An Arbitrary-Lagrangian-Eulerian hybrid finite volume/finite element method on moving unstructured meshes for the Navier-Stokes equations

We present a novel second-order semi-implicit hybrid finite volume / finite element (FV/FE) scheme for the numerical solution of the incompressible and weakly compressible Navier-Stokes equations on moving unstructured meshes using an Arbitrary-Lagrangian-Eulerian (ALE) formulation. The scheme is based on a suitable splitting of the governing PDE into subsystems and employs staggered grids, where the pressure is defined on the primal simplex mesh, while the velocity and the remaining flow quantities are defined on an edge-based staggered dual mesh. The key idea of the scheme is to discretize the nonlinear convective and viscous terms using an explicit FV scheme that employs the space-time divergence form of the governing equations on moving space-time control volumes. For the convective terms, an ALE extension of the Ducros flux on moving meshes is introduced, which is kinetic energy preserving and stable in the energy norm when adding suitable numerical dissipation terms. Finally, the pressure equation of the Navier-Stokes system is solved on the new mesh configuration using a continuous FE method, with $\mathbb{P}_1$ Lagrange elements. The ALE hybrid FV/FE method is applied to several incompressible test problems ranging from non-hydrostatic free surface flows over a rising bubble to flows over an oscillating cylinder and an oscillating ellipse. Via the simulation of a circular explosion problem on a moving mesh, we show that the scheme applied to the weakly compressible Navier-Stokes equations is able to capture weak shock waves, rarefactions and moving contact discontinuities. We show that our method is particularly efficient for the simulation of weakly compressible flows in the low Mach number limit, compared to a fully explicit ALE schem

Relationship between breastfeeding, epigenetics and gut microbiota

RESUMEN: La lactancia materna además de ser beneficiosa para el bebé, también lo es para la madre y crea un fuerte vínculo entre ambos, por lo que la labor de la enfermería en la promoción de la lactancia materna, así como la enseñanza para llevar a cabo una correcta práctica es imprescindible. En este trabajo se muestra que la lactancia materna produce cambios epigenéticos, y que, además, es por sí misma un factor protector contra el desarrollo de enfermedades epigenéticas, como la obesidad, la diabetes o enfermedades cardiovasculares. Por ello, no sólo hay que tener en cuenta la toma de leche materna, sino la duración de ésta, que disminuye la incidencia de este tipo de enfermedades. Además, los lactantes amamantados con leche materna adquieren una microbiota intestinal más diversa y rica que los amamantado con lactancia artificial. Actualmente esta práctica no es igual en todo el mundo: varía en función del nivel socioeconómico, el país y de la decisión de los padres. Pero quizá en el futuro, teniendo en cuenta su impacto sobre la regulación epigenética y la microbiota intestinal, y gracias a las promoción de esta práctica por parte de la enfermería, aumente su tasa y se consiga disminuir el riesgo de los niños de padecer ciertas enfermedades a corto y largo plazo.ABSTRACT: Breastfeeding is not only beneficial for the baby, but also for the mother and it creates a strong bond between both. Therefore, nursing labor in promoting breastfeeding is essential, as well as teaching to carry out a correct breastfeeding. This review shows not only that breastfeeding causes epigenetic changes, but also that it is a protective factor against the development of epigenetic diseases, such as obesity, diabetes or cardiovascular diseases. Therefore, in addition to the type of feeding, the duration is key to diminish the incidence of these types of disease. In addition, breastfed infants acquire a richer and more diverse gut microbiota than formula-fed infants. Nowadays, this practice is not the same all over the world: it varies depending on the socioeconomic level, the country and the parents’ decision. But, taking into account its impact on epigenetics and on gut microbiota modulation, and thanks to the promotion of this practice by nursing, it will be possible to increase its rate and to reduce the risk of children suffering from certain diseases in the short and long term.Grado en Enfermerí

A semi-implicit hybrid finite volume / finite element scheme for all Mach number flows on staggered unstructured meshes

In this paper a new hybrid semi-implicit finite volume / finite element (FV/FE) scheme is presented for the numerical solution of the compressible Euler and Navier-Stokes equations at all Mach numbers on unstructured staggered meshes in two and three space dimensions. The chosen grid arrangement consists of a primal simplex mesh composed of triangles or tetrahedra, and an edge-based / face-based staggered dual mesh. The governing equations are discretized in conservation form. The nonlinear convective terms of the equations, as well as the viscous stress tensor and the heat flux, are discretized on the dual mesh at the aid of an explicit local ADER finite volume scheme, while the implicit pressure terms are discretized at the aid of a continuous $\mathbb{P}^{1}$ finite element method on the nodes of the primal mesh. In the zero Mach number limit, the new scheme automatically reduces to the hybrid FV/FE approach forwarded in \cite{BFTVC17} for the incompressible Navier-Stokes equations. As such, the method is asymptotically consistent with the incompressible limit of the governing equations and can therefore be applied to flows at all Mach numbers. Due to the chosen semi-implicit discretization, the CFL restriction on the time step is only based on the magnitude of the flow velocity and not on the sound speed, hence the method is computationally efficient at low Mach numbers. In the chosen discretization, the only unknown is the scalar pressure field at the new time step. Furthermore, the resulting pressure system is symmetric and positive definite and can therefore be very efficiently solved with a matrix-free conjugate gradient method. In order to assess the capabilities of the new scheme, we show computational results for a large set of benchmark problems that range from the quasi incompressible low Mach number regime to compressible flows with shock waves

Quantitation of endogenous amount of ethanol, methanol and acetaldehyde in ripe fruits of different Spanish olive varieties

BACKGROUND The use of healthy olives and their good management along the production process are necessary to obtain the best quality virgin olive oils. One parameter related to the health of the olives is the content of fatty acid alkyl esters. Because these come from the esterification of C16 and C18 free fatty acids with short chain alcohols, the control of methanol, ethanol and acetaldehyde (precursor of ethanol) and their origin (endogenous or from fermentation) is essential. The present study reports the endogenous amount of these compounds in some of the main Spanish olive varieties. For their analyses, headspace solid phase micro‐extraction was applied and, to ensure quantitation reliability, the matrix‐matched technique was used to build the calibration lines. RESULTS For healthy and mature olives, the contents of ethanol and methanol are much higher and vary within a wider range than those corresponding to acetaldehyde. Because olives were not directly analyzed but previously homogenized, there was no correlation between the olive size parameters and the contents of the compounds investigated. However, these contents are characteristic of each variety. When comparing healthy and unhealthy olives, significant differences were only observed for ethanol contents. CONCLUSION Higher contents of short alcohols are not only the result of an unhealthy or poor state of the fruits, but also the variety. Therefore, because these alcohols are precursors of fatty acid alkyl esters, the maximum permissible content of the latter should not be set at a single value for all olive varieties.info:eu-repo/semantics/acceptedVersio

Kinetic Modeling, Thermodynamic Approach and Molecular Dynamics Simulation of Thermal Inactivation of Lipases from Burkholderia cepacia and Rhizomucor miehei

The behavior against temperature and thermal stability of enzymes is a topic of importance for industrial biocatalysis. This study focuses on the kinetics and thermodynamics of the thermal inactivation of Lipase PS from B. cepacia and Palatase from R. miehei. Thermal inactivation was investigated using eight inactivation models at a temperature range of 40–70 ◦C. Kinetic modeling showed that the first-order model and Weibull distribution were the best equations to describe the residual activity of Lipase PS and Palatase, respectively. The results obtained from the kinetic parameters, decimal reduction time (D and tR), and temperature required (z and z’) indicated a higher thermal stability of Lipase PS compared to Palatase. The activation energy values (Ea) also indicated that higher energy was required to denature bacterial (34.8 kJ mol−1 ) than fungal (23.3 kJ mol−1 ) lipase. The thermodynamic inactivation parameters, Gibbs free energy (∆G# ), entropy (∆S # ), and enthalpy (∆H# ) were also determined. The results showed a ∆G# for Palatase (86.0–92.1 kJ mol−1 ) lower than for Lipase PS (98.6–104.9 kJ mol−1 ), and a negative entropic and positive enthalpic contribution for both lipases. A comparative molecular dynamics simulation and structural analysis at 40 ◦C and 70 ◦C were also performed

Methodologies based on ASCA to elucidate the influence of a subprocess: vinification as a case of study

In food manufacturing and processing, food matrix complexity usually makes it difficult to detect unwanted subprocesses, which can impact thequality of thefinal product. In the case of wine alcoholic fermentation, themain process is the conversion of sugars into ethanol and carbon dioxide, but the presence of some unwanted microorganismscould lead to wine contamination by production of undesired minor compounds. In thestudywe present, an intentional contamination of the vinification processby the addition ofacetic acid bacteria was studied using a portable Fourier Transform Infrared (FT-IR) spectrometer. ANOVA Simultaneous Component Analysis (ASCA) was usedto unravel these minor variability sources. However, as the subprocess is twoorders of magnitude lowerin concentration than the main process, different methodologies were used to enhance theASCAresults, suchasto selecta specific spectral regionrelated to acetic acid bacteria metabolism, to dividethe process in time intervals related to the different phases, or to unfold the data matrix in different ways. In addition, spectral pre-processing was optimized to scale up small peaks related to the subprocess. Our results show that several methodologies to build ASCA models can be applied to emphasize and better characterize bacteria contamination subprocesses

Integration of Solvent Extraction and Non-Catalytic Esterification for the Treatment of Acidic Feedstocks

The possibility of directly feeding the extract of a liquid-liquid extraction unit to a chemical reactor is analyzed. An example of extraction and noncatalytic esterification of naphthenic acids from acid petroleum crudes is used. Methanol is used both as a solvent and as a reactant. Separate tests of extraction and reaction are performed, and the performance of an integrated process is deduced by computer simulation. Thermodynamic and kinetic parameters for the extraction of naphthenic acids from an acid crude were determined. A partition coefficient of m = 0.66 at 60 °C between the alcoholic and petroleum phases was found. Three successive batch extractions with a 1:1 v/v ratio reduced the acidity from 4.3 to about 1.1 mgKOH g-1. Naphthenic acid concentrates were reacted with supercritical methanol in a batch reactor at high temperatures (280 °C), yielding naphthenic esters. Reaction of 1-2 h with methanol-to-oil molar ratios of 3-6 yielded 92-96% conversion because of a relatively low value of the equilibrium constant. Total conversion could, however, be achieved with the highly diluted extracts. Simulations were run using three countercurrent mixer-settlers and a noncatalytic reactor. The results indicated that extraction/supercritical esterification is a convenient pretreatment step of acidic feedstocks because of its simplicity, the good quality of the deacidified feedstock (acidity <0.5 mgKOH g-1), the total removal of the acids, and the good properties of the ester product as a fuel additive. Characterization of the methyl naphthenate product showed that it had a lower viscosity than the crude or the naphthenic acids; a high flash point; and total miscibility in gasoline, kerosene, and diesel. These and other properties showed that it could be sent to the diesel or fuel oil pools.Fil: Busto, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Torresi, Pablo Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Manuale, Débora Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Yori, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Vera, Carlos Roman. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentin

ATR-MIR spectroscopy as a process analytical technology in wine alcoholic fermentation – A tutorial

Abstract The goal of this article is to guide the reader through the critical points to be faced when monitoring a fermentation following a Process Analytical Technology (PAT) approach. To achieve this purpose Attenuated Total Reflectance – Mid-Infrared (ATR-MIR) spectroscopy coupled to chemometric techniques are proposed. Each of the crucial steps (set up of microvinifications, sampling, spectroscopic analysis and chemometric data treatment) is deeply investigated, revealing how the sampling is decisive for the subsequent modeling phase, suggesting how to set parameters to obtain good quality signals, and explaining how to prepare the data for the chemometric modeling and to perform the calculations. The modeling strategies here presented, based mainly on basic chemometric tools such as principal component analysis and partial least square regression, proved to be effective to the purposes and affordable even for non-expert chemometric users. The article shows, using real examples, how to obtain or predict several parameters from a fermentation data set – control of the fermentation evolution, prediction of oenological parameters during the alcoholic fermentation and detection of deviations from the normal operation condition

Consequences of genetic recombination on protein folding stability

Genetic recombination is a common evolutionary mechanism that produces molecular diversity. However, its consequences on protein folding stability have not attracted the same attention as in the case of point mutations. Here, we studied the effects of homologous recombination on the computationally predicted protein folding stability for several protein families, finding less detrimental effects than we previously expected. Although recombination can affect multiple protein sites, we found that the fraction of recombined proteins that are eliminated by negative selection because of insufficient stability is not significantly larger than the corresponding fraction of proteins produced by mutation events. Indeed, although recombination disrupts epistatic interactions, the mean stability of recombinant proteins is not lower than that of their parents. On the other hand, the difference of stability between recombined proteins is amplified with respect to the parents, promoting phenotypic diversity. As a result, at least one third of recombined proteins present stability between those of their parents, and a substantial fraction have higher or lower stability than those of both parents. As expected, we found that parents with similar sequences tend to produce recombined proteins with stability close to that of the parents. Finally, the simulation of protein evolution along the ancestral recombination graph with empirical substitution models commonly used in phylogenetics, which ignore constraints on protein folding stability, showed that recombination favors the decrease of folding stability, supporting the convenience of adopting structurally constrained models when possible for inferences of protein evolutionary histories with recombination.Agencia Estatal de Investigación | Ref. PID2019-107931GA-I00/AEI/10.13039/501100011033Agencia Estatal de Investigación | Ref. PID2019-109041GBC22/10.13039/501100011033Ministerio de Economía y Competitividad | Ref. RYC-2015-18241Financiado para publicación en acceso aberto: Universidade de Vigo/CISU

Two-step approach for occupancy estimation in intensive care units based on Bayesian optimization techniques

Due to the high occupational pressure suffered by intensive care units (ICUs), a correct estimation of the patients’ length of stay (LoS) in the ICU is of great interest to predict possible situations of collapse, to help healthcare personnel to select appropriate treatment options and to predict patients’ conditions. There has been a high amount of data collected by biomedical sensors during the continuous monitoring process of patients in the ICU, so the use of artificial intelligence techniques in automatic LoS estimation would improve patients’ care and facilitate the work of healthcare personnel. In this work, a novel methodology to estimate the LoS using data of the first 24 h in the ICU is presented. To achieve this, XGBoost, one of the most popular and efficient state-of-the-art algorithms, is used as an estimator model, and its performance is optimized both from computational and precision viewpoints using Bayesian techniques. For this optimization, a novel two-step approach is presented. The methodology was carefully designed to execute codes on a high-performance computing system based on graphics processing units, which considerably reduces the execution time. The algorithm scalability is analyzed. With the proposed methodology, the best set of XGBoost hyperparameters are identified, estimating LoS with a MAE of 2.529 days, improving the results reported in the current state of the art and probing the validity and utility of the proposed approach.Agencia Gallega de Innovación | Ref. IN845D-2020/29Agencia Gallega de Innovación | Ref. IN607B-2021/1