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result(s) for
"GARCÍA, Miguel A."
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Cosmological constraints on alternative model to Chaplygin fluid revisited
In this work we explore an alternative phenomenological model to Chaplygin gas proposed by Hova et al. (Int J Mod Phys D 26:1750178, 2017), consisting on a modification of a perfect fluid, to explain the dynamics of dark matter and dark energy at cosmological scales immerse in a flat or curved universe. Adopting properties similar to a Chaplygin gas, the proposed model is a mixture of dark matter and dark energy components parameterized by only one free parameter denoted as \\[\\mu \\]. We focus on contrasting this model with the most recent cosmological observations of Type Ia supernovae and Hubble parameter measurements. Our joint analysis yields a value \\[\\mu = 0.843^{+0.014}_{-0.015}\\,\\] (\\[0.822^{+0.022}_{-0.024}\\]) for a flat (curved) universe. Furthermore, with these constraints we also estimate the deceleration parameter today \\[q_0=-0.67 \\pm 0.02\\,(-0.51\\pm 0.07)\\], the acceleration-deceleration transition redshift \\[z_t=0.57\\pm 0.04\\, (0.50 \\pm 0.06)\\], and the universe age \\[t_A = 13.108^{+0.270}_{-0.260}\\,\\times (12.314^{+0.590}_{-0.430})\\,\\]Gyrs. We also report a best value of \\[\\varOmega _k = 0.183^{+0.073}_{-0.079}\\] consistent at \\[3\\sigma \\] with the one reported by Planck Collaboration. Our analysis confirm the results by Hova et al. this Chaplygin gas-like is a plausible alternative to explain the nature of the dark sector of the universe.
Journal Article
Essential role of cleavage of Polycystin-1 at G protein-coupled receptor proteolytic site for kidney tubular structure
Polycystin-1 (PC1) has an essential function in renal tubular morphogenesis and disruption of its function causes cystogenesis in human autosomal dominant polycystic kidney disease. We have previously shown that recombinant human PC1 is cis-autoproteolytically cleaved at the G protein-coupled receptor proteolytic site domain. To investigate the role of cleavage in vivo, we generated by gene targeting a Pkd1 knockin mouse (Pkd1V/V) that expresses noncleavable PC1. The Pkd1V/V mice show a hypomorphic phenotype, characterized by a delayed onset and distal nephron segment involvement of cystogenesis at postnatal maturation stage. We show that PC1 is ubiquitously and incompletely cleaved in wild-type mice, so that uncleaved and cleaved PC1 molecules coexist. Our study establishes a critical but restricted role of cleavage for PC1 function and suggests a differential function of the two types of PC1 molecules in vivo.
Journal Article
Polymeric Implants for the Treatment of Intraocular Eye Diseases: Trends in Biodegradable and Non-Biodegradable Materials
Intraocular/Intravitreal implants constitute a relatively new method to treat eye diseases successfully due to the possibility of releasing drugs in a controlled and prolonged way. This particularity has made this kind of method preferred over other methods such as intravitreal injections or eye drops. However, there are some risks and complications associated with the use of eye implants, the body response being the most important. Therefore, material selection is a crucial factor to be considered for patient care since implant acceptance is closely related to the physical and chemical properties of the material from which the device is made. In this regard, there are two major categories of materials used in the development of eye implants: non-biodegradables and biodegradables. Although non-biodegradable implants are able to work as drug reservoirs, their surgical requirements make them uncomfortable and invasive for the patient and may put the eyeball at risk. Therefore, it would be expected that the human body responds better when treated with biodegradable implants due to their inherent nature and fewer surgical concerns. Thus, this review provides a summary and discussion of the most common non-biodegradable and biodegradable materials employed for the development of experimental and commercially available ocular delivery implants.
Journal Article
Quantum correlations and spatial localization in trapped one-dimensional ultra-cold Bose–Bose–Bose mixtures
We systematically investigate and illustrate the complete ground-state phase diagram for a one-dimensional, three-species mixture of a few repulsively interacting bosons trapped harmonically. To numerically obtain the solutions to the many-body Schrödinger equation, we employ the improved Exact Diagonalization method (Anh-Tai et al 2023 SciPost Phys. 15 048), which is capable of treating strongly-correlated few-body systems from first principles in an efficiently truncated Hilbert space. We present our comprehensive results for all possible combinations of intra- and interspecies interactions in the extreme limits that are either the ideal limit ( g = 0) or close to the hard-core limit ( g → ∞ ). These results show the emergence of unique ground-state properties related to correlations, coherence and spatial localization stemming from strongly repulsive interactions.
Journal Article
DESI and fast radio burst used to constrain modified theories of gravity
This paper is devoted to the study of the viability of DESI and the fast radio burst to constrain the free parameters of modified theories of gravity. Thus, we present a model supported in
f
(
R
) gravity involving a function of the Ricci scalar named Starobinsky-type with the peculiarity that the non-commutative essence is intrinsic to the coefficients. Additionally, to understand the dynamics within a flat Friedmann–Lemaitre–Robertson–Walker universe, we explore the possibility of deriving a Friedman equation (in measure) that results from an adequate mathematical treatment. As we mentioned previously, to test the outlined model, a Monte Carlo Markov chain analysis is implemented, using cosmic chronometers, type Ia supernovae, Hydrogen II galaxies, Intermediate-luminosity quasars, Baryon Acoustic oscillations and Fast Radio Bursts data, to constraint the free parameters of the model and presenting
H
(
z
),
q
(
z
) and
ω
eff
(
z
)
. The final results are compared with the
Λ
CDM model and a robust discussion is presented about the viability of DESI and fast radio burst to constraint free parameters in specific to a modified theory of gravity.
Journal Article
A hybrid model of viscous and Chaplygin gas to tackle the Universe acceleration
Motivated by two seminal models proposed to explain the Universe acceleration, this paper is devoted to study a hybrid model which is constructed through a generalized Chaplygin gas with the addition of a bulk viscosity. We call the model a viscous generalized Chaplygin gas (VGCG) and its free parameters are constrained through several cosmological data like the Observational Hubble Parameter, Type Ia Supernovae, Baryon Acoustic Oscillations, Strong Lensing Systems, HII Galaxies and using Joint Bayesian analysis. In addition, we implement a Om-diagnostic to analyze the VGCC dynamics and its difference with the standard cosmological model. The hybrid model shows important differences when compared with the standard cosmological model. Finally, based on our Joint analysis we find that the VGCG could be an interesting candidate to alleviate the well-known Hubble constant tension.
Journal Article
CystAnalyser: A new software tool for the automatic detection and quantification of cysts in Polycystic Kidney and Liver Disease, and other cystic disorders
The Polycystic Kidney Disease (PKD) is characterized by progressive renal cyst development and other extrarenal manifestation including Polycystic Liver Disease (PLD). Phenotypical characterization of animal models mimicking human diseases are commonly used, in order to, study new molecular mechanisms and identify new therapeutic approaches. The main biomarker of disease progression is total volume of kidney and liver in both human and mouse, which correlates with organ function. For this reason, the estimation of the number and area of the tissue occupied by cysts, is critical for the understanding of physiological mechanisms underlying the disease. In this regard, cystic index is a robust parameter commonly used to quantify the severity of the disease. To date, the vast majority of biomedical researchers use ImageJ as a software tool to estimate the cystic index by quantifying the cystic areas of histological images after thresholding. This tool has imitations of being inaccurate, largely due to incorrectly identifying non-cystic regions. We have developed a new software, named CystAnalyser (register by Universidade de Santiago de Compostela-USC, and Fundación Investigación Sanitaria de Santiago-FIDIS), that combines automatic image processing with a graphical user friendly interface that allows investigators to oversee and easily correct the image processing before quantification. CystAnalyser was able to generate a cystic profile including cystic index, number of cysts and cyst size. In order to test the CystAnalyser software, 795 cystic kidney, and liver histological images were analyzed. Using CystAnalyser there were no differences calculating cystic index automatically versus user input, except in specific circumstances where it was necessary for the user to distinguish between mildly cystic from non-cystic regions. The sensitivity and specificity of the number of cysts detected by the automatic quantification depends on the type of organ and cystic severity, with values 76.84-78.59% and 76.96-89.66% for the kidney and 87.29-93.80% and 63.42-86.07% for the liver. CystAnalyser, in addition, provides a new tool for estimating the number of cysts and a more specific measure of the cystic index than ImageJ. This study proposes CystAnalyser is a new robust and freely downloadable software tool for analyzing the severity of disease by quantifying histological images of cystic organs for routine biomedical research. CystAnalyser can be downloaded from https://citius.usc.es/transferencia/software/cystanalyser (for Windows and Linux) for research purposes.
Journal Article
Gravitational waves in braneworlds after multi-messenger events
The GW170817 event opened a new window to test modifications to General Relativity with the aim of discard or impose strong constraints in extra dimension theories of gravity. Concerning these theories, the Randall–Sundrum brane-world theory – 4+1 spacetime model where its covariant Einstein field equations are composed with new extra terms that comes from extra dimensions – is begin tested in the multi-messenger astronomy field. In the same context, the aim of this paper is to impose new constrictions through measurements of the time-delay between the gravitational and electromagnetic signals: GW170817 and the recent S190425z, over the free cosmological parameters of this modified model. We assume that Gravitational Waves travel along a shortcut on the extra dimension. In addition, we consider the standard
Λ
CDM model and perform a likelihood analysis in order to study effects like the
H
0
tension in comparison to this extra-dimensional theory, obtaining a reduced
H
0
value of the order of
0.2
%
in the low energy limit of this theory.
Journal Article
Taxonomy of Dark Energy Models
The accelerated expansion of the Universe is one of the main discoveries of the past decades, indicating the presence of an unknown component: the dark energy. Evidence of its presence is being gathered by a succession of observational experiments with increasing precision in its measurements. However, the most accepted model for explaining the dynamic of our Universe, the so-called Lambda cold dark matter, faces several problems related to the nature of such energy component. This has led to a growing exploration of alternative models attempting to solve those drawbacks. In this review, we briefly summarize the characteristics of a (non-exhaustive) list of dark energy models as well as some of the most used cosmological samples. Next, we discuss how to constrain each model’s parameters using observational data. Finally, we summarize the status of dark energy modeling.
Journal Article