Una aplicación didáctica de la modelización matemática: control de velocidad de vehículos en vías rurales

[EN] In this paper a didactic model for the control of the speed of the vehicles in a road is presented. Based on empirical assumptions, the model provides an answer to the problem of finding the best road from the point of view of the time that is needed for going from the top of a hill to a certain point in the valley under the assumption that certain restrictions for the speed are imposed. Thus, we construct a simple model for representing the time dependence of the traffic in a road as an exercise of mathematical modelling adequate for a basic level of a civil engineering career.[ES] En este artículo presentamos un modelo didáctico para el control de la velocidad de los vehículos en una carretera. Basado en supuestos empíricos, el modelo da una respuesta al problema de encontrar el mejor trazado de carretera desde el punto de vista del tiempo que se necesita para ir desde la cima de una colina a un cierto punto en el valle, respetando las limitaciones de velocidad necesarias. Así, construimos un modelo simple para representar la dependencia temporal del tráfico en una carretera como un ejercicio de modelización matemático para un nivel básico de una carrera de ingeniería civil.Juan, M.; Sánchez-Pérez, E. (2012). Una aplicación didáctica de la modelización matemática: control de velocidad de vehículos en vías rurales. Modelling in Science Education and Learning. 5:65-75. doi:10.4995/msel.2012.2134SWORD65755M. P. Do Carmo, "Geometría diferencial de curvas y super cies". Alianza Universidad Textos, Madrid, 1990. L. M. García Raffi, M. Figueres Moreno, M. J. Pérez Pe-alver y E. A. Sánchez Pérez, "Métodos numéricos con Mathematica". Alfaomega Grupo Editor Argentino, México, 2003.Garcia-Raffi, L. M., Sánchez-Pérez, E. A., & Sopena Novales, M. (2008). Realidad y educación: un modelo didáctico para la catástrofe del Prestige. Modelling in Science Education and Learning, 1, 29. doi:10.4995/msel.2008.3131E. A. Sánchez Pérez, J. V. Sánchez Pérez y L. M. García Raffi, "Introducción de las técnicas de modelización para el estudio de la Física y de las Matemáticas en los primeros cursos de las carreras técnicas". Ense-anza de las Ciencias, 17 (1999), 119-13

Quality Control Process for EQ-5D-5L Valuation Studies

Background: The values of the five-level EuroQol five-dimensional questionnaire (EQ-5D-5L) are elicited using composite time trade-off and discrete choice experiments. Unfortunately, data quality issues and interviewer effects were observed in the first few EQ-5D-5L valuation studies. To prevent these issues from occurring in later studies, the EuroQol Group established a cyclic quality control (QC) process. Objectives: To describe this QC process and show its impact on data quality. Methods: A newly developed QC tool provided information about protocol compliance, interviewer effects, and mean values by health state severity. In a cyclic process, this information is initially used to evaluate whether new interviewers meet minimal quality requirements and later to provide feedback about how their performance may be improved. To investigate the impact of this cyclic process, we compared the quality of the data in Dutch and Spanish valuation studies that did not have this QC process with that in the follow-up studies in the same countries that used the QC process. Data quality was measured using protocol violations, variability between interviewers, the proportion of inconsistent responders, and clustering of composite time trade-off values. Results: In Spain, protocol violations were reduced from 87% in the valuation study to 5% in the follow-up study and in the Netherlands from 20% to 8%. In both countries, interviewers performed more homogeneously in the follow-up studies. The number of inconsistent respondents was reduced by 23.2% in Spain and 23.6% in the Netherlands. Values were less clustered in the follow-up studies. Conclusions: The implementation of a strict QC process in EQ-5D-5L valuation studies increases interviewer protocol compliance and promotes data quality

Low protein intake during the preconception period in beef heifers affects offspring and maternal behaviour

Maternal low protein diets prior to conception alter embryo and fetal development and are associated with detrimental outcomes in the offspring in many species. The aim of this study in beef cattle was to investigate the effect of preconception dietary protein upon maternal and offspring behaviour at birth concomitant with the associated hormonal profile. Sixty days prior to conception, nulliparous yearling heifers (n = 85) were fed either a High (PreH: 18%; n = 43) or Low (PreL: 10%; n = 42) crude protein diet, followed by a control diet throughout gestation. After calving, each cow-calf pair was penned individually, accelerometers fitted, and each pen observed continuously via video recordings. Cows fed on the low protein diet during preconception showed an increase in standing time (P [less than] 0.01); while calves born to heifers receiving the PreL diet showed an increase in suckling time (P = 0.04). These calves were also heavier at birth than calves from PreH mothers (P [less than] 0.01). In conclusion, low maternal dietary protein prior to conception in beef heifers modifies both offspring feeding behaviour and birth weight, and cow’s standing times

Modelling non-dust fluids in cosmology

Currently, most of the numerical simulations of structure formation use Newtonian gravity. When modelling pressureless dark matter, or `dust', this approach gives the correct results for scales much smaller than the cosmological horizon, but for scenarios in which the fluid has pressure this is no longer the case. In this article, we present the correspondence of perturbations in Newtonian and cosmological perturbation theory, showing exact mathematical equivalence for pressureless matter, and giving the relativistic corrections for matter with pressure. As an example, we study the case of scalar field dark matter which features non-zero pressure perturbations. We discuss some problems which may arise when evolving the perturbations in this model with Newtonian numerical simulations and with CMB Boltzmann codes.Comment: 5 pages; v2: typos corrected and refs added, submitted version; v3: version to appear in JCA

Renormalization group and nonequilibrium action in stochastic field theory

We investigate the renormalization group approach to nonequilibrium field theory. We show that it is possible to derive nontrivial renormalization group flow from iterative coarse graining of a closed-time-path action. This renormalization group is different from the usual in quantum field theory textbooks, in that it describes nontrivial noise and dissipation. We work out a specific example where the variation of the closed-time-path action leads to the so-called Kardar-Parisi-Zhang equation, and show that the renormalization group obtained by coarse graining this action, agrees with the dynamical renormalization group derived by directly coarse graining the equations of motion.Comment: 33 pages, 3 figures included in the text. Revised; one reference adde

Microbiome network analysis in skin and gills of Sparus aurata fed with Nannochloropsis gaditana microalgae

1416 and 694 ASVs in gills and skin respectively were preserved in the taxonomic analysis after filtering. The predominant phylum in gills was Proteobacteria (~50%) in the control and hydrolyzed groups and reached 70.58% in the raw diet. The Bacteroidota phylum was the most represented and Firmicutes and Actinobacteria were close to 3% in all treatments in this tissue. However, in all three different treatments, the phyla abundance was similar in skin samples, ~90% of which corresponded to Proteobacteria. Bateroidota (5.5%–5.9%), Firmicutes (1.8%–2%) and Actinobacteria (<1%) constitute the other phyla. In gills, 13 significantly higher ASVs were obtained in the control (such as Achromobacter, Acidobacter) versus 4 whose abundance was higher in the hydrolyzed diet. The number of ASVs that differed significantly between the gill microbiota in the control vs. raw group amounted to 70, most of them being ASVs corresponding to the genus Shewanella (43) higher in the raw diet. Nevertheless, in the skin samples, Control group showed a significant increase of abundance related to Acinetobacter, Achromobacter, Pseudomonas, Shewanella, Vibrio and Sphingomonas among others. In the hydrolyzed group, the most significant abundance was associated with the genus Pseudomonas, Vibrio, Pseudoalteromonas, Ralstonia o Cutibacterium. In the case of the skin raw samples, there were ASVs corresponding to the genus Acinetobacter, Streptococcus or Pseudoalteromonas that were significantly different respect of control. Taking ASV abundance matrix for each diet and tissue, 6 co-occurrence networks were constructed. In all treatments in gills, Acinetobacter was a central genus in the network, and exhibited a negative correlation with Polaribacter. Besides, in the raw group, Polaribacter also showed negative correlation with Aeromonas, Pseudomonas and Francisellacea. This work shows that Acinetobacter has a key role in the balance of mucosa microbiota and was in co-exclusion with Polaribacter.This work was funded by research projects for young researchers, CEIMAR 2019 (Evaluation of hydrolysates of Nannochloropsis gaditana for use in high value-added finishing feed for farmed gilthead sea bream (Sparus aurata) (NAN2BREAM))

The influence of gene expression time delays on Gierer-Meinhardt pattern formation systems

There are numerous examples of morphogen gradients controlling long range signalling in developmental and cellular systems. The prospect of two such interacting morphogens instigating long range self-organisation in biological systems via a Turing bifurcation has been explored, postulated, or implicated in the context of numerous developmental processes. However, modelling investigations of cellular systems typically neglect the influence of gene expression on such dynamics, even though transcription and translation are observed to be important in morphogenetic systems. In particular, the influence of gene expression on a large class of Turing bifurcation models, namely those with pure kinetics such as the Gierer–Meinhardt system, is unexplored. Our investigations demonstrate that the behaviour of the Gierer–Meinhardt model profoundly changes on the inclusion of gene expression dynamics and is sensitive to the sub-cellular details of gene expression. Features such as concentration blow up, morphogen oscillations and radical sensitivities to the duration of gene expression are observed and, at best, severely restrict the possible parameter spaces for feasible biological behaviour. These results also indicate that the behaviour of Turing pattern formation systems on the inclusion of gene expression time delays may provide a means of distinguishing between possible forms of interaction kinetics. Finally, this study also emphasises that sub-cellular and gene expression dynamics should not be simply neglected in models of long range biological pattern formation via morphogens

Bovine sperm defects are affected by breed, age, season and region

This study reports the distribution of sperm morphology defects by breed, age, season and region of 11,387 bulls in 500 herds in Australia and near Pacific Islands during annual BBSE. Bull location was divided into 4 broad climatic regions based upon temperature, vegetation and climatic risk. Taking into account the impact of age, season, region, and breed there were differences between breeds in both percent morphologically normal sperm and in some individual categories of sperm abnormality (P < 0.001). Independent of breed, season and region, proximal droplets were significantly increased in bulls less than 20 months of age. This is the first study to comprehensively collect data from this wide geographical area and compare sperm morphology profiles among the Bos indicus and Bos taurus breeds. The findings of this study will act as a guide for veterinary practitioners and cattle breeders in the proportion of bulls that can be expected to pass the PNS test, by breed, age and region, based on a robust data set