67 research outputs found

    Qualitative characterization and clustering in tomato (Solanum lycopersicum L.) germplasm accessions

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    Most of the tomato genotypes are inbred in nature, indicating the need to assess and characterize germplasm accessions as they are the reserve for genotypes with desired traits. Documentation on morphological traits is quite informative in tomato breeding programs since higher levels of diversity on morphological traits are associated with genotypes with lower genetic diversity when assessed using molecular markers. The present investigation aimed to evaluate morphological diversity in tomato germplasm accessions. Morphological characterization was performed in 104 genotypes acquired from various sources. Thirty-three morphological traits, such as seedling, plant, inflorescence and fruit, were scored based on the tomato descriptors. Out of 33 characters studied, 26 traits exhibited diverse modalities, 4 traits exhibited varied classes in genotypes and 3 traits did not show any variants. Qualitative characterization highlighted greater variability among genotypes, as witnessed by their diverse modalities for each trait. The collected data was subjected to Agglomerative Hierarchical Clustering following Ward’s method. Cluster analysis and dendrogram construction displayed genetic diversity's richness in the germplasm accessions. Cluster analysis placed these 104 genotypes in six clusters. The largest cluster comprised 55 genotypes, whereas the smallest cluster had three. Agglomerative Hierarchical Clustering helped to find similarities between genotypes. This efficiently assigned genotypes into groups and thus provided guidelines for parental selection in tomato hybridization and breeding programmes.

    Water and Sanitation in Mumbai\u27s Slums: Education through Inquiry Based Learning in Social Work

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    Water and sanitation are the most important services necessary for life and dignity of citizens. But slum dwellers are excluded from these services, resulting in environmental degradation, marginalization and poor health. Through inquiry based learning, the first author has attempted to give his students an first hand and innovative learning experience by helping them to explore water and sanitation issues in the Ambujwadi slum of Mumbai (India) on their own. The paper highlights the pedagogical approach and by the way of illustrations helps the reader to understand its usefulness in teaching students of social work

    Plastic strain-induced olivine-ringwoodite phase transformation at room temperature: main rules and the mechanism of the deep-focus earthquake

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    Deep-focus earthquakes that occur at 350-660 km are theorized to be caused by strain-induced olivine-spinel phase transformation (PT). We introduce and apply dynamic rotational diamond anvil cell with rough diamond anvils to deform San Carlos olivine. While olivine was never transformed to spinel at any pressure at room temperature, we obtained olivine-ringwoodite PT under severe plastic shear at 15-28 GPa within seconds. This is conceptual proof of the difference between pressure- and plastic strain-induced PTs and that plastic straining can accelerate this PT from million years to timescales relevant for the earthquake. The PT pressure linearly reduces with increasing plastic strain, corresponding increasing dislocation density and decreasing crystallite size. The main rules of the coupled severe plastic flow, PT, and microstructure evolution are found

    Effect of particle size on the phase transformation behavior and equation of state of Si under hydrostatic loading

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    High-pressure synchrotron X-ray diffraction (XRD) studies have been conducted on three types of Si particles (micron, 100 nm, and 30 nm). The pressure for initiation of Si-I->Si-II phase transformation (PT) essentially increases with a reduction in particle size. For 30 nm Si particles, Si-I directly transforms to Si-XI by skipping the intermediate Si-II phase, which appears during the pressure release. The evolution of phase fractions of Si particles under hydrostatic compression is studied. The equation of state (EOS) of Si-I, Si-II, Si-V, and Si-XI for all three particle sizes is determined, and the results are compared with other studies. A simple iterative procedure is suggested to extract the EOS of Si-XI and Si-II from the data for a mixture of two and three phases with different pressures in each phase. Using previous atomistic simulations, EOS for Si-II is extended to ambient pressure, which is important for plastic strain-induced phase transformations. Surprisingly, the EOS of micron and 30 nm Si are identical, but different from 100 nm particles. In particular, the Si-I phase of 100 nm Si is less compressible than that of micron and 30 nm Si. The reverse Si-V->Si-I PT is observed for the first time after complete pressure release to the ambient for 100 nm particles.Comment: 19 pages, 10 figures, 2 table

    In-situ study of rules of nanostructure evolution, severe plastic deformations, and friction under high pressure

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    Severe plastic deformations under high pressure are used to produce nanostructured materials but were studied ex-situ. We introduce rough diamond anvils to reach maximum friction equal to yield strength in shear and perform the first in-situ study of the evolution of the pressure-dependent yield strength and nanostructural parameters for severely pre-deformed Zr. {\omega}-Zr behaves like perfectly plastic, isotropic, and strain-path-independent. This is related to reaching steady values of the crystallite size and dislocation density, which are pressure-, strain- and strain-path-independent. However, steady states for {\alpha}-Zr obtained with smooth and rough anvils are different, which causes major challenge in plasticity theory.Comment: arXiv admin note: substantial text overlap with arXiv:2208.0802

    Prolonged mixed phase induced by high pressure in MnRuP

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    Hexagonally structured MnRuP was studied under high pressure up to 35 GPa from 5 to 300 K using synchrotron X-ray diffraction. We observed that a partial phase transition from hexagonal to orthorhombic symmetry started at 11 GPa. The new and denser orthorhombic phase coexisted with its parent phase for an unusually long pressure range, {\Delta}P ~ 50 GPa. We attribute this structural transformation to a magnetic origin, where a decisive criterion for the boundary of the mixed phase lays in the different distances between the Mn-Mn atoms. In addition, our theoretical study shows that the orthorhombic phase of MnRuP remains steady even at very high pressures up to ~ 250 GPa, when it should transform to a new tetragonal phase.Comment: 15 pages, 5 figures, supplementary materia

    Unusual plastic strain-induced phase transformation phenomena in silicon

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    Pressure-induced phase transformations (PTs) in Si, the most important electronic material, have been broadly studied, whereas strain-induced PTs have never been studied in situ. Here, we reveal in situ various important plastic strain-induced PT phenomena. A correlation between the direct and inverse Hall-Petch effect of particle size on yield strength and pressure for strain-induced PT is predicted theoretically and confirmed experimentally for Si-I→Si-II PT. For 100 nm particles, the strain-induced PT Si-I→Si-II initiates at 0.3 GPa under both compression and shear while it starts at 16.2 GPa under hydrostatic conditions. The Si-I→Si-III PT starts at 0.6 GPa but does not occur under hydrostatic pressure. Pressure in small Si-II and Si-III regions of micron and 100 nm particles is ∼5–7 GPa higher than in Si-I. For 100 nm Si, a sequence of Si-I → I + II → I + II + III PT is observed, and the coexistence of four phases, Si-I, II, III, and XI, is found under torsion. Retaining Si-II and single-phase Si-III at ambient pressure and obtaining reverse Si-II→Si-I PT demonstrates the possibilities of manipulating different synthetic paths. The obtained results corroborate the elaborated dislocation pileup-based mechanism and have numerous applications for developing economic defect-induced synthesis of nanostructured materials, surface treatment (polishing, turning, etc.), and friction.This article is published as Yesudhas, Sorb, Valery I. Levitas, Feng Lin, K_K Pandey, and Jesse S. Smith. "Unusual plastic strain-induced phase transformation phenomena in silicon." Nature Communications 15, no. 1 (2024): 7054. doi: https://doi.org/10.1038/s41467-024-51469-5. © The Author(s) 2024. This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (http://creativecommons.org/licenses/by-nc-nd/4.0/)

    Sustainability reporting practices and their social impact to NGO funding in Italy

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    This study analyses the growing social trends of sustainability reporting practices in non-governmental organisations (NGOs). Taking a preliminary step toward NGO funding, we consider the current lack of information disclosure in existing reporting practices, which are diverse and unsustainable. We investigate key organisational information in order to discover any potential links between funding sources and disclosure practices. In Italy, today there is an on-going effort to encourage public engagement in civil society. A percentage-tax law allows taxpayers to dedicate ‘cinque per mille’ (one-half percent)of their income to NGOs, which is then deducted from their tax obligation (Hereafter, ‘5 per thousand’). Our primary research objective is to understand if there is a link between the ‘5 per thousand’ donations that NGOs receive for providing social impact, and their reporting practices. Therefore, we critically analyse if and how sustainable reporting practices are achieved within the top 100 most funded NGOs that receive the ‘5 per thousand’ donation. We examine public data from official government records published by the Italian Revenue Agency. The findings suggest that sustainability reporting offers a number of financial and social advantages, including social impact that builds trust towards the idea of civil society and its funders. © 2019 Elsevier Lt
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