307 research outputs found

    Analysis of a VTOL hover task with predictor displays using an optimal control model of the human operator

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    The influence of different types of predictor displays in a longitudinal VTOL hover task is analyzed in a theoretical study. It was assumed that pitch angle and position are presented to the pilot in separate displays namely the artificial horizon and position display. The predictive information is calculated by means of a Taylor series. From earlier experimental studies it is well known that predictor displays improve human and system performance and result in reducing human workload. In this study, an optimal control model is used to prove this effect theoretically. Several cases with differing amounts of predictive and rate information are compared

    Modeling the human as a controller in a multitask environment

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    Modeling the human as a controller of slowly responding systems with preview is considered. Along with control tasks, discrete noncontrol tasks occur at irregular intervals. In multitask situations such as these, it has been observed that humans tend to apply piecewise constant controls. It is believed that the magnitude of controls and the durations for which they remain constant are dependent directly on the system bandwidth, preview distance, complexity of the trajectory to be followed, and nature of the noncontrol tasks. A simple heuristic model of human control behavior in this situation is presented. The results of a simulation study, whose purpose was determination of the sensitivity of the model to its parameters, are discussed

    The human as a detector of changes in variance and bandwidth

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    The detection of changes in random process variance and bandwidth was studied. Psychophysical thresholds for these two parameters were determined using an adaptive staircase technique for second order random processes at two nominal periods (1 and 3 seconds) and damping ratios (0.2 and 0.707). Thresholds for bandwidth changes were approximately 9% of nominal except for the (3sec,0.2) process which yielded thresholds of 12%. Variance thresholds averaged 17% of nominal except for the (3sec,0.2) process in which they were 32%. Detection times for suprathreshold changes in the parameters may be roughly described by the changes in RMS velocity of the process. A more complex model is presented which consists of a Kalman filter designed for the nominal process using velocity as the input, and a modified Wald sequential test for changes in the variance of the residual. The model predictions agree moderately well with the experimental data. Models using heuristics, e.g. level crossing counters, were also examined and are found to be descriptive but do not afford the unification of the Kalman filter/sequential test model used for changes in mean

    Operator modeling in commerical aviation: Cognitive models, intelligent displays, and pilot's assistants

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    One of the goals of the National Aviation Safety/Automation program is to address the issue of human-centered automation in the cockpit. Human-centered automation is automation that, in the cockpit, enhances or assists the crew rather than replacing them. The Georgia Tech research program focused on this general theme, with emphasis on designing a computer-based pilot's assistant, intelligent (i.e, context-sensitive) displays, and an intelligent tutoring system for understanding and operating the autoflight system. In particular, the aids and displays were designed to enhance the crew's situational awareness of the current state of the automated flight systems and to assist the crew's situational awareness of the current state of the automated flight systems and to assist the crew in coordinating the autoflight system resources. The activities of this grant included: (1) an OFMspert to understand pilot navigation activities in a 727 class aircraft; (2) an extension of OFMspert to understand mode control in a glass cockpit, Georgia Tech Crew Activity Tracking System (GT-CATS); (3) the design of a training system to teach pilots about the vertical navigation portion of the flight management system -VNAV Tutor; and (4) a proof-of-concept display, using existing display technology, to facilitate mode awareness, particularly in situations in which controlled flight into terrain (CFIT) is a potential

    Identification of Fe and Zn Responsive Genes in Pearl Millet (Pennisetum glaucum L.) through Whole Genome Transcriptome Approach

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    Micronutrient malnutrition due to iron and zinc deficiencies is a serious public health problem in developing countries. In India alone, about 80% of the pregnant women and 74% of children suffer from iron and zinc deficiency. At present, knowledge of the genes controlling specific steps in the Fe and Zn pathways is still rudimentary hence studying genes of Fe and Zn density has become important. A whole genome RNA-Seq approach was carried out to understand the genes and pathways related to Fe and Zn accumulation in pearl millet. Seedlings of a high Fe and Zn grain density pearl millet inbred ICMB 1505 were exposed to four Fe and Zn stress treatments namely, ā€“Fe ā€“Zn, ā€“Fe +Zn, +Fe ā€“Zn and +Fe +Zn in hydroponics for 12 days (Figure 1). Seedlings were expressed interveinal chlorosis in the leaves due to the non-availability of Fe and Zn compared to control during the stress treatments. At that time, the leaf and root tissues in four treatments were harvested separately. Total RNA was extracted from the treated samples followed by cDNA synthesis. Illumina HiSeq 2500 platform was used to sequence the constructed cDNA libraries. Analysis of differentially expressed genes and pathways associated Fe and Zn is underway. Simultaneously, a set of 40 genotypes with variable Fe and Zn grain density were selected and tissue samples from different plant parts such as seed, flag leaf, root, stem sheath, panicles at anthesis and panicle at milky-stage were collected. RNA was extracted from the samples to validate the genes associated with Fe and Zn homeostasis. The information will be used for accelerated breeding programmes to improve the Fe and Zn density in pearl millet

    Crystal structure of 2-methylamino-3-nitro-4-p-tolylpyrano[3,2-c]chromen-5(4H)-one

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    The authors thank Dr Babu Varghese, SAIF, IIT, Chennai, India, for the data collection.Peer reviewedPublisher PD

    Light interception and radiation use efficiency (RUE) in maize (Zea mays. L) intercropping with greengram (Vigna radiata L.)

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    Intercropping is growing two or more crop species simultaneously, different canopy architectures by row configuration, changing light interception, radiation utilisation, and increased yield. The present study aimed to evaluate different intercropping systems affected light interception per cent and radiation use efficiency in maize (Zea mays L.) intercropping with greengram (Vigna radiata L.) different ratios. Field experiments were conducted for Kharif 2022 and Rabi 2022-2023 seasons, which were laid out in a split-plot design and replicated three times. Three Nitrogen levels viz., N1 - 75 % RDN (Recommended dose of Nitrogen), N2 ā€“ 100% RDN, N3-125% RDN had taken as the main plot and three intercropping treatments were taken as subplot viz., M2G2- replacement series (two row of maize and two row of Greengram), M4G2- replacement series (four rows of maize and two row of Greengram), M2G3-paired row system (two rows of maize and three rows of Greengram), and sole maize. Both light interception and radiation use efficiency were significantly affected by intercropping systems. Light interception per cent of the main crop (maize) was significantly higher (69.0, 75.5 and 71.0 % during Kharif and 60.1, 78.1 and 76.6 during rabi) at vegetative, flowering and maturity phases, respectively. The Kharif 2022 and Rabi 2022-2023 maximum Radiation Use Efficiency (RUE) of Maize intercropping with green gram (maize + greengram) was higher in T12 (M2G3 paired row with 125 % Recommended Dose of Nitrogen) recorded as 2.46 (Kharif) and 1.43 (rabi). The outcome might be utilised to optimise the row configuration of intercropping design, explain the mechanism of intercropping on light utilisation, and improve radiation use efficiency

    Genomics-Integrated Breeding for Carotenoids and Folates in Staple Cereal Grains to Reduce Malnutrition

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    Globally, two billion people suffer from micronutrient deficiencies. Cereal grains provide more than 50% of the daily requirement of calories in human diets, but they often fail to provide adequate essential minerals and vitamins. Cereal crop production in developing countries achieved remarkable yield gains through the efforts of the Green Revolution (117% in rice, 30% in wheat, 530% in maize, and 188% in pearl millet). However, modern varieties are often deficient in essential micronutrients compared to traditional varieties and land races. Breeding for nutritional quality in staple cereals is a challenging task; however, biofortification initiatives combined with genomic tools increase the feasibility. Current biofortification breeding activities include improving rice (for zinc), wheat (for zinc), maize (for provitamin A), and pearl millet (for iron and zinc). Biofortification is a sustainable approach to enrich staple cereals with provitamin A, carotenoids, and folates. Significant genetic variation has been found for provitamin A (96ā€“850 mg and 12ā€“1780 mg in 100 g in wheat and maize, respectively), carotenoids (558ā€“6730 mg in maize), and folates in rice (11ā€“51 mg) and wheat (32.3ā€“89.1 mg) in 100 g. This indicates the prospects for biofortification breeding. Several QTLs associated with carotenoids and folates have been identified in major cereals, and the most promising of these are presented here. Breeding for essential nutrition should be a core objective of next-generation crop breeding. This review synthesizes the available literature on folates, provitamin A, and carotenoids in rice, wheat, maize, and pearl millet, including genetic variation, trait discovery, QTL identification, gene introgressions, and the strategy of genomics-assisted biofortification for these traits. Recent evidence shows that genomics-assisted breeding for grain nutrition in rice, wheat, maize, and pearl millet crops have good potential to aid in the alleviation of micronutrient malnutrition in many developing countries

    Does Soil Micronutrient Variability in Test Locations Influence Performance of Biofortified Pearl Millet in India?

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    Testing of biofortified hybrids across varying pearl millet-growing regions of India indicated the need for maintaining sufficient Fe and Zn levels in soil to express the cropsā€™s full genetic potential and ensure successful loading of micronutrients in the grain. The study suggested the need for practicing balanced fertilization while growing biofortified hybrids to increase grain yield and micronutrient accumulation in grains

    Breaking the intergeneric hybridization barrier in Carica papaya and Vasconcellea cauliflora

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    The present investigation was undertaken to develop PRSV (Papaya ringspot virus) resistant hybrids through intergeneric hybridization. Intergeneric hybridization was done involving nine Carica papaya cultivars as female and Vasconcellea cauliflora as male. To break the intergeneric hybridization barrier, various nutrient combinations were used. Among the combinations used, sucrose 5%, sucrose 5% + boron 0.5% and sucrose 5% + CaCl2 0.5% improved the fruit set and seed set percentage. A total number of 1197 flowers were pollinated and 308 fruits were obtained. On extraction, 721 seeds were obtained from CO 7, Pusa Nanha and CP 50. Out of 721 F0 seeds (crossed seeds) sown, 419 seeds germinated and artificial screening for PRSV was carried out 27 days after sap inoculation. Out of 29 F1 hybrid plants from CO 7 x V. cauliflora cross, only six plants namely CO 7V1 to CO 7V6 were found free from PRSV symptoms. Similarly, out of 55 F1 hybrids from cross involving Pusa Nanha x V. cauliflora only 23 plants namely PNV1 to PNV23 were found free from the symptoms and 70 plants namely CPV1 to CPV70 out of 335 plants of CP50 x V. cauliflora cross were found free from PRSV symptoms. Among the crosses, Pusa Nanha x V. cauliflora had higher yield under PRSV infected conditions, however, total soluble solids and total sugars were found lesser than the CO 7 x V. cauliflora cross. The hybridity of the progenies were confirmed by using ISSR (Inter Simple Sequence Repeats) primers by the amplification of DNA from progenies and their parents. ISSR primers UBC 856, UBC807 and ISSR primer combinations UBC 856-817, UBC 810-817, UBC 861-817, UBC 856-810, UBC 861-810 and UBC 856-817 clearly amplified specific bands of the male parent, which were present in F1 progenies, but it was absent in female parents
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