1,720,958 research outputs found
Spatio-Temporal Changes and Fragmentation Patterns of Sinharaja Forest Peripheral Area Using Morphological Spatial Pattern Analysis
No full textForest fragmentation is a landscape process that significantly impacts the spatial structure and ecological dynamics of natural ecosystems. As human populations continue to grow, this phenomenon has emerged as a pressing challenge. Consequently, high rates of forest degradation and fragmentation, especially in tropical regions, have become more prevalent. In recent decades, human activities have intensified in the peripheral areas surrounding the Sinharaja forest reserve, leading to forest fragmentation. The advancement of remote sensing-based approaches has provided valuable insights into forest cover change analysis. The objective of this research was to analyze the fragmentation patterns in the peripheral areas of the Sinharaja forest using Morphological Spatial Pattern Analysis (MSPA). MSPA is a method used for landscape pattern analysis related to forest fragmentation and other natural land cover classes. The study spans 24 years, from 1995 to 2019, using Landsat imagery. A forest cover map was created using Normalized Difference Vegetation Index (NDVI) analysis. Its accuracy was checked done by the accuracy assessment and assessing with the Google Earth images. The accuracy was 85.4% and 89.5% in 1995 and 2019 respectively. The study aimed to quantify the spatial and temporal changes, the fragmentation pattern of forest cover, and its associated ecological impacts. Various landscape indices such as Largest Patch Index (LPI), Number of Patches (NP), Patch Density (PD), and Shannon’s Diversity Index (SDI) were applied to characterize the spatial pattern and assess the connectivity of forested and non- forested areas. SDI was analyzed using Leco’s plugin after confirming accuracy for forest and non-forest patches through the validation procedure. The results revealed that forested areas decreased from 186 km² in 1995 to 180 km² in 2019, with the northern and northwestern parts of the peripheral zone being more susceptible to fragmentation. The core forest patches in the area increased over the 24-year period, while non-forest areas expanded by 3.23%. LPI for forest patches decreased from 1.88% to 2.06%, and SDI increased from 0.31 to 0.37 during this time frame. These findings indicated that the forest patches in 2019 became smaller and exhibited higher diversity compared to 1995. Overall, the results suggested that the peripheral areas of the Sinharaja forest reserve are vulnerable to forest fragmentation. MSPA contributes to our understanding of the landscape and fragmentation patterns in the area, which are essential for conservation and sustainable forest management. Additionally, this study demonstrated the effectiveness of using geospatial tools to quantify forest fragmentation even with limited data availability.
Keywords: Ecological impacts, Forest fragmentation, Landscape metrics, Morphological Spatial Pattern Analysi
Analysing Sustainable Urban Growth: Spatio-Temporal Dynamics of Urban Expansion in Gampola Urban Centre
No full textUrbanization is a dynamic process which can be considered as one of the most significant indicators of development. It occurs both horizontally and vertically on the Earth’s surface according to a pattern which has positive and negative implications. Some countries measure their development by the level of urbanization because it directly affects for a country’s economy. During past decades, Gampola urban centre was experiencing a gradual urban growth and several implications. This study focuses on investigating urban expansion pattern of Gampola during 16 years by analysing three distinct years 2006, 2013, and 2022. Geographic Information System (GIS) and Remote Sensing (RS) techniques were employed to examine spatio-temporal transformations and urban expansion patterns of Gampola and its outskirts. Landsat images for three distinct years were classified using pixel-based supervised classification to determine Land Use Land Cover (LULC) of the study area which achieved an impressive overall accuracy of approximately 90%. Four major LULC types were identified those are prominent in the area namely, water, built-up, forest, paddy lands and bare lands. Temporal changes of vegetation cover for 16 years were analysed further using Normalized Difference Vegetation Index (NDVI). Consequent implications on Land Surface Temperature (LST) across the time period were analysed using thermal band of Landsat images. NDVI value has decreased from +0.7 to +0.5 during 2006-2013 and up to +0.4 during 2013-2022. LST analysis revealed a rise in temperature, increasing from 29.89° C up to 31.11° C during 2006- 2013 and surging to 33.14° C by 2022. Quantifying the urban expansion of Gampola was performed using buffer analysis. Analysis of urban areas grown within 1km distanced five buffer zones from urban core was performed to quantify urban expansion. Fourth buffer zone exhibited the highest urban growth, while first buffer zone displayed lowest urban growth during 2006 to 2022. In the interval between 2013 and 2022, the fifth buffer zone appeared as the zone with the highest urban growth. Further, Landscape Expansion Index (LEI) was employed to identify the urban expansion patterns, and Gampola urban area displayed an Edge Expansion growth type. We recommend the development of urbanized areas in a sustainable and efficient manner to mitigate adverse consequences and promote balanced growth.
Keywords: GIS and RS, Urban expansion, LEI, LST, Sustainable developmen
A Geospatial Analysis of Demarcating Landslide Susceptibility and Risk Assessment for Landslide Disaster Management: A Case Study of Rathnapura District
No full text
Natural hazards are environmental phenomena that can significantly impact society and the surrounding ecosystem. In Sri Lanka, landslides are recognized as a major natural hazard, with nearly 20,000 km2 spanning ten districts susceptible to landslides. Rathnapura District has historically experienced a high incidence of landslides. This study utilizes Geographic Information System (GIS) and multicriteria evaluation to identify landslide susceptibility and high-risk zones, providing geospatial insights aimed at mitigating adverse consequences on lives, property, and the environment. The study identifies slope, elevation, topographic wetness, vegetation cover, and annual average rainfall as the primary physical and environmental factors influencing landslide susceptibility. Employing Analytical Hierarchy Process (AHP) for ranking these factors, areas susceptible for landslides within the Rathnapura District were identified through geospatial analysis. Analysis revealed that Kalawana, Imbulpe, Rathnapura and Balangoda DSDs (District Secretariat Divisions) are the major four high susceptible zones for landslides than other ten DSDs of Rathnapura District. Assessing the vulnerability of landslides is crucial for mitigating impacts and minimizing damages to lives, property, and environment. Therefore, considering factors like built- up areas, road networks, and population data, this study identified socio-economic vulnerable zones within a 1,000 m buffer zone of highest four landslide-susceptible areas. Specifically, GNDs (Grama Niladhari Divisions) where susceptibility 50% or more out of area of the GNDs were selected for the vulnerability analysis. Out of the overall 308 GNDs, this research identified 96 GNDs as high landslide-vulnerable zones in four high susceptible DSDs. All 96 highly vulnerable GNDs have some level of landslide risk, as they meet at least one of the socio-economic vulnerability analysis criteria. As a non-structural mitigation approach for landslides, the results of this geospatial analysis can guide the implementation of structural mitigations in both susceptible and high-risk zones. This serves as the initial step in the disaster management cycle, ultimately enhancing disaster preparedness and prevention efforts.
Keywords: Landslide, Susceptibility, Geo-spatial approach, Analytical hierarchy process, Vulnerability
 
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Identifying Forest Fires and their Impact on Forest Cover in Anuradhapura District Using GIS and Remote Sensing
No full textLablab purpureus (L.) is an important leguminous crop that ensures food security. Despite being considered an underutilized crop in Sri Lanka, it is a promising climate-resilient crop with higher protein amounts. However, none of the studies on the diseases in this crop have been performed within the country. Our objective was to identify the diseases and management packages. The disease identification was conducted using the germplasm collection of L. purpureus established at the Horticultural Crops Research and Development Institute. Morphological character analyses of diseased plant samples were followed by culturing parts on a PDA medium to isolate pathogens. The pathogenicity of isolated pathogens was confirmed through standard procedures in Koch's postulate. Pathogen isolates were identified morphologically, and species-level identification was done by extracting genomic DNA and amplifying and sequencing ITS-1 and ITS-4 regions. NCBI BLAST analysis corroborated the results obtained from morphological observations and colony characteristics. This study's findings hold promise for identifying and managing diseases affecting L. purpureus in future cultivation. Under pathogenicity testing, there were 6% foot and root rot disease incidences, and 4% Charcoal rot (ash stem blight) disease incidences were recorded. The distinguishing symptoms of foot and root rot were yellowing, wilting, and basal rot with the presence of Sclerotia in the plant base and symptoms of charcoal rot were yellowing and browning of leaves, stem discoloration with characteristic black patches in root and stem. The causal organisms of foot and root rot were identified as Athelia rolfsii (Sclerotium rolfsii), and charcoal rot was identified as Macrophomina phasealina. With the use of literature and the use of poison food techniques, we developed two disease management packages for both diseases. For foot and root rot control; remove infected plants with soil, Crop rotation, or following, Spot application of recommended fungicides (Captan 50% WP, Thiram 80% WP, Thiophanate-methyl 50% + Thiram 30% WP), Improve the drainage at field preparation, Deep plowing and expose soil to the direct sunlight, Minimize the root damage, and Seed treatment (Captan 50% WP3g/1kg, Thiram 80% WP2g/1kg, thiophanate- methyl 50% + Thiram 30% WP2g/1kg). And also, for ash stem blight control; Following the field or crop rotation (recommended for at least 2yrs), Proper spacing with recommended plant density, Proper nutrient management, Improving the plant vigor, Flood the field 3-4 weeks before planting to destroy the pathogen, and cannot take efficient control by chemical control only.
Keywords: Athelia rolfsii, Charcoal rot, Foot and root rot, Lablab bean, Macrophomina phaseolin 
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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