2,031 research outputs found
How vegetation in flows modifies the turbulent mixing and spreading of jets
While studies on vegetated channel flows have been developed in many research centers, studies on jets interacting with vegetation are still rare. This study presents and analyzes turbulent jets issued into an obstructed cross-flow, with emergent vegetation simulated with a regular array of cylinders. The paper presents estimates of the turbulence diffusion coefficients and the main turbulence variables of jets issued into a vegetated channel flow. The experimental results are compared with jets issued into unobstructed cross-flow. In the presence of the cylinder array, the turbulence length-scales in the streamwise and transverse directions were reduced, relative to the unobstructed crossflow. This contributed to a reduction in streamwise turbulent diffusion, relative to the unobstructed conditions. In contrast, the transverse turbulent diffusion was enhanced, despite the reduction in length-scale, due to enhanced turbulent intensity and the transverse deflection of flow around individual cylinders. Importantly, in the obstructed condition, the streamwise and transverse turbulent diffusion coefficients are of the same order of magnitude
Structural health monitoring of engineered structures using a space-borne synthetic aperture radar multi-temporal approach: from cultural heritage sites to war zones
Structural health monitoring (SHM) of engineered structures consists of an automated or semi-automated survey system that seeks to assess the structural condition of an anthropogenic structure. The aim of an SHM system is to provide insights into possible induced damage or any inherent signals of deformation affecting the structure in terms of detection, localization, assessment, and prediction. During the last decade there has been a growing interest in using several remote sensing techniques, such as synthetic aperture radar (SAR), for SHM. Constellations of SAR satellites with short repeat time acquisitions permit detailed surveys temporal resolution and millimetric sensitivity to deformation that are at the scales relevant to monitoring large structures. The all-weather multi-temporal characteristics of SAR make its products suitable for SHM systems, especially in areas where in situ measurements are not feasible or not cost effective. To illustrate this capability, we present results from COSMO-SkyMed (CSK) and TerraSAR-X SAR observations applied to the remote sensing of engineered structures. We show how by using multiple-geometry SAR-based products which exploit both phase and amplitude of the SAR signal we can address the main objectives of an SHM system including detection and localization. We highlight that, when external data such as rain or temperature records are available or simple elastic models can be assumed, the SAR-based SHM capability can also provide an interpretation in terms of assessment and prediction. We highlight examples of the potential for such imaging capabilities to enable advances in SHM from space, focusing on dams and cultural heritage areas. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only
Comments on "Blockade of angiogenesis by small molecule antagonists to protease-activated receptor-1: association with endothelial cell growth suppression and induction of apoptosis".
Alteration of hydrological conditions and spreading processes in vegetated natural flows
Aquatic vegetation provides a wide range of ecosystem services. The uptake of nutrients and production of oxygen improve water quality. The widespread planting in waterways could strongly contribute to the removal of nitrogen and phosphorous. Seagrasses form the foundation of many food webs and vegetation promotes biodiversity by creating different habitats with spatial heterogeneity in the stream velocity. Marshes and mangroves reduce coastal erosion by damping waves and storm surge, as well riparian vegetation enhances bank stability. Even more in times of a changing climate, which could alter hydrological conditions, the monitoring of vegetation development is a fundamental activity in coastal and river management, to both protect ecological services and control flood or erosion risks. A further key point remains poorly investigated and still deserves a thorough study, that is the effect induced by vegetation or similar obstructions on a discharged effluent assumed as a turbulent jet. The present paper shows how vegetation greatly affects the jet entrainment, reversing it into a detrainment process, the diffusion and advection of the jet solute and particles and the jet momentum, demonstrating that it is one of the main cause of the river morphology alteration
Hydrodynamic flow structures at an obstructed-unobstructed interface in a partially vegetated channel
In this manuscript we focus on the study of flow structures in a channel partially obstructed by an array of equispaced,
vertical, rigid, emergent, circular steel cylinders.
Emergent vegetation strongly affects the flow hydrodynamic structures, forming a transversal abrupt velocitytransition
region at the interface between the obstructed and the unobstructed domains.
A modified log-law predicting the representative transversal profile of the mean flow velocity at the obstructedunobstructed
interface is proposed and validated
coastline evolution based on statistical analysis and modeling
Abstract. Wind, waves, tides, sediment supply, changes in relative
sea level and human activities strongly affect shorelines, which constantly
move in response to these processes, over a variety of timescales. Thus,
the implementation of sound coastal zone management strategies needs
reliable information on erosion and/or deposition processes. To suggest a
feasible way to provide this information is the main reason for this work. A
chain approach is proposed here, tested on a vulnerable coastal site located
along southern Italy, and based on the joint analysis of field data,
statistical tools and numerical modeling. Firstly, the coastline morphology
has been examined through interannual field data, such as aerial
photographs, plane-bathymetric surveys and seabed characterization. After this,
rates of shoreline changes have been quantified with a specific GIS tool.
The correlations among the historical positions of the shoreline have been
detected by statistical analysis and have been satisfactorily confirmed by
numerical modeling, in terms of recurrent erosion–accretion area and beach
rotation trends. Finally, based on field topographic, sediment, wave and
wind data, the response of the beach through numerical simulation has been
investigated in a forecasting perspective. The purpose of this study is to
provide a feasible, general and replicable chain approach, which could help
to thoroughly understand the dynamics of a coastal system, identify typical
and recurrent erosion–accretion processes, and predict possible future
trends, useful for planning of coastal activities
Machine learning methods to predict outcomes of pharmacological treatment in psychosis
In recent years, machine learning (ML) has been a promising approach in the research of treatment outcome prediction in psychosis. In this study, we reviewed ML studies using different neuroimaging, neurophysiological, genetic, and clinical features to predict antipsychotic treatment outcomes in patients at different stages of schizophrenia. Literature available on PubMed until March 2022 was reviewed. Overall, 28 studies were included, among them 23 using a single-modality approach and 5 combining data from multiple modalities. The majority of included studies considered structural and functional neuroimaging biomarkers as predictive features used in ML models. Specifically, functional magnetic resonance imaging (fMRI) features contributed to antipsychotic treatment response prediction of psychosis with good accuracies. Additionally, several studies found that ML models based on clinical features might present adequate predictive ability. Importantly, by examining the additive effects of combining features, the predictive value might be improved by applying multimodal ML approaches. However, most of the included studies presented several limitations, such as small sample sizes and a lack of replication tests. Moreover, considerable clinical and analytical heterogeneity among included studies posed a challenge in synthesizing findings and generating robust overall conclusions. Despite the complexity and heterogeneity of methodology, prognostic features, clinical presentation, and treatment approaches, studies included in this review suggest that ML tools may have the potential to predict treatment outcomes of psychosis accurately. Future studies need to focus on refining feature characterization, validating prediction models, and evaluate their translation in real-world clinical practice
SP382NUTRITIONAL AND FUNCTIONAL ASSESSMENT IN OLDER CKD OUTPATIENTS ON TERTIARY CARE: PROTEIN INTAKE AND RISK OF SARCOPENIA
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Spatial Olfactory Memory and Spatial Olfactory Navigation, Assessed with a Variant of Corsi Test, Is Modulated by Gender and Sporty Activity
Many studies have focused on navigation, spatial skills, and the olfactory system in comparative models, including those concerning the relationship between them and physical activity. Although the results are often in contrast with each other, it is assumed that physical activity can affect cognition in different ways-both indirectly and through a certain influence on some brain structures. In contrast, there is little research that focuses on the relationship between spatial abilities and olfactory abilities in humans. This research aimed to evaluate and compare the performance in working memory tasks of athletes and non-athletes who require good visual-spatial navigation, olfactory-spatial navigation, and olfactory-semantic skills. The study involved 236 participants (83 athletes) between the ages of 18 and 40. All subjects were matched by age or sex. The standard Corsi Block Tapping Test (CBTT) was administrated to investigate the visual-spatial memory. Olfactory-spatial navigation and olfactory-semantic skills were assessed with two modified versions of CBTT: Olfactory CBTT (OCBTT) and Semantic-Olfactory CBTT (SOCBTT) respectively. The results show differences between the CORSI conditions in direction of a poor performance for athletes. A gender effect in favor of men was also found, particularly in the classic version of the CBTT. Both groups performed better in the classic version of the CBTT than OCBTT and SOCBTT. The mean of SOCBTT results is markedly lower, perhaps due to the different information processing systems needed to perform this kind of task. It is possible to explain how sports practice can affect tasks that require spatial skills and olfactory perception differently, thus supporting new hypotheses and opening new scientific horizons
Unraveling the Antimicrobial Effectiveness of Coridothymus capitatus Hydrolate against Listeria monocytogenes in Environmental Conditions Encountered in Foods: An In Vitro Study
The increased resistance of bacteria to antimicrobials, as well as the growing interest in innovative and sustainable alternatives to traditional food additives, are driving research towards the use of natural food preservatives. Among these, hydrolates (HYs) have gained attention as "mild" alternatives to conventional antimicrobial compounds. In this study, the response of L. monocytogenes ATCC 7644 exposed to increasing concentrations of Coridothymus capitatus HY (CHY) for 1 h at 37 °C was evaluated by means of Phenotype Microarray, modelling the kinetic data obtained by inoculating control and treated cells into GEN III microplates, after CHY removal. The results revealed differences concerning the growth dynamics in environmental conditions commonly encountered in food processing environments (different carbon sources, pH 6.0, pH 5.0, 1-8% NaCl). More specifically, for treated cells, the lag phase was extended, the growth rate was slowed down and, in most cases, the maximum concentration was diminished, suggesting the persistence of stress even after CHY removal. Confocal Laser Scanner Microscopy evidenced a diffuse aggregation and suffering of the treated cells, as a response to the stress encountered. In conclusion, the treatment with HY caused a stressing effect that persisted after its removal. The results suggest the potential of CHY application to control L. monocytogenes in food environments
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