Frequency Domain Based Solution for Certain Class of Wave Equations: An exhaustive study of Numerical Solutions

The paper discusses the frequency domain based solution for a certain class of wave equations such as: a second order partial differential equation in one variable with constant and varying coefficients (Cantilever beam) and a coupled second order partial differential equation in two variables with constant and varying coefficients (Timoshenko beam). The exact solution of the Cantilever beam with uniform and varying cross-section and the Timoshenko beam with uniform cross-section is available. However, the exact solution for Timoshenko beam with varying cross-section is not available. Laplace spectral methods are used to solve these problems exactly in frequency domain. The numerical solution in frequency domain is done by discretisation in space by approximating the unknown function using spectral functions like Chebyshev polynomials, Legendre polynomials and also Normal polynomials. Different numerical methods such as Galerkin Method, Petrov- Galerkin method, Method of moments and Collocation method or the Pseudo-spectral method in frequency domain are studied and compared with the available exact solution. An approximate solution is also obtained for the Timoshenko beam with varying cross-section using Laplace Spectral Element Method (LSEM). The group speeds are computed exactly for the Cantilever beam and Timoshenko beam with uniform cross-section and is compared with the group speeds obtained numerically. The shear mode and the bending modes of the Timoshenko beam with uniform cross-section are separated numerically by applying a modulated pulse as the shear force and the corresponding group speeds for varying taper parameter m are obtained numerically by varying the frequency of the input pulse. An approximate expression for calculating group speeds corresponding to the shear mode and the bending mode, and also the cut-off frequency is obtained. Finally, we show that the cut-off frequency disappears for large m, for ε > 0 and increases for large m, for ε < 0

Biological control of tomato leaf curl New Delhi virus using cucurbitaceous endophytes in bitter gourd (Momordica charantia)

Momordica charantia L., known as bitter gourd, is a vine species classified under the Cucurbitaceae family and is extensively cultivated across Southeast Asia. The tomato leaf curl New Delhi virus (ToLCNDV), a member of the Begomovirus genus and Geminiviridae family, significantly affects bitter gourd. In this study, endophytes were isolated from different cucurbitaceous crops. The germination potential of the bacterial and actinobacterial isolates was evaluated via the roll towel method. Notably, isolate B-BGR1 demonstrated a 100 percent germination rate with vigor index of 5636.00 compared with the sterile water control, which presented a vigor index of 1013.00. Subsequent pot culture experiments indicated that a 2 percent application of B-BGR1 resulted in the lowest disease incidence, with a 78.57 percent reduction over the control, followed by B-BGL1, which showed a 71.43 percent reduction over the control. The isolate B-BGR1 was molecularly confirmed as Bacillus licheniformis through sequencing. The presence of secondary metabolites in B. licheniformis was identified via gas chromatography-mass spectrometry (GC-MS). To further explore the mechanism of action, the ToLCNDV coat protein was designed via MODELLER software, yielding a model with the highest DOPE score of -22439.755859. Molecular docking experiments revealed strong binding affinities for compounds 7,9-di-tert-butyl-1-oxaspiro(4,5)deca-6,9-dien and Mandelic acid, with values of -5.0 and -4.9 kcal/mol, respectively. This study represents the first investigation to confirm the antiviral potential of B. licheniformis through molecular docking against the ToLCNDV coat protein. These results indicate that B. licheniformis is a potential biological control agent for managing ToLCNDV in bitter gourd

Identification of false smut – resistant donors in Rice (Oryza sativa L.) and analysis of their morpho-molecular diversity for resistance breeding

False smut disease of rice caused by the pathogen Ustilaginoidea virens is a growing threat to the rice farmers as it affects both quality and quantity. Development of resistant variety becomes difficult, since very few resistant donors were available for false smut resistant breeding programme. Therefore, to identify potential donors for resistance breeding a total of 60 genotypes were screened at hotspot location (Gudalur) during kharif 2023 which led to identification of 12 highly resistant genotypes and the notable ones are Koolavalai, Periya chandikar, Kapikar selection and Earapalli. Genetic variability studies indicated the presence of additive gene action for all the agronomic and disease related traits. Principal component analysis revealed the first 5 principal components collectively contributing 78.79 % of the total variance with disease-related traits contributing significantly to divergence. Ten clusters were delineated using Mahalanobis D2 statistics with clusters IX and V showing higher inter cluster distance (3453.64). Forty-one polymorphic markers were used to analyse the genotypes and The Unweighted Pair Group method with Arithmetic Mean (UPGMA) clustering by Jaccard distance formed 6 clusters. The Bayesian clustering classified the entire population into 2 subpopulations. False smut linked marker RM336 and RM218 were found to be the most informative marker with high Polymorphism Information Content (0.71, 0.69) and Heterozygosity Index (0.76, 0.73). The resistant genotypes such as IG71, Thulasi vasanai sambha, Arupatham vellai, Kaltikar and Chinna aduku nel can be used in the future breeding programmes to develop the resistant cultivar and to identify the candidate genes governing resistance

Molecular breeding approaches for sustainable rice blast management: recent advances and challenges

Rice (Oryza sativa. L) is a staple crop globally, but blast disease caused by fungal pathogens Magnaporthe oryzae is one of the most devastating and results in severe economic losses in rice production worldwide. Recent technological advancements have opened new possibilities for developing blast resistance. The dynamic and highly adaptable nature of M. oryzae allows it to overcome plant defense mechanisms rapidly, posing a major threat to global food security and agricultural sustainability. While foundational to early resistance development, traditional breeding approaches have been limited by their time-consuming nature and reliance on phenotypic selection. These methods often require several generations to establish stable resistance traits. However, with the emergence of molecular breeding technologies, resistance breeding has experienced significant acceleration and precision. Tools such as marker-assisted selection (MAS), marker-assisted backcross breeding (MABB), and quantitative trait locus (QTL) mapping allow for the identification and introgression of resistance genes (R genes) more efficiently and accurately. Recent advances in genome engineering techniques, particularly CRISPR-Cas 9, have transformed the capability to manipulate resistance genes directly, enabling targeted editing and stacking of multiple genes (gene pyramiding) for durable resistance. Moreover, omics technologies—including genomics, transcriptomics, proteomics, and metabolomics—offer a comprehensive understanding of the molecular interactions between host and pathogen, facilitating the discovery of novel resistance mechanisms and regulatory pathways. The integration of allele mining with advanced biotechnological tools has further promoted the development of cisgenic and intragenic plants, where resistance genes from related cultivars or wild species are introduced without foreign DNA, thus addressing public concerns over transgenic crops. These strategies enhance resistance and help retain the desirable agronomic traits of elite rice varieties. Despite these advancements, the high mutation rate and genetic plasticity of M. oryzae enable it to evolve and overcome resistance provided by single R genes. Therefore, understanding host–pathogen interactions at the molecular and cellular levels remains essential. Emerging technologies such as nanotechnology show promise in developing targeted fungicide delivery systems and innovative diagnostic tools. Synthetic biology opens avenues for constructing synthetic resistance pathways or deploying plant biosensors. Additionally, machine learning and artificial intelligence (AI) algorithms are increasingly used to predict disease outbreaks, model gene interactions, and optimize breeding strategies based on large datasets. Thus, managing rice blast disease necessitates a holistic approach combining conventional breeding wisdom with modern molecular tools and emerging technologies. The synergy among these approaches holds promise to enhance resistance durability and protect global rice production against evolving fungal threats. This review emphasizes recent advancements in managing rice blast disease, offering valuable insights to sustain resilient breeding programs against this pathogen

Monsoon prawn fishery of Neendakara coast, Kerala - a critical study

The results of a detailed analysis of the prawn fishery of Neendakara area with special reference to the trends in production, fishing operations, species composition, seasonal abundance and other biological aspects have been reported. The outcome of this critical evaluation in continuation of the earlier study is reported in the present contribution

Species prioritization for marine fish stock assessments in India

Stock assessments of fish stocks are critical for framing effective management measures of fishery resources to ensure sustainability. While species-wise national assessments have been done in the past, India has not had a prioritized list of species/resources to be assessed regularly to provide an index of the health of the country’s fishery resources. In a first of its kind for the country, a marine fish stock status (MFSS) report was published recently (CMFRI, 2023). The MFSS report indicated the sustainability status of 70 important species, encompassing 135 stocks (region-based management units) spread across 5 different coastal regions of India, viz., north-east (NE), north-west (NW), south-east (SE), south-west (SW) and Lakshadweep islands, under the prevalent fisheries management regime of the country. The assessments of the 49 finfish and 21 shellfish species were carried out using globally accepted methodologies and sustainability indicators. The study indicated that 91% of the stocks evaluated were healthy and optimally exploited, whereas the remaining 9% were found to be overfished. The report also highlighted concerns on select species and actions needed to sustain the marine fisheries sector

Levering proteomic analysis of Pseudomonas fluorescens mediated resistance responses in tomato during pathogenicity of Fusarium oxysporum f. sp. oxysporum

The tomato, one of the world’s most extensively cultivated and consumed vegetable crops is negatively impacted by various pathogens. This study aimed to observe the differentially expressed proteins in tomato samples in plant–pathogen-biocontrol interactions. The fungal pathogen associated with wilted plants were isolated and identified based on its morphological and molecular characteristics. Fourteen strains of Pseudomonas fluorescens from agricultural soils were identified and described using biochemical assays, molecular analyses, and screening for antagonistic ability against the Fusarium wilt pathogen. Results demonstrated that the potential of P. fluorescens (TPf12) positively influenced the expression of antagonism against tomato wilt disease. A total of 14 proteins expressed differently were revealed in the 2D-PAGE-MS investigation. Proteins such as nucleoside diphosphate kinase, phenylalanine ammonia-lyase, protein kinase family protein, Ser/Thr protein kinase-like are unchanged in FOL pathogen interaction, but up-regulated in FOL + TPf12 treated roots, and lipid transfer-like protein, and phenylalanine ammonia-lyase were down-regulated in FOL infested roots and upregulated in FOL + TPf12 treated tomato roots. Phenylalanine ammonia-lyase protein expression is commonly found in TPf12 bioenriched roots, and FOL + TPf12 treated roots, indicating its role in response to the application of TPf12 in tomato. A GC–MS analysis was performed to detect the bioactive metabolites synthesized by TPf12. Molecular docking investigations were conducted using the maestro’s GLIDE docking module of the Schrodinger Software program. Among the secondary metabolites, Cyclohexanepropanoic acid, 2-oxo-, methyl ester (CAS), and 3-o-(4-o-Beta-D-Galactopyranosyl-Beta-D-Galactopyraosyl)-2-Acetylamino-2-Deoxy-D-Galactose were shown to be top-ranked with a least docking score against each differently expressed proteins. The profiled molecules expressed differently due to plant-pathogen-biocontrol interactions may be directly or incidentally involved in the wilt disease resistance of tomato plants

Mapping of potential sea-cage farming sites through spatial modelling: Preliminary operative suggestions to aid sustainable mariculture expansion in India

Sea cage farming in marine open waters is considered as the most viable technique in Indian mariculture to enhance production. Owing to the support of the government in research and development, and policy initiatives, marine cage farming is progressing steadily in the country. Technological guidance from research institutions and financing under the ambitious “Pradhan Mantri Matsya Sampada Yojana (PMMSY)” and blue growth mission objectives have inspired stakeholders and fisheries administrators in maritime states to explore open sea cage culture. Site selection is a key parameter affecting the success of cage culture systems and, technically analysed geo-referenced demarcation of spatial information is necessary for minimising the risks. Thus, in the light of rising demand for spatial allocation of coastal areas, the present study identifies and aggregates locations within 3 km of the coastline, that have the potential for sea cage farming operations in the country. The site suitability was examined based on optimal standards required for the prospective candidate species selected for mariculture in India. The locations were vectorised in a GIS platform, and the potential areas available for sea cage installations were demarcated. An optimised site suitability schema was developed for the spatial demarcation of potential site selection.The preliminary results identified 134 sites covering a total area of 46,823.2 ha suitable for marine cage culture along Indian territorial waters. Among the coastal states, the top three states holding the maximum area suitable for sea cage farming are Andhra Pradesh (11,792 ha), Gujarat (11,572.2 ha) and Tamil Nadu (7,673 ha). It is envisaged that spatial suitability demarcation even on this pilot scale will accelerate the expansion of sea cage farming in the country

Preliminary estimates of potential areas for seaweed farming along the Indian coast

India has enormous potential for seaweed mariculture; however, mass scale commercial farming of seaweeds is yet to take off successfully in the country. R&D efforts over the years have resulted in techno-scientific improvements in farming technologies such as floating rafts, net-tubes, long-lines, and cage based IMTA systems for seaweed culture. However, a few challenges remain, particular in identifying potential sites, its demarcation and developing suitable and sustainable spatial plans for seaweed farming on a country-wide, commercial perspective. In view of the emerging importance of seaweed mariculture and policy thrust by the Government of India, an all India preliminary site selection survey suitable for seaweed farming was conducted by ICAR-CMFRI along all maritime states of India. From this survey a total of 23,970 ha area were identified as potential seaweed farming along the Indian coast. In the present article, we present details of the suitable sites and its demarcation on a preliminary spatial map for facilitating the imminent expansion and effective adoption of seaweed farming in the country

Wave propagation of phonon and phason displacement modes in quasicrystals: Determination of wave parameters

The paper presents the study of wave propagation in quasicrystals. Our interest is in the computation of the wavenumber (k(n)) and group speed (c(g)) of the phonon and phason displacement modes of one, two, and three dimensional quasicrystals. These wave parameter expressions are derived and computed using the elasto-hydrodynamic equations for quasicrystals. For the computation of the wavenumber and group speeds, we use Fourier transform approximation of the phonon and the phason displacement modes. The characteristic equations obtained are a polynomial equation of the wavenumber (k(n)), with frequency as a parameter. The corresponding group speeds (c(g)) for different frequencies are then computed from the wavenumber k(n). The variation of wavenumber and group speeds with frequency is plotted for the 1-D quasicrystal, 2-D decagonal Al-Ni-Co quasicrystals, and 3-D icosahedral Al-Pd-Mn and Zn-Mg-Sc quasicrystals. From the wavenumber and group speeds plots, we obtain the cut-off frequencies for different spatial wavenumber eta(m). The results show that for 1-D, 2-D, and 3-D quasicrystals, the phonon displacement modes are non-dispersive for low values of eta(m) and becomes dispersive for increasing values of eta(m). The cut-off frequencies are not observed for very low values of eta(m), whereas the cut-off frequency starts to appear with increasing eta(m). The group speeds of the phason displacement modes are orders of magnitude lower than that of the phonon displacement modes, showing that the phason modes do not propagate, and they are essentially the diffusive modes. The group speeds of the phason modes are also not influenced by eta(m). The group speeds for the 2-D quasicrystal at 35 kHz is also simulated numerically using Galerkin spectral finite element methods in frequency domain and is compared with the results obtained using wave propagation analysis. The effect of the phonon and phason elastic constants on the group speeds is studied using 3-D icosahedral Al-Pd-Mn and Zn-Mg-Sc quasicrystals. It is also shown that the phason elastic constants and the coupling coefficient do not affect the group speeds of the phonon displacement modes. (C) 2015 AIP Publishing LLC