672 research outputs found
A spatially distributed analysis of erosion susceptibility and sediment yield in a river basin by means of geomorphic parameters and regression relationships
International audienceIn the present work, an application of statistical regression relationships utilising geomorphic parameters is attempted in a spatially distributed mode, in order to predict the amount of river sediment supply at varying sections of the drainage network. Simple and multiple regression relationships utilising drainage density Dd and hierarchical anomaly index ?a as independent variables were applied to the Calvano watershed (Central Italy) at different degree of subdivision in tributary drainage basins, so as to assess their contribution to the whole watershed sediment yield balance. In the same way, the role of small hill-reservoirs as sediment-trap and that of areas affected by badlands and of tributary basins exposure were also investigated. Results were tested on the basis of sedimentation estimates from selected reservoirs. The relationships provided a yearly specific sediment yield (SSY) value for the Calvano stream which is according to the average observed SSY in river basins of central Italy flowing to the Adriatic Sea. The use of simple statistical relationships, such as those here adopted, can allow to recognise the sections along the main stream which are more critical in terms of sediment accumulation, which, on turn, can cause sudden water discharge increments and dangerous floods. This approach can provide a tool enabling to locate the hydraulic risk and to point out the areas where soil conservation practices or hydraulic works, such as periodic maintenance of riverbeds, are needed in order to reduce soil erosion and sediment accumulation
Corrigendum to "Estimating the suspended sediment yield in a river network by means of geomorphic parameters and regression relationships" published in Hydrol. Earth Syst. Sci., 12, 177–191, 2008
No abstract available
A Data-Driven Slip Estimation Approach for Effective Braking Control under Varying Road Conditions
The performances of braking control systems for robotic platforms, e.g.,
assisted and autonomous vehicles, airplanes and drones, are deeply influenced
by the road-tire friction experienced during the maneuver. Therefore, the
availability of accurate estimation algorithms is of major importance in the
development of advanced control schemes. The focus of this paper is on the
estimation problem. In particular, a novel estimation algorithm is proposed,
based on a multi-layer neural network. The training is based on a synthetic
data set, derived from a widely used friction model. The open loop performances
of the proposed algorithm are evaluated in a number of simulated scenarios.
Moreover, different control schemes are used to test the closed loop scenario,
where the estimated optimal slip is used as the set-point. The experimental
results and the comparison with a model based baseline show that the proposed
approach can provide an effective best slip estimation
Basic knowledge and new advances in panoramic radiography imaging techniques: A narrative review on what dentists and radiologists should know
Objectives: A panoramic radiograph (PAN) is the most frequently diagnostic imaging technique carried out in dentistry and oral surgery. The correct performance of image acquisition is crucial to obtain adequate image quality. The aim of the present study is to (i) review the principles of PAN image acquisition and (ii) describe positioning errors and artefacts that may affect PAN image quality. Methods: Articles regarding PAN acquisition principles, patient’s positioning errors, artefacts, and image quality were retrieved from the literature. Results: Head orientation is of the utmost importance in guaranteeing correct image acquisition. Symmetry, occlusal plane inclination, mandibular condyles localization, cervical spine position, aspect of upper teeth root apexes, exposure parameters, and metal and motion artefacts are factors that greatly affect the image quality of a successful PAN. Conclusions: Several factors are the basis for PAN performance; therefore, a systematic approach that takes into account correct patient positioning and preparation is strongly suggested to improve overall examination quality
Optimization of 4-amino-pyridazin-3(2H)-one as a valid core scaffold for FABP4 inhibitors
Current clinical research suggests that fatty acid-binding protein 4 inhibitors (FABP4is), which are of biological and therapeutic interest, may show potential in treating cancer and other illnesses. We sought to uncover new structures through the optimization of the previously reported 4-amino and 4-ureido pyridazinone-based series of FABP4is as part of a larger research effort to create more potent FABP4 inhibitors. This led to the identification of 14e as the most potent analog with IC₅₀ = 1.57 μM, which is lower than the IC₅₀ of the positive control. Advanced modeling investigations and in silico absorption, distribution, metabolism, and excretion - toxicity calculations suggested that 14e represents a potential candidate for in vivo studies such as FABP4i
Ligand Growing Experiments Suggested 4-amino and 4-ureido pyridazin-3(2H)-one as Novel Scaffold for FABP4 Inhibition
Fatty acid binding protein (FABP4) inhibitors are of synthetic and therapeutic interest and ongoing clinical studies indicate that they may be a promise for the treatment of cancer, as well as other diseases. As part of a broader research effort to develop more effective FABP4 inhibitors, we sought to identify new structures through a two-step computing assisted molecular design based on the established scaffold of a co-crystallized ligand. Novel and potent FABP4 inhibitors have been developed using this approach and herein we report the synthesis, biological evaluation and molecular docking of the 4-amino and 4-ureido pyridazinone-based series
Fracture and migration in right atrium of a permanent venous central access system in a elderly patient: case report and literature review
Catheter dislocation and fracture with migration of central venous lines have been reported in the International literature. Catheter fracture with consequent migration has been observed in 0.5-3.0% and may either be consequent to catheter removal or it can occur spontane-ously. Our case report concerns the migration of a Hickman catheter connected to a venous port to the right atrium in a 61-year old patient. A literature up-to-date has been performed to assess the risk of port-a-cath positioning. The position of catheter tip is considered critical for the risk of migration, that is greater as higher the tip localization respect to the carina. The aim of our study is to underline the critical role of X-ray to visualize the exact location of the catheter tip, regard-less of the approach used for catheter positioning
Is lung ultrasound imaging a worthwhile procedure for severe acute respiratory syndrome coronavirus 2 pneumonia detection?
Objectives: We compared 2 imaging modalities in patients suspected of having coronavirus disease 2019 (COVID-19) pneumonia. Blinded to the results of real-time reverse transcriptase polymerase chain reaction (rRT-PCR) testing, lung ultrasound (LUS) examinations and chest computed tomography (CT) were performed, and the specific characteristics of these imaging studies were assessed. Methods: From March 15, 2020, to April 15, 2020, 63 consecutive patients were enrolled in this prospective pilot study. All patients underwent hematochemical tests, LUS examinations, chest CT, and confirmatory rRT-PCR. The diagnostic performance of LUS and chest CT was calculated with rRT-PCR as a reference. The interobserver agreement of radiologists and ultrasound examiners was calculated. Ultrasound and CT features were compared to assess the sensitivity, specificity, positive predictive value, and negative predictive value. Positive and negative likelihood ratios measured the diagnostic accuracy. Results: Nineteen (30%) patients were COVID-19 negative, and 44 (70%) were positive. No differences in demographics and clinical data at presentation were observed among positive and negative patients. Interobserver agreement for CT had a κ value of 0.877, whereas for LUS, it was 0.714. The sensitivity, specificity, positive predictive value, and negative predictive value of chest CT for COVID-19 pneumonia were 93%, 90%, 85%, and 95%, respectively; whereas for LUS, they were 68%, 79%, 88%, and 52%. On receiver operating characteristic curves, area under the curve values were 0.834 (95% confidence interval, 0.711–0.958) and 0.745 (95% confidence interval, 0.606–0.884) for chest CT and LUS. Conclusions: Lung ultrasound had good reliability compared to chest CT. Therefore, our results indicate that LUS may be used to assess patients suspected of having COVID-19 pneumonia
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