Using Hyperheuristics to Improve the Determination of the Kinetic Constants of a Chemical Reaction in Heterogeneous Phase

AbstractThe reaction in the human stomach when neutralizing acid with an antacid tablet is simu- lated and the evolution over time of the concentration of all chemical species present in the reaction medium is obtained. The values of the kinetic parameters of the chemical reaction can be determined by integrating the equation of the reaction rate. This is a classical opti- mization problem that can be approached with metaheuristic methods. The use of a parallel, parameterized scheme for metaheuristics facilitates the development of metaheuristics and their application. The unified scheme can also be used to implement hyperheuristics on top of pa- rameterized metaheuristics, so selecting appropriate values for the metaheuristic parameters, and consequently the metaheuristic itself. The hyperheuristic approach provides satisfactory values for the metaheuristic parameters and, consequently, satisfactory metaheuristics for the problem of determining the kinetic constants

A compartmental model for Xylella fastidiosa diseases with explicit vector seasonal dynamics

The bacterium Xylella fastidiosa (Xf) is mainly transmitted by the spittlebug, Philaenus spumarius, in Europe, where it has caused significant economic damage to olive and almond trees. Understanding the factors that determine disease dynamics in pathosystems that share similarities can help design control strategies focused on minimizing transmission chains. Here we introduce a compartmental model for Xf-caused diseases in Europe that accounts for the main relevant epidemiological processes, including the seasonal dynamics of P. spumarius. The model was confronted with epidemiological data from the two major outbreaks of Xf in Europe, the olive quick disease syndrome (OQDS) in Apulia, Italy, caused by the subspecies pauca, and the almond leaf scorch disease (ALSD) in Majorca, Spain, caused by subspecies multiplex and fastidiosa. Using a Bayesian inference framework, we show how the model successfully reproduces the general field data in both diseases. In a global sensitivity analysis, the vector-plant and plant-vector transmission rates, together with the vector removal rate, were the most influential parameters in determining the time of the infected host population peak, the incidence peak and the final number of dead hosts. We also used our model to check different vector-based control strategies, showing that a joint strategy focused on increasing the rate of vector removal while lowering the number of annual newborn vectors is optimal for disease control.Comment: 18 pages, 8 figure

Spatial effects in parasite-induced marine diseases of immobile hosts

Emerging marine infectious diseases pose a substantial threat to marine ecosystems and the conservation of their biodiversity. Compartmental models of epidemic transmission in marine sessile organisms, available only recently, are based on non-spatial descriptions in which space is homogenized and parasite mobility is not explicitly accounted for. However, in realistic scenarios epidemic transmission is conditioned by the spatial distribution of hosts and the parasites' mobility patterns, calling for an explicit description of space. In this work, we develop a spatially explicit individual-based model to study disease transmission by waterborne parasites in sessile marine populations. We investigate the impact of spatial disease transmission through extensive numerical simulations and theoretical analysis. Specifically, the effects of parasite mobility into the epidemic threshold and the temporal progression of the epidemic are assessed. We show that larger values of pathogen mobility imply more severe epidemics, as the number of infections increases, and shorter timescales to extinction. An analytical expression for the basic reproduction number of the spatial model, R~0, is derived as a function of the non-spatial counterpart, R 0, which characterizes a transition between a disease-free and a propagation phase, in which the disease propagates over a large fraction of the system.Fil: Giménez Romero, Àlex. Consejo Superior de Investigaciones Científicas. Instituto de Física Interdisciplinar y Sistemas Complejos; EspañaFil: Vazquez, Federico. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Calculo. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Calculo; Argentina. Consejo Superior de Investigaciones Científicas. Instituto de Física Interdisciplinar y Sistemas Complejos; EspañaFil: López, Cristóbal. Consejo Superior de Investigaciones Científicas. Instituto de Física Interdisciplinar y Sistemas Complejos; EspañaFil: Matías, Manuel A.. Consejo Superior de Investigaciones Científicas. Instituto de Física Interdisciplinar y Sistemas Complejos; Españ

A potential role of tannins in the control of American Foulbrood

Aim of study: to evaluate the use of tannins extracts in the control of the American Foulbroodpathology; and investigated if these extracts present levels of toxicity on Apis melliferaArea of study: Paenibacillus larvae Strains C1 and C2 were from Balcarce, province ofBuenos Aires (37°52?S-58°15?W), strain C6 from Rio Cuarto, in Cordoba province(33°08′00″S 64°21′00″O) and strain C9 from Concordia in Entre Rios province(31°23′32″S 58°01′01″O). Bees larvae used for toxicological assays were collected in SantaPaula experimental apiary, Mar del Plata (National Route 226, Km 10, Argentina)(37°55′48″S 57°40′59″O), belonging to the Centro de Investigación en Abejas Sociales (CIAS- IIPROSAM) from UNMdP.Material and methods: The Minimal Inhibitory Concentration (MIC) of 5 different tanninextracts were obtained by agar diffusion method on four P. larvae strains; using the MICvalue, the toxicity test on Apis mellifera larvae was performed afterwards.Main results: The MIC value presented a range of 6.9 to 898.6 µg/mL; and three tanninextracts do not present toxicity against bee larvae. Once the test was finished, the larvae fedwith the extracts that did not show toxicity, showed a significant increase in weight. Research highlights: The tanning extracts show a good antimicrobial activity against bee larvae.Fil: Giménez Martínez, Pablo Darian. Universidad Nacional de Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente.; ArgentinaFil: Maggi, Matías Daniel. Universidad Nacional de Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente.; ArgentinaFil: Fuselli, Sandra Rosa. Universidad Nacional de Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente.; Argentin

Suelos loéssicos influenciados por depósitos de conchilla pleistocenos de la formación pascua, noreste de la provincia de Buenos Aires, Argentina

En el litoral de la provincia de Buenos Aires se encuentran varias unidades litoestratigráficas cuaternarias carbonáticas vinculadas a ingresiones marinas. En la Formación Las Escobas (Holoceno) se desarrollan suelos calcáreos litogénicos que han sido objeto de estudios taxonómicos, mineralógicos y micromorfológicos. La unidad marina más antigua es la Formación Pascua (Pleistoceno medio a superior) intercalada en la parte superior de sedimentos loéssicos de la Formación Pampiano y constituida por sedimentos arenosos, cuya parte superior posee alta concentración de valvas de moluscos fuertemente cementadas con carbonato de calcio, constituyendo una coquina. Los suelos actuales, de los cuales hay escasa información y son motivo de esta presentación, se desarrollan principalmente en los sedimentos suprayacentes de la Formación Pampiano y están afectados por procesos de carbonatación, argiluviación y vertisolización. Los objetivos de esta contribución son: a) analizar las propiedades de los suelos desarrollados en sedimentos loéssicos que cubren a la Formación Pascua, y b) estimar la influencia de los depósitos carbonáticos de esta formación en la génesis de los suelos. Se estudiaron cinco pedones (cuatro Molisoles y un Vertisol) en los partidos de La Plata, Magdalena y Punta Indio (provincia de Buenos Aires), en los cuales los depósitos carbonáticos tienen influencia en los horizontes inferiores de los suelos. Los pedones se desarrollan en sucesiones estratigráficas donde en la parte inferior se encuentra la Formación Pascua y donde los procesos de pedogénesis afectan a veces el techo de la misma. Es decir, que en algunos suelos hay un ciclo pedológico completo (horizontes A, B y C) desarrollado en materiales loéssicos y en otros casos, parte del ciclo pedológico (solum: horizontes A y B) se desarrolla en el loess y parte en la coquina (horizontes C). Todos los suelos poseen evolución calcárea, con horizontes enriquecidos con carbonato de calcio y/o horizontes cálcicos y/o horizontes petrocálcicos (calcreta). Los horizontes enriquecidos en carbonato de calcio y los horizontes cálcicos están desarrollados en los depósitos loéssicos, mientras que el horizonte petrocálcico se desarrolla en la parte superior de la coquina, por alteración epigénica de la misma, y cuyo contacto con el depósito loéssico suprayacente es neto (espesor <2 cm) y de forma plana u ondulada. Los horizontes petrocálcicos constituyen una calcreta pedogénica de clima húmedo, compacta, sin estructura (masiva) o laminar, de menos de 10 cm de espesor. El origen del carbonato pedogénico puede atribuirse a varios mecanismos: a) disolución de carbonatos en la parte superior del perfil, translocación descendente y precipitación; b) ascenso capilar y evaporación de agua carbonatada acumulada en la parte superior de capas compactas, casi impermeables; c) disolución y reprecipitación in situ de los carbonatos de la coquina y d) precipitación biogénica debida a la acción de bacterias, hongos y raíces, como proceso complementario. El proceso de carbonatación sería de origen mixto: a) por reorganización de la roca basal y b) por translocación en clima húmedo; en ambos casos el carbonato pedogenético tendría origen abiótico con participación biótica. Predomina la cristalización y recristalización, ya sea por disolución de depósitos preexistentes o por soluciones carbonatadas de desplazamiento vertical y lateral, interviniendo asimismo la biomineralización en estructuras orgánicas

Polymeric films based on blends of 6FDA-6FpDA polyimide plus several copolyfluorenes for CO2 separation

Producción CientíficaThree emitting copolyfluorenes, based on 2,7-(9,9-dihexyl)fluorene and different aryl groups (1,4-bencene, PFH-B; 1,4-bencen-1,2,5-thiadiazole PFH-BT; 1,4-naphthalen- 1,2,5-thiadiazole, PFH-NT), showing diverse acceptor character, in different proportions were blended with a polyimide 6FDA-6FpDA to make a series of films. These copolyfluorene-polyimide blends were prepared and characterized in solid state, using several techniques. The fluorescence of conjugated polymers can be used as a tool to understand the formation of the membrane and also to increase permeability and selectivity in comparison to films without fluorescence. The relationship between the intrinsic fluorescence of conjugated polyfluorenes and their gas separation properties has been explored in order to establish the influence of the composition and the nature of the aryl group, in the conjugated polymer, on the gas separation performances. In all cases, a low proportion of copolyfluorenes (< 1%weight) gives better CO2/CH4 permselectivity properties than the original pure polyimide matrix. The best results were found for the samples that contain PFH-NT. This sample gives 25 % increase in the CO2 permeability with 15 % increase in CO2/CH4 selectivity. Finally, the loss of efficiency in conjugation mechanisms of absorption and emission of the samples could be explained on the basis of the π-staking of the polymer chains produced when a certain low percentage of conjugated polymers in the blend is surpassed. When this π- staking starts, gas permeation properties start to decline too.Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA302U13

Exploiting Heterogeneous Parallelism on Hybrid Metaheuristics for Vector Autoregression Models

In the last years, the huge amount of data available in many disciplines makes the mathematical modeling, and, more concretely, econometric models, a very important technique to explain those data. One of the most used of those econometric techniques is the Vector Autoregression Models (VAR) which are multi-equation models that linearly describe the interactions and behavior of a group of variables by using their past. Traditionally, Ordinary Least Squares and Maximum likelihood estimators have been used in the estimation of VAR models. These techniques are consistent and asymptotically efficient under ideal conditions of the data and the identification problem. Otherwise, these techniques would yield inconsistent parameter estimations. This paper considers the estimation of a VAR model by minimizing the difference between the dependent variables in a certain time, and the expression of their own past and the exogenous variables of the model (in this case denoted as VARX model). The solution of this optimization problem is approached through hybrid metaheuristics. The high computational cost due to the huge amount of data makes it necessary to exploit High-Performance Computing for the acceleration of methods to obtain the models. The parameterized, parallel implementation of the metaheuristics and the matrix formulation ease the simultaneous exploitation of parallelism for groups of hybrid metaheuristics. Multilevel and heterogeneous parallelism are exploited in multicore CPU plus multiGPU nodes, with the optimum combination of the different parallelism parameters depending on the particular metaheuristic and the problem it is applied to.This work was supported by the Spanish MICINN and AEI, as well as European Commission FEDER funds, under grant RTI2018-098156-B-C53 and grant TIN2016-80565-R

Immune-related gene expression in honey bee larva (Apis mellifera) exposed to plant extracts from Humulus lupulus with antimicrobial activity against Paenibacillus larvae

American foulbrood caused by Paenibacillus larvae brings with it several problems on beekeepers for the use of synthetic antibiotics, likewise led to the appearance of resistant strains and the presence of chemical residues in the commercial products of the hive. In recent years, the use of natural compounds for the control of P. larvae has increased. Herein, we propose to determine the value of the Minimal Inhibitory Concentration (MIC) of a hydroalcoholic extract of Humulus lupulus (hop) leaves of Victoria variety on P. larvae strain, and to evaluate its toxicity and effect on the expression of three genes of the immune system on honey bee larvae. For the extract, the MIC value was 83.79 μg/mL. For larvae, the extract did not show toxicity, on the other hand presented a down-regulation in the gene expression for the three genes evaluated. The results obtained here are a first report on the evaluation in the effect of natural extracts on the expression of genes related to the immune system in bee larvae.Fil: Giménez Martínez, Pablo Darian. Universidad Nacional de Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente.; ArgentinaFil: Zuñiga, Fabian. Universidad del Desarrollo; ChileFil: Junges, Celina Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; ArgentinaFil: Maggi, Matías Daniel. Universidad Nacional de Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente.; ArgentinaFil: Fuselli, Sandra Rosa. Universidad Nacional de Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente.; ArgentinaFil: Martínez, Jessica. Universidad del Desarrollo; Chil

DNA damage triggers squamous metaplasia in human lung and mammary cells via mitotic checkpoints

Epithelial transdifferentiation is frequent in tissue hyperplasia and contributes to disease in various degrees. Squamous metaplasia (SQM) precedes epidermoid lung cancer, an aggressive and frequent malignancy, but it is rare in the epithelium of the mammary gland. The mechanisms leading to SQM in the lung have been very poorly investigated. We have studied this issue on human freshly isolated cells and organoids. Here we show that human lung or mammary cells strikingly undergo SQM with polyploidisation when they are exposed to genotoxic or mitotic drugs, such as Doxorubicin or the cigarette carcinogen DMBA, Nocodazole, Taxol or inhibitors of Aurora-B kinase or Polo-like kinase. To note, the epidermoid response was attenuated when DNA repair was enhanced by Enoxacin or when mitotic checkpoints where abrogated by inhibition of Chk1 and Chk2. The results show that DNA damage has the potential to drive SQM via mitotic checkpoints, thus providing novel molecular candidate targets to tackle lung SCC. Our findings might also explain why SCC is frequent in the lung, but not in the mammary gland and why chemotherapy often causes complicating skin toxicity