigeon pea rotation, and thus the discussed
crop rotations in each major bio-climatic zone
stand for wide acceptance by the SAT farmers
Pre-breeding for genetic enhancement of grain legumes
Grain legumes such as chickpea (Cicer arietinum L.) and pigeonpea (Cajanus cajan (L.) millsp) play an important role in ensuring food and nutrition security and sustainable agriculture. Due to narrow genetic base, genetic enhancement in grain legumes is not adequate and the crops are prone to biotic (pests and diseases) adn abiotic (drought, water-logging, salinity, heat and cold) stresses
Cross-Dehydrogenative Couplings between Indoles and β-Keto Esters : Ligand-Assisted Ligand Tautomerization and Dehydrogenation via a Proton-Assisted Electron Transfer to Pd(II)
Cross-dehydrogenative coupling reactions between -ketoesters and electron-rich arenes, such as indoles, proceed with high regiochemical fidelity with a range of -ketoesters and indoles. The mechanism of the reaction between a prototypical -ketoester, ethyl 2-oxocyclopentanonecarboxylate and N-methylindole, has been studied experimentally by monitoring the temporal course of the reaction by 1H NMR, kinetic isotope effect studies, and control experiments. DFT calculations have been carried out using a dispersion-corrected range-separated hybrid functional (B97X-D) to explore the basic elementary steps of the catalytic cycle. The experimental results indicate that the reaction proceeds via two catalytic cycles. Cycle A, the dehydrogenation cycle, produces an enone intermediate. The dehydrogenation is assisted by N-methylindole, which acts as a ligand for Pd(II). The compu-tational studies agree with this conclusion, and identify the turnover-limiting step of the dehydrogenation step, which involves a change in the coordination mode of the -keto ester ligand from an O,O’-chelate to an C-bound Pd enolate. This ligand tautom-erization event is assisted by the -bound indole ligand. Subsequent scission of the ’-C–H bond takes place via a proton-assisted electron transfer mechanism, where Pd(II) acts as an electron sink and the trifluoroacetate ligand acts as a proton acceptor, to pro-duce the Pd(0) complex of the enone intermediate. The coupling is completed in cycle B, where the enone is coupled with indole. Pd(TFA)2 and TFA-catalyzed pathways were examined experimentally and computationally for this cycle, and both were found to be viable routes for the coupling step
Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.
BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700
Georeferenced soil information system: assessment of database
Land-use planning is a decision-making process that
facilitates the allocation of land to different uses that
provide optimal and sustainable benefit. As land-use
is shaped by society–nature interaction, in land-use
planning different components/facets play a significant
role involving soil, water, climate, animal (ruminant/
non-ruminant) and others, including forestry
and the environment needed for survival of mankind.
At times these components are moderated by human
interference. Thus land-use planning being a dynamic
phenomenon is not guided by a single factor, but by a
complex system working simultaneously,which largely
affects the sustainability. To address such issues a
National Agricultural Innovation Project (NAIP) on
‘Georeferenced soil information system for land-use
planning and monitoring soil and land quality for
agriculture’ was undertaken to develop threshold
values of land quality parameters for land-use planning
through quantitative land evaluation and crop
modelling for dominant cropping systems in major
agro-ecological sub-regions (AESRs) representing
rice–wheat cropping system in the Indo-Gangetic
Plains (IGP) and deep-rooted crops in the black
soil regions (BSR). To assess the impact of landuse
change, threshold land quality indicator values
are used. A modified AESR map for agricultural landuse
planning is generated for effective land-use planning
Soil information system: use and potentials in humid and semi-arid tropics
The articles presented in this special section emanated from the researches of consortium members of the National Agricultural Innovative Project (NAIP, Component 4) of the Indian Council of Agricultural Research (ICAR), New Delhi. These researches have helped develop a soil information system (SIS). In view of the changing scenario all over the world, the need of the hour is to get assistance from a host of researchers specialized in soils, crops, geology, geography and information technology to make proper use of the datasets. Equipped with the essential knowledge of data storage and retrieval for management recommendations, these experts should be able to address the issues of land degradation, biodiversity, food security, climate change and ultimately arrive at an appropriate agricultural land-use planning. Moreover, as the natural resource information is an essential prerequisite for monitoring and predicting global environmental change with special reference to climate and land use options, the SIS needs to be a dynamic exercise to accommodate temporal datasets, so that subsequently it should result in the evolution of the soil information technology. The database developed through this NAIP would serve as an example of the usefulness of the Consortium and the research initiative of ICAR involving experts from different fields to find out the potentials of the soils of humid and semi-arid bioclimatic systems of the country
Quantitative assessment of red mud constituents by combined thin layer chromatography and scanning densitometry
99-106Quantitative analysis of aluminium, iron,
silicon and titanium present in bauxite residue (red mud) has been achieved by
thin layer chromatography coupled with optical scanning densitometry. Silicon
in red mud sample is detected at pH range 0.75-0.95 on chromatography plates
prepared with microcrystalline cellulose modified with 10% sodium molybdate.
Aluminium, iron and titanium are detected on silica gel H layers impregnated
with 0.2% sodium formate and developed with mixture of 10% aqueous solutions of
sodium chloride and formic acid in 8:2 v/v. The chromatograms obtained for the
cations are quantitatively evaluated by optical scanning densitometry by
measuring absorbance at 530-520 nm for aluminium, 660-528 nm for iron and
395-410 nm for titanium and silicon in reflectance mode. The quantitative
densitometric data has been evaluated with analogous data obtained by wet
analysis
<span style="font-size:11.0pt;font-family: "Times New Roman";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family: Mangal;mso-ansi-language:EN-GB;mso-fareast-language:EN-US;mso-bidi-language: HI" lang="EN-GB">Quantitative thin layer chromatographic study of Al<sup>3+</sup> in geological samples</span>
146-154A facile and sensitive quantitative visual
analytical method has been developed for the determination of Al3+
in geological samples. The alumina (Al2O3) content in
gibbsitic bauxite and related samples of geological origin is extracted in
triple acidic medium. The sample solutions are purified and then subjected to
quantitative thin layer chromatography (TLC) analysis. Combination of plain
silica gel H and dilute aqueous solution of aluminon (0.005-0.50%) has been
identified as the best chromatographic systems for the selective detection of
Al3+. The important chromatographic parameters such as sample
composition, pH effect, nature of adsorbent and mobile phase composition
as well as detection limit are optimized in terms of spot size, colour
stability and resolution of Al3+. The TLC chromatograms of Al3+
are quantitatively assessed by scanning densitometry and digital image
analysis. Analytical potential of the optical quantitative methods have been
verified for the quantitative TLC assessment of Al3+ in bauxite,
soil, rock and aluminium spent potlining (SPL) samples with respect to the
analogous wet analysis. Repeatability and reproducibility of the method are
also evaluated under the optimized experimental conditions such as sample
concentration, components and pH, slurry volume and layer thickness
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