Cosmological parameter inference with Bayesian statistics

Bayesian statistics and Markov Chain Monte Carlo (MCMC) algorithms have found their place in the field of Cosmology. They have become important mathematical and numerical tools, especially in parameter estimation and model comparison. In this paper, we review some fundamental concepts to understand Bayesian statistics and then introduce MCMC algorithms and samplers that allow us to perform the parameter inference procedure. We also introduce a general description of the standard cosmological model, known as the $\Lambda$CDM model, along with several alternatives, and current datasets coming from astrophysical and cosmological observations. Finally, with the tools acquired, we use an MCMC algorithm implemented in python to test several cosmological models and find out the combination of parameters that best describes the Universe.Comment: 30 pages, 17 figures, 5 tables; accepted for publication in Universe; references adde

Model selection applied to non-parametric reconstructions of the Dark Energy

The main aim of this paper is to perform a model comparison for non-parametric reconstructions of the key properties that describe the dark energy of the Universe i.e. energy density and the equation of state (EoS). We carry out this process by using a binning and a linear interpolation methodologies, and on the top of that, we incorporate a correlation function mechanism. An extension of the two of them was also introduced, where internal amplitudes are allowed to vary in height as well as in position. The reconstructions were made with data from the Hubble parameter, Supernovae Type Ia and Baryon Acoustic Oscillations (H+SN+BAO), all of which span a range from $z=0.01$ to $z=2.8$. First we perform the parameter estimation for each of the reconstructions to then provide a model selection through the Bayesian Evidence. Throughout our process we found a better fit to the data, up to $4\sigma$ compared to $\Lambda$CDM, and the presence of some interesting features, i.e. an oscillatory behaviour at late times, a decrease in the dark energy density component at early times and a transition to the phantom divide-line in the EoS. To discern these features from noisy contributions, we include a principal component analysis and found that some of these characteristics should be taken into account to satisfy observations.Comment: 14 pages, 7 figure

The state of the dark energy equation of state circa 2023

We critically examine the state of current constraints on the dark energy (DE) equation of state (EoS) $w$. Our study is partially motivated by the observation that, while broadly consistent with the cosmological constant value $w=-1$, several independent probes appear to point towards a slightly phantom EoS ($w \sim -1.03$). We pay attention to the apparent preference for phantom DE from Planck Cosmic Microwave Background (CMB) data alone, whose origin we study in detail and attribute to a wide range of (physical and geometrical) effects. We deem the combination of Planck CMB, Baryon Acoustic Oscillations, Type Ia Supernovae, and Cosmic Chronometers data to be particularly trustworthy, inferring from this final consensus dataset $w=-1.013^{+0.038}_{-0.043}$, in excellent agreement with the cosmological constant value. Overall, despite a few scattered hints, we find no compelling evidence forcing us away from the cosmological constant (yet).Comment: 21 pages, 10 figures, 3 table

Health-Related Conditions and Depression in Elderly Mexican American and Non-Hispanic White Residents of a United States-Mexico Border County: Moderating Effects of Educational Attainment

We investigated the prevalence of “high” levels of depressive symptomatology and 13 health-related medical conditions in elderly Mexican American (MA) and non-Hispanic white (NHW) residents of El Paso County, Texas. We analyzed the extent to which depressive symptoms in this population are associated with these conditions. Elderly MA residents possessed a higher prevalence of current depression, a relatively unique health-related condition profile, and were more likely to experience a set of conditions that impede participation in daily life—conditions that we found to be strongly associated with high depressive symptomatology in the elderly. After adjusting for educational attainment, using multiple regression analyses, depression was not associated with ethnicity and only six of the health related conditions showed significant differences between MA and NHW subjects. We believe these results provide an important insight into the mechanism of health-related conditions and depressive symptomatology in a large sample of elderly MAs; and how conditions typically attributed to MA ethnicity may in actuality be an artifact of socioeconomic status variables such as educational-attainment

Root Density in \u3cem\u3ePanicum maximum\u3c/em\u3e cv. Tanzania Monoculture and in a Mixture with \u3cem\u3eLeucaena leucocephala\u3c/em\u3e with Different Densities in Mexico

In Yucatan cattle production is limited by forage availability during the dry season. L. leucocephala has good nutritive value (24 - 30% CP) and can stand drought and grazing, therefore its use in mixture with grasses is recommended. However, in association both species could compete for light, water and nutrients. The aim of this study was to assess the effect of introduction of L. leucocephala with different densities on root density of P. maximum

Targeting hydroxycinnamoyl CoA: shikimate hydroxycinnamoyl transferase for lignin modification in Brachypodium distachyon

This article conducts a study to evaluate the utility of Hydroxycinnamoyl CoA: shikimate hydroxycinnamoyl transferase (HCT) as a target for lignin modification in a species with an “incomplete” shikimate shunt. Results imply that this gene is a preferred target for biotechnological improvement of grasses for bioprocessing

Gastrointestinal cancer: Relationship between histology and microbiota

Este trabajo fue presentado como comunicación tipo póster en el citado congreso.Objectives: Review of the published literature concerning the relationship between microbiome and gastrointestinal cancer. Methods: Present work is focused on systematic research in the most prominent biomedical databases finds relevant works in Pubmed and the library’s catalog of the University of Málaga (Jábega) of published journals in the last 5 years. Results: In this work, the mechanisms used by the microbiome to damage gastrointestinal epithelial cells and cause cancer are explained. Some of them are the dysbiosis, destruction of the mucosal barrier, chronic inflammation, damage caused by metabolites produced in the digestion and the direct attack of certain toxins to the cell’s DNA. These mechanisms adjust the immune response, by activation or inhibition using different cytokines. There is also a deeper look into several microorganisms and how they cause gastrointestinal cancer using toxins or virulence factors to activate them. Conclusions: The evidence found so far about the microbiota and gastrointestinal cancer is enough to assume the relationship between them, although there is much left to research. With these findings, it can be expected that in a near future certain microorganisms could be used for screening purposes, due to their increase in early stages of the tumor genesis and also, in a preventive way to try to eradicate them, even avoid cancer. Studies on the microbiota are hardly beginning, and results appear to be promising.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech