9 results on '"Jayawardena I"'
Search Results
2. Impacts of the Madden-Julian Oscillation (MJO) on rainfall in Sri Lanka
- Author
-
Wheeler Matthew C, Basnayake B R S B, Jayawardena I M Shiromani Priyanthika, and Sumathipala W L
- Subjects
Troposphere ,Atmospheric Science ,Indian ocean ,Geophysics ,Boreal ,Anomaly (natural sciences) ,Climatology ,Environmental science ,Madden–Julian oscillation ,Sri lanka ,Monsoon - Abstract
The influence of the Madden Julian Oscillation (MJO) on rainfall in Sri Lanka (SL) is examined based on 30 years of daily station data from 1981-2010. Composites are constructed for each of the eight phases of the MJO defined with the Real-time Multivariate MJO (RMM) index, using daily rainfall data from 44 stations over SL for four climatic seasons and comparing to similar results from a satellite-based rainfall product. Composites of lower tropospheric wind and convective anomaly are also investigated in order to examine how the local rainfall anomalies are associated with large-scale circulations. The greatest impact of the MJO on rainfall over SL occurs in the Second Inter-Monsoon (SIM) and Southwest Monsoon (SWM) seasons. Enhanced rainfall generally occurs over SL during RMM phases 2 and 3 when the MJO convective envelop is located in the Indian Ocean and conversely suppressed rainfall in phases 6 and 7. This rainfall impact is due to the direct influence of the MJO’s tropical convective anomalies and associated low-level circulations in the vicinity of SL. In contrast, the MJO influence during the Northeast Monsoon (NEM) season is slightly less than during the SWM and SIM seasons as a result of the southward shift of the MJO convective envelop during boreal winter. Occurrence of extreme rainfall events is most frequent during phase 2 in First Inter-Monsoon (FIM) phases 2 and 3 in SWM, phases 1, 2 and 3 in SIM and phases 2 and 3 in NEM seasons. The analysis of this study provides a useful reference of when and where the MJO has significant impacts on rainfall as well as extreme rainfall events during four climatic seasons in SL. This information can be used along with accurately predicted MJO phase by dynamical or statistical models, to improve extended range forecasting in SL.
- Published
- 2021
- Full Text
- View/download PDF
3. A Comparison of Three Prolonged Periods of Heavy Rainfall over the Hawaiian Islands
- Author
-
Jayawardena, I. M. Shiromani, Chen, Yi-Leng, Nash, Andrew J., and Kodama, Kevin
- Published
- 2012
4. Student-Proposed Cruise Captured Wakes of Oahu and Kauai Islands
- Author
-
Ma, Jian, da Silva, Sara C., Levine, Aaron, Yang, Yang, Fuentes, Paul, Zhou, Li, Tu, Chuan-Chi, Hu, Jia, Jayawardena, I. M. Shiromani, Pessi, Antti, and Carlis, DaNa
- Published
- 2009
5. Effect of Indian Ocean Dipole (IOD) Events on the Second Inter-monsoonal Rainfall in the Wet Zone of Sri Lanka
- Author
-
Abeysekera, A. B., primary, Punyawardena, B. V. R., additional, Marambe, B., additional, Jayawardena, I. M. S. P., additional, Sivananthawerl, T., additional, and Wickramasinghe, V. N. M., additional
- Published
- 2021
- Full Text
- View/download PDF
6. Impact of Madden Julian oscillation (MJO) and other meteorological phenomena on the heavy rainfall event from 19th - 28th December, 2014 over Sri Lanka.
- Author
-
Jayawardena, I. M. S. P., Sumathipala, W. L., and Basnayake, B. R. S. B.
- Subjects
RAINFALL ,MONSOONS ,WINDS ,CYCLONES ,CONVECTION (Meteorology) - Abstract
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]
- Published
- 2017
- Full Text
- View/download PDF
7. Mobile health clinics for distribution of vaccinations to underserved communities during health emergencies: A COVID-19 case study.
- Author
-
Rennert L, Gezer F, Jayawardena I, Howard KA, Bennett KJ, Litwin AH, and Sease KK
- Abstract
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.)
- Published
- 2024
- Full Text
- View/download PDF
8. SARS-CoV-2 variant introduction following spring break travel and transmission mitigation strategies.
- Author
-
Napolitano JM, Srikanth S, Noorai RE, Wilson S, Williams KE, Rosales-Garcia RA, Krueger B, Emerson C, Parker S, Pruitt J, Dango R, Iyer L, Shafi A, Jayawardena I, Parkinson CL, McMahan C, Rennert L, Peng CA, and Dean D
- Subjects
- Humans, Universities, Whole Genome Sequencing, Phylogeny, Seasons, COVID-19 transmission, COVID-19 prevention & control, COVID-19 epidemiology, COVID-19 virology, SARS-CoV-2 genetics, SARS-CoV-2 isolation & purification, Travel
- Abstract
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.)
- Published
- 2024
- Full Text
- View/download PDF
9. Migration of BTEX and phthalates from natural rubber latex balloons obtained from the Sri Lankan market.
- Author
-
Jayawardena I, Godakumbura PI, and Prashantha MA
- Abstract
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.
- Published
- 2016
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.