University of Ruhuna

Matthews J., Veliz L., Gunawardane R., Partridge D.

Theorizing teacher identity is an important component of effective language teacher education. The current study maps the professional identities of 20 practicing teachers of English as an additional language (EAL) from two distinct contexts: Sri Lanka ( n = 10) and Australia ( n = 10). Data tapping each participant’s professional identity was elicited with semi-structured interviews structured around three domains: personal experience, professional context and external political environment. From the resultant teacher discourse, thematic analysis was applied to identify nine themes that teachers from both contexts perceived as being influential in the development of their professional identities, with two of these themes being perceived by some teachers as being of limited or no influence. These themes are defined and elucidated with quotes. Key differences in the way themes were manifested among the Sri Lankan and Australian teachers are also described. Findings provide a reference for language teachers’ critical reflection on their professional identities, especially those at the beginning of their careers.

Ahamed A., Samaranayake P., Silva V.D., Kooh M.R., Wickramage N., Rajapaksha I.G., Thotagamuge R.

This study investigates the pH-responsive dissociation mechanism of carbon dot (CD) conjugated with the anticancer peptide proximicin-A (PROXI) using density functional theory (DFT) simulations. The CD@PROXI system, designed for targeted cancer therapy, releases the drug in acidic environments typical of cancer sites. DFT simulations, with the B3LYP-D3BJ functional and 6-311G (d, p) basis set, optimized the conjugate’s geometry under neutral and acidic conditions. The focus was on the pH-sensitive C=N bond, existing in two protonation states. Key parameters evaluated included the HOMO-LUMO gap, bond length, IR spectroscopy, non-covalent interaction (NCI), electron localization function (ELF), density of states (DOSs), and electrostatic potential (ESP). Under neutral pH, the system showed stability with a HOMO-LUMO gap of 3.22 eV, indicating low reactivity. In acidic pH, this gap decreased to 0.40 eV, suggesting higher reactivity and potential for drug release. IR spectroscopy indicated weakened C=N bonds in acidic conditions, with bond length increasing from 1.288 Å to 1.324 Å. NCI analysis revealed increased van der Waals interactions, supporting bond weakening. ELF analysis showed electron localization at reactive sites, while DOS profiles and ESP maps highlighted distinct electronic states and potential dissociation regions in acidic conditions. These findings confirm the potential of CD@PROXI for targeted cancer therapy, with drug release triggered by the acidic tumor microenvironment.

Tumasyan A., Adam W., Andrejkovic J.W., Bergauer T., Chatterjee S., Damanakis K., Dragicevic M., Escalante Del Valle A., Frühwirth R., Jeitler M., Krammer N., Lechner L., Liko D., Mikulec I., Paulitsch P., et. al.

Abstract A search is presented for the resonant production of a pair of standard model-like Higgs bosons using data from proton-proton collisions at a centre-of-mass energy of 13 TeV, collected by the CMS experiment at the CERN LHC in 2016–2018, corresponding to an integrated luminosity of 138 fb −1. The final state consists of two b quark-antiquark pairs. The search is conducted in the region of phase space where at least one of the pairs is highly Lorentz-boosted and is reconstructed as a single large-area jet. The other pair may be either similarly merged or resolved, the latter reconstructed using two b-tagged jets. The data are found to be consistent with standard model processes and are interpreted as 95% confidence level upper limits on the product of the cross sections and the branching fractions of the spin-0 radion and the spin-2 bulk graviton that arise in warped extradimensional models. The limits set are in the range 9.74–0.29 fb and 4.94–0.19 fb for a narrow radion and a graviton, respectively, with masses between 1 and 3 TeV. For a radion and for a bulk graviton with widths 10% of their masses, the limits are in the range 12.5–0.35 fb and 8.23–0.23 fb, respectively, for the same masses. These limits result in the exclusion of a narrow-width graviton with a mass below 1.2 TeV, and of narrow and 10%-width radions with masses below 2.6, and 2.9 TeV, respectively.

Hayrapetyan A., Tumasyan A., Adam W., Andrejkovic J.W., Bergauer T., Chatterjee S., Damanakis K., Dragicevic M., Hussain P.S., Jeitler M., Krammer N., Li A., Liko D., Mikulec I., Schieck J., et. al.

Abstract A search for long-lived heavy neutral leptons (HNLs) using proton-proton collision data corresponding to an integrated luminosity of 138 fb −1 collected at $$ \sqrt{s} $$ s = 13 TeV with the CMS detector at the CERN LHC is presented. Events are selected with a charged lepton originating from the primary vertex associated with the proton-proton interaction, as well as a second charged lepton and a hadronic jet associated with a secondary vertex that corresponds to the semileptonic decay of a long-lived HNL. No excess of events above the standard model expectation is observed. Exclusion limits at 95% confidence level are evaluated for HNLs that mix with electron and/or muon neutrinos. Limits are presented in the mass range of 1–16.5 GeV, with excluded square mixing parameter values reaching as low as 2 × 10 −7. For masses above 11 GeV, the presented limits exceed all previous results in the semileptonic decay channel, and for some of the considered scenarios are the strongest to date.

Tennakoon A., Galahitigama H., Samarakoon S.M., Perera I.J., Thakshila G.P., Thiruketheeswaranathan S., Roshana M.R., Sandamal S., Sewwandi G.P., Bellanthudawa B.K.

Weerakoon T., Halloluwa T.

Cricket, a sport steeped in history with a well-established governing body and thriving economy, places immense importance on selecting winning team combinations comprising batsmen, bowlers, and all-rounders. The traditional selection process is meticulous but often biased. This study proposes a data-driven approach utilizing historic match data under complex dynamics for optimal team selection in cricket. Secondary data from Sri Lankan One Day International matches since 2009 was feature-engineered, including derived pitch conditions from historic pitch report data. A neural network with 7 dense layers, using 7 input features and classifying into three outputs, achieved a 76% performance under an 80:20 split on training and testing data for 100 epochs. Additionally, three Fuzzy Inference Systems were developed for player rating based on historic performances, achieving accuracies of 75%, 67%, and 62% for Batting Performance FIS, Bowling Performance FIS, and All-rounder Performance FIS, respectively. Despite inheriting a data imbalance problem and unmeasurable attributes such as psychological and physiological aspects, the study's deliverables serve as decision support models for cricket team selection. Future work should focus on empirical methodologies to enhance the performance of neural network models and Fuzzy Logic Inference Systems, ensuring a more adaptable squad selection model in cricket.

Hayrapetyan A., Tumasyan A., Adam W., Andrejkovic J. ., Bergauer T., Chatterjee S., Damanakis K., Dragicevic M., Hussain P. ., Jeitler M., Krammer N., Li A., Liko D., Mikulec I., Schieck J., et. al.

A search is presented for an extended Higgs sector with two new particles, X and ϕ, in the process X→ϕϕ→(γγ)(γγ). Novel neural networks classify events with diphotons that are merged and determine the diphoton masses. The search uses LHC proton-proton collision data at s=13  TeV collected with the CMS detector, corresponding to an integrated luminosity of 138  fb−1. No evidence of such resonances is seen. Upper limits are set on the production cross section for mX between 300 and 3000 GeV and mϕ/mX between 0.5% and 2.5%, representing the most sensitive search in this channel. © 2025 CERN, for the CMS Collaboration 2025 CERN

Kajakokulan P., Santoso A., Zhao S.

Many studies have highlighted an asymmetry in rainfall anomalies over India between the warm phase (El Niño) and the cold phase (La Niña) of the El Niño-Southern Oscillation (ENSO). However, the extent to which the distinctive phases of ENSO influence the asymmetry pattern of Sri Lanka rainfall remains unclear. In this study, utilizing observational/reanalysis datasets for the period 1981–2022, we found that Sri Lanka's winter rainfall response to El Niño/La Niña is asymmetric, with a significant response during El Niño. During the El Niño peak winter, the presence of PSAC (Philippine Sea anomalous anticyclone) results in the prevailing anticyclone over the Bay of Bengal (BoB), suppressing moisture convergence and rainfall over Sri Lanka. On the other hand, the PSCC (Philippine Sea anomalous cyclone), which has shifted westward during the La Niña. This shift enhances cyclone over the BoB, resulting in enhanced moisture convergence and rainfall over Sri Lanka, with a magnitude that is weaker than that of the El Niño-induced PSAC. This results in the emergence of asymmetric rainfall anomaly patterns in Sri Lanka in the El Niño and La Niña peak phases. Thus, this study highlights that the asymmetric circulation of PSAC/PSCC during the ENSO phenomenon contributes to the observed asymmetry in rainfall anomalies between El Niño and La Niña events and has important implications for seasonal forecasting.

Hayrapetyan A., Tumasyan A., Adam W., Andrejkovic J. ., Bergauer T., Chatterjee S., Damanakis K., Dragicevic M., Escalante Del Valle A., Hussain P. ., Jeitler M., Krammer N., Liko D., Mikulec I., Schieck J., et. al.

A search is performed for charged-lepton flavor violating processes in top quark (t) production and decay. The data were collected by the CMS experiment from proton-proton collisions at a center-of-mass energy of 13 TeV and correspond to an integrated luminosity of 138  fb−1. The selected events are required to contain one opposite-sign electron-muon pair, a third charged lepton (electron or muon), and at least one jet of which no more than one is associated with a bottom quark. Boosted decision trees are used to distinguish signal from background, exploiting differences in the kinematics of the final states particles. The data are consistent with the standard model expectation. Upper limits at 95% confidence level are placed in the context of effective field theory on the Wilson coefficients, which range between 0.024–0.424  TeV−2 depending on the flavor of the associated light quark and the Lorentz structure of the interaction. These limits are converted to upper limits on branching fractions involving up (charm) quarks, t→eμu (t→eμc), of 0.032(0.498)×10−6, 0.022(0.369)×10−6, and 0.012(0.216)×10−6 for tensorlike, vectorlike, and scalarlike interactions, respectively. © 2025 CERN, for the CMS Collaboration 2025 CERN

Rajakulasooriya R.S., Fernando S.S., Gunasekara T.D., Jayaweera P.M., Kumarasinghe K.G., Thabrew H.H., Chan E., Buddhika R.B., Weerasinghe G.G., Karunarathna K.A.

Dermatophytes, the primary causative agents of superficial cutaneous fungal infections in humans, present a significant therapeutic challenge owing to the increasing prevalence of recurrent infections and the emergence of antifungal resistance. To address this critical gap, this study was designed to investigate the antifungal potential of 3-benzylideneindolin-2-one against dermatophytes and assess its in vivo toxicological profile using brine shrimp and zebrafish embryo models. The antifungal activity of 3-benzylideneindolin-2-one was evaluated against 30 clinical isolates of dermatophyte species, including Trichophyton mentagrophytes, Trichophyton rubrum, Microsporum gypseum, Microsporum canis, and Epidermophyton floccosum, by determining the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) using the broth microdilution method. The fungicidal activity was evaluated using time-kill assays. Toxicological effects were investigated using the brine shrimp lethality assay to determine Artemia salina nauplii mortality after 48 h of exposure, and the fish embryo acute toxicity test, which assessed lethality and developmental abnormalities in zebrafish (Danio rerio) embryos over a 96 h post-fertilization period. 3-Benzylideneindolin-2-one exhibited consistent fungicidal activity across all dermatophyte species, with MICs ranging from 0.25 to 8 mg/L and MFCs ranging from 1 to 32 mg/L. Time-kill assays revealed a concentration-dependent fungicidal effect on the microconidia. The compound exhibited moderate toxicity to A. salina nauplii, with LC50 values of 69.94 mg/L and 52.70 mg/L at 24 and 48 h, respectively, while showing no significant lethality within the MIC range. In zebrafish embryos, concentrations below 7.5 mg/L did not significantly affect lethality, hatchability, or induce morphological abnormalities. However, at a concentration of 10 mg/L, the compound induced mild toxicity in embryos, evidenced by a significant increase in mortality and the presence of morphological anomalies such as yolk-sac and pericardial edema compared to the control group. The consistent antifungal activity of 3-benzylideneindolin-2-one against clinically significant dermatophyte species, combined with its low toxicity within the therapeutic window, underscores its potential as a promising lead compound for the development of effective therapeutics for dermatophytosis.

Kusuminda T., Chandrathilake G.G., Abegunawardhana P.D., Abeyrathne S., Senthila V.T., Amarasinghe C., Mannakkara A., Yapa W.B.

Abstract Tickell’s bat (Hesperoptenus tickelli) is a medium-sized bat belonging to the family Vespertilionidae. This species was rarely recorded in recent surveys in its range. Similarly, this species has not been recorded in Sri Lanka since 1963. Further, it is assumed to roost in dense foliage of tall trees. We report three opportunistic records of this species from Sri Lanka after 58 years, along with notes on its roosting ecology. We highlight the importance of comprehensive studies on the life history of this species for better conservation and management.

Kumar R., Pan C., Lin Y., Shiue Y., Chung T., Janesha U.G.

Background: The global burden of respiratory diseases such as influenza, tuberculosis, and viral pneumonia necessitates rapid, accurate diagnostic tools to improve healthcare responses. Current methods, including RT-PCR and chest radiography, face limitations in accuracy, speed, accessibility, and cost-effectiveness, especially in resource-constrained settings, often delaying treatment and increasing transmission. Methods: This study introduces an Enhanced Multi-Model Deep Learning (EMDL) approach to address these challenges. EMDL integrates an ensemble of five pre-trained deep learning models (VGG-16, VGG-19, ResNet, AlexNet, and GoogleNet) with advanced image preprocessing (histogram equalization and contrast enhancement) and a novel multi-stage feature selection and optimization pipeline (PCA, SelectKBest, Binary Particle Swarm Optimization (BPSO), and Binary Grey Wolf Optimization (BGWO)). Results: Evaluated on two independent chest X-ray datasets, EMDL achieved high accuracy in the multiclass classification of influenza, pneumonia, and tuberculosis. The combined image enhancement and feature optimization strategies significantly improved diagnostic precision and model robustness. Conclusions: The EMDL framework provides a scalable and efficient solution for accurate and accessible pulmonary disease diagnosis, potentially improving treatment efficacy and patient outcomes, particularly in resource-limited settings.

Hayrapetyan A., Tumasyan A., Adam W., Andrejkovic J.W., Bergauer T., Chatterjee S., Damanakis K., Dragicevic M., Hussain P.S., Jeitler M., Krammer N., Li A., Liko D., Mikulec I., Schieck J., et. al.

Abstract The first measurement of the inclusive and normalised differential cross sections of single top quark production in association with a W boson in proton-proton collisions at a centre-of-mass energy of 13.6 TeV is presented. The data were recorded with the CMS detector at the LHC in 2022, and correspond to an integrated luminosity of 34.7 fb −1. The analysed events contain one muon and one electron in the final state. For the inclusive measurement, multivariate discriminants exploiting the kinematic properties of the events are used to separate the signal from the dominant top quark-antiquark production background. A cross section of $$ 82.3\pm 2.1{\left(\textrm{stat}\right)}_{-9.7}^{+9.9}\left(\textrm{syst}\right)\pm 3.3\left(\textrm{lumi}\right) $$ 82.3 ± 2.1 stat − 9.7 + 9.9 syst ± 3.3 lumi pb is obtained, consistent with the predictions of the standard model. A fiducial region is defined according to the detector acceptance to perform the differential measurements. The resulting differential distributions are unfolded to particle level and show good agreement with the predictions at next-to-leading order in perturbative quantum chromodynamics.

Dilanthi H.W., Jayasena K.L., Dhammika N.D., Indika N.L., De Silva M.M., Kankananarachchi I., Punchihewa P.M., Irugalbandara D., Schroeder S., Karunaratne K., Jasinge E.

ABSTRACTHomocystinuria due to cystathionine beta‐synthase (CBS) deficiency is a rare metabolic disorder inherited as an autosomal recessive trait. Spectrum of genetic variants in CBS gene and their correlation with the phenotypes of homocystinuria in Sri Lankan patients have not been reported to date. The objective of this study was to identify the genotypes and genotype–phenotype correlations in a cohort of Sri Lankan patients with homocystinuria due to CBS deficiency. We determined the variants in CBS gene in 14 Sri Lankan patients with homocystinuria, from 9 unrelated families. The clinical features and the biochemical response to pyridoxine were studied for further correlations. Among the 14 patients, the common clinical features were ectopia lentis (100%), intellectual disability (92%) and marfanoid features (78%) at presentation while three of them had developed osteoporosis (21%). Median age at diagnosis was 8 years (range 2–12). Three pathogenic variants (c.1006C>T, c.785C>T and c.19del) and two likely pathogenic variants (c.869C>T, c.772G>A) in CBS gene were identified. Thirteen patients with homozygous genotypes were non‐responsive to pyridoxine while the only patient with the compound heterozygous genotype (c.869C>T/c.772G>A) responded to pyridoxine treatment. The genotypic spectrum observed in Sri Lankan patients is unique and mostly associated with pyridoxine non‐responsiveness. The majority of the patients were identified clinically at a later stage of the disease due to lack of a screening programme in the country. Therefore, it is important to improve the awareness of the disease among the clinicians in the interest of early diagnosis and early commencement of metabolic treatment.

Kajakokulan P.

Recent studies have shown that the Pacific-Japan (PJ) pattern is the dominant climate mode and has a relationship with rainfall anomalies in East Asia. However, the influence of the PJ pattern on the rainfall of Sri Lanka remains largely unclear. Therefore, the present study examines the impact of the PJ pattern on the rainfall of Sri Lanka during the boreal summer utilizing observational and reanalysis datasets from 1981 to 2020. It is noted that the PJ pattern has a significant positive relationship with rainfall in Sri Lanka during the boreal summer. Furthermore, based on the composite analysis, we found that Sri Lanka experiences wet conditions during the positive phase of the PJ pattern in the summer, while the negative phase of the PJ pattern contributes to dry conditions. During the positive phase of the PJ pattern, moisture convergence over Sri Lanka is associated with the easterlies extending from the southern flank of Western North Pacific anomalous anticyclonic circulation, which results in enhanced convection and wet conditions over Sri Lanka. On the other hand, moisture divergence over Sri Lanka is linked with the westerlies extending from the southern flank of the Western North Pacific anomalous cyclonic circulation, decreasing the convection and dry conditions over Sri Lanka. This study suggests that the PJ pattern is a significant climate mode for understanding the rainfall pattern in Sri Lanka.