1,368 research outputs found

    Computationally Efficient Lumped Floodplain Modelling Using Data-Driven Methods

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    Modelling floodplains adequately is crucial for numerous water management applications. Many of these applications require a large number of simulations or long term analyses, such as optimization problems at catchment scale, uncertainty analyses or real time control of hydraulic structures to prevent flooding. Therefore, models with a limited calculation time are necessary. Various computationally efficient models exist that describe the flow in rivers, but the modelling of floodplains is often overlooked. This study focuses on the computationally efficient lumped modelling of floodplains. Two different data-driven modelling approaches are proposed that predict the inundation level in the floodplain and the flow between the river and the floodplain for a given set of river stages. On the one hand, the flow is estimated using a set of optimized weir equations that are deemed to describe the flow over hydraulic structures. On the other hand, hybrid models are studied that combine physical principles with artificial neural networks. Such networks are highly flexible and can learn from the data provided during the model set-up procedure. Two set-up procedures are investigated to ensure that physically sound networks with good generalization capabilities are obtained. The derived methodologies are tested on a case study by emulating the results of a detailed full hydrodynamic model of the Dender River in Belgium. The results show that the hybrid models can predict the water levels and flows in/to floodplains with great accuracy. The novel modelling approach that incorporates artificial neural networks outperforms the conceptual models with rigid equations. Both types of models are more than 10.000 times faster when simulating events compared to a 1D hydrodynamic model that solves the full de Saint-Venant equations. Because the model build-up requires expert knowledge and can be time-consuming, a tool was developed that assists the modeller during the calibration procedure. When simulation results from detailed models and information on the detailed model lay-out are presented, the tool suggests an optimal model structure and accompanying set of parameters

    Public Housing after Hurricane, Urban Renewal or Removal? The Case Studies of Beaumont and Galveston, Texas.

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    Decent housing is a goal for many people not only in the United States but elsewhere in the world. A house becomes the symbol of family spirit whether it is a single-family or multiple-family home. Public housing in the United States is housing of “last resort,” for families whose incomes do not allow them to find housing in the private market. Yet, many studies focusing on public housing find a host of social issues plaguing these units. The US Government has initiated various programs to improve the quality of public housing as well as the living condition of local resident through agenda of Department of Housing and Urban Development (HUD). HOPE VI is one of the major programs that focuses on distressed public housing. This program funds local government and housing authority in order to revitalized or rebuild public housing. This program has been very successful in providing high-quality housing for public housing residents. However, as any type of construction, housing usually received great damage when natural disaster happening. It can be partly damaged or completely destroyed due to the direct and indirect effects of disaster. Public housing, like most affordable housing, is often built in highly vulnerable areas, such as floodplains or other low-lying areas. When disasters such as hurricanes strike, housing located in these areas is likely to receive the greatest damage and recovery may be slower. This study looks at the case study of public housing in Galveston and Beaumont after Hurricane Ike (2008) and Rita (2005). After Hurricane Rita in 2005, Beaumont has rebuilt some public housing development with a HOPE VI grant awarded in 2007. These areas have successfully rebuilt through the cooperation of housing authority, local government, local residents, and developers. In contrast, Galveston could not reach agreement about the destiny of public housing after Hurricane Ike in 2008. This story becomes more serious when HUD announced that if Galveston cannot rebuild public housing in disaster area, they must refund the money to the federal Government. These two cities provide a comparative case study of the rebuilding of public housing after disaster, where on one successfully rebuilt while other did not. By looking at the secondary data sources, this research analyzes the situation of these places in different period: before the Hurricane, when the Hurricane happened, and after the Hurricane. The paper will address the similarities as well as differences between two case studies in term of historical profile, demography, public housing program characteristics, damage, and recovery. Besides, economic change after hurricane approached is addressed. The housing situation will be further analyzed in Galveston to clearly show the obstacles in which this city coped with. Finally, the study will conclude by suggesting some implications for theory, housing policy, management, and further research

    Nationwide evaluation of mutation-tailored treatment of gastrointestinal stromal tumors in daily clinical practice

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    Background Molecular analysis of KIT and PDGFRA is critical for tyrosine kinase inhibitor treatment selection of gastrointestinal stromal tumors (GISTs) and hence recommended by international guidelines. We performed a nationwide study into the application of predictive mutation testing in GIST patients and its impact on targeted treatment decisions in clinical practice. Methods Real-world clinical and pathology information was obtained from GIST patients with initial diagnosis in 2017-2018 through database linkage between the Netherlands Cancer Registry and the nationwide Dutch Pathology Registry. Results Predictive mutation analysis was performed in 89% of the patients with high risk or metastatic disease. Molecular testing rates were higher for patients treated in expertise centers (96%) compared to non-expertise centers (75%, P < 0.01). Imatinib therapy was applied in 81% of the patients with high risk or metastatic disease without patient's refusal or adverse characteristics, e.g., comorbidities or resistance mutations. Mutation analysis that was performed in 97% of these imatinib-treated cases, did not guarantee mutation-tailored treatment: 2% of these patients had the PDGFRA p.D842V resistance mutation and 7% initiated imatinib therapy at the normal instead of high dose despite of having a KIT exon 9 mutation. Conclusion In conclusion, nationwide real-world data show that over 81% of the eligible high risk or metastatic disease patients receive targeted therapy, which was tailored to the mutation status as recommended in guidelines in 88% of cases. Therefore, still 27% of these GIST patients misses out on mutation-tailored treatment. The reasons for suboptimal uptake of testing and treatment require further study

    WALOWA (wave loads on walls) : large-scale experiments in the delta flume

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    Overtopping wave loads on vertical structures on top of a dike have been investigated in several small scale experiments in the past. A large-scale validation for a mild foreshore situation is still missing. Hence the WALOWA experimental campaign was carried out to address this topic. In the present paper the objectives of the WALOWA project are outlined in detail, the model and measurement set-up described and the test program presented. Furthermore, preliminary results featuring a single 1000 irregular waves test of the test program are highlighted. This includes the study of the mild and sandy foreshore evolution by comparing profiles before and after the test execution. The profile measurements are obtained with a mechanical profiler. The wave parameters offshore and at the dike toe are numerically simulated using a SWASH model. The numerical results are validated against the measurements. Finally, the force and pressure time series of the waves impacting against the wall are processed and filtered. The load cell measurements and the time series of integrated pressures are compared to each other and for each impact event the maximum force is derived.Hydraulic Structures and Flood RiskEnvironmental Fluid Mechanic

    Real-Time Control Of Floods Along The Demer River, Belgium, By Means Of MPC In Combination With GA And A Fast Conceptual River Model

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    Climate model projections show that climate change will further increase the risk of flooding in many regions of the world. There is a need for climate adaptation, but building new infrastructure or additional retention basins has its limits, especially in densely populated areas where open spaces are limited. Another solution is the more efficient use of the existing infrastructure. This research investigates a method for real-time flood control by means of existing gated weirs and retention basins. The method was tested for the specific study area of the Demer basin in Belgium but is generally applicable. Today, retention basins along the Demer River are controlled by means of adjustable gated weirs based on fixed logic rules. However, because of the high complexity of the system, only suboptimal results are achieved by these rules. By making use of precipitation forecasts and combined hydrological-hydraulic river models, the state of the river network can be predicted. To fasten the calculation speed, a conceptual river model was used. The conceptual model was combined with a Model Predictive Control (MPC) algorithm and a Genetic Algorithm (GA). The MPC algorithm predicts the state of the river network depending on the positions of the adjustable weirs in the basin. The GA generates these positions in a semi-random way. Cost functions, based on water levels, were introduced to evaluate the efficiency of each generation, based on flood damage minimization. In the final phase of this research the influence of the most important MPC and GA parameters was investigated by means of a sensitivity study. The results show that the MPC-GA algorithm manages to reduce the total flood volume during the historical event of September 1998 by 46% in comparison with the current regulation. Based on the MPC-GA results, some recommendations could be formulated to improve the logic rules

    Effects of two intervention programs in covid-long patients with cognitive complaints : multiple case studies

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    Long-term cognitive sequels are reported after infection by COVID-19, more particularly for attention, executive functions, working memory and long-term memory. We aim to assess the effectiveness of two psycho-educational interventions (cognitive vs. emotion management) on cognitive complaints and difficulties in patients with long-COVID

    Pituitary tumors contain a side population with tumor stem cell-associated characteristics

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    Pituitary adenomas cause significant endocrine and mass-related morbidity. Little is known about the mechanisms that underlie pituitary tumor pathogenesis. In the present study, we searched for a side population (SP) in pituitary tumors representing cells with high efflux capacity and potentially enriched for tumor stem cells (TSCs). Human pituitary adenomas contain a SP irrespective of hormonal phenotype. This adenoma SP, as well as the purified SP (pSP) that is depleted from endothelial and immune cells, is enriched for cells that express ‘tumor stemness’ markers and signaling pathways, including epithelial–mesenchymal transition (EMT)-linked factors. Pituitary adenomas were found to contain self-renewing sphere-forming cells, considered to be a property of TSCs. These sphere-initiating cells were recovered in the pSP. Because benign pituitary adenomas do not grow in vitro and have failed to expand in immunodeficient mice, the pituitary tumor cell line AtT20 was further used. We identified a SP in this cell line and found it to be more tumorigenic than the non-SP ‘main population’. Of the two EMT regulatory pathways tested, the inhibition of chemokine (C-X-C motif) receptor 4 (CXCR4) signaling reduced EMT-associated cell motility in vitro as well as xenograft tumor growth, whereas the activation of TGFβ had no effect. The human adenoma pSP also showed upregulated expression of the pituitary stem cell marker SOX2. Pituitaries from dopamine receptor D2 knockout (Drd2−/−) mice that bear prolactinomas contain more pSP, Sox2+, and colony-forming cells than WT glands. In conclusion, we detected a SP in pituitary tumors and identified TSC-associated characteristics. The present study adds new elements to the unraveling of pituitary tumor pathogenesis and may lead to the identification of new therapeutic targets.Fil: Mertens, Freya. Ku Leuven University (University of Leuven). Research Unit of Stem Cell Research; BélgicaFil: Gremeaux, Lies. Ku Leuven University (University of Leuven). Research Unit of Stem Cell Research; Bélgica; BélgicaFil: Chen, Jianghai. Huazhong University of Science and Technology. Tongji Medical College Union Hospital; China. Ku Leuven University (University of Leuven). Research Unit of Stem Cell Research; BélgicaFil: Fu, Qiuli. Ku Leuven University (University of Leuven). Research Unit of Stem Cell Research; Bélgica. Zhejiang Provincial Key Laboratory of Ophthalmology; China. Medical College of Zhejiang University. Eye Center of the 2nd Affiliated Hospital; ChinaFil: Willems, Christophe. Ku Leuven University (University of Leuven). Research Unit of Stem Cell Research; BélgicaFil: Roose, Heleen. Ku Leuven University (University of Leuven). Research Unit of Stem Cell Research; BélgicaFil: Govaere, Olivier. KU Leuven. Department of Imaging and Pathology; BélgicaFil: Roskams, Tania. KU Leuven. Department of Imaging and Pathology; BélgicaFil: Cristina, Silvia Carolina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro de Investigaciones y Transferencia del Noroeste de la Provincia de Buenos Aires; ArgentinaFil: Becu Villalobos, Damasia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Joriseen, Mark. University Hospitals Leuven. Unit Head and Neck Oncology; BélgicaFil: Vander Poorten, Vincent. University Hospitals Leuven. Research Group Experimental Oto-Rhino-Laryngology, ; BélgicaFil: Bex, Marie. University Hospitals Leuven. Unit Clinical and Experimental Endocrinology; BélgicaFil: Van Loon, Johannes. University Hospitals Leuven. Research Group Experimental Neurosurgery and Neuroanatomy; BélgicaFil: Vankelecom, Hugo. Ku Leuven University (University of Leuven). Research Unit of Stem Cell Research; Bélgic

    Fas engagement induces the maturation of dendritic cells (DCs), the release of interleukin (IL)-1beta, and the production of interferon gamma in the absence of IL-12 during DC-T cell cognate interaction: a new role for Fas ligand in inflammatory responses

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    Ligation of the Fas (CD95) receptor leads to an apoptotic death signal in T cells, B cells, and macrophages. However, human CD34(+)-derived dendritic cells (DCs) and mouse DCs, regardless of their maturation state, are not susceptible to Fas-induced cell death. This resistance correlates with the constitutive expression of the Fas-associated death domain-like IL-1beta-converting enzyme (FLICE)-inhibitory protein (FLIP) ligand. We demonstrate a new role of Fas in DC physiology. Engagement of Fas on immature DCs by Fas ligand (FasL) or by anti-Fas antibodies induces the phenotypical and functional maturation of primary DCs. Fas-activated DCs upregulate the expression of the major histocompatibility complex class II, B7, and DC-lysosome-associated membrane protein (DC-LAMP) molecules and secrete proinflammatory cytokines, in particular interleukin (IL)-1beta and tumor necrosis factor alpha. Mature DCs, if exposed to FasL, produce even higher amounts of IL-1beta. Importantly, it is possible to reduce the production of IL-1beta and interferon (IFN)-gamma during DC-T cell interaction by blocking the coupling of Fas-FasL with a Fas competitor. Finally, during cognate DC-T cell recognition, IL-12 (p70) could not be detected at early or late time points, indicating that Fas-induced, IFN-gamma secretion is independent of IL-12

    AsrR Is an Oxidative Stress Sensing Regulator Modulating Enterococcus faecium Opportunistic Traits, Antimicrobial Resistance, and Pathogenicity

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    Oxidative stress serves as an important host/environmental signal that triggers a wide range of responses in microorganisms. Here, we identified an oxidative stress sensor and response regulator in the important multidrug-resistant nosocomial pathogen Enterococcus faecium belonging to the MarR family and called AsrR (antibiotic and stress response regulator). The AsrR regulator used cysteine oxidation to sense the hydrogen peroxide which results in its dissociation to promoter DNA. Transcriptome analysis showed that the AsrR regulon was composed of 181 genes, including representing functionally diverse groups involved in pathogenesis, antibiotic and antimicrobial peptide resistance, oxidative stress, and adaptive responses. Consistent with the upregulated expression of the pbp5 gene, encoding a low-affinity penicillin-binding protein, the asrR null mutant was found to be more resistant to \u3b2-lactam antibiotics. Deletion of asrR markedly decreased the bactericidal activity of ampicillin and vancomycin, which are both commonly used to treat infections due to enterococci, and also led to over-expression of two major adhesins, acm and ecbA, which resulted in enhanced in vitro adhesion to human intestinal cells. Additional pathogenic traits were also reinforced in the asrR null mutant including greater capacity than the parental strain to form biofilm in vitro and greater persistance in Galleria mellonella colonization and mouse systemic infection models. Despite overexpression of oxidative stress-response genes, deletion of asrR was associated with a decreased oxidative stress resistance in vitro, which correlated with a reduced resistance to phagocytic killing by murine macrophages. Interestingly, both strains showed similar amounts of intracellular reactive oxygen species. Finally, we observed a mutator phenotype and enhanced DNA transfer frequencies in the asrR deleted strain. These data indicate that AsrR plays a major role in antimicrobial resistance and adaptation for survival within the host, thereby contributes importantly to the opportunistic traits of E. faecium
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