Machine Learning Based Weather Prediction Model for Short Term Weather Prediction in Sri Lanka

Weather forecasting is the field of making predictions of the future state of the atmosphere of a certain location by analyzing initial values of relevant atmospheric characteristics which are obtained by meteorological observations. Since weather prediction has substantial effect in economic sectors such as agriculture, health, aviation, hydro power generation and even in daily lives of people, issuing accurate weather forecasts is a major responsibility of meteorological authorities across the world. Even though forecasting weather in mid-latitudes is uncomplicated and reliable, weather prediction in a tropical country like Sri Lanka is notoriously difficult as sudden changes of convective tropical weather phenomena are quite difficult to be predicted by prevailing Numerical Weather Prediction (NWP) methods. Therefore, the current research aims to present machine learning based weather prediction models for Sri Lanka for making short term forecasts for the most significant weather attributes such as temperature and precipitation. This paper discusses on implementing two multivariate Long Short-Term Memory Network models (LSTM) to make predictions on temperature and precipitation separately for a selected weather station in Sri Lanka and review the applicability of machine learning to solve highly nonlinear and complex weather problems. The prediction performances of the implemented LSTM models are evaluated using standard evaluation techniques such as Root Mean Squared Error (RMSE) and Mean Absolute Error (MAE). The results show that two LSTM models have made predictions with least RMSE and MAE values, evidencing the successful applicability of machine learning for solving complex and nonlinear patterns of past observational weather data and making accurate weather forecasts. KEYWORDS: Weather Prediction, Neumerical Weather Prediction, Artificial Neural Network, LST

Cement and Clay Bricks Reinforced with Coconut Fiber and Fiber Dust

For generations, Sri Lankans use cement bricks and clay bricks as common building materials in the construction field. This study investigates the feasibility of improving the strength while lowering the mass and thermal conductivity of bricks by adding coconut fiber or coconut fiber dust as a reinforcing material. Each reinforcing material is used in both clay and cement bricks. The mixtures are prepared according to varying volume ratios of the raw materials used. Coconut fibers are combed and cut into 4-5 cm pieces and dry coconut fiber dust is sieved using a 4 mm sieving mesh.  The mixture is prepared by hand mixing and the traditional processes are replicated in making the bricks. Tests are carried out to understand the variation of mass, compressive strength, thermal conductivity, and water absorption of the reinforced bricks in comparison to bricks with no reinforced material. The cement brick reinforced with coconut fiber achieves the expected results in the compressive strength test and thermal conductivity test but underperformed when comparing masses and water absorption. Clay bricks reinforced with coconut fiber dust show impressive results in compressive tests and with the addition of dust, the appearance seems to have changed. It is observed that reinforcing cement bricks with coconut fiber could double the compressive strength along with a 5% reduction in mass. Reinforcing clay bricks with coconut fiber dust increases its compressive strength by over 70% while decreasing the mass by over 30 %. The study proves that it is feasible to use reinforced coconut fiber or coconut fiber dust to improve the properties of both clay and cement bricks, while clay bricks reinforced with coconut fiber are an exception

Hybrid-organic-inorganic anatase as a bifunctional catalyst for enhanced production of HMF from glucose in water

Herein, we report a synthetic route for the preparation of hybrid-organic-inorganic anatase (hybrid-TiO2) via a facile hydrothermal synthesis method employing citric acid. The synthetic approach results in a high surface area nanocrystalline anatase polymorph of TiO2. The uncalcined hybrid-TiO2 is directly studied here as the catalyst for the conversion of glucose into HMF. In the presence of the hybrid-TiO2, HMF yields up to 45% at glucose conversions up to 75% were achieved in water at 130 oC in a monophasic batch reactor. As identified by Ti K-edge XANES, hybrid-TiO2 contains a large fraction of five-fold coordinatively unsaturated Ti(IV) sites, which act as the Lewis acid catalyst for the conversion of glucose into fructose. As citric acid is anchored in the structure of hybrid-TiO2, carboxylate groups seem to catalyze the sequential conversion of fructose into HMF. The fate of citric acid bounded to anatase and the Ti(IV) Lewis acid sites throughout recycling experiments is also investigated. In a broader context, the contribution outlines the importance of hydrothermal synthesis for the creation of water-resistant Lewis acid sites for the conversion of sugars. Most importantly, the utilization of the hybrid-TiO2 with no calcination step contributes to dramatically decreasing the energy consumption in the catalyst preparation

Kinetics of immune responses to the AZD1222/Covishield vaccine with varying dose intervals in Sri Lankan individuals

Background To understand the kinetics of immune responses with different dosing gaps of the AZD1222 vaccine, we compared antibody and T cell responses in two cohorts with two different dosing gaps. Methods Antibodies to the SARS-CoV-2 virus were assessed in 297 individuals with a dosing gap of 12 weeks, sampled 12 weeks post second dose (cohort 1) and in 77 individuals with a median dosing gap of 21.4 weeks (cohort 2) sampled 6 weeks post second dose. ACE2-blocking antibodies (ACE2-blocking Abs), antibodies to the receptor-binding domain (RBD) of variants of concern (VOC), and ex vivo T cell responses were assessed in a subcohort. Results All individuals (100%) had SARS-CoV-2-specific total antibodies and 94.2% of cohort 1 and 97.1% of cohort 2 had ACE2-blocking Abs. There was no difference in antibody titers or positivity rates in different age groups in both cohorts. The ACE2-blocking Abs (p Conclusions Both dosing schedules resulted in high antibody and T cell responses post vaccination, although those with a longer dosing gap had a higher magnitude of responses, possibly as immune responses were measured 6 weeks post second dose compared to 12 weeks post second dose

Immune responses to Sinopharm/BBIBP-CorV in individuals in Sri Lanka

As there are limited data of the immunogenicity of the Sinopharm/BBIBP-CorV in different populations, antibody responses against different SARS-CoV-2 variants of concern and T cell responses, we investigated the immunogenicity of the vaccine, in individuals in Sri Lanka. SARS-CoV-2-specific antibodies were measured in 282 individuals who were seronegative at baseline, and ACE2 receptor blocking antibodies, antibodies to the receptor-binding domain (RBD) of the wild-type (WT), alpha, beta and delta variants, ex vivo and cultured IFNγ ELISpot assays, intracellular cytokine secretion assays and B cell ELISpot assays were carried out in a sub cohort of the vaccinees at 4 and 6 weeks (2 weeks after the second dose). Ninety-five percent of the vaccinees seroconverted, although the seroconversion rates were significantly lower (p 60 years (93.3%) compared to those who were 20–39 years (98.9%); 81.25% had ACE2 receptor blocking antibodies at 6 weeks, and there was no difference in these antibody titres in vaccine sera compared to convalescent sera (p = 0.44). Vaccinees had significantly less (

Effects of Eyjafjallajökull volcanic ash on innate immune system responses and bacterial growth in vitro.

To access publisher's full text version of this article click on the hyperlink at the bottom of the pageOn 20 March 2010, the Icelandic volcano Eyjafjallajökull erupted for the first time in 190 years. Despite many epidemiological reports showing effects of volcanic ash on the respiratory system, there are limited data evaluating cellular mechanisms involved in the response to ash. Epidemiological studies have observed an increase in respiratory infections in subjects and populations exposed to volcanic eruptions.We physicochemically characterized volcanic ash, finding various sizes of particles, as well as the presence of several transition metals, including iron. We examined the effect of Eyjafjallajökull ash on primary rat alveolar epithelial cells and human airway epithelial cells (20-100 µg/cm(2)), primary rat and human alveolar macrophages (5-20 µg/cm(2)), and Pseudomonas aeruginosa (PAO1) growth (3 µg/104 bacteria).Volcanic ash had minimal effect on alveolar and airway epithelial cell integrity. In alveolar macrophages, volcanic ash disrupted pathogen-killing and inflammatory responses. In in vitro bacterial growth models, volcanic ash increased bacterial replication and decreased bacterial killing by antimicrobial peptides.These results provide potential biological plausibility for epidemiological data that show an association between air pollution exposure and the development of respiratory infections. These data suggest that volcanic ash exposure, while not seriously compromising lung cell function, may be able to impair innate immunity responses in exposed individuals.National Institutes of Health (NIH) R01 HL079901 NIH RO1 HL096625 R21HL109589 National Science Foundation NSF-EAR0821615 National Institute of Environmental Health Sciences (NIEHS) through the University of Iowa Environmental Health Sciences Research Center NIEHS/NIH P30 ES005605 National Center for Research Resources, NI

Cytotoxicity of ZnO Nanoparticles Can Be Tailored by Modifying Their Surface Structure: A Green Chemistry Approach for Safer Nanomaterials

ZnO nanoparticles (NP) are extensively used in numerous nanotechnology applications; however, they also happen to be one of the most toxic nanomaterials. This raises significant environmental and health concerns and calls for the need to develop new synthetic approaches to produce safer ZnO NP, while preserving their attractive optical, electronic, and structural properties. In this work, we demonstrate that the cytotoxicity of ZnO NP can be tailored by modifying their surface-bound chemical groups, while maintaining the core ZnO structure and related properties. Two equally sized (9.26 ± 0.11 nm) ZnO NP samples were synthesized from the same zinc acetate precursor using a forced hydrolysis process, and their surface chemical structures were modified by using different reaction solvents. X-ray diffraction and optical studies showed that the lattice parameters, optical properties, and band gap (3.44 eV) of the two ZnO NP samples were similar. However, FTIR spectroscopy showed significant differences in the surface structures and surface-bound chemical groups. This led to major differences in the zeta potential, hydrodynamic size, photocatalytic rate constant, and more importantly, their cytotoxic effects on Hut-78 cancer cells. The ZnO NP sample with the higher zeta potential and catalytic activity displayed a 1.5-fold stronger cytotoxic effect on cancer cells. These results suggest that by modifying the synthesis parameters/conditions and the surface chemical structures of the nanocrystals, their surface charge density, catalytic activity, and cytotoxicity can be tailored. This provides a green chemistry approach to produce safer ZnO NP

Gravity-driven transport of three engineered nanomaterials in unsaturated soils and their effects on soil pH and nutrient release

The gravity-driven transport of TiO2, CeO2, and Cu(OH)2 engineered nanomaterials (ENMs) and their effects on soil pH and nutrient release were measured in three unsaturated soils. ENM transport was found to be highly limited in natural soils collected from farmland and grasslands, with the majority of particles being retained in the upper 0-3 cm of the soil profile, while greater transport depth was seen in a commercial potting soil. Physical straining appeared to be the primary mechanism of retention in natural soils as ENMs immediately formed micron-scale aggregates, which was exacerbated by coating particles with Suwannee River natural organic matter (NOM) which promote steric hindrance. Small changes in soil pH were observed in natural soils contaminated with ENMs that were largely independent of ENM type and concentration, but differed from controls. These changes may have been due to enhanced release of naturally present pH-altering ions (Mg(2+), H(+)) in the soil via substitution processes. These results suggest ENMs introduced into soil will likely be highly retained near the source zone