In machine translation (MT), one of the challenging tasks is to translate the proper nouns and technical terms from the source language to the target language while preserving the phonetic equivalent of original term. Machine transliteration, an essential part of MT systems, plays a vital role in handling proper nouns and technical terms. In this paper, a hybrid attention-based encoder–decoder machine transliteration system is proposed for the low-resource English to the Assamese language. In this work, the proposed machine transliteration system is integrated with the previously published hybrid attention-based encoder–decoder neural MT model to improve the translation quality of English to the Assamese language. The proposed integrated MT system demonstrated good results across various performance metrics such as BLEU, sacreBLEU, METEOR, chrF, RIBES, and TER for English to Assamese translation. Additionally, human evaluation was also conducted to assess translation quality. The proposed integrated MT system was compared with two existing systems: the Bing translation service model and the Samanantar Indic translation model.

Flow through sudden expansion finds its application in several engineering and biological processes. Though the stability of flow through steady sudden expansion has garnered much attention, little to none is given to the pulsatile flow through sudden expansion. Hence, in the present work we study the influence of inflow pulsatility on flow characteristics in a sudden expansion. The inflow velocity is a sinusoidal waveform that is modulated to encompass a wide range of amplitudes, ${{a}}$, and reduced velocities, ${{U_{r}}}$. We report four different modes, namely, synchronized growth of the recirculation region (at high ${{U_{r}}}$), necking and diffusion of the recirculation region (at moderately high ${{U_{r}}}$), splitting and convection of the recirculation region (at moderate ${{U_{r}}}$) and inverse growth of the recirculation region (at low ${{U_{r}}}$). In each mode, the symmetry-breaking critical Reynolds number is obtained through numerical experiments and compared with those of Floquet stability analysis. We found that diffusion and the convection mode of the recirculation region increases the stability of the flow while the inverse growth mode of the recirculation region decreases the same. The effect of the expansion ratio, ${{ER}}$, is also explored, and we found that as ${{ER}}$ increases, the absolute stability of flow decreases, but relative stability between the modes remains similar. Finally, we explain the dynamics of the modes by using terms involving the vorticity transport equation.

Flow of a shear-thinning fluid over curved and moving geometries demands special attention owing to its industrial and biological relevance. The present study reports a numerical simulation of the motion of a Carreau fluid over a transversely oscillating cylinder for a range of oscillation amplitudes and frequencies at Reynolds number $Re = 100$, and compares the flow behaviour with that of a Newtonian fluid. The numerical solver uses the sharp-interface immersed boundary method to reconstruct the flow variables at the intercepted cells in the vicinity of the moving cylinder geometry. Synchronized vortex shedding is observed during the locked-in oscillation mode, whereas paired counter-rotating vortices are shed during the non-locked-in mode. The generation of vorticity and enstrophy variations in the Carreau and Newtonian fluids are compared. The vortex patterns in the Carreau fluid show a strong difference from those of the Newtonian fluid at higher amplitude of oscillation ($A^{*} = 1.2$). This difference in the flow structures is explained through the behaviour of the diffusion terms in the vorticity transport equation. Further, the effect of the Carreau fluid properties on the flow structures and vorticity dynamics are also discussed.

Manganiferous garnets occur in metamorphosed Mn silicate-oxide and silicate-carbonate-oxide rocks of the Sausar Group, India. The garnets of the carbonatic rock show maximum calderite content (∼50 mole%). Increased Ca content in the bulk has been observed to be sympathetically related to the concentration of calderite, rather than the expected andradite component of the garnets. This is the consequence of the preferential partitioning of Ca in coexisting pyroxmangite and/or carbonate. Petrochemical characteristics of the diverse assemblages in response to the physical conditions of metamorphism show that the calderite solubility in manganiferous garnet is not only a function of pressure. Such characteristics only indicate that the mobile components in the bulk influenced the mineralogy of the assemblages at the ambient physical conditions of metamorphism, and this in turn controlled the calderite solubility in garnet.

Mg-Mn amphibole (tirodite), with or without pyroxmangite in the total absence of pyroxenes and high-calcic pyroxenoids, occurs in the Mn silicate rocks of the Sausar Group, India. The rocks were metamorphosed to amphibolite facies condition (T ∼ 650°C, P ∼ 6 kbar). Tirodite-pyroxmangite pairs developed in both carbonate-free and rhodochrosite-bearing assemblages. Also tirodite coexists with either kutnahorite or manganoan calcite in the absence of pyroxmangite. Mineral reactions inferred from modal abundances and compositions of the phases indicate stabilization of the amphibole alone from a bivalent cation-bearing residual unbuffered XCO2 system with XMn < 0.3. On the other hand, tirodite-pyroxmangite pairs appeared in unbuffered low to intermediate XCO2 assemblages with XMn > 0.35. Pyroxenes and high-calcic pyroxenoids did not appear in the present situation, though they occur elsewhere in rocks with broadly similar contents of immobile components. Closely associated assemblages of diverse mineralogy suggest that the XMn and XCO2, rather than the physical conditions of metamorphism, are the decisive factors in promoting the observed phase assemblages.

Redshifted HI 21-cm signal from the cosmic dawn and epoch of reionization evolve considerably along the LoS. We study the impact of this evolution (so called the light cone effect) on the HI 21-cm power spectrum. It is found that the LC effect has a significant impact on the 3D power spectrum and the change could be up to a factor of few. The LC effect is particularly strong during the cosmic dawn near the ‘peaks’ and ‘dips’ in the power spectrum when plotted with redshift. We also show that the 3D power spectrum, which could fully describe ergodic and periodic signal, losses out some information regarding the second order statistics of the signal as the EoR/CD 21-cm signal is non-ergodic and non-periodic along the line of sight. We show that the multi-frequency angular power spectrum (MAPS) ${\mathcal {C}}_{\ell }(\nu _1, \nu _2)$ captures all the information regarding the second order statistics of the signal even in the presence of the LC effect.

Characterizing the diffuse Galactic synchrotron emission (DGSE) at arcminute angular scales is needed to remove this foregrounds in cosmological 21-cm measurements. Here, we present the angular power spectrum (Cℓ) measurement of the diffuse Galactic synchrotron emission using two fields observed by the TIFR GMRT Sky Survey (TGSS). We apply 2D Tapered Gridded Estimator (TGE) to estimate the Cℓ from the visibilities. We find that the residual data after subtracting the point sources is likely dominated by the diffuse Galactic synchrotron radiation across the angular multipole range 240 ≤ ℓ ≲ 500. We fit a power law to the measured Cℓ over this ℓ range. We find that the slopes in both fields are consistent with earlier measurements. For the second field, however, we interpret the measured Cℓ as an upper limit for the DGSE as there is an indication of a significant residual point source contribution.

Laboratory and field studies were undertaken to establish the efficacy of some selected botanicals in the control of the tea red spider mite, Oligonychus coffeae Nietner, a major pest of tea. Bioassays were performed to evaluate the dose-mortality response of adults and eggs of O. coffeae to aqueous plant extracts. The order of adulticidal toxicity based on LC50 and slope values was Sapindus mukorossi L. > Nyctanthes arbor-tristis L. > Phlogacanthus thyrsiformis Nees. The order of ovicidal activity was reversed and was P. thyrsiformis > N. arbor-tristis > S. mukorossi. In addition, different concentrations of the aqueous extract of these plants exhibited repellent properties against adult mites and also significantly decreased the deposition of eggs by the mites on treated tea leaf surfaces. In field conditions, the extracts significantly reduced O. coffeae populations compared to propargite, a synthetic acaricide. There was no phytotoxic effect and the quality of tea was not adversely affected by the treatments. Further, the plant extracts caused no mortality or decrease in the predation efficacy of the adults and fourth instar larvae of Stethorus aptus Kapur, a natural predator of O. coffeae. Using the procedure adopted in this study, tea growers can easily formulate these low-cost eco-friendly botanicals for O. coffeae management in tea plantations.

We evaluated an aqueous extract of Duranta repens L. in the laboratory against the tea red spider mite, Oligonychus coffeae Nietner, to determine its effect on adult mortality, viability of eggs, oviposition deterrence and repellent properties. We also evaluated the same extract in the field to determine its effect on mite populations. The direct spray method was used in the laboratory at concentrations of 2, 4, 6, 8 and 10 g/l. Mortality of O. coffeae was dependent on both concentration and time after application. Deposition of eggs by adult mites on treated leaf surfaces decreased and the viability of eggs was also reduced. Its bioefficacy was comparable to that of the commonly used commercial neem oil formulation (azadirachtin 0.03EC). In addition, different concentrations of the aqueous extract of D. repens also exhibited repellent properties against adult mites. In the field, the application of the aqueous extract of D. repens reduced the mite population and its bioefficacy was comparable to that of the synthetic pesticide Propargite 57 EC. No phytotoxic effect was observed when tea bushes were sprayed with different concentrations of D. repens. Tea samples were taint free. Treatment of plants with the extract did not affect the quality (appearance of liquor, flavour, taint and taste) of made tea. Availability and distribution of this plant in and around tea growing areas of Assam, along with its processing, and the possibility of including D. repens extracts in the current IPM programme are discussed.

Helopeltis theivora Waterhouse is a major sucking pest of tea in northeast India. No effective predators or parasitoids have been recorded from the field, and, therefore, insecticides play a significant role in the control of this pest. Potassium is known to impart physiological resistance to plants against sucking pests. The present study conducted two field trials to evaluate the bioefficacy of thiamethoxam 25 WG and bifenthrin 8 SC applied alone at the dosage recommended by the Tocklai Tea Research Institute and in combination with 2% potassium chloride (KCl) and mined potassium sulphate (K2SO4) against H. theivora. No phytotoxic effects were observed in the field when tea bushes were sprayed. The control of H. theivora achieved by the combinations of thiamethoxam+KCl/K2SO4 and bifenthrin+KCl/K2SO4 was found to be statistically significant (P< 0.05) compared with the sole application of the insecticides. These treatments could be included in the current integrated pest management programme against H. theivora.

Rice landraces have been developed through artificial selection imposed by farmers during the long-term domestication process. Although the global rice diversity is well characterized, few studies have conducted an in-depth analysis of genetic diversity on a local scale. In India, there are many locally adapted non-Basmati aromatic rice landraces in which the pace of improvement is slow, despite their high economic values. The aromatic and quality rice landraces of Manipur, locally called Chakhao (delicious), are important, considering their high economic and cultural values. To conserve and encourage improvement of these landraces, we collected Chakhao accessions from eight districts of Manipur. The aim of the current study was to investigate the level of genetic diversity and structure of 37 Chakhao landraces based on genotyping with 47 microsatellite markers. The genetic diversity analysis revealed high gene diversity (0.673) within the Chakhao population, with values ranging from 0.303 (Poireiton) to 0.471 (mixed Chakhao). The Chakhao rice accessions could be divided into six subgroups based on genetic structure analyses. The population structure derived from the STRUCTURE analysis largely correlated with the farmers' classification of Chakhao landraces. The results of genetic diversity analyses and the indigenous knowledge of the names and use of Chakhao landraces would facilitate the conservation and utilization of this unique genetic resource.

Nagaland is one of the eight states in the north-eastern region of India, where a considerable diversity exists in cultivated rice. Recent exploration in this tribal-dominated state has resulted in a collection of 130 rice accessions growing under diverse agroecological conditions. The agromorphological characterization data of 124 rice landraces revealed a significant variability in plant architecture and grain morphological and quality traits. Multivariate analyses including principal component analysis (PCA) and cluster analysis were performed to assess the patterns of morphological variation. The PCA extracted 12 components, which explained 75.4% of the total variation for 38 quantitative and qualitative traits. The cluster analysis grouped 124 rice landraces into five clusters, and the number of landraces in each cluster ranged from 1 to 59. The correlations among the traits are discussed, which will be useful in considering traits for genetic improvement in grain yield and quality. The landraces have been conserved in the national genebank for further utilization.

Despite the continuous use of synthetic insecticides during the last two decades, the tea mosquito bug Helopeltis theivora Waterhouse still exists as the most destructive pest of tea in North East India. The susceptibility levels of the female sucking bug collected from conventional (synthetic insecticide treated: Terai and Dooars plain regions) and organic (synthetic insecticide untreated: low-altitude Darjeeling region) tea plantations of the northern part of West Bengal to two synthetic insecticides, quinalphos and cypermethrin, and the activity of three principal detoxifying enzymes were assayed. Compared with the susceptible Darjeeling population, the Terai and Dooars populations showed a resistance factor at the lethal concentrations for 50% level ranging from 547- to 2680.87-fold and from 3810- to 7480-fold for quinalphos and cypermethrin, respectively. General esterases (GEs), glutathione S-transferases (GSTs) and cytochrome P450-mediated mono-oxygenases (CYPs) also showed an increased activity in the Terai and Dooars populations compared with those from Darjeeling. Defence enzyme activity was enhanced by 15.4- and 17.6-fold for GEs, 1.8- and 1.9-fold for GSTs and 2.1- and 2.4-fold for CYPs in the synthetic insecticide-treated H. theivora populations when compared with the untreated Darjeeling populations. Electrophoretic analysis for GEs showed a higher level of expression for esterase I–VI isozymes in the Terai and Dooars populations when compared with that in the Darjeeling populations. This study reveals a reduced efficacy of quinalphos and cypermethrin against field populations of H. theivora, possibly due to enhanced activities of GEs, GSTs and CYPs. The findings may be used in developing integrated resistance management strategies that can help in the effective control of this major tea pest.

The tea mosquito bug Helopeltis theivora (Waterhouse) is an important economic pest of tea in India. The development of resistance in H. theivora populations obtained from a conventional plantation and an organic plantation was studied in the laboratory for five generations, and associated changes in life cycle traits were assessed. Selection using sub-lethal concentrations of endosulphan resulted in a 4.4-fold increase in insecticide resistance ratio from the F1 to the F5 generation in the H. theivora population from the conventional plantation. By the F5 generation, nymphal duration was higher and fecundity was lower in the endosulphan-selected strain than in the non-selected strain from a conventional plantation and the susceptible strain from an organic plantation. These findings have practical implications for insecticide resistance management of this important sucking pest of tea.