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Sri Lanka is affected by extreme precipitation events every year, which cause floods, landslides and tremendous economic losses. We use the ERA5 reanalysis data set to understand the association of extreme precipitation events with 30 weather patterns, which were originally derived to represent the variability of the Indian climate during January–December 1979–2016. We find that weather patterns that are most common during the northeast monsoon (December–February) and second intermonsoon (October–November) seasons produce the highest number of extreme precipitation events. Furthermore, extreme precipitation events occurring during these two seasons are more persistent than those during the southwest monsoon (May–September) and first intermonsoon (March–April) seasons. We analyze the modulation of extreme precipitation events by the Madden‐Julian Oscillation, and find that their frequency is enhanced (suppressed) in phases 1–4 (5–8) for most weather patterns. Plain Language Summary: Extreme rainfall events affect Sri Lanka every year, causing floods, landslides and tremendous losses. Thus, it is important to identify weather patterns that are associated with these events. Furthermore, it is important to understand how the dominant modes of the tropical intraseasonal variability, such as the Madden‐Julian Oscillation, modulate their occurrence. In this study, we use the European Centre for Medium‐Range Weather Forecasts ERA5 reanalysis data set to understand the association between extreme precipitation events and a set of 30 weather patterns that were originally derived to understand the variability of the Indian climate. Our results suggest that weather patterns that are most common during winter and autumn seasons produce the highest number of extreme precipitation events in Sri Lanka, and these events are more persistent than those occurring during summer and spring seasons. The frequency of extreme precipitation events is enhanced when the Madden‐Julian Oscillation is active over the Indian Ocean. Key Points: Extreme precipitation in Sri Lanka occurs most frequently in weather patterns associated with the northeast and second intermonsoon seasonsIn weather patterns with the largest frequency of extreme precipitation events, extreme precipitation can persist for five consecutive daysThe frequency of extreme precipitation events is enhanced in phases 1–4 of the Madden‐Julian Oscillation [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the application of gridded precipitation datasets for applications in Sri Lanka and to identify suitable products that can be used for hydrological applications in data sparse regions. Here, nine global datasets were considered for this study, and after initial screening, four datasets, such as Integrated Multi-Satellite Retrievals for GPM (IMERG) early run calibrated, Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS), European Center for Medium range Weather Forecasting (ECMWF)—ReAnalysis (ERA5) and Indian Monsoon Data Assimilation and Reanalysis (IMDAA), were selected for detailed comparison. These data products were analysed at monthly, seasonal and annual time scale for whole Sri Lanka and also for three distinguished climate zones (wet, intermediate and dry) for the period 2001–2015. The datasets were further evaluated based on their ability to capture the extreme events, based on recent designated dry year and wet year. All four datasets represent the annual and monthly climatology of Sri Lanka well; however, discrepancies are seen at seasonal scale. CHIRPS had the best performance in the wet zone and ERA5 in dry and intermediate zones. Although all datasets distinctly identified the wet year and dry year with respect to the normal average, the interannual variability was explicitly identified by CHIRPS and ERA5. Therefore, for replicating the national and zonal climatology, both ERA5 (dry and intermediate zones) and CHIRPS (wet zone) are suitable. With the perspective of hydrological applications, both datasets can be used in development of hydrological models for applications such as flood forecasting, reservoir management and climate change impact assessment as an alternative to observed rainfall data in data scarce regions. [ABSTRACT FROM AUTHOR]

The climatic variations in the Indian Ocean have a strong relationship with the rainfall anomaly of Sri Lanka. Indian Ocean Dipole (IOD) is an ocean-atmospheric coupled phenomenon associated with an east-west gradient in the tropical Indian Ocean Sea Surface Temperature (SST) anomalies. Identifying the impact of IOD phenomenon on the spatial and temporal variation of the rainfall pattern is a useful tool for seasonal climate forecasting. The present study examined the influence of IOD on the Second Inter-monsoon (SIM) rains of the Wet zone (WZ) of Sri Lanka. Considering 16 rain-gauge locations scattered in the WZ of Sri Lanka covering nine Agro-ecological Regions (AERs), daily rainfall time series for 44-years (1976-2019) were collected. The IOD-positive and IOD-negative years were extracted based on the Dipole Mode Index (DMI) over the neutral years. Five rainfall indices, namely, cumulative rainfall, the maximum rainfall received within a day, number of wet days, heavy rainfall events and the maximum consecutive dry days were statistically analysed. The results revealed a significant positive anomaly of mean cumulative rainfall in the SIM season during the IOD-positive years while in IOD-negative years this anomaly was negative (p<0.05). An apparent increase or decrease of number of wet days and heavy rainfall events was observed during IOD-positive or IOD-negative years, respectively. However, the mean maximum consecutive dry days showed a distinct negative anomaly with the positive IOD events and positive anomaly with the negative IOD events. Further investigations are suggested to elucidate the El Niño Southern Oscillation (ENSO)-induced anomalous variation over IOD impacts. [ABSTRACT FROM AUTHOR]

This study revealed the influence of Madden Julian oscillation (MJO) and cold surge (CS) on the extreme rainfall events that occurred in Sri Lanka from 19th to 28th December 2014. During this period, the Northeast Monsoon winds over the Bay of Bengal were strengthened by a CS, which intensified convective activity over the Bay of Bengal. Simultaneously, convective phase 3 of the MJO, which was located over the eastern Indian Ocean is associated with a positive rainfall anomaly over Sri Lanka. Westerly wind anomalies associated with MJO phase 3 shifted southward due to the strengthening of northeasterly winds by the CS, forming an incipient vortex to the southeast of Sri Lanka. The low level moisture transport was enhanced by this vortex circulation together with strong cross-equatorial moisture flux transportation. The convectively active phase of MJO provided favourable conditions such as low level convergence, cyclonic relative vorticity, and deep convection for the intensification of vortex into a tropical depression over the southwest Bay of Bengal. Strong upward motion and combination of strong low level convergence with upper-level divergence allowed evacuation of the ascending air mass, aiding the intensification of deep convection. This persistent vertical coupling structure allowed deep convection of moist warm air, which led to heavy rainfall during the period. Combination of a number of factors, such as local terrain effects, CS at low levels, MJO wet phase and a vortex to southeast of Sri Lanka led to an intensification of the tropical depression that caused an extreme rainfall event over the Eastern and Northeastern parts of Sri Lanka. [ABSTRACT FROM AUTHOR]

Objectives: Mobile health clinics (MHCs) effectively provide healthcare to underserved communities. However, their application during health emergencies is understudied. We described the implementation of an MHC program delivering vaccinations during the COVID-19 pandemic, examined the program's reach to medically underserved communities, and investigated characteristics of vaccination uptake in order to inform the utility of MHCs during health emergencies., Study Design: The study observed COVID-19 MHC vaccination rates and factors associated with uptake between February 20th, 2021, and February 17th, 2022., Methods: Prisma Health deployed six MHCs to underserved communities. We described the characteristics of individuals who utilized the MHCs and evaluated census tract-level community factors associated with use of the MHCs through generalized linear mixed effects models., Results: The MHCs conducted 260 visits at 149 unique sites in South Carolina, providing 12,102 vaccine doses to 8545 individuals: 2890 received a partial dose, 4355 received a primary series, and 1300 received a booster dose. Among individuals utilizing the MHC, the median age was 42 years (IQR: 22-58), 44.0 % were Black, 49.2 % were male, and 44.2 % were uninsured. Black, Hispanic, and uninsured individuals were significantly more likely to utilize MHC services for COVID-19 vaccination. During periods when vaccines were limited, MHC utilization was significantly greater in communities facing access barriers to healthcare., Conclusions: The high COVID-19 vaccination uptake at MHCs demonstrated that the MHC framework is an effective and acceptable intervention among medically underserved populations during health emergencies, especially when resources are scarce. The identified factors associated with vaccination uptake demonstrated that the MHCs had the greatest impact in higher-risk communities and can be used to inform allocation of such field-level interventions in future health emergencies., Competing Interests: This study was funded by the National Library of Medicine of the National Institutes of Health and the Center for Forecasting and Outbreak Analytics of the Centers for Disease Control and Prevention. The MHC program was supported by The Greenville County CARES Program; the Coronavirus Aid, Relief, and Economic Security Act; and Prisma Health. LR, FG, IJ, KJB, AHL, and KKS received support from the National Library of Medicine of the National Institutes of Health (R01LM014193) during this study; LR, FG, KAH, KJB, AHL, and KKS received support from the Centers for Disease Control and Prevention (NU38FT000011). The funders had no role in the design, conduct, reporting of the study, or decision to submit for publication.This study was funded by the National Library of Medicine of the National Institutes of Health and the Center for Forecasting and Outbreak Analytics of the Centers for Disease Control and Prevention. The MHC program was supported by The Greenville County CARES Program as part of a Covid-19 Funding Program. LR, FG, IJ, KJB, AHL, and KKS received support from the National Library of Medicine of the National Institutes of Health (R01LM014193) during this study; LR, FG, KAH, KJB, AHL, and KKS received support from the Centers for Disease Control and Prevention (NU38FT000011). The funders had no role in the design, conduct, reporting of the study, or decision to submit for publication., (© 2024 The Authors.)

Background: University spring break carries a two-pronged SARS-CoV-2 variant transmission risk. Circulating variants from universities can spread to spring break destinations, and variants from spring break destinations can spread to universities and surrounding communities. Therefore, it is critical to implement SARS-CoV-2 variant surveillance and testing strategies to limit community spread before and after spring break to mitigate virus transmission and facilitate universities safely returning to in-person teaching., Methods: We examined the SARS-CoV-2 positivity rate and changes in variant lineages before and after the university spring break for two consecutive years. 155 samples were sequenced across four time periods: pre- and post-spring break 2021 and pre- and post-spring break 2022; following whole genome sequencing, samples were assigned clades. The clades were then paired with positivity and testing data from over 50,000 samples., Results: In 2021, the number of variants in the observed population increased from four to nine over spring break, with variants of concern being responsible for most of the cases; Alpha percent composition increased from 22.2% to 56.4%. In 2022, the number of clades in the population increased only from two to three, all of which were Omicron or a sub-lineage of Omicron. However, phylogenetic analysis showed the emergence of distantly related sub-lineages. 2022 saw a greater increase in positivity than 2021, which coincided with a milder mitigation strategy. Analysis of social media data provided insight into student travel destinations and how those travel events may have impacted spread., Conclusions: We show the role that repetitive testing can play in transmission mitigation, reducing community spread, and maintaining in-person education. We identified that distantly related lineages were brought to the area after spring break travel regardless of the presence of a dominant variant of concern., Competing Interests: I have read the journal’s policy and the authors of this manuscript have the following competing interests: SW is currently employed by Illumina. BK, SP, JP, RD, LI, and AS are employed by Labcorp. The other authors declare no competing interest. This does not alter our adherence to PLOS ONE policies on sharing data and materials., (Copyright: © 2024 Napolitano et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

New approaches to rapid, simple, in vitro diagnostic immunoassays that do not rely on centralized laboratory facilities are urgently needed for disease diagnosis and to inform treatment strategies. The recent and ongoing COVID-19 pandemic has emphasized that rapid diagnostics are needed to help guide government policies on quarantines, social distancing measures, and community lockdowns. A common approach to developing new immunoassays is to modify existing platforms ( e.g. , automated ELISA and lateral flow assays) for the new analyte, even though this does not address the drawbacks of existing platforms. An alternate approach is to search for robust assays that have been superseded but could in fact solve important challenges using modern technologies. Immunodiffusion is one such platform based on unique "precipitin ring" patterns formed in gels or paper following interactions between proteins and cognate antibodies in diffusion/reaction systems. Herein, we investigate the microstructure of these precipitin rings using a combination of fluorescence and electron microscopy and also perform a mass spectrometry investigation to determine the proteomic composition of the rings. We observed that the rings were composed of microparticles, which we termed "precipitin complexes", and that these complexes were composed of at least 19 key proteins, including immunoglobulins and complement factors along with a range of plasma proteins, possibly related to immune complexes and/or high-density lipoprotein particles. This information will be useful in developing new in vitro diagnostics using reaction/diffusion systems-techniques that require a single assay step and that only require calibrated length measurements for target protein quantification.

The current study evaluates the migration of benzene, toluene, ethylbenzene, xylene (BTEX) and phthalates into artificial saliva from natural rubber latex (NRL) balloons available for sale in Sri Lanka. It was discovered that at least one BTEX compound migrated from almost all the brands. The migration of four phthalates; diethyl phthalate, dibutyl phthalate, di-isobutyl phthalate and butyl benzyl phthalate were also observed. Migratory levels of BTEX and phthalates in most of the balloon brands were above the permissible levels set by the European Union. Assessment of factors affecting the migratory levels indicated migration under active mouthing conditions and migration from the neck region of the balloons were significantly higher. The migratory levels were observed to decrease with storage time, and in certain brands the BTEX levels decreased below the permissible level. One-way ANOVA indicated no significant differences (p ≥ 0.05) in migratory levels of each individual compound within the same brand for both BTEX and phthalates. When compared among different brands, BTEX levels indicated significant differences (p ≤ 0.05), while phthalate levels were observed to not be significantly different (p ≥ 0.05). A significant difference was also observed (p ≤ 0.05) among the migratory levels of compounds under each test condition evaluated as factors affecting the migratory level. Furthermore, the solvent based colorants added to color the latex were found to be the source of BTEX and phthalates in the NRL balloons.

Quarter wave matching of ultrasonic transducers with two layers (glass and parylene) were studied with computer simulation. These layers are located between the piezoelectric transducer and the acoustic load. The purpose is to achieve a short impulse response and high efficiency broadband transfer in a practical manner for high frequency transducers. The acoustic impedances of these layers were chosen based on transmission line theory. A method to measure acoustic properties of the matching layers and a method to choose the material are discussed. The advantages in using a quarter wavelength of glass and parylene as the matching layers are given. The 6 dB fractional bandwidth of the simulated transmission-reception transfer was found to be 0.75, which is a factor of at least 6 improvement over a nonmatched transducer.