The science about the usage of face masks by the common public to avert COVID-19 transmission is proceeding swiftly. A primary route of transmission of COVID-19 is probably through small respiratory droplets, and it is transmissible from asymptomatic and pre-symptomatic individuals. According to the World Health Organization, wearing a mask in public can help reduce the transmission of the COVID-19 virus. Different categories and types of mask and their usage are reviewed in this work. In a nutshell, this review work elucidates the aspects of utilizing the various face masks along with all possibilities to fight against the ongoing pandemic of COVID-19.

Traces of predation by drilling gastropods and peeling crabs provide important insights about predator-prey interaction in ecological as well as evolutionary times. Predation on turritelline gastropods, in this context, has been frequently discussed in literature. Here, we have estimated the intensity of predation (both drilling and peeling) on Recent turritelline gastropods from the Indian subcontinent, which has been underrepresented in previous studies. Our samples include our own collections from several Indian coasts as well as a vast collection which was locked in the archive of the Zoological Survey of India (ZSI) in Kolkata for the past 150 years. It includes samples from different parts of the Indian subcontinent as well as from many other countries. Drilling frequency (DF) of Indian turritelline species is low compared to average values of global data. We suggest that this is mainly because most of the Indian species are larger (> 4 cm) than species living elsewhere. Smaller species show higher DF and lower values of peeling frequency. Size selectivity of drill holes shows both intra-and interspecific variation. Shell thickness and ornamentation appear to be antipredatory in nature.We have compared our results with a revised global database. Distribution of intensity of predation shows latitudinal variation where both drilling and peeling frequencies increase towards the tropics.

Content-based image retrieval focuses on intuitive and efficient methods for retrieving images from databases based on the content of the images. A new entropy function that serves as a measure of information content in an image termed as 'an information theoretic measure' is devised in this paper. Among the various query paradigms, query by example (QBE) is adopted to set a query image for retrieval from a large image database. In this paper, colour and texture features are extracted using the new entropy function and the dominant colour is considered as a visual feature for a particular set of images. Thus colour and texture features constitute the two-dimensional feature vector for indexing the images. The low dimensionality of the feature vector speeds up the atomic query. Indices in a large database system help retrieve the images relevant to the query image without looking at every image in the database. The entropy values of colour and texture and the dominant colour are considered for measuring the similarity. The utility of the proposed image retrieval system based on the information theoretic measures is demonstrated on a benchmark dataset.

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Music is a heavenly way of expressing feelings about the world. The language of music has vast diversity. For centuries, people have indulged in debates to stratisfy between Western and Indian Classical Music. But through this paper, an understanding can be fabricated while differentiating the types of Indian Classical Music. Classical music is one of the essential characteristics of Indian Cultural Heritage. Indian Classical Music is divided into two major parts, i.e. Hindustani and Carnatic. Models have been sculptured and trained to classify between Hindustani and Carnatic Music. In this paper, two approaches are used to implement classification models. MFCCs are used as features and implemented models like DNN (1 Layer, 2 Layers, 3 Layers), CNN (1 Layer, 2 Layers, 3 Layers), RNN-LSTM, SVM (Sigmoid, Polynomial & Gaussian Kernel) as one approach. A 3 channels input is created by merging features like MFCC, Spectrogram and Scalogram and implemented models like VGG-16, CNN (1 Layer, 2 Layers, 3 Layers), ResNet-50 as another approach. 3 Layered CNN and RNN-LSTM model performed best among all the approaches.