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A thick-disk galaxy model and simulations of equal-mass galaxy pair collisions

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Research in Astronomy and Astrophysics 2020年第11期20卷 333-353页

作者： guillermo Arreaga-garcıa Departamento de Investigacion en Fsica Universidad de Sonora.Apdo.Postal 14740C.P.83000HermosilloSonoraMexico

We implement a numerical model reported in the literature to simulate the evolution of a galaxy composed of four matter components,such as:a dark-matter halo;a rotating disk of stars;a spherical bulge of stars and a ring of molecular *** show that the evolution of this galaxy model is stable at least for 10 Gyr(Gyr=109 years).We characterize the resulting configuration of this galaxy model by figures of the circular velocity and angular momentum distribution;the tangential and radial components of the velocity;the peak density evolution and the radial density ***,we calculate several models of equal-mass galaxy binary collisions,such as:(i)frontal and(ii)oblique(with an impact parameter),(iii)two models with initial conditions taken from a 2-body orbit and(iv)a very close *** allow comparison with the galaxy model,we characterize the dynamics of the collision models in an analogous ***,we determine the de Vaucouleurs fitting curves of the radial density profile,on a radial scale of 0–100 kpc,for all the collision models irrespective of the pre-collision *** study the radial mass density and radial surface density profiles at a smaller radial scale,0–20 kpc,we use a four-parameter fitting curve.

关键词： galaxies kinematics and dynamics galaxies interaction methods numerical

Using Cartesian Slice Plots of a Cosmological Simulation as Input of a Convolutional Neural Network

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Research in Astronomy and Astrophysics 2024年第11期24卷 225-242页

作者： guillermo Arreaga-garcía Departamento de Investigación en Física Universidad de Sonora.Apdo.Postal 14740C.P.83000HermosilloSonoraMexico

Using a uniform partitioning of cubic cells,we cover the total volume of aΛCDM cosmological simulation based on *** define a visualization cell as a spatial extension of the cubic cell,so that we collect all simulation particles contained in this visualization cell to create a series of Cartesian plots in which the overdensity of matter is clearly *** then use these plots as input to a convolutional neural network(CNN)based on the Keras library and TensorFlow for image *** assign a class to each plot,we approximate the Hessian of the gravitational potential in the center of the cubic *** selected cubic cell is then assigned a label of 1,2 or 3,depending on the number of positive eigenvalues obtained for the Householder reduction of the Hessian *** apply the CNN to several models,including two models with different visualization volumes,one with a cell size of type L(large)and the other with a cell type S(small).A third model combines the plots of the previous L and S cell *** far,we have mainly considered a slice parallel to the XY plane to make the *** last model is considered based on visualizations of cells that also include slices parallel to the ZX and ZY *** find that the accuracy in classification plots is acceptable,and the ability of the models to predict the class works *** results allow us to demonstrate the aim of this paper,namely that the usual Cartesian plots contain enough information to identify the observed structures of the cosmic web.

关键词： methods numerical cosmology theory (cosmology:)large scale structure of universe

Empirical formulae to describe some physical properties of small groups of protogalaxies with multiplicity

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Research in Astronomy and Astrophysics 2021年第8期21卷 141-158页

作者： guillermo Arreaga-garcia Departamento de Investigacion en Fisica Universidad de Sonora Apdo.Postal 14740C.P.83000HermosilloSonoraMexico

By means of identical cubic elements,we generate a partition of a volume in which a particle-based cosmological simulation is carried *** each cubic element,we determine the gas particles with a normalized density greater than an arbitrarily chosen density *** using a proximity parameter,we calculate the neighboring cubic elements and generate a list of *** imposing dynamic conditions on the gas particles,we identify gas clumps and their neighbors,so that we calculate and fit some properties of the groups so identified,including the mass,size and velocity dispersion,in terms of their multiplicity(here defined simply as the number of member galaxies).Finally,we report the value of the ratio of kinetic energy to gravitational energy of such dense gas clumps,which will be useful as initial conditions in simulations of gravitational collapse of gas clouds and clusters of gas clouds.

关键词： galaxies:kinematics and dynamics hydrodynamics methods:numerical

An Indoor Radon Survey in Three Different Climate Regions in Mexico, and the Influence of Climate in the Obtained Values

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Journal of Environmental Protection 2011年第9期2卷 1143-1148页

作者： guillermo espinosa Richard Gammage 不详

In this paper we present the results of a survey of indoor radon concentration levels in Mexico. In order to investigate whether differences in climate translate into significant differences in indoor radon concentrations, the country was divided into three climate regions: the northern semi-desert region, the central semitropical region and the southern tropical region. The survey was carried out using nuclear track methodology. The dosimeters employed for the survey were based on the passive closed-end cup device, developed at the Physics Institute of the National Autonomous University of Mexico, and used PADC as detector material. A well-established protocol for chemically etching and reading the detectors was followed. Average annual temperatures differ between regions (from 15℃ to 28℃) but vary relatively little within each region. Atmospheric temperature is one of the most important factors which need to be considered when carrying out a survey of indoor radon concentrations because temperature largely determines building ventilation habits, and ventilation habits are known to have significant effects on indoor radon concentrations. Other factors, including building construction materials, architectural styles, geological and hydrological characteristics, and seismicity, vary from region to region and within each region. In each of the three regions low levels of indoor radon (from 37 to 179 Bq·m-3) were found.

关键词： Radon Indoor Radon Climate Influence Nuclear Tracks Methodology

Taking advantage of the potential of mesenchymal stromal cells in liver regeneration:Cells and extracellular vesicles as therapeutic strategies

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World Journal of Gastroenterology 2018年第23期24卷 2427-2440页

作者： Esteban Juan Fiore Luciana María Domínguez Juan Bayo Mariana Gabriela garcía guillermo Daniel Mazzolini Laboratory of Gene Therapy Instituto de Investigaciones en Medicina TraslacionalCONICET-Universidad Austral

Cell-based therapies for acute and chronic liver diseases are under continuous progress. Mesenchymal stem/stromal cells(MSCs) are multipotent cells able to migrate selectively to damaged tissue and contribute to its healing and regeneration. The MSC pro-regenerative effect occurs due to their immunomodulatory capacity and their ability to produce factors that promote cell protection and survival. Likewise,it has been observed that part of their paracrine effect is mediated by MSC-derived extracellular vesicles(EVs). EVs contain proteins,lipids and nucleic acids(DNA,m RNA,mi RNA,lnc RNA) from the cell of origin,allowing for intercellular communication. Recently,different studies have demonstrated that MSC-derived EVs could reproduce,at least in part,the biological effects obtained by MSCbased therapies. Moreover,due to EVs' stability for long periods of time and easy isolation methods they have become a therapeutic option to MSCs treatments. This review summarizes the latest results achieved in clinical trials using MSCs as cell therapy for liver regeneration,the role of EVs in liver physiopathology and the potential of MSC-derived EVs as intercellular mediators and therapeutic tools in liver diseases.

关键词： Mesenchymal stem cells Extracellular vesicles Cirrhosis Liver Acute damage Regeneration

Radon and Thoron （222Rn and 220Rn） Concentration Distribution Study on Three Detection Planes inside of a Closed Room Using Nuclear Track Methodology

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Journal of Environmental Science and Engineering(A) 2017年第3期6卷 149-154页

作者： guillermo espinosa Jose-Ignacio Golzarri Physics Institute National Autonomous University of Mexico Mexico City 04510 Mexico

The aim of this study is to determine the indoor radon and thoron concentration distribution on three detection planes, inside of a controlled closed room with microclimate conditions with NTM （Nuclear Track Methodology）, using CR-39 Lantrack bared detectors. One hundred sixty two （162） 1.9 cm × 0.9 cm CR-39 polycarbonate chips were placed in each one of the three planes, 2.0 m × 2.0 m square structures, distributed uniformly in 18 columns and 18 lines, in each plane. After three months exposure to indoor radon and thoron inside of the closed room, with a main concentration value of 862 ± 49 Bq/m3, all the detectors were chemically etched in KOH-6.25M solution to 60 ± 1 ℃ for 18 h, following the well established protocols for indoor radon survey, by the Dosimetry Applications Laboratory of the Physics Institute, UNAM （National Autonomous University of Mexico） and later on read by DIAS （Digital Image Analysis System）.The results show that the radon and thoron concentration distribution is not homogeneous in anyone of the planes faces. The six faces of the three planes measured, have a very particular distribution. From the results, it can be observed that each side of each plane shows a peculiar distribution, with gradients of concentrations higher than 50% from one area to another of the same measured plane. These results can help to understand the dynamics of the radioactive gases,and their measurements.

关键词： Indoor radon radon nuclear tracks

Indoor Radon （^222Rn） Concentration Level Study in Child Care Centers and Kindergartens, Using Nuclear Track Methodology （NTM）

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Journal of Environmental Science and Engineering(A) 2016年第12期5卷 599-605页

作者： guillermo espinosa Jose-Ignacio Golzarri Physics Institute National Autonomous University of Mexico Mexico City 04510 Mexico

As it is known, staying for long periods of time in a place with high concentration of radon is a health hazard. This health risk can be increased into adulthood, if at infant ages the young people grow inside places with important indoor radon levels. Causal associations between exposure level and lung cancer have been demonstrated in epidemiological studies around the world, suggesting that for younger age children groups, the risk coefficient of lung cancer for inhaled radon and their daughters is about a factor of 4 on children from recent born to 10 years old, and 2 for ages between 10 to 20 years old. The aim of this work is to determine the indoor radon levels where infants, from 3 months to 6 years old, remain long times in child care centers and kindergartens. Indoor radon （222Rn） concentration levels were measured in the child care centers and kindergartens of the 16 political administrative regions, covering 5% of the total in Mexico City. This study was conducted over a one-year period, divided into four three-month periods coinciding with the seasons. Nuclear Track Methodology was selected for the measurements, and a passive close-end-cup-device was designed specifically to be used in children places. In this study, the results of measurements of indoor radon concentration in child care centers and kindergartens in Mexico City are encouraging, finding indoor radon levels between 26 Bq/m^3 and 75 Bq/m^3 with an average value of 51 Bq/m^3. It can be considered that the indoor radon concentration levels are low in this type of buildings, due to the benign climate in the city, the architecture design of the constructions, and the ventilation habits of the population.

关键词： Indoor radon radon nuclear tracks kindergartens.

US children with special health care needs and ethnic discrimination: results from multivariate modeling

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World Journal of Pediatrics 2019年第2期15卷 182-189页

作者： guillermo Montes St.John Fisher College Alesi 106C3690 East Ave.RochesterNY 14618USA Children's Institute Inc. RochesterNYUSA

Background To determine the prevalence of parent-reported ethnic/racial discrimination,and to determine if children with special health care needs are more likely to experience ethnic discrimination than other children who have similar family income,age,sex,race,parental education and Hispanic *** Using the National Survey of Children's Health 2011-2012 (n =95,677),ethnic discrimination was measured by two questions that asked 'was child ever treated or judged unfairly because of his/her race or ethnic group?' and if so,how often it occurred in the last 12 months prior to the *** An estimated 3 million US children aged 0-17 years have experienced parent-reported ethnic discrimination (1.4% White,9.1% Black,9.9% other race,4.7% Hispanic).The likelihood to experience ethnic discrimination is much higher for Black and other race children,compared to White *** with special health care needs were two times more likely to experience ethnic discrimination frequently in the 12 months prior to the survey than comparable children in terms of age,sex,race,family income,parental education,and social *** family income did not prevent the exposure to ethnic discrimination but was associated with fewer *** Theoretical frameworks,such as social determinants of health,must account for the bidirectional nature of the relationship between health and ethnic *** care must assess if ethnic discrimination has occurred and whether trauma-informed approaches are needed.

关键词： Children with special health care needs Ethnic discrimination United States

The dorsal root ganglion as a target for neurorestoration in neuropathic pain

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Neural Regeneration Research 2024年第2期19卷 296-301页

作者： guillermo Estivill-Torrús Ana Belen Martínez-Padilla Lourdes Sánchez-Salido Anne Baron-Van Evercooren Beatriz garcía-Díaz Instituto de Investigación Biomédica de Málaga y Plataforma en Nanomedicina(IBIMA Plataforma BIONAND) MálagaSpain Unidad Clínica de Neurociencias Hospital Regional Universitario de MálagaMálagaSpain Departamento de Biología Molecular y Bioquímica Universidad de MálagaSpain Sorbonne Université Institut du Cerveau-Paris Brain Institute-ICMINSERMCNRSAP-HPHôpital Pitié-SalpêtrièreParisFrance

Neuropathic pain is a severe and chronic condition widely found in the general *** reason for this is the extensive variety of damage or diseases that can spark this unpleasant constant feeling in *** the processing of pain,the dorsal root ganglia constitute an important region where dorsal root ganglion neurons play a crucial role in the transmission and propagation of sensory electrical ***,the dorsal root ganglia have recently exhibited a regenerative capacity that should not be neglected in the understanding of the development and resolution of neuropathic pain and in the elucidation of innovative ***,we will review the complex interplay between cells(satellite glial cells and inflammatory cells)and factors(cytokines,neurotrophic factors and genetic factors)that takes place within the dorsal root ganglia and accounts for the generation of the aberrant excitation of primary sensory neurons occurring in neuropathic *** importantly,we will summarize an updated view of the current pharmacologic and nonpharmacologic therapies targeting the dorsal root ganglia for the treatment of neuropathic pain.

关键词： cytokines dorsal root ganglia genetic factors neuropathic pain neurotrophic factors pharmacologic and nonpharmacologic therapies satellite glial cells sensory neurons