112 research outputs found

    Random regression model of growth during the first three months of age in Spanish Merino sheep

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    A total of 88,727 individual BW records of Spanish Merino lambs, obtained from 30,214 animals between 2 and 92 d of age, were analyzed using a random regression model (RRM). These animals were progeny of 546 rams and 15,586 ewes raised in 30 flocks, between 1992 and 2002, with a total of 45,941 animals in the pedigree. The contemporary groups (animals of the same flock, year, and season, with 452 levels), the lambing number (11 levels), the combination sex of lambs with type of litter (4 levels), and a fixed regression coefficient of age on BW were included as fixed effects. A total of 7 RRM were compared, and the best fit was obtained for a model of order 3 for the direct and maternal genetic effects and for the individual permanent environmental effect. For the maternal permanent environmental effect the best model had an order 2. The residual variance was assumed to be heterogeneous with 10 age classes; the covariance between both genetic effects was included. According to the results of the selected RRM, the heritability for both genetic effects (ha2 and hm2) increased with age, with estimates of 0.123 to 0.186 for ha2 and of 0.059 to 0.108 for hm2. The correlations between direct and genetic maternal effects were −0.619 to −0.387 during the first 45 d of age and decreased as age increased, until reaching values from −0.366 to −0.275 between 45 to 75 d of age. Important changes in ranking of the animals were found based on the breeding value estimation with the current method and with the random regression procedure. The use of RRM to analyze the genetic trajectory of growth in this population of Merino sheep is highly recommended

    Técnicas de aprendizaje estadístico en modelos de valoración dinámica de precios

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    En el presente trabajo se estudian diversas técnicas de aprendizaje por refuerzo con la idea de solucionar varios problemas de fijación y planificación de precios. Para ello, se lleva a cabo una introducción al aprendizaje por refuerzo, estudiando los problemas de decisión de Markov en el caso de un único agente. En estos juegan un papel fundamental las ecuaciones de optimalidad de Bellman, que permiten el desarrollo de métodos para la resolución del problema. En el trabajo se verán los algoritmos Q-Learning, SARSA y dos de sus variantes. En el caso de varios agentes se estudian los juegos matriciales y su generalización a varios estados, los juegos estocásticos. En estos problemas, y bajo el soporte de la teoría de juegos, aparecen los equilibrios de Nash. Veremos dos de las principales técnicas para resolver estos problemas, los métodos de mejor respuesta y los métodos de los equilibrios. Finalmente se analizarán los resultados obtenidos tras aplicar los algoritmos estudiados a problemas de fijación de precios.<br /

    Constitutive modeling of hot deformation of carbon steels in the intercritical zone

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    A previous constitutive modeling for single-phase steels is extended using the mixing law to predict the behavior of hot deformation in the dual phase ferritic-austenitic intercritical zone of Fe-C-Mn-Si alloys. Mixing law considers two phases instead one, so one phase formula was modified. The constant’s values used represents average values to the same conditions in austenitic and ferritic model. The amount of each phase is determined as function of temperature and chemical composition. The developed constitutive modeling is validated by comparing the theoretical stress-strain curves with experimental isothermal uniaxial compression tests of 1008 and 1035 carbon steels at different temperatures and strain rates. The compression tests were carried out in a dilatometer with the compression load at strain rate of 10-3, 10-2 and 10-1 s-1. A good agreement was obtained between the calculated and experimental results over different stages of deformation and hardening. Microstructural analysis was also carried out to relate the deformation results to the microstructure of the steels. Finally, a general constitutive equation has been proposed for hot deformation of steels in the intercritical zone.Peer ReviewedPostprint (published version

    Análisis de la disponibilidad a pagar por carne de cerdo libre de antibióticos, un enfoque de Experimentos de Elección

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    Health issues and the production of differentiated foods influence the consumers' decisions and lead them to opt for products with particular organoleptic characteristics. The objective of this research was to estimate the preferences and willingness to pay for antibiotic-free pork in the municipality of Texcoco, State of Mexico, in order to determine the existence or absence of an incentive for the commercialization of antibiotic-free pork. The Discrete Choice Method of Experiments was used. The attributes considered in the design were: color, fat content, and presence of antibiotics. A survey of 196 consumers was carried out for this purpose. The results were analyzed with the NLOGIT 4.0 software, using a mixed logit model. The most valued attribute was antibiotic content, which means that respondents would be willing to pay an additional premium of 30.65MXN/kgforantibioticfreepork.Itwasfoundthatthehighertheincomeandthehigherthefrequencyofporkconsumption,thegreaterthewillingnesstopayanadditionalpremiumforantibioticfreemeat.AWTPof30.65 MXN/kg for antibiotic-free pork. It was found that the higher the income and the higher the frequency of pork consumption, the greater the willingness to pay an additional premium for antibiotic-free meat. A WTP of 5.78 MXN was determined for meat with normal fat, and of 3.73MXNforredmeat.PorkconsumersintheeasternpartoftheStateofMexicowouldbewillingtopayanadditionalpremiumforantibioticfreeporkandforsuchqualityaspectsasfatcontentandcolor.Losproblemasdesaludylaproduccioˊndealimentosdiferenciadosinfluyenenlasdecisionesdelosconsumidoresylosorientaaoptarporproductosconcaracterıˊsticasorganoleˊpticasparticulares.ElobjetivodeestainvestigacioˊnfueestimarlaspreferenciasydisposicioˊnapagarporcarnedecerdolibredeantibioˊticosenelmunicipiodeTexcoco,EstadodeMeˊxico,paradeterminarlaexistenciaonodeunincentivoparalacomercializacioˊndecarnedeestetipo.SeutilizoˊelMeˊtododeExperimentosdeEleccioˊnDiscreta.Losatributosconsideradoseneldisen~ofueron:color,contenidodegrasaypresenciadeantibioˊticos.Paraelloseaplicoˊunaencuestaa196consumidores.LosresultadosseanalizaronconelsoftwareNLOGIT4.0,medianteunmodelologitmixto.Elatributomaˊsvaloradofuecontenidodeantibioˊticos,loquesignificaquelosentrevistadosestarıˊandispuestosapagarunaprimaadicionalde3.73 MXN for red meat. Pork consumers in the eastern part of the State of Mexico would be willing to pay an additional premium for antibiotic-free pork and for such quality aspects as fat content and color.Los problemas de salud y la producción de alimentos diferenciados influyen en las decisiones de los consumidores y los orienta a optar por productos con características organolépticas particulares. El objetivo de esta investigación fue estimar las preferencias y disposición a pagar por carne de cerdo libre de antibióticos en el municipio de Texcoco, Estado de México, para determinar la existencia o no de un incentivo para la comercialización de carne de este tipo. Se utilizó el Método de Experimentos de Elección Discreta. Los atributos considerados en el diseño fueron: color, contenido de grasa y presencia de antibióticos. Para ello se aplicó una encuesta a 196 consumidores. Los resultados se analizaron con el software NLOGIT 4.0, mediante un modelo logit mixto. El atributo más valorado fue contenido de antibióticos, lo que significa que los entrevistados estarían dispuestos a pagar una prima adicional de 30.65 MXN/kg de carne de cerdo libre de antibióticos. Se encontró que, a mayor ingreso y a mayor frecuencia de consumo en carne de cerdo, mayor disposición a pagar una prima adicional por carne libre de antibióticos. Se determinó una DAP de 5.78MXNporcarnecongrasanormalyde5.78 MXN por carne con grasa normal y de 3.73 MXN más por carne de color rojo. Los consumidores de carne de cerdo del oriente del Estado de México estarían dispuestos a pagar una prima adicional por carne de cerdo libre de antibióticos y aspectos de calidad como contenido de grasa y color

    Disposición a pagar por carne de cerdo sin antibióticos en el Estado de México

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    Pork represents the second source of protein in Mexico due to the multiple benefits of its consumption. However, several studies link the indiscriminate use of antibiotics with public health problems. This study aimed to know the willingness to pay for antibiotic-free pork with the contingent valuation method (CV). Questionnaires were applied to 156 consumers in eastern State of Mexico and the data were analyzed with a binomial logit model. It was found on average, a willingness to pay a premium of 16.34% (17.81MXNkg1)asamarkupprice.Themostrepresentativevariableswerepremiumamount,age,numberofdependentsinhousehold,incomeandfrequencyofconsumption.Theresultsindicatedthatthereisapotentialmarketfordifferentiatedantibioticfreeporkmeat,sothatconsumersarewillingtopayapremiumperkgof16.3417.81 MXN kg-1) as a markup price. The most representative variables were premium amount, age, number of dependents in household, income and frequency of consumption. The results indicated that there is a potential market for differentiated antibiotic-free pork meat, so that consumers are willing to pay a premium per kg of 16.34% over the price of conventional meat.La carne de cerdo representa la segunda fuente de proteína en México debido a los múltiples beneficios de su consumo. Sin embargo, diversos estudios relacionan el uso indiscriminado de antibióticos con problemas de salud pública. Este estudio tuvo como objetivo conocer la disposición a pagar por carne de cerdo libre de antibióticos con el método de valoración contingente (VC). Se aplicaron cuestionarios a 156 consumidores en la zona oriente del Estado de México y se analizaron los datos con un modelo logit binomial. Se encontró en promedio, una disposición a pagar una prima de 16.34% (MXN 17.81 kg-1) como sobreprecio. Las variables más representativas fueron monto de la prima, edad, número de dependientes en el hogar, ingreso y frecuencia de consumo. Los resultados indicaron que existe un mercado potencial para carne de cerdo diferenciada libre de antibióticos y que los consumidores están dispuestos a pagar una prima por kg 16.34% adicional al precio de la carne convencional

    Tectono-Sedimentary Cenozoic Evolution of the El Habt and Ouezzane Tectonic Units (External Rif, Morocco)

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    An interdisciplinary study based on lithostratigraphic, biostratigraphic, petrographic and mineralogical analyses has been performed in order to establish the Cenozoic tectono-sedimentary evolution of the El Habt and Ouezzane Tectonic Units (External Intrarif Subzone, External Rif, Morocco). The reconstructed record allowed identification of the depositional architecture and related sedimentary processes of the considered units. The Cenozoic successions were biochronologically defined allowing, at the same time, identification of unconformities and associated stratigraphic gaps. The presence of five unconformities allowed for the definition of the main stratigraphic units arranged in a regressive trend: (1) lower Paleocene interval (Danian p.p.) assigned to a deep basin; (2) Eocene interval (lower Ypresian-lower Bartonian p.p.) from a deep basin to an external carbonate-siliceous platform; (3) lower Rupelian-upper Chattian p.p. interval deposited on unstable slope with turbidite channels passing upward to an external siliciclastic platform; (4) Burdigalian p.p. interval from a slope; (5) Langhian-Serravallian p.p. interval from slope to external platform realms. The petrography of the arenites and calcarenites allowed for the identification of the supplies derived from erosion of a recycled orogen (transitional and quartzose subtypes). The clay-mineralogy analysis indicates an unroofing (first erosion of Cretaceous terrains followed by upper Jurassic rocks) always accomplished by erosion of Cenozoic terrains. Several tectofacies checked in some stratigraphic intervals seem to indicate the beginning of deformation of the basement generating gentle folds and first activation of blind thrusts, mainly during the Paleogene. A preorogenic tectonic framework is considered as responseto the generalized tectonic inversion (from extension to compression) as frequently registered in the central-western peri-Mediterranean areas. The large volumes of reworked terrigeneous supply during the latest Oligocene-Miocene p.p. indicates the beginningsof the synorogenic sedimentation (foredeep stage of the basins) controlled by active tectonics.Research Project CGL2016-75679-P (Spanish Ministry of Education and Science); Research Groups, Projects of the Generalitat Valenciana, Alicante University (CTMA-IGA); Grants from the University of Urbino Carlo Bo (M. Tramontana)

    Analysis of children strollers and prams safety in urban buses

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    The wide incorporation of low floor buses in our cities encourages that child younger than three years, seated on their stroller could use the buses. Currently, the UNECE Regulation No 107 at its revision 5 has included general provisions for the accessibility and basic safety for this type of users. An applied research has been performed to analyze the level of protection offered for the stroller restraint systems included in R107, by performing dynamic tests with instrumented dummies. More than 20 dynamic sled tests were performed to assess the child safety in urban buses. Two types of configurations have been tested: a vehicle specific CRS for urban buses and the own stroller with different restraint systems. The specific vehicle built-in CRS tested is a rearward facing group 0/I that is currently in use in the city of Madrid (Spain) by the public urban buses. This CRS was tested in frontal and rear impact with the acceleration pulse defined in the UNECE regulation No 80. On the other hand, to make suggestions for using the stroller in urban buses, a very low severity crash pulse (up to 2 g peak acceleration and AV = 20 km/h) was defined and used in this study. Four stroller models with three types of restraint devices (safety belt, PRM wheelchair backrest and a folding backrest device) were tested with this pulse. The strollers were selected in order to reduce biasing of the results. Several dummies (P3, Q3 and Q1) were used to evaluate the injuries and the kinematics. Furthermore, different sources of IRAV have been applied for the Q dummies (R94 and FMVSS 208 scaled by applying Mertz 2003 techniques), an extended range of injury criteria is obtained and an in depth analysis of the protection offered by the different restraints systems used is performed

    Miocene evolution of the External Rif Zone (Morocco): comparison with similar and lateral southern Mediterranean Tethyan margins

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    The Miocene evolution of the External Rif Zone (NW Africa Plate) was determined through the multidisciplinary analysis of fourteen successions. The updated stratigraphic framework shows how Miocene sediments rest on the Cretaceous–Paleogene terrains through unconformity surfaces, whereas it rests with sedimentary continuity in two sectors. After recognition of lithofacies and three unconformities located near the Oligocene–Aquitanian, Aquitanian–Burdigalian and Serravallian–Tortonian boundaries, the Miocene sedimentary record was divided into three stratigraphic intervals representing deep to shallow marine deposits as Aquitanian–Burdigalian, Langhian and Upper Serravallian–Missinian. The two oldest unconformites are restricted to the central sector, while the upper one is generalized and probably related to the nappe tectonics registered in all sectors of the External Rif. Data from analysis of tectofacies, petrology, mineralogy, meaning and implications of unconformities, and subsidence indicate that: (i) mass flow deposits (turbidites, slumps, olistostromes) are common in all successions but more frequent during the Lower Miocene; (ii) petrology of the detrital components of the arenites indicates recycled orogen-derived sediments, with quartz coming from erosion of metamorphic rocks of the Atlas orogen and/or the African craton; (iii) mineralogy of mudstones suggests a complex erosional evolution of local emerged areas derived from a mixture of contributions coming from the erosion of Upper Jurassic to Paleogene suites, and especially from kaolinite-rich Albian–Cenomanian to Paleogene successions with absence of a clear unroofing. The conjunction of all these clues reinforce the idea of a synsedimentary tectonics affecting the margin/basin system during the Miocene. A thickness analysis of the studied sedimentary successions allows proposing the evolution of the orogenic front and main depozones (foredeep, bulges, wedge-top and intramontane sub-basins) integrated in a complex foreland system migrating from north to south with the Atlas-Mesetas area acting as foreland during MIocene. The orogenic front moved from the Internal Intrarif to Mesorif and later to Internal Prerif. The main wedge-top basin also migrated from the Internal Intrarif to External Intrarif. The foredeep migrated from the Mesorif to the Internal Prerif, while the main forebulge was located in the External Prerif and a asecondary bulge developed in the External Intrarif. Intramontane basins developed behind the orogenic front in relative extensional conditions moving from the Internal Extrarif to External Intrarif. The reconstructed Miocene evolution was inserted into a 2D paleogeographic-geodynamic evolutionary model using Gplates software, and then compared to those reported in other external margins of the western Tethys (Betic Chain, Tunisian Tell, Sicilian Maghrebids and Apennines), revealing important similarities and local differences.Research supported by PID2020-114381GB-I00 Research Project (Spanish Ministry of Education and Science), EU HORIZON project CiROCCO under Grant Agreement No 101086497, Research Groups and projects of the Generalitat Valenciana from Alicante University (CTMA-IGA), and Research Group RNM-188 of the Junta de Andalucía from EEZA–CSIC
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