Contrastive Self-Supervised Learning Based Approach for Patient Similarity: A Case Study on Atrial Fibrillation Detection from PPG Signal

In this paper, we propose a novel contrastive learning based deep learning framework for patient similarity search using physiological signals. We use a contrastive learning based approach to learn similar embeddings of patients with similar physiological signal data. We also introduce a number of neighbor selection algorithms to determine the patients with the highest similarity on the generated embeddings. To validate the effectiveness of our framework for measuring patient similarity, we select the detection of Atrial Fibrillation (AF) through photoplethysmography (PPG) signals obtained from smartwatch devices as our case study. We present extensive experimentation of our framework on a dataset of over 170 individuals and compare the performance of our framework with other baseline methods on this dataset.Comment: 10 pages, 4 figures, Preprint submitted to Journal of Computers in Biology and Medicin

The relationship between elevation roughness and tornado activity: A spatial statistical model fit to data from the central great plains

The statistical relationship between elevation roughness and tornado activity is quantified using a spatial model that controls for the effect of population on the availability of reports. Across a large portion of the central Great Plains the model shows that areas with uniform elevation tend to have more tornadoes on average than areas with variable elevation. The effect amounts to a 2.3% [(1.6%, 3.0%) = 95% credible interval] increase in the rate of a tornado occurrence per meter of decrease in elevation roughness, defined as the highest minus the lowest elevation locally. The effect remains unchanged if the model is fit to the data starting with the year 1995. The effect strengthens for the set of intense tornadoes and is stronger using an alternative definition of roughness. The elevation-roughness effect appears to be strongest over Kansas, but it is statistically significant over a broad domain that extends from Texas to South Dakota. The research is important for developing a local climatological description of tornado occurrence rates across the tornado-prone region of the Great Plains

Change Vector Analysis, Tasseled Cap, and NDVI-NDMI for Measuring Land Use/Cover Changes Caused by a Sudden Short-Term Severe Drought: 2011 Texas Event

Sudden short-term severe droughts have major impacts on ecosystem balance. Synoptic and replicable measurements from remotely sensed data are essential for calculating changes to land use/cover caused by severe drought conditions. In the US, Texas experienced a particularly severe drought in 2011, which adversely affected forest and grassland ecosystems in addition to $7.62 billion of agricultural loss. To assess the extent and severity of the drought we use satellite sensor data and image processing techniques to measure changes in land use/cover. Our methodology uses change vector analysis (CVA), the normalized difference vegetation index, the normalized difference moisture index, and three variables-brightness, greenness, and wetness-extracted from tasseled cap transforms (TCT). All are established techniques in remote sensing but have as yet been applied in combination to measure land use/cover changes affected by intense short-term drought conditions. Our objective is to calculate not only vegetation and bare soil indices, but also the intensity of change (magnitude) and the type of change (direction). For CVA direction, we include an improved methodology using the arctangent function based on two arguments, ATAN2 which produces results in all four possible quadrants, and complete characterization of all possible change directions. The three variables of TCT are applied to CVA magnitude and direction using vectors in three dimensions, resulting in eight change categories. Our results are based on Landsat TM sensor data for the years 2009, 2010 and 2011, which represent a short period of severe drought, above average precipitation, and severe drought respectively, for two study sites in Texas. Results indicate that land use/cover changes were affected by both an increase in precipitation in 2010 as well as a considerable decrease of precipitation in 2011 resulting in the devastating sudden drought

PRESENT STATUS, PROSPECTS AND CONSERVATION OF HILSA, Tenualosa ilisha (CLUPEIFORMES: CLUPEIDAE) FISHERY IN BANGLADESH

Belonging to the family Clupeidae, hilsa shad Tenualosa ilisha (Hamilton, 1822) is an important fish species in the South and Southeast Asia, especially in Bangladesh. Due to its unique nature, the fish has gained national and international demands for its nutritional values, taste qualities, special aroma and high delicacy, and provides livelihoods to the millions of fishers directly or indirectly along the coastal and riverine stretches in its range of natural distribution. It is considered as the national and most important commercial fish species of Bangladesh and contributes significantly to the national economy. In this study, an attempt is made in evaluating the data currently available on hilsa to determine the impact of the current management approaches and improvement strategies of this important fishery. Hilsa is found primarily in marine and estuarine environments, but it has been declining gradually over the last 30 years, reaching a low point in 1991-1992 and continuing until 2002-2003. Recognizing the declining trend of hilsa, the government took action to increase production by implementing regulations on jatka (juvenile) catch and restrictions on brood hilsa catch during the breeding season. As a result, total hilsa catch increased from 2.55 million MT (metric ton) in 2003-04 to 3.94 million MT in 2015-2016. Under the Protection and Conservation of Fish Act of 1950, Hilsa production peaked in 2016-2017, with a total of 4.96 lakh metric tons. Hilsa management techniques contribute 12.9% of all fish produced, while in Bangladesh, the rate of increase in hilsa production is 25.69%. The annual increase of total hilsa production climbed from 3.5% to 9.0% after 2015 as a result of the government's general management activities, payments for ecosystem service (PES) and the environmental management strategies, resulting in annual total hilsa production of 5.50 lakh MT in 2019–2020. A number of recommendations for effective management of the hilsa fisheries that might be implemented into the national policy are elicited in order to improve the situation because the current hilsa management plan has an impact on the conservation of this important fishery to a greater extent in commensurate with its national and international demands

Diversity of bacterial communities in the Sundarbans mangrove, Bangladesh, with special focus on pathogens affecting aquatic organisms

The Sundarbans, located in Bangladesh, is the world's largest mangrove forest with a rich and diverse microbial community. The main objective of this study was to use 16S rRNA sequencing to identify the bacterial community in the Sundarban mangrove forest, particularly pathogenic bacteria to aquatic organisms. This study conducted in Bangladesh collected 225 samples of soil, water, fish, and shellfish from five locations with a typical mangrove environment. All samples underwent genomic DNA extraction, quantification, gel documentation, and subsequent sequencing. Sanger sequencing was then carried out, followed by sequencing 11 concentrated samples using the universal bacterial primer 16S rRNA. The study found 872 bacterial species, 94 genera, 38 families, and 6 phyla. Pseudomonades or proteobacteria accounted for 92% of the phylum composition, with firmicutes, bactericides, cyanobacteria, Verrucomicrobia, and actinobacteria also present at smaller percentages. Chromatiaceae had the highest species count (20.3%), followed by Ectothiorhodospiraceae (15.5%), Methylococcaceae (12.3%), Moraxellaceae (10.7%), Thiotrichaceae (8.7%), Idiomarinaceae (5.4%), and smaller groups. All the species that were identified were gram-negative bacteria and were found in different environments, mainly halophilic ones. Based on 16 s rRNA sequencing, additional experimental and clinical data, as well as NCBI (BLAST), approximately 49.3% of the 872 bacterial species are typically harmless and not classified as pathogenic. The pathogenic characteristics of 24.9% of the species are still unidentified. 13.4% showed either pathogenic or non-pathogenic characteristics (a bacterium as having the potential to exhibit pathogenic or non-pathogenic characteristics in certain circumstances), while 8.4% were exclusively pathogenic, potentially capable of causing disease. Also, the bacterial species are categorized as 2.6% non-highly pathogenic (a bacterium can still have a significant impact on health, especially in weakened immune systems or other underlying health conditions), 1.3% sometimes pathogenic and 0.1% potentially pathogenic (a bacterium don't always cause disease). Sequence analysis, combination of phylogenetic, biochemical characterization (data were not shown), and other experimental validation conclude a genetic baseline of bacterial community, this research may serve as a valuable reference for future ecological and taxonomical studies as well as addressing further research scope on bacterial diversity found in the Sundarbans mangrove of Bangladesh

Bacteriophage and non-pathogenic Vibrio to control diseases in shrimp aquaculture

The study aimed to address the recurring outbreaks of microbial diseases in shrimp aquaculture in Bangladesh the study focused on the utilization of bacteriophages and non-pathogenic Vibrio. The bacteriophages were isolated from sewage water sample collected from shrimp farm, hatchery, and the JUST campus. The bacteriophages were tested for their ability to infect different Vibrio strains in order to assess their bacteriolytic activity. Non-pathogenic Vibrio strains were obtained from suspected diseased isolates collected from the south-western region of Bangladesh through PCR amplification. In laboratory tests, the bacteriophages successfully infected 91 % of the tested Vibrio strains (19 out of 21 strains). In the experimental unit, shrimp treated with phage prophylaxis and phage treatment demonstrated notable protection against AHPND and was able to survive a deadly bacterial challenge. A total of 35 suspected diseased isolates were tested, and PCR amplification revealed 6 non-pathogenic Vibrio strains. In field trials, cultured bacteriophages were applied at a concentration of 1.5×106 PFU/ml, while non-pathogenic Vibrio was applied at 5×105 CFU/ml. The trials showed increased protection against infections and no severe deaths during the adaptive research phase. The cultured shrimp were analyzed morphologically and showed a muscle gut ratio greater than 4:1. No abnormal deformities were observed in their appendages or overall body, suggesting their overall health and well-being. The bacteriological tests conducted on the shrimp samples (application of bacteriophages and non-pathogenic Vibrio) revealed that 18 % of them were infected with bacteria, primarily Vibrio cholerae, Vibrio parahaemolyticus, and other bacterial species. Despite this, the infections did not lead to a disease outbreak; PCR amplification showed negative results for AHPND, White Spot Syndrome Virus (WSSV), and Enterocytozoon hepatopenaei (EHP). The results highlight the potential of using bacteriophages and non-pathogenic Vibrio as a sustainable solution for preventing and controlling microbial diseases in shrimp aquaculture. Furthermore, this study will contribute valuable insights into the development of alternative strategies to combat antibiotic resistance and promote the growth of the shrimp industry in Bangladesh