Novel approach to the derivation of dam breach parameters in 2D hydrodynamic modeling of earthquake induced dam failures.

Current methods of dam breach analyses adopt a deterministic approach. Applying these methods to Concrete Faced Rockfill Dams (CFRD) is fraught with huge levels of uncertainty, especially in the context of natural hazards. The frequency and magnitude of rainfall and earthquakes are higher in today's world. In the literature, the complete collapse of dams is modelled on dam breach parameters that define the dam break outflow but are not related to the return periods of natural hazards. As more new dams are constructed to control the floods in intra-plate seismic regions, this study presents a novel approach to the derivation of generalized dam break parameters for CFRD based on the structural analysis of Finite Element Model (FEM) simulations for peak ground accelerations corresponding to 475 and 2475 year return periods. Furthermore, the occurrence of rainfall and earthquake for different return periods are modelled using 2D hydrodynamic simulations. Results show the significance of generalized dam breach parameters for planning and managing CFRDs during earthquakes. The study emphasizes the utilization of structural analysis outputs for the hydraulic modeling of dam breaks, which will result in more specific and accurate dam break parameters. Additionally, the study has shown that the flood risk and the severity will increase with the intensity of earthquake and rainfall magnitudes. Disaster mitigation strategies can be optimized by considering the integrated occurrence of rainfall and earthquakes based on the probability of occurrence, demonstrated using a case-study dam. Another significant outcome of the study is the effect of soil saturation condition during a dam break, which reveals that areas within 40 km of the dam breach location might be worst affected.

Vertical variation of bacterial production and potential role in oxygen loss in the southern Bay of Bengal.

Marine environments wherein long-term microbial oxygen consumption exceeds oxygen replenishment can be associated with oxygen minimum zones (OMZ). The Bay of Bengal OMZ (BOB-OMZ) is one of the most intense OMZs globally. To assess the contribution of bacterial oxygen consumption to oxygen loss in BOB-OMZ, we measured bacterial production (BP), temperature, salinity, and dissolved oxygen (DO) in the whole water column. We then compared the estimated bacterial oxygen demand (BOD) with diapycnal oxygen supply (DOS) at depths of 50-200 m in the southern BOB in January 2020. The average BP was 3.53 ± 3.15 µmol C m-3 h-1 in the upper 200 m of four stations, which was lower than those reported in other tropical waters. The vertical distribution of BP differed between the open ocean and nearshore areas. In the open ocean, temperature and DO were the most important predictors for BP in the whole water column. In the nearshore areas, when DO increased sharply from the suboxic state, extremely high BP occurred at 200 m. The average estimated BOD/DOS could reach up to 153% at depths of 50-200 m, indicating advection and anticyclonic eddies probably are important DO replenishment pathways in the BOB.

Impact of clinical note format on diagnostic accuracy and efficiency.

BACKGROUND: Clinician notes are structured in a variety of ways. This research pilot tested an innovative study design and explored the impact of note formats on diagnostic accuracy and documentation review time. OBJECTIVE: To compare two formats for clinical documentation (narrative format vs. list of findings) on clinician diagnostic accuracy and documentation review time. METHOD: Participants diagnosed written clinical cases, half in narrative format, and half in list format. Diagnostic accuracy (defined as including correct case diagnosis among top three diagnoses) and time spent processing the case scenario were measured for each format. Generalised linear mixed regression models and bias-corrected bootstrap percentile confidence intervals for mean paired differences were used to analyse the primary research questions. RESULTS: Odds of correctly diagnosing list format notes were 26% greater than with narrative notes. However, there is insufficient evidence that this difference is significant (75% CI 0.8-1.99). On average the list format notes required 85.6 more seconds to process and arrive at a diagnosis compared to narrative notes (95% CI -162.3, -2.77). Of cases where participants included the correct diagnosis, on average the list format notes required 94.17 more seconds compared to narrative notes (75% CI -195.9, -8.83). CONCLUSION: This study offers note format considerations for those interested in improving clinical documentation and suggests directions for future research. Balancing the priority of clinician preference with value of structured data may be necessary. IMPLICATIONS: This study provides a method and suggestive results for further investigation in usability of electronic documentation formats.

Exploring Variability of Trichodesmium Photophysiology Using Multi-Excitation Wavelength Fast Repetition Rate Fluorometry.

Fast repetition rate fluorometry (FRRf) allows for rapid non-destructive assessment of phytoplankton photophysiology in situ yet has rarely been applied to Trichodesmium. This gap reflects long-standing concerns that Trichodesmium (and other cyanobacteria) contain pigments that are less effective at absorbing blue light which is often used as the sole excitation source in FRR fluorometers-potentially leading to underestimation of key fluorescence parameters. In this study, we use a multi-excitation FRR fluorometer (equipped with blue, green, and orange LEDs) to investigate photophysiological variability in Trichodesmium assemblages from two sites. Using a multi-LED measurement protocol (447+519+634 nm combined), we assessed maximum photochemical efficiency (F v /F m ), functional absorption cross section of PSII (σ PSII ), and electron transport rates (ETRs) for Trichodesmium assemblages in both the Northwest Pacific (NWP) and North Indian Ocean in the vicinity of Sri Lanka (NIO-SL). Evaluating fluorometer performance, we showed that use of a multi-LED measuring protocol yields a significant increase of F v /F m for Trichodesmium compared to blue-only excitation. We found distinct photophysiological differences for Trichodesmium at both locations with higher average F v /F m as well as lower σ PSII and non-photochemical quenching (NPQ NSV ) observed in the NWP compared to the NIO-SL (Kruskal-Wallis t-test df = 1, p < 0.05). Fluorescence light response curves (FLCs) further revealed differences in ETR response with a lower initial slope (α ETR ) and higher maximum electron turnover rate ( E T R P S I I m a x ) observed for Trichodesmium in the NWP compared to the NIO-SL, translating to a higher averaged light saturation E K (= E T R P S I I m a x /α ETR ) for cells at this location. Spatial variations in physiological parameters were both observed between and within regions, likely linked to nutrient supply and physiological stress. Finally, we applied an algorithm to estimate primary productivity of Trichodesmium using FRRf-derived fluorescence parameters, yielding an estimated carbon-fixation rate ranging from 7.8 to 21.1 mgC mg Chl-a-1 h-1 across this dataset. Overall, our findings demonstrate that capacity of multi-excitation FRRf to advance the application of Chl-a fluorescence techniques in phytoplankton assemblages dominated by cyanobacteria and reveals novel insight into environmental regulation of photoacclimation in natural Trichodesmium populations.

An unusual case of gross myoglobinuria in a child following Russell's viper (Daboia russelii) envenomation.

Overt myoglobinuria associated with myotoxicity is a classic feature of sea snake envenomation. Russell's viper bites usually result in coagulopathy, neurotoxicity and nephrotoxicity but rarely myotoxicity has been reported, especially in the Sri Lankan variety (Daboia russelii). All those studies have demonstrated mild degree myotoxicity with microscopic level myoglobinuria. We report what is probably the first case of gross myoglobinuria in a child following a Russell's viper bite with biochemical evidence of significant myotoxicity well beyond the levels that have been previously reported.

High-dose intravenous metoprolol usage for reducing heart rate at CT coronary angiography: efficacy and safety.

AIM: To evaluate the usage, safety, and efficacy of high-dose intravenous metoprolol for heart rate reduction in computer tomographic (CT) coronary angiography. MATERIALS AND METHODS: As this was retrospective analysis of anonymous data, medical ethics committee approval was waived by the regional health research authority. Patients, who had known iodinated contrast medium allergy, contraindications to ß-blockers, atrial fibrillation, and indications other than suspected coronary artery disease, were excluded from analysis. The ultimate study population of 662 were analysed with details of intravenous metoprolol doses, complications, heart rate before administration of intravenous metoprolol (resting heart rate, RHR), heart rate at acquisition of scan (acquisition heart rate, AHR), and usage of low radiation dose protocols. RESULTS: Of the ultimate study population of 662 patients, 183 had no intravenous metoprolol with mean acquisition heart rate (AHR) of 58 beats per minute (bpm), 257 had 1-15 mg intravenous metoprolol with mean AHR of 57 bpm, 114 had 16-29 mg intravenous metoprolol with mean AHR of 62 bpm and 108 had ≥30 mg intravenous metoprolol with mean AHR of 66 bpm. In the group receiving intravenous metoprolol, average usage was 19 mg (maximum 67 mg) with average reduction in HR of 15 bpm. There were no clinical incidents in relation to the use of high-dose intravenous metoprolol. CONCLUSION: Higher doses of intravenous metoprolol are beneficial in achieving target heart rates to facilitate usage of low radiation dose protocols. With appropriate exclusion criteria, higher doses of intravenous metoprolol, well in excess of 15 mg, can be safely administered when carefully titrated.

Auditory event-related potential changes in chronic occupational exposure to organophosphate pesticides.

OBJECTIVE: To determine whether chronic occupational exposure to organophosphates (OP) pesticides leads to cognitive impairment using event-related potentials (ERPs). METHODS: ERPs of 38 vegetable farmers applying OP pesticides and 35 controls were recorded using an auditory oddball paradigm. The N1, P2, N2 and P300 ERP components and the number of counting errors were compared between the groups. RESULTS: The farmers made significantly more counting errors than controls in the oddball task. The mixed model ANOVA of component latencies revealed a significant componentxgroup interaction, suggesting farmers had a greater delay in later ERP components. Intergroup comparisons of individual components showed significant delays in N2 and P300 latencies. Subsequent ANCOVA showed significant P300 delay even after adjusting for the latency of the preceding component, N2. Intergroup differences of P300 amplitudes were not significant, although there was limited evidence of a difference in scalp topography. CONCLUSION: Our findings indicate that chronic low-level occupational exposure to OP pesticides is associated with progressively increasing delay in successive ERP components, particularly P300. SIGNIFICANCE: Chronic exposure to OP pesticides may delay the neurophysiological processes underlying early stages of selective attention and late stages of sensory information processing that include stimulus evaluation and updating of working memory.

Terminal triplication of the left vertebral artery: a unique variation.

SUMMARY: This report describes a unique case of triplication of the terminal left vertebral artery, forming the basilar artery in a 75-year-old male. CT angiography of cranio-cervical vessels also demonstrated the right vertebral artery originating from the right common carotid and an aberrant right subclavian artery.To the best of our knowledge this is the first report of a variation of this nature. The embryology and the clinical importance are discussed.

Acute myocardial infarction in a patient with Russell's viper bite.

We describe a previously healthy patient who developed and acute anterolateral Q wave myocardial infarction after a Russell's viper bite. Severe chest pain persisted despite intravenous morphine and polyspecific antivenom therapy. The pain subsided with intravenous heparin. The patient recovered.

A study of meconium staining and meconium aspiration syndrome in a maternity hospital.

OBJECTIVE: To determine the incidence of meconiumstaining and meconium aspiration syndrome in a maternity hospital in Colombo and to evolve a suitable protocol for management. DESIGN: A prospective study of 366 meconium stained babies delivered during 1988. SETTING: Castle Street Hospital for Women, Colombo. OUTCOME: 113 babies developed the 'meconium aspiration syndrome' and 16 of them died.