Showing papers by "Central University of Kerala published in 2023"

An Efficient Method for Skin Cancer Detection Using Convolutional Neural Network

Abstract: Skin cancer (melanoma) prediction is a necessity for the society. But the early prediction of skin cancer is possible from its dermoscopic images, it often fails due to the visual similarity between different types of melanocytes and the visual similarity with the normal skin. So the development of an automatic system for melanoma recognition can help patients and doctors in diagnosing the disease early and starting the treatment. Based on these motivations, the proposed work employs a novel approach to skin cancer detection using neural network with convolution layers. The method has achieved the highest accuracy of 81.11% with the GoogleNet network and it has been compared with the results from AlexNet, EfficientNetbo and ResNet50.

Endophytic Fungi: Application in Combating Plant Pathogens and Sustainable Agriculture

Abstract: Globally, there is an escalating demand for improved crop production and the development of sustainable agriculture. With the ill effects caused by chemical pesticides and fertilizers on the environment and nontarget life-forms, there is an urgent need to explore alternative green strategies replacing chemical control methods. Biological control uses microorganisms from nature for pest control and improves agricultural produce. Endophytic fungi represent an exclusive group of microorganisms inhabiting the tissues of healthy plants. These fungi involve in a beneficial plant-microbe interaction, significantly contributing to the host’s survival. The most striking attribute of these fungal endophytes is their ability to produce many diverse bioactive metabolites that find application in food, industries, pharmaceutical, agriculture, etc. These fungi exhibit extraordinary diversity and interactions with the plant hosts. Fungal endophytes promote plant growth and enhance plant resistance to biotic and abiotic stresses. The array of phytohormones and antimicrobial metabolites they produce finds application in controlling plant pathogens, including insects and nematodes. They also facilitate plant survival in nutrient-poor soils and detoxify soil contaminants. These enormous benefits make fungal endophytes potential sources for exploration as safe and economical biocontrol agents. Bioprospecting the diverse metabolic pathways functional in these fungi can be unraveled to develop novel agrochemicals in pathogen control and sustainable agriculture.

Late quaternary carbonate (pteropod) preservation in the Indian Ocean sediments: inferences on the paleoclimate and paleoceanography

Abstract: To evaluate the preservation pattern of pteropods and their relationship with climatic and oceanographic history in the Laccadive Sea, a temporal variation analysis of pteropod abundance was done. For that, we employed preservation indices from calcite (Globigerina bulloides%, Globorotalia menardii abundance), as well as aragonite (e.g., total pteropod abundance, Limacina Dissolution Index (LDX), fragmentation ratio). To determine if pteropod shells have been preserved over time, we used estimated pteropod abundance. The pteropod preservation record displays excellent preservation during cold stadials, evidenced by the lower values of aragonite dissolution proxies than during the interglacials/interstadials, similar to the preservation records from other northern Indian Ocean cores evidenced by the lower values of aragonite dissolution proxies than during the interglacials/interstadials. The shallow aragonite compensation depth (ACD), weaker oxygen minimum zone (OMZ), and the lower southwest monsoon (SWM)-induced productivity are thought to be the cause of the basin-wide pteropod preservation events during the cold stadials (ACD). Additionally, during an intense northeast monsoon (NEM), the advection of cold, low-saline waters from the Bay of Bengal to the Laccadive Sea, as well as the intrusion of southern-sourced intermediate water ventilation, may have caused a deep vertical mixing of oxygen-rich surface waters, raised the pH of thermocline waters and deepened the ACD. However, the local fluctuations in the water mass properties, such as the increased productivity maxima, the intense OMZ, and shallow ACD, as well as changes in the aragonite, are responsible for the poor pteropod abundance, poor preservation and strong dissolution during the Holocene, Bølling-Allerød (B/A) and interstadial periods.The calcification proxy indicates that the aragonite undersaturation and reduced calcification occurred during 19-16.5 kyr, preferably due to the depletion in the oceanic alkalinity caused by enhanced upwelling-induced carbonate ion exchange between the intermediate and deep water. In contrast, the preferential dissolution of smaller shells in the sediments (marked by increased average shell size and higher values of Limacina dissolution index (LDX) corresponds to strengthened OMZ and shallower ACD, pointing towards the post-depositional dissolution of aragonite shells. Therefore, the overall decrease of pteropod content of the deposits in the stadial/interstadials suggests a combination of monsoon-associated changes in water column properties, variability in aragonite saturation, intermediate water ventilation and sediment rate.

Chemicals and Their Interaction in the Aquaculture System

Abstract: Aquaculture is well-acknowledged as one of the few options of food security and economic growth that contribute significantly at the global level. All commercial varieties of fishery products, including shrimp, prawn, lobster, crab, fish, and other aquatic animals and plants, have been cultured for quite a long time in India and worldwide. Disease vulnerabilities and substandard water are the crucial factors that affect the production rates in aquaculture. Therefore, disease control is an active field of research in aquaculture, and aquaculturists identified various control measures over the years. Consequently, drugs and chemicals are often applied to treat diseases of cultured aquatic animals and improve the water quality in culture facilities. Parallel to the intensification of aquaculture practices in recent years, the usage of chemicals has also increased, particularly in the culture systems of commercially important species such as shrimps. On the flip side, chemical use in aquaculture has specific adverse effects. Despite various statutory regulations set on the usage of chemicals, the public health hazards related to the chemical inter-mixture in freshwater, brackish water, and coastal saline waters of culture facilities are usually ignored. However, it is all-important that the aquaculturists, producers, and suppliers of chemicals, government agencies, and scientists should also be attentive to the chemical inter-mixture in the aquaculture systems. This chapter summarizes relevant information and highlights the chemistry of the commonly used chemicals in aquaculture systems.

Deglacial- Holocene carbonate preservation in the Bay of Bengal

Abstract: Deep-sea carbonate dissolution/preservation history is important to better understand marine carbonate system and surface ocean productivity. To understand carbonate dissolution during the last deglacial and Holocene periods in the Eastern BoB, we analyzed foraminifera carbonate dissolution indices viz., perfect test ratio (PTR) of Globorotalia menardii, Menardii fragmentation index (MFI), percentage of total resistant species (RSP), and percentage of total susceptible species (SSP). The core yielded rich assemblages of planktonic foraminifera though retrieved from deeper water depth (3019 m) of the Eastern Bay of Bengal. In general, the preservation is better during last glacial period on record (16-11.7 ka) and poor during Holocene. During Holocene, carbonate dissolution is intense in the early Holocene (12.5 to 8 ka), marked by increased MFI, and decreased PTR values along with less abundance of susceptible species. A slight decrease in the MFI was seen from 8 to 4.9 ka. The late Holocene period was characterized by less MFI and high PTR values. In general, MFI (PTR) was high (low) during the early Holocene compared to the deglacial and mid to late Holocene periods. Interestingly, the dissolution record shows a good relationship with Indian summer monsoon variability. The intense dissolution of the early Holocene might be due to changes in water column chemistry due to the increased river runoff and direct precipitation. We compared our data with existing records from the Andaman Sea and the Central Indian Ocean. The assemblages from the Bay of Bengal show a high degree of dissolution and low preservation during interglacial periods. The result of this study explains that dissolution is more pronounced during the warm interglacial and interstadials and MFI and PTR can be a potential proxy for quantitatively tracking deep marine CaCO3 dissolution in the Bay of Bengal. Keywords: Carbonate dissolution; Planktonic foraminifera, Globorotalia Menardii, deglacial, Holocene.