Global multimodel wave climate projections are obtained at 1.0° × 1.0° scale from 30 Coupled Model Intercomparison Project Phase 5 (CMIP5) global circulation model (GCM) realizations. A ...semi‐supervised weather‐typing approach based on a characterization of the ocean wave generation areas and the historical wave information from the recent GOW2 database are used to train the statistical model. This framework is also applied to obtain high resolution projections of coastal wave climate and coastal impacts as port operability and coastal flooding. Regional projections are estimated using the collection of weather types at spacing of 1.0°. This assumption is feasible because the predictor is defined based on the wave generation area and the classification is guided by the local wave climate. The assessment of future changes in coastal impacts is based on direct downscaling of indicators defined by empirical formulations (total water level for coastal flooding and number of hours per year with overtopping for port operability). Global multimodel projections of the significant wave height and peak period are consistent with changes obtained in previous studies. Statistical confidence of expected changes is obtained due to the large number of GCMs to construct the ensemble. The proposed methodology is proved to be flexible to project wave climate at different spatial scales. Regional changes of additional variables as wave direction or other statistics can be estimated from the future empirical distribution with extreme values restricted to high percentiles (i.e., 95th, 99th percentiles). The statistical framework can also be applied to evaluate regional coastal impacts integrating changes in storminess and sea level rise.
Key Points
Statistical global multimodel wave climate projections under different representative concentration pathways
The proposed global statistical downscaling framework allows an easy regional projection of wave climate
Climate change coastal impact assessment based on downscaling impact indicators using the global statistical framework
Quadrotors are highly maneuverable lightweight drones, which are prone to aerodynamic disturbances, vibrations, and uncertainties. These factors stand for a problem that demands robust control laws. ...For position tracking, the control problem is exacerbated, because the plant is underactuated in the coordinates of interest, requiring a high-performance attitude tracking to resolve underactuation. In this brief, a novel fractional-order controller is proposed by considering a well-posed map that relates the position/yaw control to the desired attitude references. The attitude control is continuous and enforces and sustains a sliding motion in finite time for exponential convergence of the tracking errors to fulfill a "virtual" position controller. The resulting closed-loop system is robust against the continuous disturbances that are not necessarily differentiable in the conventional sense. A numerical study based on the simulations is presented to analyze the advantages of the fractional actions to design a physically realizable controller, and the experiments are discussed to expose the reliability of the proposed fractional scheme implemented in an "X" configuration quadrotor.
Recent advances in the description of environmental and geophysical extreme events allow incorporating smooth time variations for the parameters of the GEV distribution using harmonic functions, ...long-term trends and covariates (North Atlantic Oscillation, El Niño, etc.). Most of the proposed models rely on the maximum likelihood estimation method for a given parameterization. However, finding the best parameter selection for each case is not an easy task, since the number of possible combinations grows exponentially with the number of possible parameters to be considered. This problem is usually overcome by assuming simplified models based on experience or using heuristic approaches, which are computationally very expensive. In this paper, a method to obtain a pseudo-optimal parameterization using the maximum likelihood method is presented. The proposed algorithm automatically selects the parameters which minimize the Akaike Information Criterion within an iterative scheme, including one parameter at a time based on a score perturbation criteria. The process is repeated until no further improvement in the objective function is achieved. The proposed method is applied for the adjustment of monthly maximum significant wave height at different locations around the Atlantic coast and results are compared with those obtained using an existing heuristic approach, showing an important reduction in computational time and comparable results in terms of fitting quality.
Quadrotors are Unmanned Aerial Systems (UAS), whose nonlinearities, uncertainties, and unavoidable aerodynamic disturbances stand for a difficult control problem. Additionally, the highly nonlinear ...coupling between the position and the orientation dynamics exacerbates the underactuation problem when the objective is the position tracking. In this paper, aiming at designing a robust position controller without resolving underactuation, a novel “reactive orientation control” is proposed. The orientation controller is model-free and it is build upon differintegral fractional operators to react to a continuous and bounded additive term that stands for an affine exogenous position controller. Such term indeed becomes an attitude disturbance that is purposely injected to displace the quadrotor towards the desired position of the underactuated coordinates. The closed-loop analysis shows that the norm of the transfer function between the disturbance and the position tracking error is minimized for a stable and robust position regime. Simulations and experimental results are given to discuss the feasibility of the proposed scheme.
•Robust stabilization without resolving underactuation.•The fractional attitude reactive controller assures boundedness of the orientation coordinates.•Input–output stability is demonstrated against square integrable disturbances.•Fractional operators filter out high frequencies from the control signal.•Experiments and simulations show the reliability of the proposed scheme.
Endotracheal cuff after multiple injury Dosset Izaguirre, C; Serna Gandía, M; Carpi, I ...
Revista española de anestesiología y reanimación
61, Številka:
8
Journal Article
Disruptions in harbor operations have significant implications for local, regional and global economies due to ports strategic role as part of the supply chain. A probabilistic evaluation of port ...operations considering the influence of climate change is required in order to secure optimal exploitation during their useful life. Here, we propose a hybrid statistic-dynamical framework combining a weather generator and a metamodel. The stochastic generator is based on weather types to project climate variability on hourly multivariate dependent climate drivers outside ports. The metamodel efficiently transforms hourly sea conditions from the entrance of the harbor towards the inside port adding the advantages of a physical process model. Thousands of hourly synthetic time series based on present climate conditions and future ones were transferred inside the port to perform a probabilistic analysis of port operations. Future forcing conditions were defined adding several sea level rise (SLR) scenarios, sampled from their probability distribution, to the synthetic sea level fluctuation time series. Wave amplification due to non-linear interactions between wave and sea level variations and changes in the reflection coefficients inside the port induced by SLR were modelled. Probabilistic future changes of operation downtimes were quantified considering the uncertainty associated with the historical forcing conditions outside the port and likely SLR scenarios. The methodology was applied to a specific case study on a regional port located in the north coast of Spain, were port operability due to wave agitation was assessed.
•Probabilistic evaluation of climate change impacts on port operations including the uncertainty due to SLR projections.•The proposed hybrid framework combines a weather generator and a metamodel for an efficient physical-process modelling.•The framework can be applied to define design criteria with an specific acceptable operability risk.•The framework can be used for climate change adaptation plans.
Bestatin, an inhibitor of leucine aminopeptidase (LAPase), significantly decreased HIV infection as reflected by a reduced number of positive immunofluorescent cells, p24 levels, reverse ...transcriptase activity and the number of proviral copies found in Bestatin-treated cells. Cellular and extracellular LAPase activity in infected cells was higher than the LAPase activity found in uninfected cells. However, cellular and extracellular LAPase activity as well as total protein kinase C activity was lower in Bestatin-treated cells. Conversely, the incubation of human lymphocytic HUT78 cells with LAPase promotes HIV infectivity. The possible role of LAPase in the pathophysiology of HIV was assessed by determining LAPase serum levels in HIV infected patients. LAPase activity levels were three orders of magnitude greater in sera obtained from HIV patients than those detected in sera of uninfected individuals. Although Bestatin reduced HIV infection, a moderate decrease in the reverse transcriptase activity of chronically-infected H9 human T-lymphocytic cells was observed. Based on the higher levels of LAPase present in the serum of HIV patients and on the combined inhibitory effect of Bestatin on LAPase and on protein kinase C activities, we suggest that LAPase may play an important role in the early events of HIV infection such as viral entry.
Abstract
Background
The Coronavirus Disease 2019 (COVID-19) pandemic has transformed health systems worldwide. There is conflicting data regarding the degree of cardiovascular involvement following ...infection, generating uncertainty in patients and an additional healthcare burden with increased diagnostic testing. A registry was designed to evaluate the prevalence of echocardiographic abnormalities in Latin American adults recovered from COVID-19.
Methods
We prospectively evaluated 595 participants (mean age 45.5±14.9 years; 50.8% female) from 10 institutions in Argentina and Brazil. Echocardiographic studies were conducted with General Electric equipment; 2DE imaging and global longitudinal strain (GLS) of both ventricles were performed. Comparisons between groups were made with Chi-square, Fisher and Student's t-test. Logistic regression was performed to determine variables associated with abnormal echocardiogram findings.
Results
A total of 61.7% of the participants denied any relevant cardiovascular medical history. Table 1 summarizes the comorbidities of the included patients. The majority of patients (82.5%) had the disease at home or in an out-of-hospital center. Of the patients who required hospitalization, 15.3% were in a general ward, 1.9% in intensive care and 0.3% required mechanical ventilation during the disease. The median time between infection and performance of the echocardiographic study was two months (IQR 1–3 months). Among patients who reported symptoms following COVID-19 recovery (41.8%), the most frequently reported was dyspnea (47.4%), followed by mild symptoms such as asthenia, arterial hypertension or palpitations (32.9%), 12.9% referred chest pain, 6% of patients reported dyspnea and chest pain, and 0.8% reported various other symptoms. The mean left ventricular ejection fraction (LVEF) was 61.0±5.5% and the mean left atrial volume was 33.1±13.2 ml/m2. In patients without prior comorbidities, 8.2% had some echocardiographic abnormality (Figure 1). We found no significant differences in LVEF between symptomatic and asymptomatic patients (61.4% versus 60.6% respectively, p=0.104). Symptomatic patients showed slightly reduced GLS (−20.3% versus −20.9%, p=0.012) with a trend in the same direction in the RV free wall GLS (−25.6% versus −26.3%, p=0.103).
Male patients were more likely to have any new echocardiographic abnormalities (OR 2.82, p=0.002). Time elapsed since infection resolution (p=0.245), the presence of symptoms (p=0.927), or history of hospitalization during infection (p=0.671) did not have any correlation with echocardiographic abnormalities. The difference between sexes remains unchanged after adjusting for left atrial volume, wall thicknesses, diastolic function and abnormal wall motion.
Conclusion
Our results suggest that cardiovascular abnormalities after COVID-19 infection are rare and usually mild, especially in cases of mild disease. These abnormalities may be more frequent among males
Funding Acknowledgement
Type of funding sources: None.
This paper examines the vulnerability to flooding and erosion of four open beach study sites in Europe. A framework for the quantitative estimation of present and future coastal flood and erosion ...risks is established using methods, data and tools from across a range of disciplines, including topographic and bathymetric data, climate data from observation, hindcast and model projections, statistical modelling of current and future climates and integrated risk analysis tools. Uncertainties in the estimation of future coastal system dynamics are considered, as are the consequences for the inland systems. Different implementations of the framework are applied to the study sites which have different wave, tidal and surge climate conditions. These sites are: Santander, Spain—the Atlantic Ocean; Bellocchio, Italy—the Adriatic Sea; Varna, Bulgaria—the Black Sea; and the Teign Estuary, UK—the northern Atlantic Ocean. The complexity of each system is first simplified by sub-division into coastal “impact units” defined by homogeneity in the local key forcing parameters: wave, wind, tide, river discharge, run-off, etc. This reduces the simulation to that of a number of simpler linear problems which are treated by applying the first two components of the Source–Pathway–Receptor–Consequence (S–P–R–C) approach. The case studies reveal the flexibility of this approach, which is found useful for the rapid assessment of the risks of flooding and erosion for a range of scenarios and the likely effectiveness of flood defences.
•A methodology to assess flooding and erosion risk in coastal areas is presented.•Allows derivation of water levels/flood maps for extreme events•Allows prediction of the impacts of climate change•Assessment of the ‘benefits’ of different flood defence interventions•Results were derived for specific return periods.
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