1,484 research outputs found

    From Simulations to Reality: Dark Energy Reconstruction with Simulated SNIa data from the Vera C. Rubin Observatory

    Full text link
    In this paper, we present an Artificial Neural Network (ANN) based reconstruction analysis of the Supernova Ia (SNIa) distance moduli (μ(z)\mu(z)), and hence dark energy, using LSST simulated three-year SNIa data. Our ANN reconstruction architecture can model both the distance moduli and their corresponding error estimates. For this we employ astroANN and incorporate Monte Carlo dropout techniques to quantify uncertainties in our predictions. We tune our hyperparameters through advanced genetic algorithms, including elitism, utilizing the DEAP library. We compared the performance of the ANN based reconstruction with two theoretical descriptions of dark energy models, Λ\LambdaCDM and Chevallier-Linder-Polarski (CPL). We perform a Bayesian analysis for these two theoretical models using the LSST simulations and also compare with observations from Pantheon and Pantheon+ SNIa real data. We show that our model-independent reconstruction using ANN is consistent with both of them. We assessed the performance using mean squared error (MSE) and showed that the ANN can produce distance estimates in better agreement with the LSST dataset than either Λ\LambdaCDM or CPL, albeit very small. We included an additional residual analysis and a null test with FF-scores to show that the reconstructed distances from the ANN model, are in excellent agreement with the Λ\LambdaCDM or CPL model.Comment: 14 Pages, 5 figures. Submitted to journa

    Analysis of Dark Matter Halo Structure Formation in NN-body Simulations with Machine Learning

    Full text link
    The properties of the matter density field in the initial conditions have a decisive impact on the features of the large-scale structure of the Universe as observed today. These need to be studied via NN-body simulations, which are imperative to analyze high density collapsed regions into dark matter halos. In this paper, we train Machine Learning algorithms with information from N -body simulations to infer two properties: dark matter particle halo classification that leads to halo formation prediction with the characteristics of the matter density field traced back to the initial conditions, and dark matter halo formation by calculating the Halo Mass Function (HMF), which offers the number density of dark matter halos with a given threshold. We map the initial conditions of the matter density field into classification labels of dark matter halo structures. The Halo Mass Function of the simulations is calculated and reconstructed with theoretical methods as well as our trained algorithms. We test several Machine Learning techniques where we could find that the Random Forest and Neural Networks proved to be the better performing tools to classify dark matter particles in cosmological simulations. We also show that that it is not compulsory to use a high amount of data to train the algorithms in order to reconstruct the HMF, giving us a very good fitting function for both simulation and theoretical results.Comment: 10 pages, 6 figure

    Cosmological parameter estimation with Genetic Algorithms

    Full text link
    Genetic algorithms are a powerful tool in optimization for single and multi-modal functions. This paper provides an overview of their fundamentals with some analytical examples. In addition, we explore how they can be used as a parameter estimation tool in cosmological models to maximize the likelihood function, complementing the analysis with the traditional Markov Chain Monte Carlo methods. We analyze that genetic algorithms provide fast estimates by focusing on maximizing the likelihood function, although they cannot provide confidence regions with the same statistical meaning as Bayesian approaches. Moreover, we show that implementing sharing and niching techniques ensures an effective exploration of the parameter space, even in the presence of local optima, always helping to find the global optima. This approach is invaluable in the cosmological context, where exhaustive space exploration of parameters is essential. We use dark energy models to exemplify the use of genetic algorithms in cosmological parameter estimation, including a multimodal problem, and we also show how to use the output of a genetic algorithm to obtain derived cosmological functions. This paper concludes that genetic algorithms are a handy tool within cosmological data analysis, without replacing the traditional Bayesian methods but providing different advantages.Comment: 19 pages, 6 figures; matches version published in Univers

    Análisis de la agenda pública y privada de la Bioeconomía en Centroamérica y el Caribe: Estudios de Caso de El Salvador, Honduras, Cuba y Nicaragua

    Get PDF
    Rev. iberoam. bioecon. cambio clim. Vol.1(1) 2015; 242-284El presente trabajo se focalizó en investigar la política que los gobiernos están implementando para desarrollar la Bioeconomìa en los países de El Salvador, Honduras, Nicaragua y Cuba. Se utilizó la metodología de estudio de caso, donde los especialistas de la Red de Bioeconomía y Cambio Climático donde se aborda la situación de la política y normativas que los gobiernos han venido implementado. La investigación brinda como resultado la necesidad de ir introduciendo el tema de la Bioeconomía en la agenda pública y privada de los senderos de la bioeconomia como una alternativa de las comunidades rurales para dar respuesta a las variaciones del cambio climático y la creciente demanda de alimentos y fibras que presupone el crecimiento exponencial de la población. El trabajo investigativo se organizó en de la siguiente manera: Políticas sectoriales y normas regulatorias de la Bioeconomía: Caso El Salvador que lo abordan los especialista del grupo país de El Salvador el segundo caso es Agenda de política pública y privada para la bioeconomia: caso Honduras elaborada por los especialista del grupo país de Honduras, el tercer caso es Políticas Públicas para la Bioeconomía en Cuba realizada por los especialistas del grupo país de Cuba y finalmente Nicaragua que refiere la política que sobre el tema se viene impulsando.Rev. iberoam. bioecon. cambio clim. Vol.1(1) 2015; 242-28

    Análisis de la agenda pública y privada de la Bioeconomía en Centroamérica y el Caribe: Estudios de Caso de El Salvador, Honduras, Cuba y Nicaragua

    Get PDF
    El presente trabajo se focalizó en investigar la política que los gobiernos están implementando para desarrollar la Bioeconomìa en los países de El Salvador, Honduras, Nicaragua y Cuba.   Se utilizó la metodología de estudio de caso, donde los especialistas de la Red de Bioeconomía y Cambio Climático abordan la situación de la política y normativas que los gobiernos han venido implementado. La investigación brinda como resultado la necesidad de ir introduciendo el tema de la Bioeconomía en la agenda pública y privada de los senderos de la bioeconomia como una alternativa de las comunidades rurales para dar respuesta a las variaciones del cambio climático y la creciente demanda de alimentos y fibras que presupone el crecimiento exponencial de la población.El trabajo investigativo se organizó en de la siguiente manera: Políticas sectoriales y normas regulatorias de la Bioeconomía: Caso El Salvador que lo abordan los especialista del grupo país de El Salvador el segundo caso es Agenda de política pública y privada para la bioeconomia: caso Honduras elaborada por los especialista del grupo país de Honduras, el tercer caso es Políticas Públicas para la Bioeconomía en Cuba realizada por los especialistas del grupo país de Cuba y finalmente Nicaragua que refiere la política que sobre el tema se viene impulsando.

    Reproductive characterization of hair ewe in the American tropics: a review part 1

    Get PDF
    Objective: to make a reproductive characterization of the hair sheep breeds in the American tropics. Design/methodology/approach: reproductive variables information was collected from scientific search engines, such as Web of Science, Redalyc, Dialnet, PubMed, SciELO and Latindex. Results: the age of puberty in ewe lambs is highly variable. Similar results were found in adult ewes regarding estrus duration and incidence, estrous cycle length, seasonal anestrus, ovulation rate, fertility, gestation, and prolificacy. Limitations on study/implications: information on reproductive variables of hair sheep breeds is poorly known or non-existent. Findings/conclusions: puberty onset in ewe lambs ranges from 175 to 335 d of age when animals weight 15 to 43 kg. The length of the estrous cycle of hair sheep in Mexico is 17 d during the autumn-winter and 21 d in spring-summer. In Brazil, it lasts 17 d in spring-summer and 18 d in autumn-winter. In the United States of America and Venezuela, the estrous cycle length was similar in both periods of the year. The estrous occurrence was 97.1% in autumn-winter and 76.5 % in spring-summer. The estrous duration ranges from 16 to 52 hours. Seasonal anestrous occurs from May to July. The ovulation rate ranges from 1 to 3 oocytes. Fertility is 80 to 100 % in temperate and 37 % in warm months. Gestation length ranges from 144 to 152 d. Prolificacy ranges from 1.0 to 2.2 offspring per ewe. The lambing interval range from 244 to 294 d.Objective: To carry out a reproductive characterization of the breeds of hair ewe in the tropical region of the Americas. Design/Methodology/Approach: A search of scientific information about the reproductive variables of breeds of hair ewe was carried out and the results were analyzed in the Web of Science, Redalyc, Dialnet, PubMed, SciELO, and Latindex databases. Results: We described and discussed the highly-variable onset of puberty in ewe lambs. Similar results were found in adult ewes regarding the duration and occurrence of the estrous, estrous cycle length, seasonal anestrous, ovulation rate, fertility, gestation, and prolificacy. Study Limitations/Implications: Information about the reproductive variables of breeds of hair ewe is poorly known or non-existent. Findings/Conclusions: The onset of puberty in 15-43 kg ewe lambs ranges from 175 to 335 d of age. The estrous cycle of hair ewe in Mexico lasts 17 d in autumn-winter and 21 d in spring-summer. In Brazil, this cycle lasts 17 d in spring-summer and 18 d in autumn-winter. In the United States of America and Venezuela, the estrous cycle length was similar in both periods of the year. The occurrence of the estrous reached 97.1 % in autumn-winter and 76.5 % in spring-summer. The duration of the estrous ranges from 16 to 52 hours. Seasonal anestrous occurs from May to July. The ovulation rate ranges from 1 to 3 oocytes. The percentage of fertility fluctuates between 80 and 100 % in temperate months and reaches 37 % in warm ones. Gestation lasts from 144 to 152 d. Prolificacy ranges from 1.0 to 2.2 offspring per ewe. The lambing interval ranges from 244 to 294 d

    Fertilidade de ovelhas Katahdin inseminadas laparoscopicamente com sêmen refrigerado ou criopreservado nos trópicos

    Get PDF
    El objetivo del estudio fue comparar la fertilidad seminal y taza de preñes en un hato de ovinos katahdin mediante inseminación laparoscópica con semen refrigerado y congelado en ambiente tropical, fueron utilizados el reproductor y veinte vientres de la raza katahdin. Se realizaron dos evaluaciones para valorar la calidad del semen de acuerdo con sus características macroscópicas y microscópicas y las hembras fueron sincronizadas con dispositivos intravaginales con 0.3 g de progesterona natural (CIDR®, Zoetis), más una dosis de 400 UI de gonadotropina coriónica humana (GCH). La fertilidad fue mayor (p< 0,05) (30% de preñez) en borregas inseminadas con semen congelado, comparada al 20% de preñez en las inseminadas con semen frío. Las variables de fertilidad seminal evaluadas demostraron que el semen en el semental katahdin en ambiente tropical fue de buena calidad para su manipulación en la práctica de la inseminación artificial. El grupo racial de los animales utilizados respondieron satisfactoriamente a la sincronización y el semen estuvo dentro de los parámetros establecidos para la especie además toleró la manipulación, en cuanto a la inseminación por laparoscopía, es una técnica de cruzamiento poco diseminada en la región, sin embargo, el estudio desarrollado sugiere mayor investigación para aportar conocimientos suficientes para fortalecer el procedimiento y con ello incrementar la concepción en ovejas servidasThe objective of the study was to compare the semen fertility and pregnancy rate in a katahdin sheep herd by laparoscopic insemination with refrigerated and frozen semen in a tropical environment. The breeder and twenty bellies of the katahdin breed were used. Two evaluations were performed to assess the quality of the semen according to its macroscopic and microscopic characteristics and the females were synchronized with intravaginal devices with 0.3 g of natural progesterone (CIDR®, Zoetis), plus a dose of 400 IU of human chorionic gonadotropin (HCG). Fertility was higher (p< 0.05) (30% pregnancy) in ewes inseminated with frozen semen, compared to 20% pregnancy in those inseminated with cold semen. The evaluated seminal fertility variables demonstrated that the semen in katahdin stallions in a tropical environment is of good quality for handling in the practice of artificial insemination. It is concluded that the breed group of the animals used responded satisfactorily to the synchronization and the semen was within the parameters established for the species, it also tolerated the manipulation, in terms of insemination by laparoscopy, it is a crossbreeding technique that is not widely disseminated in the region however, the study developed suggests further research to provide sufficient knowledge to strengthen the procedure and thereby increase conception in ewes bred.O objetivo do estudo foi comparar a fertilidade seminal e a taxa de prenhez em um rebanho de ovelhas katahdin por meio de inseminação laparoscópica com sêmen refrigerado e congelado em ambiente tropical, foram utilizados o reprodutor e vinte úteros da raça katahdin. Foram realizadas duas avaliações para avaliar a qualidade do sêmen de acordo com suas características macroscópicas e microscópicas, e as fêmeas foram sincronizadas com dispositivos intravaginais com 0,3 g de progesterona natural (CIDR®, Zoetis), mais uma dose de 400 UI de gonadotrofina coriônica humana (HCG) . A fertilidade foi maior (p< 0,05) (30% de prenhez) em ovelhas inseminadas com sêmen congelado, em comparação com 20% de prenhez naquelas inseminadas com sêmen frio. As variáveis ​​de fertilidade seminal avaliadas demonstraram que o sêmen do garanhão katahdin em ambiente tropical era de boa qualidade para sua manipulação na prática da inseminação artificial. O grupo racial dos animais utilizados respondeu satisfatoriamente à sincronização e o sêmen estava dentro dos parâmetros estabelecidos para a espécie, também tolerou a manipulação, no que diz respeito à inseminação por laparoscopia, é uma técnica de cruzamento pouco difundida na região, porém , o estudo desenvolvido sugere novas pesquisas para fornecer conhecimento suficiente para fortalecer o procedimento e, assim, aumentar a concepção em ovelhas criadas
    corecore