National Academy Science Letters最新文献

The present study documents Padina ditristromatica Ni-Ni-Win and H. Kawai as a new record from the coast of Tiruchendur, Tamil Nadu, on the Bay of Bengal, India. The investigation into the morphological and anatomical characterizations highlights key diagnostic features of P. ditristromatica, including a flabellate thallus with moderate to heavy calcification on both surfaces, two cell layers at the inrolled margins, 2–3 cell layers in the middle to basal portions, a thickness of 56–145 μm, hairlines on both surfaces with unequal distance, and sporangial lines on the inferior surface parallel to the hairlines. The presence of an indusium and the absence of a vaughaniella stage are also noted as prominent diagnostic features. Morphometric variables were analyzed to provide additional information for identification keys. The results are consistent with previous studies on P. ditristromatica and highlight the potential for misidentifying it with other species that also have a flabellate thallus in Indian waters.

The objective of this research paper is to employ the Method of Initial Functions for analyzing the elastic behavior of concrete beams under various loads, comparing its performance with traditional models like the Reissner–Mindlin theory. We aim to assess the accuracy and efficiency of MIF in modelling beam responses to uniformly distributed and sinusoidal loads, each at an intensity of 100 N/mm. Our results show a stress deviation of only 6.94% from traditional theories, with deflections of 1.18 mm for UDL and 0.59 mm for UVL. The study further explores MIF’s precision in dynamic analysis, particularly its superior amplitude responses to triangular and sinusoidal loads, underscoring its potential to enhance structural analysis in engineering applications.

Volatile organic compounds (VOCs) constitute an important component of plant-soil-microbiome interactions. However, the soil VOCs diversity of cotton species has not been studied so far. With this research gap, this work was conducted to profile soil VOCs diversity among wild and cultivated cotton species. Widely used plasticizers such as dibutyl phthalate (14–65%), benzenedicarboxylic acid (2–45%), and phthalic acid (2–13%) were the dominant volatile compounds detected in wild cotton species, whereas alkanes [heneicosane (3–49%), hexatriacontane (16–35%), tetracontane (10–21%)] and dibutyl phthalate (4–34%) were detected in cultivated cotton species. The bulk soil contained alkanes, including eicosane (40%), trimethyltridecane (30%), and Nonane (10%).

This study records the distribution and occurrence of Juglans regia L. [Juglandaceae: Magnoliophyta], commonly known as walnut, a wild tree, in the Ramban district of the Union Territory of Jammu and Kashmir and the Chamba district of Himachal Pradesh. Despite the historical cultivation of walnuts in these regions, there is a lack of comprehensive documentation on the presence of naturally occurring wild populations. During 2021–2023, field surveys were conducted in the Ramban District of JKUT and the Chamba District of Himachal Pradesh in the North Western Himalayas to assess the distribution and occurrence of Juglans regia L. Various sampling sites based on their habitat suitability and accessibility were selected. Photographic documentation and herbarium preparation to record the occurrence of Juglans regia L. botanical, capturing diagnostic morphological features such as flowers, leaves, stems, and fruits for species identification were done. Nomenclature, taxonomy, distribution, phenology, ecological notes, and colour photographs of the botanical specimens were provided for easy identification. These findings represent a significant addition to the botanical records of the North Western Himalayas, providing new insights into the natural distribution and occurrence of walnuts.

This study examines foot trembling behaviour in shorebirds at an important wintering ground along the west coast of India, challenging the traditional notion that this behaviour is limited to visual foragers. The research was carried out in two primary habitats within the Kadalundi-Vallikkunnu Community Reserve: mudflats and mangroves. The investigation focused on seven migratory shorebird species, including visual foragers (Tibetan Sand Plover, Greater Sand Plover, and Pacific Golden Plover), tactile foragers (Sanderling and Terek Sandpiper), and opportunistic foragers (Common Redshank and Common Greenshank). Shorebird monitoring was conducted during low tide using direct visual counts and video recording. The findings demonstrate that foot trembling is prevalent across all species studied, regardless of their foraging strategy, and is closely linked to habitat conditions affecting prey availability. Moreover, the study indicates that tactile foragers are particularly reliant on foot trembling, suggesting significant habitat degradation that impacts prey availability for species with specialized evolutionary adaptations.

Microplastics (MPs) are an emerging pollutant that has been extensively detected in all the compartments of the environment. However, little study has been done on MP pollution in terrestrial environments. In this study, we investigated the MPs abundance in the agricultural soil of Bahour, Puducherry, during pre and post-irrigation periods. A total of 995 MPs were found in pre-irrigation samples ranging from 53 to 90 particles/kg of soil with a mean (± SE) of 66.33 ± 2.61 particles/kg. In the post-irrigation samples, 899 MPs ranged from 53 to 72 particles/kg of soil, with a mean (± SE) of 59.93 ± 1.76 particles/kg were detected. The average abundance of MPs found was 63.13 ± 2.19 particles/kg of soil. MPs size ranges from 50 µm to 4.5 mm were detected using microscopic identification. The main morphotypes of MPs observed were fiber, fragments, film, foams, and pellets. Fibers were the most abundant polymer, with 63.67%, and foams were the least abundant polymer, with 0.89%. FTIR data showed the probable presence of Nylon as a major polymer type along with Polystyrene, High-Density Polyethylene, Low-Density Polyethylene, and Polypropylene. MPs in this agricultural soil may result from the degradation of macroplastics due to UV radiations, mechanical weathering, contamination through wastewater irrigation, atmospheric deposition, and contaminated composts. This is the first report on the prevalence and characteristics of microplastics in the agricultural soil of Puducherry’s ‘rice bowl.’ The results of this study will motivate further research to enhance our understanding of the sources, impacts, and accumulation of MPs in agricultural soil and to identify effective management practices and mitigation strategies.

The present paper thoroughly discussed the morphological characteristics, distribution, and systematic position of the Honeycomb worm Sabellaria alveolata (Linnaeus, 1767) belonging to the family Sabellaridae Johnston, 1865, which has not been previously reported from the coastal waters of West Bengal, Eastern coast of India, Bay of Bengal. The species identification has been confirmed by examining the morphometric characteristics such as opercular stalk, crown, types of palea, body colour, and absence of nuchal spine; the details of these characteristics are discussed in the paper.

The construction industry has long relied on river sand for concrete production, but environmental concerns and dwindling sand reserves have prompted the search for alternatives. Manufactured sand (M-sand) has emerged as a viable eco-friendly substitute. This paper examines M-sand’s potential in concrete, analyzing its fresh and hardened properties and highlighting its compatibility and, in some cases, superiority over natural sand. M-sand adoption offers environmental benefits, including conserving natural sand and improving energy efficiency. Despite these advantages, challenges remain in its widespread acceptance and technical implementation, emphasizing the need for further research and industry adoption.

Manual transplanted rice is labor-intensive, requires a large amount of water, and makes soil poor. Keeping this in view, Non-puddled machine transplanted rice (NPMTR) as an alternative planting technique for puddled machine transplanted rice (PMTR) was tested at Tamil Nadu Rice Research Institute (TRRI), Aduthurai during Kharif seasons 2016 to 2020. The experimental data was analyzed using an independent two-sample t-test. The statistical analysis results indicated that NPMTR and PMTR rice planting techniques did not show any significant difference in rice grain yields and recorded 4.82 and 5.06 t/ha respectively. However, a significant (P < 0.00) higher water use efficiency (4.852 kg/ ha mm) was observed under NPMTR, saving approximately 21% water with a 4.97% yield penalty compared to PMTR. In addition, economic analysis results also indicated a higher benefit-cost ratio (B: C Ratio) of 2.29 under NPMTR than 2.09 in PMTR. NPMTR is cost-effective (less production cost ₹ 5880/ha), resource-saving (fuel 26 L/ ha, energy (1220 MJ/ ha), time (5.5 h/ ha) and water (250.4 mm/ ha), easy to practice and reliable rice transplanting method under fast-changing global climatic conditions.

Image classification is a crucial task in computer vision that involves identifying and labeling objects within images. This study proposes a hybrid feature extraction method for image classification, combining local features (SIFT, Haralick descriptors) with deep features (VGG19) to capture a wide range of image characteristics. We use k-means clustering and locality-preserving projection for feature selection and dimensionality reduction. The method was tested on the Caltech-101 dataset and achieved high accuracies of 96.18%, 96.76%, 97.39%, and 97.78% using k-NN, MLP, Random Forest, and Adaptive Boosting classifiers, respectively. Cross-validation results confirm the model’s robustness, making it suitable for real-world applications.