A trendline and predictive analysis of the first-wave COVID-19 infections in Malta

Following the first COVID-19 infected cases, Malta rapidly imposed strict lockdown measures, including restrictions on international travel, together with national social distancing measures, such as prohibition of public gatherings and closure of workplaces. The study aimed to elucidate the effect of the intervention and relaxation of the social distancing measures upon the infection rate by means of a trendline analysis of the daily case data. In addition, the study derived a predictive model by fitting historical data of the SARS-CoV-2 positive cases within a two-parameter Weibull distribution, whilst incorporating swab-testing rates, to forecast the infection rate at minute computational expense. The trendline analysis portrayed the wave of infection to fit within a tri-phasic pattern, where the primary phase was imposed with social measure interventions. Following the relaxation of public measures, the two latter phases transpired, where the two peaks resolved without further escalation of national measures. The derived forecasting model attained accurate predictions of the daily infected cases, attaining a high goodness-of-fit, utilising uncensored government-official infection-rate and swabbing-rate data within the first COVID-19 wave in Malta

Blade-explicit fluid structure interaction of a ducted high-solidity tidal turbine

This work elaborates a computational fluid dynamic (CFD) model utilised in the investigation of the structural performance concerning a ducted high-solidity tidal turbine in aligned and yawed inlet flows. Analysing the hydrodynamic performance at aligned flows portrayed the distinctive power curve at which energy is transferred via the fluid-structure interaction. At distinct bearing angles with the axis of the turbine, variations in the blade-interaction due to the presence of the duct was acknowledged within a limited angular range at distinct tip-speed ratio values. As a result of the hydrodynamic analysis, a structural investigation of the blades was discretely evaluated in an effort to acknowledge fluid-structure phenomena

A numerical structural analysis of ducted, high-solidity, fibre-composite tidal turbine rotor configurations in real flow conditions

Establishing a design and material evaluation of unique tidal turbine rotors in true hydrodynamic conditions by means of a numerical structural analysis has presented inadequacies in implementing spatial and temporal loading along the blade surfaces. This study puts forward a structural performance investigation of true-scale, ducted, high-solidity, fibre-composite tidal turbine rotor configurations in aligned and yawed flows by utilising outputs from unsteady blade-resolved computational fluid dynamic models as boundary condition loads within a finite-element numerical model. In implementation of the partitioned-approach fluid–structure interaction procedure, three distinct internal blade designs were analysed. Investigating criteria related to structural deformation and induced strains, hydrostatic & hydrodynamic analyses are put forward in representation of the rotor within the flow conditions at the installation depth. The resultant axial deflections for the proposed designs describe a maximum deflection-to-bladespan ratio of 0.04, inducing a maximum strain of 0.9%. A fatigue response analysis is undertaken to acknowledge the blade material properties required to prevent temporal failure

A numerical performance analysis of a ducted high-solidity tidal turbine

This study puts forward an investigation into the hydrodynamic performance concerning a ducted, high-solidity tidal turbine utilising blade-resolved computational fluid dynamics. The model achieves similarity values of over 0.96 with experimentation data regarding a three-bladed horizontal-axis tidal turbine in validation of three distinct parameters: power & torque coefficient, thrust coefficient, and wake velocity profiles. Accordingly, the model was employed for the analysis of a ducted, high-solidity turbine in axially-aligned flows at distinct free-stream velocities. The resultant hydrodynamic performance characteristics portrayed a peak power coefficient of 0.34, with a thrust coefficient of 0.97, at a nominal tip-speed ratio of 1.75. Coefficient trend agreement was attained between the numerical model and experimentation data established in literature and blade-element momentum theory; the model furthers the analysis by elaborating the temporal hydrodynamic features induced by the fluid-structure interaction in specification to the wake formation velocity profiles, pressure distribution along the blades and duct, mass flow rate, and vortex shedding effects to establish the characteristic flow physics of the tidal turbine

Numerically analysing liquid-cargo sloshing diminishment in partitioned rectangular tanks

This study puts forward an analysis of the influence of liquid sloshing upon oscillating vessels by means of numerical modeling. Rectangular cross-sectional tanks incorporating an open-bore and partitioned setups at 20%, 40%, and 60% fill-volume levels were implemented to establish the torque and static pressure exerted solely by the fluid dynamics upon oscillation within the tanks. Through verification of dam-break dynamics, the sloshing models coupled the explicit volume-of-fluid and non-iterative time-advancement schemes within a computational fluid dynamic solver. Utilising an oscillatory frequency of 1 Hz, the resultant liquid impact reduced within the partitioned setup due to the suppression of wave dynamics

A numerical analysis of dynamic slosh dampening utilising perforated partitions in partially-filled rectangular tanks

Conventional liquefied natural gas (LNG) cargo vessels are imposed with tank-fill limitations as precautions to prevent structural damage and stability-loss due to high-impact sloshing, enforcing cargo volume-fills to be lower than 10% or higher than 70% of the tank height. The restrictions, however, limit commercial operations, specifically when handling spot trades and offshore loading/unloading at multiple ports along a shipping route. The study puts forward a computational fluid dynamic (CFD) sloshing analysis of partially-filled chamfered rectangular tanks undergoing sinusoidal oscillatory kinetics with the use of the explicit volume-of-fluid and non-iterative time-advancement schemes utilising the commercial solver ANSYS-Fluent. Establishing a 20% to 60% fill-range, the sloshing dynamics were acknowledged within an open-bore, partitioned, and perforated-partitioned tank when oscillating at frequencies of 0.5 Hz and 1 Hz. The overall torque and static pressure induced on the tank walls were investigated. High-impact slamming at the tank roof occurred at 40% and 60% fills, however, the implementation of the partition and perforated-partition barriers successfully reduced the impact due to suppression and dissipation of the wave dynamics.peer-reviewe

Neural Network Mechanisms Underlying Stimulus Driven Variability Reduction

It is well established that the variability of the neural activity across trials, as measured by the Fano factor, is elevated. This fact poses limits on information encoding by the neural activity. However, a series of recent neurophysiological experiments have changed this traditional view. Single cell recordings across a variety of species, brain areas, brain states and stimulus conditions demonstrate a remarkable reduction of the neural variability when an external stimulation is applied and when attention is allocated towards a stimulus within a neuron's receptive field, suggesting an enhancement of information encoding. Using an heterogeneously connected neural network model whose dynamics exhibits multiple attractors, we demonstrate here how this variability reduction can arise from a network effect. In the spontaneous state, we show that the high degree of neural variability is mainly due to fluctuation-driven excursions from attractor to attractor. This occurs when, in the parameter space, the network working point is around the bifurcation allowing multistable attractors. The application of an external excitatory drive by stimulation or attention stabilizes one specific attractor, eliminating in this way the transitions between the different attractors and resulting in a net decrease in neural variability over trials. Importantly, non-responsive neurons also exhibit a reduction of variability. Finally, this reduced variability is found to arise from an increased regularity of the neural spike trains. In conclusion, these results suggest that the variability reduction under stimulation and attention is a property of neural circuits

Open‐label, clinical trial extension:Two‐year safety and efficacy results of seladelpar in patients with primary biliary cholangitis

SummaryBackgroundSeladelpar is a potent and selective peroxisome proliferator‐activated receptor‐δ agonist that targets multiple cell types involved in primary biliary cholangitis (PBC), leading to anti‐cholestatic, anti‐inflammatory and anti‐pruritic effects.AimsTo evaluate the long‐term safety and efficacy of seladelpar in patients with PBC.MethodsIn an open‐label, international, long‐term extension study, patients with PBC completing seladelpar lead‐in studies continued treatment. Seladelpar was taken orally once daily at doses of 5 or 10 mg with dose adjustment permitted for safety or tolerability. The primary analysis was for safety and the secondary efficacy analysis examined biochemical markers of cholestasis and liver injury. The study was terminated early due to the unexpected histological findings in a concurrent study for non‐alcoholic steatohepatitis, which were subsequently found to predate treatment. Safety and efficacy data were analysed through 2 years.ResultsThere were no serious treatment‐related adverse events observed among 106 patients treated with seladelpar for up to 2 years. There were four discontinuations for safety, one possibly related to seladelpar. Among 53 patients who completed 2 years of seladelpar, response rates increased from years 1 to 2 for the composite endpoint (alkaline phosphatase [ALP] &lt;1.67 × ULN, ≥15% decrease in ALP, and total bilirubin ≤ULN) and ALP normalisation from 66% to 79% and from 26% to 42%, respectively. In those with elevated bilirubin at baseline, 43% achieved normalisation at year 2.ConclusionsSeladelpar was safe, and markedly improved biochemical markers of cholestasis and liver injury in patients with PBC. These effects were maintained or improved throughout the second year. Clinicaltrials.gov: NCT03301506; Clinicaltrialsregister.eu: 2017‐003910‐16.</jats:sec

Open-label, clinical trial extension: Two-year safety and efficacy results of seladelpar in patients with primary biliary cholangitis

BACKGROUND: Seladelpar is a potent and selective peroxisome proliferator-activated receptor-δ agonist that targets multiple cell types involved in primary biliary cholangitis (PBC), leading to anti-cholestatic, anti-inflammatory and anti-pruritic effects. AIMS: To evaluate the long-term safety and efficacy of seladelpar in patients with PBC. METHODS: In an open-label, international, long-term extension study, patients with PBC completing seladelpar lead-in studies continued treatment. Seladelpar was taken orally once daily at doses of 5 or 10 mg with dose adjustment permitted for safety or tolerability. The primary analysis was for safety and the secondary efficacy analysis examined biochemical markers of cholestasis and liver injury. The study was terminated early due to the unexpected histological findings in a concurrent study for non-alcoholic steatohepatitis, which were subsequently found to predate treatment. Safety and efficacy data were analysed through 2 years. RESULTS: There were no serious treatment-related adverse events observed among 106 patients treated with seladelpar for up to 2 years. There were four discontinuations for safety, one possibly related to seladelpar. Among 53 patients who completed 2 years of seladelpar, response rates increased from years 1 to 2 for the composite endpoint (alkaline phosphatase [ALP] <1.67 × ULN, ≥15% decrease in ALP, and total bilirubin ≤ULN) and ALP normalisation from 66% to 79% and from 26% to 42%, respectively. In those with elevated bilirubin at baseline, 43% achieved normalisation at year 2. CONCLUSIONS: Seladelpar was safe, and markedly improved biochemical markers of cholestasis and liver injury in patients with PBC. These effects were maintained or improved throughout the second year

Probabilistic change detection and visualization methods for the assessment of temporal stability in biomedical data quality

The final publication is available at Springer via http://dx.doi.org/DOI 10.1007/s10618-014-0378-6. Published online.Knowledge discovery on biomedical data can be based on on-line, data-stream analyses, or using retrospective, timestamped, off-line datasets. In both cases, changes in the processes that generate data or in their quality features through time may hinder either the knowledge discovery process or the generalization of past knowledge. These problems can be seen as a lack of data temporal stability. This work establishes the temporal stability as a data quality dimension and proposes new methods for its assessment based on a probabilistic framework. Concretely, methods are proposed for (1) monitoring changes, and (2) characterizing changes, trends and detecting temporal subgroups. First, a probabilistic change detection algorithm is proposed based on the Statistical Process Control of the posterior Beta distribution of the Jensen–Shannon distance, with a memoryless forgetting mechanism. This algorithm (PDF-SPC) classifies the degree of current change in three states: In-Control, Warning, and Out-of-Control. Second, a novel method is proposed to visualize and characterize the temporal changes of data based on the projection of a non-parametric information-geometric statistical manifold of time windows. This projection facilitates the exploration of temporal trends using the proposed IGT-plot and, by means of unsupervised learning methods, discovering conceptually-related temporal subgroups. Methods are evaluated using real and simulated data based on the National Hospital Discharge Survey (NHDS) dataset.The work by C Saez has been supported by an Erasmus Lifelong Learning Programme 2013 Grant. This work has been supported by own IBIME funds. 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