118 research outputs found
Anomalous diffusion of self-propelled particles
The transport equation of active motion is generalised to consider
time-fractional dynamics for describing the anomalous diffusion of
self-propelled particles observed in many different systems. In the present
study, we consider an arbitrary active motion pattern modelled by a scattering
function that defines the dynamics of the change of the self-propulsion
direction. The exact probability density of the particle positions at a given
time is obtained. From it, the time dependence of the moments, i.e., the mean
square displacement and the kurtosis for an arbitrary scattering function, are
derived and analysed. Anomalous diffusion is found with a crossover of the
scaling exponent from in the short-time regime to in the
long-time one, being the order of the fractional derivative
considered. It is shown that the exact solution found satisfies a fractional
diffusion equation that accounts for the non-local and retarded effects of the
Laplacian of the probability density function through a coupled temporal and
spatial memory function. Such a memory function holds the complete information
of the active motion pattern. In the long-time regime, space and time are
decoupled in the memory function, and the time fractional telegrapher's
equation is recovered. Our results are widely applicable in systems ranging
from biological microorganisms to artificially designed self-propelled
micrometer particles
Exploring Biocontrol of Unwanted Fungi by Autochthonous Debaryomyces hansenii Strains Isolated from Dry Meat Products
The exploration of alternatives to the use of chemical preservatives in food is a topic that has attracted great attention. The implementation of regulations associated with the reduction of these elements directly affects the production of cured meat products, with the premise of looking for more “natural” alternatives. From a previously identified collection of 24 strains of Debaryomyces hansenii, isolated from dry meat products of the “Valle de los Pedroches” (Córdoba), a screening was carried out to determine which strains had inhibitory potential against a battery of fungi belonging to the genera Aspergillus, Penicillium, and Candida. After a series of general trials, four strains showing the greatest potential were selected by a streak inhibition assay performed at several concentrations of NaCl. The inhibitory activity of the selected D. hansenii strains was later evaluated by measuring their fungal antagonistic diffusible and volatile compound production following radial inhibition and mouth-to-mouth approaches, respectively. Growth aspects, sporulation, and morphology changes were also considered during these assays. The results support ideas already raised in previous studies, such as the presence of D. hanseniii could imply a reduction of pathogenic fungi in food. Autochthonous yeast strains inhibited not only the mycelial growth, but also sporulation, which strengthens the biocontrol activity of this yeast. Our results show that, under certain conditions, all tested D. hansenii strains were able to alter the growth/development of fungi, being especially evident in the cases of Penicillium expansum and Aspergillus niger. Finally, our research can facilitate the future comparison of results in this area, since we contributed to standardize the methodology described to date, we quantified the number of yeast cells and spores used during the experiments, we homogenized growth conditions for both, yeasts, and molds, and applied an image analyzer software to quantify the growth of the studied microorganisms in solid media
El despojo de cosa inmueble
Tesis inédita de la Universidad de Madrid, Facultad de Derecho, leída en 1968.Fac. de DerechoTRUEProQuestpu
A Finite Element‑Based Methodology for the Thermo‑mechanical Analysis of Early Age Behavior in Concrete Structures
This paper presents a general procedure based on fracture mechanics models in order to analyze the level of cracking
and structural safety in reinforced concrete elements at early ages, depending on the stripping time. Our procedure
involves the development of a thermo-mechanical numerical model based on the finite element method that
accounts for the change in the mechanical properties of concrete with time. Moreover, fracture mechanisms are
analyzed by means of a material damage model, which is characterized via specific experimental results obtained for
standard specimens and notched beams under three-point bending testing. The loading conditions are both thermal
and mechanical, and are obtained from the hydration process for a given concrete dosage. The presented methodology
allows for the determination of the optimal stripping time, whereas it helps assessing the analysis of the cracking
and the stress states of the elements under consideration. A practical application, namely the analysis of a retaining
wall, is used to validate our methodology, showing its suitability in engineering practice.Ministerio de Economía y Competitividad BIA2016-75431-
Acciones, políticas y estrategias para el balance de género en el ámbito STEM: Resultados de una dinámica World Café
[EN]W-STEM project is working to reduce the existing gender gap in Science, specifically in STEM
fields in Latin America. During an International Leadership Summit, held in Cartagena de Indias
(Colombia) on November 26th, 2019 within the project scope, forty-four people, including
researchers and policymakers at the higher education institutions, participated in a World Café
conversation to discuss about the potential actions, policies and strategies might be develop in
the universities to reduce the above mentioned gender gap in STEM studies. Four tables were
conducted, and this paper summarizes the most outstanding conclusions of the conversations
Overcoming biochar limitations to remediate pentachlorophenol in soil by modifying its electrochemical properties
In this study, we produced modified biochars with enhanced electrochemical properties to increase PCP remediation in soil. Although all biochars enhanced PCP remediation in aerobic conditions, only a few did in anaerobic soil. The most successful modifications were (i) the preloading of biomass with 10% w/w FeCl3, to obtain a biochar rich in redox-active metals (B-Fe); (ii) the oxidation of a conductive biochar pyrolyzed at 1000 ºC with 0.025 M KMnO4, to produce a biochar with both moderate conductivity and redox capacity (B-1000-KMnO4); and (iii) KMnO4 oxidation of an amorphous biochar pyrolyzed at 400 ºC to obtain a biochar with very high redox capacity (B-KMnO4). B-Fe reduced extractable PCP to almost zero after 50 days in both incubations, but showed slow kinetics of remediation in aerobic soil. B-1000-KMnO4 had the highest rate of remediation under aerobic conditions, but no significant effect under anaerobic conditions. B-KMnO4, however, presented high rates of remediation and high removal of extractable PCP under both conditions, which made it the recommended modification strategy for increased PCP remediation. We found that the degree of remediation primarily depends on the redox capacity, while the rate of remediation was determined by both the conductivity and redox capacity of biochar
Fricke and polymer gel 2D dosimetry validation using Monte Carlo simulation
Complexity in modern radiotherapy treatments demands advanced dosimetry systems for quality control. These systems must have several characteristics, such as high spatial resolution, tissue equivalence, three-dimensional resolution, and dose-integrating capabilities. In this scenario, gel dosimetry has proved to be a very promising option for quality assurance. In this study, the feasibility of Fricke and polymer gel dosimeters suitably shaped in form of thin layers and optically analyzed by visible light transmission imaging has been investigated for quality assurance in external radiotherapy. Dosimeter irradiation was carried out with a 6-MV photon beam (CLINAC 600C). The analysis of the irradiated dosimeters was done using two-dimensional optical transmission images. These dosimeters were compared with a treatment plan system using Monte Carlo simulations as a reference by means of a gamma test with parameters of 1 mm and 2%. Results show very good agreement between the different dosimetric systems: in the worst-case scenario, 98% of the analyzed points meet the test quality requirements. Therefore, gel dosimetry may be considered as a potential tool for the validation of other dosimetric systems.Fil: Vedelago, José Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Chacón Obando, D.. Universidad Nacional. Physics Department; Costa Rica. Universidad Nacional de Córdoba; ArgentinaFil: Malano, Francisco Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Conejeros, R.. Servicio de Radioterapia, Icos. Temuco, Chile;Fil: Figueroa, R.. Universidad de la Frontera; ChileFil: Garcia, D.. Servicio de Imagenes por Resonancia Magnética; ChileFil: González, G.. Servicio de Imagenes por Resonancia Magnética; ChileFil: Romero, Marcelo Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Santibañez, M.. Servicio de Imagenes por Resonancia Magnética; ChileFil: Strumia, Miriam Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Velásquez, J.. Servicio de Radioterapia; ChileFil: Mattea, Facundo. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Valente, M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad de La Frontera. Departamento de Ciencias Físicas; Chil
The Andalusian elections of 2018. The use of bots as a tool for analyzing the election's information agenda
Esta investigación analiza el uso de Twitter por parte de diferentes fuentes informativas y políticas, durante la campaña electoral andaluza de 2018. Para su realización se creó un bot (unfaking_es) que tuiteaba informaciones relacionadas con la campaña por parte de fuentes seleccionadas previamente -partidos políticos, candidatos, medios de comunicación-. Se diferencian dos momentos en la campaña electoral que aceleran la verificación de los hechos y los discursos, los debates electorales y la jornada electoral.This research aims to analyze the use of Twitter by different news and political sources during the Andalusian election campaign of 2018. In order to do so, a specific bot (unfaking_es) was created. The bot tweeted -with a series of preconditions- information related to the campaign from selected sources. Four informative actors were distinguished: political parties, candidates, media -including factcheckers- and official sources. Our work concludes that two different moments can be distinguished in the electoral campaign, which accelerate the verification of the facts and the speeches: the electoral debates and the electoral day
Effects of water stress on the phenolic compounds of ‘Merlot’ grapes in a semi-arid Mediterranean climate
Of all the abiotic stress types to which plants grown in fields are exposed, the most influential is water stress. It is well accepted that adopting controlled deficit irrigation strategies during the growing season has beneficial effects on the chemical compositions of grapes and red wines. However, there is a discrepancy in the timing, intensity and duration of deficit. This study aimed to evaluate the changes in phenolic composition of ‘merlot’ cultivar grapes when subjected to different levels of water stress in a semi-arid Mediterranean climate. Four treatments with different water stress levels were applied within two phenological intervals (flowering-veraison, veraison-maturity) to 128 grapevines for two consecutive years. The water stress levels for Treatments 1, 2, 3 and 4 were: no-light, light-moderate, moderate-intense and intense for the flowering-veraison and veraison-maturity intervals, respectively. Water stress distinctly affected the phenolic compounds in skin and seeds. The concentrations of flavan-3-ols and total polyphenols were much higher in seeds than in skin, and in both fractions, tannins are the major compound
Informe del W-STEM International Leadership Summit World Café. Cartagena de Indias, Colombia, 26 de noviembre de 2019
En el marco de “W-STEM [1-7] ERASMUS + Capacity-building in Higher Education
European Project” (Ref. 598923-EPP-1-2018-1-ES-EPPKA2-CBHE-JP), se celebró en
Cartagena de Indias, Colombia la Cumbre de Liderazgo Internacional de W-STEM de
Indias, los días 25 y 26 de noviembre de 2019
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