494 research outputs found
Effect of surface hydrogen on the anomalous surface segregation behavior of Cr in Fe-rich Fe-Cr alloys
The segregation behavior of Cr in dilute Fe-Cr alloys is known to be
anomalous since the main barrier for surface segregation of Cr in these alloys
arises not from the topmost surface layer but from the subsurface layer where
the solution energy of Cr is much more endothermic as compared to the topmost
surface layer. The Fe-Cr alloys are candidate structural materials for the new
generation of nuclear reactors. The surfaces of these alloys will be exposed to
hydrogen or its isotopes in these reactors, and although hydrogen is soluble
neither in Fe nor in Fe-Cr alloys, it is known that the adsorption energy of
hydrogen on the surface of iron is not only exothermic but relatively large.
This clearly raises the question of the effect of the hydrogen adsorbed on the
surface of iron on the segregation behavior of chromium towards the surface of
iron. In this paper we show, on the basis of our ab initio density functional
theory calculations, that the presence of hydrogen on the surface of iron leads
to a considerably reduced barrier for Cr segregation to both the topmost
surface layer and the subsurface layer, but the subsurface layer still controls
the barrier for surface segregation. This reduction in the barrier for surface
segregation is due to the nature of the Cr-H couple that acts in a complex and
synergistic manner. The presence of Cr enhances the exothermic nature of
hydrogen adsorption that in turn leads to a reduced barrier for surface
segregation. These results should be included in the multiscale modeling of
Fe-Cr alloys
NEW INITIATIVE OF UNMANNED AERIAL VEHICLE (UAV) EMERGING TECHNOLOGY APPLICATIONS IN NORTH EAST FOR CAPACITY BUILDING AND OUTREACH ACTIVITIES OF NORTH EASTERN SPACE APPLICATIONS CENTRE
Unmanned Aerial Vehicle (UAV) technology is revolutionizing and acting as an alternative for many of remote sensing applications, particularly for very high resolution satellite requirements, considering easy of flying in the areas of persistent cloud cover like North East. According to top market reports, UAV business is growing at very fast rate. It is valued at USD 18.14 Billion in 2017 and is projected to reach USD 52.30 Billion by 2025, at a CAGR of 14.15% from 2018 to 2025.North Eastern Space Applications Centre, Umiam, Shillong, Meghalaya, which is responsible for promoting space technology tools for governance and development activities; has taken up a lead role in initiating use of Unmanned Aerial Vehicle for large number of applications such as natural resources management, infrastructure development, disaster response and rescue, project monitoring, research and development etc. Capacity building, training and outreach are important activities taken up by NESAC for promoting use of UAV remote sensing at central/state/academic/research institutions and individual level.
As part of capacity building, NESAC has successfully organized two 2 weeks training program for UAV Remote sensing & Applications for the participants all over the country. NESAC has also organised 1 week training programs for officials from State Remote Sensing Centres of North Eastern Region and North Eastern Council. More than 100 participants have been trained from different part of the country. The focus of the training was to include all aspects of UAV Remote Sensing applications. The details of course curriculum are: basic concepts of UAV, building of UAVs, UAV flight simulation, flight planning, UAV data processing, generation of DSM/DTM/Orthomosaic, use of UAV data for different applications in the field of Agriculture, Disaster management, Forestry, Infrastructure planning, construction monitoring etc. Pilot project is also incorporated as part of the training. Apart from training programs at NESAC, large numbers of application projects (> 60 nos.) have been successfully completed. Outreach activities are also carried out which includes exhibiting UAVs at seminars, demonstration to large no. of students, showcasing UAV capabilities at disaster drills carried out by State Disaster Management Authority (SDMA) etc. The new initiatives of UAV convinced all concerned at taking up UAV RS applications for governance and developmental activities. The full paper will discuss all the aspects of UAV technology and applications.</p
On the origin of the A and B electronic Raman scattering peaks in the superconducting state of YBaCuO
The electronic Raman scattering has been investigated in optimally oxygen
doped YBaCuO single crystals as well as in crystals
with non-magnetic, Zn, and magnetic, Ni, impurities. We found that the
intensity of the A peak is impurity independent and their energy to
ratio is almost constant (). Moreover, the
signal at the B channel is completely smeared out when non-magnetic Zn
impurities are present. These results are qualitatively interpreted in terms of
the Zeyher and Greco's theory that relates the electronic Raman scattering in
the A and B channels to \textit{d}-CDW and superconducting order
parameters fluctuations, respectively.Comment: Submited to Phys. Rev. Let
Contribution of Cystine-Glutamate Antiporters to the Psychotomimetic Effects of Phencyclidine
Altered glutamate signaling contributes to a myriad of neural disorders, including schizophrenia. While synaptic levels are intensely studied, nonvesicular release mechanisms, including cystine–glutamate exchange, maintain high steady-state glutamate levels in the extrasynaptic space. The existence of extrasynaptic receptors, including metabotropic group II glutamate receptors (mGluR), pose nonvesicular release mechanisms as unrecognized targets capable of contributing to pathological glutamate signaling. We tested the hypothesis that activation of cystine–glutamate antiporters using the cysteine prodrug N-acetylcysteine would blunt psychotomimetic effects in the rodent phencyclidine (PCP) model of schizophrenia. First, we demonstrate that PCP elevates extracellular glutamate in the prefrontal cortex, an effect that is blocked by N-acetylcysteine pretreatment. To determine the relevance of the above finding, we assessed social interaction and found that N-acetylcysteine reverses social withdrawal produced by repeated PCP. In a separate paradigm, acute PCP resulted in working memory deficits assessed using a discrete trial t-maze task, and this effect was also reversed by N-acetylcysteine pretreatment. The capacity of N-acetylcysteine to restore working memory was blocked by infusion of the cystine–glutamate antiporter inhibitor (S)-4-carboxyphenylglycine into the prefrontal cortex or systemic administration of the group II mGluR antagonist LY341495 indicating that the effects of N-acetylcysteine requires cystine–glutamate exchange and group II mGluR activation. Finally, protein levels from postmortem tissue obtained from schizophrenic patients revealed significant changes in the level of xCT, the active subunit for cystine–glutamate exchange, in the dorsolateral prefrontal cortex. These data advance cystine–glutamate antiporters as novel targets capable of reversing the psychotomimetic effects of PCP
A bibliography of parasites and diseases of marine and freshwater fishes of India
With the increasing demand for fish as human food, aquaculture both in freshwater
and salt water is rapidly developing over the world. In the developing countries,
fishes are being raised as food. In many countries fish farming is a very important
economic activity. The most recent branch, mariculture, has shown advances in
raising fishes in brackish, estuarine and bay waters, in which marine, anadromous and
catadromous fishes have successfully been grown and maintained
Report of the Task Force on Enhancing technology use in agriculture insurance
Pradhan Mantri Fasal Bima Yojana (PMFBY) is a flagship scheme of the Government of India to
provide insurance coverage and financial support to farmers in the event of failure of any of the
notified crops, unsown area and damage to harvest produce as a result of natural calamities, pests
and diseases to stabilise the income of farmers, and to encourage them to adopt modern agricultural
practices. The scheme is a considerable improvement over all previous insurance schemes in India
and is heavily subsidised by the state and central governments. The scheme aims to cover 50 percent
of the farming households within next 3 years.
During its implementation in the last one season, several challenges relating to enrolment, yield
estimation, loss assessment, and claim settlement were reported by farmers, insurance companies
as well as the state governments. It was also noted that several technological opportunities existed
for possibly leveraging support to the Indian crop insurance program for enhanced efficiency and
effectiveness. NITI Aayog of the Government of India, therefore, constituted a Task Force to deliberate
on this subject and identify such potential opportunities. This report summarises the recommendations
of the Task Force.
The Task Force constituted to address the issue of technology support to crop insurance comprised
the following 5 sub-groups: (1) Remote Sensing & Drones; (2) Decision Support Systems, Crop
Modelling & Integrated Approaches; (3) IT/ICT in Insurance; (4) Crop Cutting Experiments (CCEs); and
(5) Technologies for Livestock and Aquaculture Insurance. Each sub-group had several discussions
with experts in the respective areas, and submitted draft reports. More than 100 experts related to
professional research agencies, insurance industry, banks, and the government contributed to these
discussions. Technological options available in the country and abroad were considered by all groups.
The Task Force together with the sub-groups then deliberated on key issues and formulated its
recommendations as presented in this report. During the discussions it was realised that there were
many administrative and institutional issues that needed to be addressed in PMFBY. However, the
focus of the Task Force was on its main mandate, technology use in crop insurance. We hope these
recommendations would help the Indian crop insurance sector take full advantage of the technological
options suggested so as to increase its efficacy and effectiveness leading to reduced agrarian distress
in the country
Burden of typhoid and paratyphoid fever in India.
BACKGROUND: In 2017, more than half the cases of typhoid fever worldwide were projected to have occurred in India. In the absence of contemporary population-based data, it is unclear whether declining trends of hospitalization for typhoid in India reflect increased antibiotic treatment or a true reduction in infection. METHODS: From 2017 through 2020, we conducted weekly surveillance for acute febrile illness and measured the incidence of typhoid fever (as confirmed on blood culture) in a prospective cohort of children between the ages of 6 months and 14 years at three urban sites and one rural site in India. At an additional urban site and five rural sites, we combined blood-culture testing of hospitalized patients who had a fever with survey data regarding health care use to estimate incidence in the community. RESULTS: A total of 24,062 children who were enrolled in four cohorts contributed 46,959 child-years of observation. Among these children, 299 culture-confirmed typhoid cases were recorded, with an incidence per 100,000 child-years of 576 to 1173 cases in urban sites and 35 in rural Pune. The estimated incidence of typhoid fever from hospital surveillance ranged from 12 to 1622 cases per 100,000 child-years among children between the ages of 6 months and 14 years and from 108 to 970 cases per 100,000 person-years among those who were 15 years of age or older. Salmonella enterica serovar Paratyphi was isolated from 33 children, for an overall incidence of 68 cases per 100,000 child-years after adjustment for age. CONCLUSIONS: The incidence of typhoid fever in urban India remains high, with generally lower estimates of incidence in most rural areas. (Funded by the Bill and Melinda Gates Foundation; NSSEFI Clinical Trials Registry of India number, CTRI/2017/09/009719; ISRCTN registry number, ISRCTN72938224.)
Genome-Wide Distribution and Organization of Microsatellites in Plants: An Insight into Marker Development in Brachypodium
Plant genomes are complex and contain large amounts of repetitive DNA including microsatellites that are distributed across entire genomes. Whole genome sequences of several monocot and dicot plants that are available in the public domain provide an opportunity to study the origin, distribution and evolution of microsatellites, and also facilitate the development of new molecular markers. In the present investigation, a genome-wide analysis of microsatellite distribution in monocots (Brachypodium, sorghum and rice) and dicots (Arabidopsis, Medicago and Populus) was performed. A total of 797,863 simple sequence repeats (SSRs) were identified in the whole genome sequences of six plant species. Characterization of these SSRs revealed that mono-nucleotide repeats were the most abundant repeats, and that the frequency of repeats decreased with increase in motif length both in monocots and dicots. However, the frequency of SSRs was higher in dicots than in monocots both for nuclear and chloroplast genomes. Interestingly, GC-rich repeats were the dominant repeats only in monocots, with the majority of them being present in the coding region. These coding GC-rich repeats were found to be involved in different biological processes, predominantly binding activities. In addition, a set of 22,879 SSR markers that were validated by e-PCR were developed and mapped on different chromosomes in Brachypodium for the first time, with a frequency of 101 SSR markers per Mb. Experimental validation of 55 markers showed successful amplification of 80% SSR markers in 16 Brachypodium accessions. An online database ‘BraMi’ (Brachypodium microsatellite markers) of these genome-wide SSR markers was developed and made available in the public domain. The observed differential patterns of SSR marker distribution would be useful for studying microsatellite evolution in a monocot–dicot system. SSR markers developed in this study would be helpful for genomic studies in Brachypodium and related grass species, especially for the map based cloning of the candidate gene(s)
Multi-location evaluation of pigeonpea (Cajanus cajan) for broad-based resistance to sterility-mosaic disease in India
A total of 141 germplasm accessions and 725 breeding lines of pigeon pea were evaluated for resistance to pigeon pea sterility mosaic virus at 13 field locations in India from 1983-84 to 1989-90. Some 50 seeds per test entry were sown at each location and the trials were artificially inoculated by either leaf-stapling (in which 10-15-day-old seedlings were stapled with diseased leaves harbouring mites) or the infector-hedge method (with the susceptible variety NP(WR)15 sown on the border of the nursery 4-6 months in advance of the normal sowing date). The breeding lines included in the evaluation were newly bred, high-yielding lines entered into the Pigeon Pea Co-ordinated trials by ICRISAT and the All-India Co-ordinated Pulses Improvement Project. ICP7182 was used as the susceptible control line. Information is presented on lines and accessions showing broad-based resistance (percentage infection at maturity) during the trial period at each location. Line ICP7035 from Madhyha Pradesh, which contains DSLR55 in its pedigree, was resistant at 12 locations and some 18 lines were resistant at 10 locations
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