2,023 research outputs found

    Dynamical Dark Energy simulations: high accuracy Power Spectra at high redshift

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    Accurate predictions on non--linear power spectra, at various redshift z, will be a basic tool to interpret cosmological data from next generation mass probes, so obtaining key information on Dark Energy nature. This calls for high precision simulations, covering the whole functional space of w(z) state equations and taking also into account the admitted ranges of other cosmological parameters; surely a difficult task. A procedure was however suggested, able to match the spectra at z=0, up to k~3, hMpc^{-1}, in cosmologies with an (almost) arbitrary w(z), by making recourse to the results of N-body simulations with w = const. In this paper we extend such procedure to high redshift and test our approach through a series of N-body gravitational simulations of various models, including a model closely fitting WMAP5 and complementary data. Our approach detects w= const. models, whose spectra meet the requirement within 1% at z=0 and perform even better at higher redshift, where they are close to a permil precision. Available Halofit expressions, extended to (constant) w \neq -1 are unfortunately unsuitable to fit the spectra of the physical models considered here. Their extension to cover the desired range should be however feasible, and this will enable us to match spectra from any DE state equation.Comment: method definitely improved in semplicity and efficacy,accepted for publication on JCA

    Pedestrian flows in bounded domains with obstacles

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    In this paper we systematically apply the mathematical structures by time-evolving measures developed in a previous work to the macroscopic modeling of pedestrian flows. We propose a discrete-time Eulerian model, in which the space occupancy by pedestrians is described via a sequence of Radon positive measures generated by a push-forward recursive relation. We assume that two fundamental aspects of pedestrian behavior rule the dynamics of the system: On the one hand, the will to reach specific targets, which determines the main direction of motion of the walkers; on the other hand, the tendency to avoid crowding, which introduces interactions among the individuals. The resulting model is able to reproduce several experimental evidences of pedestrian flows pointed out in the specialized literature, being at the same time much easier to handle, from both the analytical and the numerical point of view, than other models relying on nonlinear hyperbolic conservation laws. This makes it suitable to address two-dimensional applications of practical interest, chiefly the motion of pedestrians in complex domains scattered with obstacles.Comment: 25 pages, 9 figure

    Association between faecal pH and fat absorption in children with cystic fibrosis on a controlled diet and enzyme supplements dose

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    [EN] Background Despite treatment with pancreatic enzyme replacement therapy (PERT), patients with cystic fibrosis (CF) can still suffer from fat malabsorption. A cause could be low intestinal pH disabling PERT. The aim of this study was to assess the association between faecal pH (as intestinal pH surrogate) and coefficient of fat absorption (CFA). Additionally, faecal free fatty acids (FFAs) were quantified to determine the amount of digested, but unabsorbed fat. Methods In a 24-h pilot study, CF patients followed a standardised diet with fixed PERT doses, corresponding to theoretical optimal doses determined by an in vitro digestion model. Study variables were faecal pH, fat and FFA excretion, CFA and transit time. Linear mixed regression models were applied to explore associations. Results In 43 patients, median (1st, 3rd quartile) faecal pH and CFA were 6.1% (5.8, 6.4) and 90% (84, 94), and they were positively associated (p < 0.001). An inverse relationship was found between faecal pH and total fat excretion (p < 0.01), as well as total FFA (p = 0.048). Higher faecal pH was associated with longer intestinal transit time (p = 0.049) and the use of proton pump inhibitors (p = 0.009). Conclusions Although the clinical significance of faecal pH is not fully defined, its usefulness as a surrogate biomarker for intestinal pH should be further explored. Impact Faecal pH is a physiological parameter that may be related to intestinal pH and may provide important physiopathological information on CF-related pancreatic insufficiency. Faecal pH is correlated with fat absorption, and this may explain why pancreatic enzyme replacement therapy is not effective in all patients with malabsorption related to CF. Use of proton pump inhibitors is associated to higher values of faecal pH. Faecal pH could be used as a surrogate biomarker to routinely monitor the efficacy of pancreatic enzyme replacement therapy in clinical practice. Strategies to increase intestinal pH in children with cystic fibrosis should be targeted.We acknowledge the support of the MyCyFAPP Project consortium. We especially thank the participation and the effort of the patients involved in the study and their families. This work was fully funded by the European Union and the Horizon 2020 Research and Innovation Framework Programme (PHC-26-2014 call Self management of health and disease: citizen engagement and mHealth) under grant number 643806.Calvo-Lerma, J.; Roca-Llorens, M.; Boon, M.; Colombo, C.; De Koning, B.; Fornés-Ferrer, V.; Masip, E.... (2021). Association between faecal pH and fat absorption in children with cystic fibrosis on a controlled diet and enzyme supplements dose. Pediatric Research. 89(1):205-210. https://doi.org/10.1038/s41390-020-0860-3S205210891Turck, D. et al. ESPEN-ESPGHAN-ECFS guidelines on nutrition care for infants, children, and adults with cystic fibrosis. Clin. Nutr. 35, 557–577 (2016).Borowitz, D., Baker, R. 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Physical–chemical behavior of dietary and biliary lipids during intestinal digestion and absorption. 2. Phase analysis and aggregation states of luminal lipids during duodenal fat digestionin healthy adult human beings. Biochemistry 29, 2041–2056 (1990).Calvo-Lerma, J. et al. A first approach for an evidence-based in vitro method to adjust pancreatic enzyme replacement therapy in cystic fibrosis. PLoS ONE 14, e0212459 (2019).Aburub, A. Comparison of pH and motility of the small intestine of healthy subjects and patients with symptomatic constipation using the wireless motility capsule. Int. J. Pharm. 544, 158–164 (2018).Calvo-Lerma, J. et al. Innovative approach for self-management and social welfare of children with cystic fibrosis in Europe: development, validation and implementation of an mHealth tool (MyCyFAPP). Br. Med. J. Open. 7, e014931 (2017).Calvo-Lerma, J. et al. 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    Compressive sampling for multispectral imaging in the vis-NIR-TIR: optical design of space telescopes

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    Micro-satellites equipped with multispectral payloads are now under development to acquire information on the radiation reflected and emitted from the earth in the vis-NIR-TIR bands. In this framework, we are studying different approaches based on the compressive sampling technique supported by innovative multispectral detectors, where the image sampling is performed on the telescope focal plane with a Digital Micromirror Device (DMD). We will describe in the paper the possibilities and the constraints given by the use of the DMD in the focal plane. The optical design of the telescope, relay system and detector in two different application cases will be provided

    Oncogenic hijacking of a developmental transcription factor evokes vulnerability toward oxidative stress in Ewing sarcoma

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    Ewing sarcoma (EwS) is an aggressive childhood cancer likely originating from mesenchymal stem cells or osteo-chondrogenic progenitors. It is characterized by fusion oncoproteins involving EWSR1 and variable members of the ETS-family of transcription factors (in 85% FLI1). EWSR1-FLI1 can induce target genes by using GGAA-microsatellites as enhancers.Here, we show that EWSR1-FLI1 hijacks the developmental transcription factor SOX6 - a physiological driver of proliferation of osteo-chondrogenic progenitors - by binding to an intronic GGAA-microsatellite, which promotes EwS growth in vitro and in vivo. Through integration of transcriptome-profiling, published drug-screening data, and functional in vitro and in vivo experiments including 3D and PDX models, we discover that constitutively high SOX6 expression promotes elevated levels of oxidative stress that create a therapeutic vulnerability toward the oxidative stress-inducing drug Elesclomol.Collectively, our results exemplify how aberrant activation of a developmental transcription factor by a dominant oncogene can promote malignancy, but provide opportunities for targeted therapy. Ewing sarcoma is characterized by the fusion of EWSR1 and FLI1. Here, the authors show that EWSR1-FLI1 increases the activity of the developmental transcription factor SOX6, which promotes tumor growth but also increases sensitivity to oxidative stress

    Phonons and related properties of extended systems from density-functional perturbation theory

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    This article reviews the current status of lattice-dynamical calculations in crystals, using density-functional perturbation theory, with emphasis on the plane-wave pseudo-potential method. Several specialized topics are treated, including the implementation for metals, the calculation of the response to macroscopic electric fields and their relevance to long wave-length vibrations in polar materials, the response to strain deformations, and higher-order responses. The success of this methodology is demonstrated with a number of applications existing in the literature.Comment: 52 pages, 14 figures, submitted to Review of Modern Physic

    Modelling home care organisations from an operations management perspective

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    Home Care (HC) service consists of providing care to patients in their homes. During the last decade, the HC service industry experienced significant growth in many European countries. This growth stems from several factors, such as governmental pressure to reduce healthcare costs, demographic changes related to population ageing, social changes, an increase in the number of patients that suffer from chronic illnesses, and the development of new home-based services and technologies. This study proposes a framework that will enable HC service providers to better understand HC operations and their management. The study identifies the main processes and decisions that relate to the field of HC operations management. Hence, an IDEF0 (Integrated Definition for Function Modelling) activity-based model describes the most relevant clinical, logistical and organisational processes associated with HC operations. A hierarchical framework for operations management decisions is also proposed. This analysis is derived from data that was collected by nine HC service providers, which are located in France and Italy, and focuses on the manner in which operations are run, as well as associated constraints, inputs and outputs. The most challenging research areas in the field of HC operations management are also discussed
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