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Bees Out of the Pandora’s Box: Economic Consequences of National Register in Assam
(Arthaniti: Journal of Economic Theory and Practice, 2021) Sengupta A.;De S.
In India, at present, there is a lot of hue and cry for and against the National Register of Citizens (NRC) in Assam. All the arguments are however based on false perception of migration and its ill or well effects on the economy. The latest 2011 Census does not provide the migration tables in detail. Hence, we had no other option but to use the Census 2001 data to understand the nature and trend of migration in Assam. Our analysis suggests that the recent uproar over illegal migrants from neighboring country in Assam is more of a myth than reality and does not hold much economic justification. Firstly, official data suggests that the flow of internal migration in various districts of Assam is miniscule. Moreover, it is showing a declining trend over the last few decades. The historical international migration that took place in Assam was due to mainly ‘push’ factor and no such ‘push’ factors have been in sight in the last few decades. Secondly and more importantly, migration of any form (though waning in Assam) adds to the prosperity and well-being of the state.
Classification of geometric forms in mosaics using deep neural network
(Journal of Imaging, 2021)
he paper addresses an image processing problem in the field of fine arts. In particular, a deep learning-based technique to classify geometric forms of artworks, such as paintings and mosaics, is presented. We proposed and tested a convolutional neural network (CNN)-based framework that autonomously quantifies the feature map and classifies it. Convolution, pooling and dense layers are three distinct categories of levels that generate attributes from the dataset images by introducing certain specified filters. As a case study, a Roman mosaic is considered, which is digitally reconstructed by close-range photogrammetry based on standard photos. During the digital transformation from a 2D perspective view of the mosaic into an orthophoto, each photo is rectified (i.e., it is an orthogonal projection of the real photo on the plane of the mosaic). Image samples of the geometric forms, e.g., triangles, squares, circles, octagons and leaves, even if they are partially deformed, were extracted from both the original and the rectified photos and originated the dataset for testing the CNN-based approach. The proposed method has proved to be robust enough to analyze the mosaic geometric forms, with an accuracy higher than 97%. Furthermore, the performance of the proposed method was compared with standard deep learning frameworks. Due to the promising results, this method can be applied to many other pattern identification problems related to artworks.
Notes on the oviposition behaviour of three Elattoneura damselflies from India (Odonata: Platycnemididae)
(Odonatologica,, 2021) Neha Mujumdar ., Ameya Deshpande ., Prosenjit Dawn ., Pankaj Koparde .,
Oviposition behaviour of three Indian Elattoneura spp. is described and discussed. Endophytic oviposition in dry rigid substrates away from water by the endemic E. nigerrima and E. tetrica is recorded; this differs from the typical recorded use of submerged vegetation substrates in the genus. Contrasting behavioural observation of oviposition in E. campioni is also discussed.
A two state model study of photo-detachment dynamics driven by an optimally designed polychromatic field: A simulated annealing based optimisation
(International Journal of Quantum Chemistry, 2021) Talukder S.;Seal D.;Naskar P.;Chaudhury P.;Ghosh S.
The surfaces of urn:x-wiley:00207608:media:qua26676:qua26676-math-0001 and F2 are two well separated surfaces modeled by two Morse potentials. In presence of a field, these two surfaces couple and transition from urn:x-wiley:00207608:media:qua26676:qua26676-math-0002 to F2 takes place resulting in the detachment of an electron. We have applied Simulated Annealing (SA) technique to design the polychromatic field which results in ∼ 95% probability of photo detachment (Pd). Also we have designed a field to achieve photo detachment followed by dissociation of FF bond with nearly 38% dissociation probability. F2 being a homo nuclear diatomic molecule, promotion to the continuum states by directly exciting it from its ground vibrational state is an impossibility and our method appears to be a feasible solution if the target is to break the FF bond.
Dragonflies and damselflies (Insecta: Odonata) of West Bengal, an annotated list of species
(Oriental Insects,, 2022) Prosenjit Dawn .,
An updated checklist of Odonata known so far from the state West Bengal is presented here consisting 239 species belonging to 114 genera and 17 families. Eight species viz. Megalestes irma, Lestes garoensis, Calicnemia nipalica, Chlorogomphus mortoni, Somatochlora daviesi, Cephalaeschna viridifrons, C. triadica, Lyriothemis mortoni, are recorded for the first time from the state; and last two species are recorded for the first time from India. This paper indicates a prominent rise in the number of species than the previous published checklist, as many isolated species distribution records were lying undocumented. This paper also reflects the data from citizen science platforms and social media groups. Reference for the original descriptions, type locality and information of specimen repository of the recorded species are provided. Some doubtful identification and distribution records are also discussed here.
Dissociation of HF molecule in position and momentum representation by an optimally controlled polychromatic field: study in the dual space using simulated annealing
(Molecular Physics, 2022) Seal D.;Naskar P.;Chaudhury P.;Ghosh S.
Complementarity of position and momentum representation is at the heart of quantum mechanics. Dissociation of diatomic molecule can be investigated and controlled in conventional coordinate space as well as in momentum space. Our objective in this article is to have the control over the dissociation process irrespective of the representation. We have applied Simulated Annealing (SA) technique for the optimisation of the field, where the effective field strength is kept sufficiently low. The optimisation is carried out in both momentum and position representation on with completely different objective function but leading to similar result.
Biotechnological methods to remove microplastics: a review
(Anand U.;Dey S.;Bontempi E, 2023) Anand U.;Dey S.;Bontempi E.;Ducoli S.;Vethaak A.D.;Dey A.;Federici S.
Microplastics pollution is major threat to ecosystems and is impacting abiotic and biotic components. Microplastics are diverse and highly complex contaminants that transport other contaminants and microbes. Current methods to remove microplastics include biodegradation, incineration, landfilling, and recycling. Here we review microplastics with focus on sources, toxicity, and biodegradation. We discuss the role of algae, fungi, bacteria in the biodegradation, and we present biotechnological methods to enhance degradation, e.g., gene editing tools and bioinformatics.
Microbial strategies for degradation of microplastics generated from COVID-19 healthcare waste
(Environmental Research, 2023) Dey S.;Anand U.;Kumar V.;Kumar S.;Ghorai M.;Ghosh A.;Kant N.;Suresh S.;Bhattacharya S.;Bontempi E.;Bhat S.A.;Dey A.
COVID-19 pandemic has led to the generation of massive plastic wastes, comprising of onetime useable gloves, masks, tissues, and other personal protective equipment (PPE). Recommendations for the employ of single-use disposable masks made up of various polymeric materials like polyethylene, polyurethane, polyacrylonitrile, and polypropylene, polystyrene, can have significant aftermath on environmental, human as well as animal health. Improper disposal and handling of healthcare wastes and lack of proper management practices are creating serious health hazards and an extra challenge for the local authorities designated for management of solid waste. Most of the COVID-19 medical wastes generated are now being treated by incineration which generates microplastic particles (MPs), dioxin, furans, and various toxic metals, such as cadmium and lead. Moreover, natural degradation and mechanical abrasion of these wastes can lead to the generation of MPs which cause a serious health risk to living beings. It is a major threat to aquatic lives and gets into foods subsequently jeopardizing global food safety. Moreover, the presence of plastic is also considered a threat owing to the increased carbon emission and poses a profound danger to the global food chain. Degradation of MPs by axenic and mixed culture microorganisms, such as bacteria, fungi, microalgae etc. can be considered an eco-sustainable technique for the mitigation of the microplastic menace. This review primarily deals with the increase in microplastic pollution due to increased use of PPE along with different disinfection methods using chemicals, steam, microwave, autoclave, and incineration which are presently being employed for the treatment of COVID-19 pandemic-related wastes. The biological treatment of the MPs by diverse groups of fungi and bacteria can be an alternative option for the mitigation of microplastic wastes generated from COVID-19 healthcare waste.
Description of the Last Instar Larva of Platylestes platystylus (Rambur, 1842) from Kerala, India (Odonata: Lestidae)
(Zootaxa,, 2023) Chandran A.V.;Jose S.K.;Dawn P.
The description of the final instar larva and the subsequent exuvia of Platylestes platystylus (Rambur, 1842) is given based on a single male larva collected from Kerala and reared in the laboratory. A brief account of the habitat of the damselfly and an updated key to the larvae of genera of Family Lestidae Calvert, 1901 are also provided.
Witchcraft: A Survey of Medieval Ecstasy
(Integrated Journal for Research in Arts and Humanities, 2023) Animesh Manna
The article examines the phenomenon of witchcraft in medieval Europe, focusing on the role of ecstasy as a key element of the witch’s experience. It shows how witchcraft was conceived as a heretical and demonic activity that involved flying through the air, having sex with devils, and joining in night-time gatherings. It also analyses the historical and religious factors that influenced the formation and expression of witchcraft beliefs, such as the impact of classical mythology, folkloric traditions, Christian theology, and popular superstition. Moreover, it investigates the legal and theological reactions to the alleged danger of witchcraft, such as the papal bull of 1484 that authorized the persecution of witches, the influential treatise Malleus Maleficarum that established the witch stereotype, and the various trials and executions that occurred across Europe. The article uses various types of evidence, such as literary works, court documents, and theological writings, to demonstrate the richness and diversity of medieval witchcraft conceptions and discourses. It also explores different regional and temporal variations of witchcraft, such as the differences between Germanic and Latin cultures, or between early and late medieval periods. The article aims to provide a comprehensive and nuanced overview of witchcraft in medieval Europe, as well as to highlight its relevance for understanding the social and psychological dynamics of pre-modern societies.
LWSNet-a novel deep-learning architecture to segregate Covid-19 and pneumonia from x-ray imagery
(Multimedia Tools and Applications, 2023) Lasker A.;Ghosh M.;Obaidullah S.M.;Chakraborty C.;Roy K.
Automatic detection of lung diseases using AI-based tools became very much necessary to handle the huge number of cases occurring across the globe and support the doctors. This paper proposed a novel deep learning architecture named LWSNet (Light Weight Stacking Network) to separate Covid-19, cold pneumonia, and normal chest x-ray images. This framework is based on single, double, triple, and quadruple stack mechanisms to address the above-mentioned tri-class problem. In this framework, a truncated version of standard deep learning models and a lightweight CNN model was considered to conviniently deploy in resource-constraint devices. An evaluation was conducted on three publicly available datasets alongwith their combination. We received 97.28%, 96.50%, 97.41%, and 98.54% highest classification accuracies using quadruple stack. On further investigation, we found, using LWSNet, the average accuracy got improved from individual model to quadruple model by 2.31%, 2.55%, 2.88%, and 2.26% on four respective datasets.
Applications and implications of carbon nanotubes for the sequestration of organic and inorganic pollutants from wastewater
(Environmental Science and Pollution Research, 2023) Majumder S.;Dhara B.;Mitra A.K.;Dey S.
The rapid growth in the population, industrial developments, and climate change over the century have contributed to a significant rise in aquatic pollution leading to a scarcity of clean, reliable, and sustainable water sources and supply. Exposure through ingestion, inhalation, and dermal absorption of organic/inorganic compounds such as heavy metals, pharmaceuticals, dyes, and persistent organic pollutants (POPs) discharged from municipalities, hospitals, textile industries, food, and agricultural sectors has caused adverse health outcomes in aquatic and terrestrial organisms. Owing to the high surface area, photocatalytic activity, antimicrobial, antifouling, optical, electronic, and magnetic properties, the application of nanotechnology offers unique opportunities in advanced wastewater management strategies over traditional approaches. Carbon nanomaterials and associated composites such as single-walled carbon nanotubes (SWCNT), multiwalled carbon nanotubes (MWCNT), and carbon nanotubes (CNT) buckypaper membranes have demonstrated efficiency in adsorption, photocatalytic activity, and filtration of contaminants and thus show immense potentiality in wastewater management. This review focuses on the application of CNTs in the sequestration of organic and inorganic contaminants from the aquatic environment. It also sheds light on the aquatic pollutant desorption processes, current safety regulations, and toxic responses associated with CNTs. Critical knowledge gaps involving CNT synthesis, surface modification processes, CNT-environment interactions, and risk assessments are further identified and discussed.
Algae and bacteria consortia for wastewater decontamination and transformation into biodiesel, bioethanol, biohydrogen, biofertilizers and animal feed: a review
(Environmental Chemistry Letters, 2023) Anand U.;Dey S.;Parial D.;Federici S.;Ducoli S.;Bolan N.S.;Dey A.;Bontempi E.
Traditional wastewater treatment has been aimed solely at sanitation by removing contaminants, yet actual issues of climate change and depletion of natural resources are calling for methods that both remove contaminants and convert waste into chemicals and fuels. In particular, biological treatments with synergic coupling of microalgae and bacteria appear promising to remove organic, inorganic, and pathogen contaminants and to generate biofuels. Here, we review the use of algae and bacteria in the treatment and valorization of wastewater with focus on cell-to-cell adhesion, wastewater properties, and techniques for algae harvesting and production of biodiesel, bioethanol, biohydrogen, exopolysaccarides, biofertilizers, and animal feeds.
Microplastics in mangroves with special reference to Asia: Occurrence, distribution, bioaccumulation and remediation options
(Science of the Total Environment, 2023) Talukdar A.;Kundu P.;Bhattacharjee S.;Dey S.;Dey A.;Biswas J.K.;Chaudhuri P.;Bhattacharya S.
Microplastics (MPs) are a new and lesser-known pollutant that has intrigued the interest of scientists all over the world in recent decades. MP (<5mm in size) can enter marine environments such as mangrove forests in a variety of ways, interfering with the health of the environment and organisms. Mangroves are now getting increasingly exposed to microplastic contamination due to their proximity to human activities and their position as critical transitional zones between land and sea. The present study reviews the status of MPs contamination specifically in mangrove ecosystems situated in Asia. Different sources and characteristics of MPs, subsequent deposition of MPs in mangrove water and sediments, bioaccumulation in different organisms are discussed in this context. MP concentrations in sediments and organisms were higher in mangrove forests exposed to fishing, coastal tourism, urban, and industrial wastewater than in pristine areas. The distribution of MPs varies from organism to organism in mangrove ecosystems, and is significantly influenced by their morphometric characteristics, feeding habits, dwelling environment etc. Mangrove plants can accumulate microplastics in their roots, stem and leaves through absorption, adsorption and entrapment helping in reducing abundance of microplastic in the surrounding environment. Several bacterial and fungal species are reported from these mangrove ecosystems, which are capable of degrading MPs. The bioremediation potential of mangrove plants offers an innovative and sustainable approach to mitigate microplastic pollution. Diverse mechanisms of MP biodegradation by mangrove dwelling organisms are discussed in this context. Biotechnological applications can be utilized to explore the genetic potential of the floral and faunal species found in the Asian mangroves. Detailed studies are required to monitor, control, and evaluate MP pollution in sediments and various organisms in mangrove ecosystems in Asia as well as in other parts of the world.
Energetics and spectroscopic studies of CNO(-)(H2O)n clusters and the temperature dependencies of the isomers: An approach based on a combined recipe of parallel tempering and quantum chemical methods
(Journal of Computational Chemistry, 2024) Naskar P.;Talukder S.
A system associated with several number of weak interactions supports numerous number of stable structures within a narrow range of energy. Often, a deterministic search method fails to locate the global minimum geometry as well as important local minimum isomers for such systems. Therefore, in this work, the stochastic search technique, namely parallel tempering, has been executed on the quantum chemical surface of the system for –8 to generate global minimum as well as several number of local minimum isomers. IR spectrum can act as the fingerprint property for such system to be identified. Thus, IR spectroscopic features have also been included in this work. Vertical detachment energy has also been calculated to obtain clear information about number of water molecules in several spheres around the central anion. In addition, in a real experimental scenario, not only the global but also the local minimum isomers play an important role in determining the average value of a particular physically observable property. Therefore, the relative conformational populations have been determined for all the evaluated structures for the temperature range between 20K and 400K. Further to understand the phase change behavior, the configurational heat capacities have also been calculated for different sizes.
Comparative study of the photocatalytic activity of g-C3N4/MN4 (M = Mn, Fe, Co) for water splitting reaction: A theoretical study
(Journal of Computational Chemistry, 2024) Dhilshada. V.N.;Sen S.;Chattopadhyaya M.
In this study, nanocomposites of g-C3N4/MN4 (where M is Mn, Fe and Co) have been designed using advanced density functional theory (DFT) calculations. A comprehensive analysis was conducted on the geometry, electronic, optical properties, work function, charge transfer interaction and adhesion energy of the g-C3N4/MN4 heterostructures and concluded that g-C3N4/FeN4 and g-C3N4/CoN4 heterojunctions exhibit higher photocatalytic performance than individual units. The better photocatalytic activity can be attributed mainly by two facts; (i) the visible light absorption of both g-C3N4/FeN4 and g-C3N4/CoN4 interfaces are higher compared to its isolated analogs and (ii) a significant enhancement of band gap energy in g-C3N4/FeN4 and g-C3N4/CoN4 heterostructures limited the electron–hole recombination significantly. The potential of the g-C3N4/MN4 heterojunctions as a photocatalyst for the water splitting reaction was assessed by examining its band alignment for water splitting reaction. Importantly, while the electronic and magnetic properties of MN4 systems were studied, this is the first example of inclusion of MN4 on graphene-based material (g-C3N4) for studying the photocatalytic activity. The state of the art DFT calculations emphasis that g-C3N4/FeN4 and g-C3N4/CoN4 heterojunctions are half metallic photocatalysts, which is limited till date.
Molecular Mechanisms of Arsenic Resistance in Bacteria: A Systematic Analysis Following the PRISMA Model
(Geomicrobiology Journal, 2024) Tamang L.D.;Wangmo S.;Dey S.;Bhattacharya S.
Arsenic ranked 20th in abundance on the earth’s crust, poses a threat to all living organisms, and has affected over 30 million people worldwide. While bacteria play a crucial role in detoxifying and modifying arsenic to a harmless form, the complex nature of the biological methods involved in the process makes it difficult to comprehend. The present study followed the PRISMA protocols to search PubMed and evaluated eligible studies up to March 20, 2023, and their references to understand the mechanisms and diversity of arsenic resistance in bacteria. The search yielded 1140 studies, of which 196 were included in the systemic review. According to the studies reviewed, most of the arsenic resistant bacteria were isolated from soil, water, and mining tails, and the highest MIC (minimum inhibitory concentration) for arsenate is 900 mM, while for arsenite, it is 180 mM. Exiguobacterium sp. As-9 exhibited the highest amount of MIC for arsenate (700 mM) and arsenite (180 mM) and can remove 99% of arsenic in less than 20 h. The transfer of arsenic in bacterial cell mainly consists of arsenite and arsenate uptake, using glycerol channel G1pF or aquaporin (AQP) and the phosphate transport system respectively. Bioremediation using bacteria to remove or detoxify arsenic toxicity is a cost-effective, and environment friendly method. The potentials of arsenic resistant microorganisms need to be harnessed to mitigate arsenic pollution in contaminated land and water.
A density functional study of type I to type II crossover in g-C3N4/CoN4 heterostructure in presence of external perturbation
(International Journal of Hydrogen Energy, 2024) V.N. D.;Sen S.;Chattopadhyaya M.
Herein, we report the impact of external perturbation on the photocatalytic performance of g-C3N4/CoN4 heterojunction and concomitant transition from type-I to type-II. The state-of-the-art theoretical modeling presented here is the first study on dynamic role of strain and electric field on g-C3N4/CoN4 heterojunction and its potential application as a solar-driven water splitting reaction. Utilizing the density functional theory (DFT) calculation, V. N. et al. recently reported the photocatalytic activity of g-C3N4/MN4 (M = Mn, Fe and Co) heterojunction [J. Comput. Chem. 2024, 45, 2518-2529, https://doi.org/10.1002/jcc.2746412] and subsequently established g-C3N4/CoN4 as a type I heterojunction for photocatalytic water splitting reaction [Phys. Chem. Chem. Phys. 2024, 26, 21117–21133]. In the present study, we applied external perturbation in the form of mechanical strain, electric field and evaluated the electronic structure properties of the system along with the detailed examination of concomitant optical and magnetic properties of g-C3N4/CoN4 heterojunction. The switching of photocatalytic feature from type I to type II originates due to the crossover between valence band maxima (VBM) of g-C3N4 and CoN4 in presence of external perturbation. Notably, the resulting system acts as a type II photocatalyst for water splitting reaction while applying compressive (negative) strain of −2 to −6% and an electric field of −0.5 and +0.5 V/Å, respectively. Accumulation of photogenerated electrons and holes separately in g-C3N4 and CoN4 units confirms the perceptible separation of charge carriers and thereby reduces the recombination compared to un-perturbed system. A red-shifted absorption maximum (689 nm), superior charge transfer (0.9e), and clear separation of photogenerated electrons and holes are the origin of enhanced photocatalytic efficiency of g-C3N4/CoN4 heterojunction in the presence of external perturbation. We believe that our work will provide enough evidence to the experimentalists to achieve such a system in practice leading to human-friendly applications.
Evidence of half metal to insulator transition and subsequent photocatalytic action in g-C4N3@Lin =1 to 4: A systematic theoretical analysis
(Solid State Communications, 2024) Biswas A.;Prasad Mitra S.;Bhowmick R.;Adak D.;Chattopadhyaya M.;Sen S.
We report herein, emergence of photocatalytic action in Li doped two-dimensional nanosheet of graphitic carbon nitride [g-C4N3@Lin = 0-4]. Doping concentration varied from 3.57 % to 14.28 %. Pristine graphitic carbon nitride is half metallic and at the highest level of doping (14.28 %) it transforms into an insulating system. Observed results have been examined through the estimation of coupling between magnetic centers and the overall magnetic moment of the system. The exchange coupling (JAB) within Heisenberg–Dirac–van Vleck Hamiltonian being negative indicates antiferromagnetic coupling in presence of Li, doping. Related optical spectrum quite clearly illustrates that only at the doping level [14.28 %] the absorption peak is in the optical region. Band structure obtained illustrates a band gap of 1.92 eV and 1.93 eV in both spin channels and both oxidation and reduction potential falls within the band gap. The presence of reduction potential below the conduction band and oxidation potential above the valence band clearly illustrates the possibility of photocatalytic action.
Density functional theory-based modeling of the half-metallic g-C3N4/CoN4 heterojunction for photocatalytic water splitting reaction
(Physical Chemistry Chemical Physics, 2024) Dhilshada V.N.;Chandran A.;Sen S.;Chattopadhyaya M.
Using density functional theory (DFT), we have investigated the structural, optical, electronic and magnetic properties of a graphitic carbon nitride (g-C3N4) and CoN4 composite to explore the effect of the heterojunction on the photocatalytic performance of g-C3N4. The structure of g-C3N4 is modified while complexing with CoN4 and the corresponding stabilization is confirmed through adhesion energy calculation. The phonon spectra analysis furthermore guaranteed the lattice-dynamic stability of the CoN4 bulk and the CoN4 slab. Pristine g-C3N4 is a wide band gap semiconductor, which becomes half metallic upon CoN4 inclusion. The metallicity in the g-C3N4/CoN4 composite originates from the spin down channel, keeping the spin up channel in a semiconducting state. The charge density analysis and work function calculation suggest a substantial amount of charge transfer from g-C3N4 to the CoN4 unit in the g-C3N4/CoN4 heterojunction. The model heterojunction of the g-C3N4/CoN4 composite can enhance the utilization ratio of visible light for the g-C3N4 photocatalyst. In g-C3N4/CoN4, the valence band maximum (VBM) has a more positive potential compared to O2/H2O (+1.23 V) on the normal hydrogen electrode (NHE) scale. However, the conduction band minimum (CBM) displays a more negative potential compared to H+/H2 (0 V) on the NHE scale. The details of the band structure, density of states and band edge position determining calculations confirm that the g-C3N4/CoN4 composite forms a type 1 heterojunction, making it a suitable photocatalyst for water splitting reaction. The practical application of the g-C3N4/CoN4 heterostructure as a photocatalyst was substantiated in the presence of polar solvent (water) by calculating the band gap, charge transfer interaction and charge density difference. There is a significant decrease of charge transfer and thereby charge density difference in the g-C3N4/CoN4 heterojunction in the presence of water; however, it still holds potential for use as a photocatalyst for water splitting reaction. The state-of-the-art theoretical modeling of the g-C3N4/CoN4 heterojunction is the first theoretical study incorporating the CoN4 crystal.

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