Multi-Fluid Simulation of the Magnetic Field Evolution in Neutron Stars

Using a numerical simulation, we study the effects of ambipolar diffusion and ohmic diffusion on the magnetic field evolution in the interior of an isolated neutron star. We are interested in the behavior of the magnetic field on a long time scale, over which all Alfven and sound waves have been damped. We model the stellar interior as an electrically neutral plasma composed of neutrons, protons and electrons, which can interact with each other through collisions and electromagnetic forces. Weak interactions convert neutrons and charged particles into each other, erasing chemical imbalances. As a first step, we assume that the magnetic field points in one fixed Cartesian direction but can vary along an orthogonal direction. We start with a uniform-density background threaded by a homogeneous magnetic field and study the evolution of a magnetic perturbation as well as the density fluctuations it induces in the particles. We show that the system evolves through different quasi-equilibrium states and estimate the characteristic time scales on which these quasi-equilibria occur.Comment: It will be published in AIP Proceedings of the Conference '40 Years of Pulsars: Milisecond Pulsars, Magnetars and More' held at University of McGill, Montreal, Canada, August 2007. Contributed Talk at Conference '40 Years of Pulsars: Milisecond Pulsars, Magnetars and More

Magneto-thermal evolution in the cores of adolescent neutron stars: The Grad-Shafranov equilibrium is never reached in the 'strong-coupling' regime

At the high temperatures present inside recently formed neutron stars ($T\gtrsim 5\times 10^{8}\, \text{K}$), the particles in their cores are in the "strong-coupling" regime, in which collisional forces make them behave as a single, stably stratified, and thus non-barotropic fluid. In this regime, axially symmetric hydromagnetic quasi-equilibrium states are possible, which are only constrained to have a vanishing azimuthal Lorentz force. In such equilibria, the particle species are not in chemical ($\beta$) equilibrium, so $\beta$ decays (Urca reactions) tend to restore the chemical equilibrium, inducing fluid motions that change the magnetic field configuration. If the stars remained hot for a sufficiently long time, this evolution would eventually lead to a chemical equilibrium state, in which the fluid is barotropic and the magnetic field, if axially-symmetric, satisfies the non-linear Grad-Shafranov equation. In this work, we present a numerical scheme that decouples the magnetic and thermal evolution, enabling to efficiently perform, for the first time, long-term magneto-thermal simulations in this regime for different magnetic field strengths and geometries. Our results demonstrate that, even for magnetar-strength fields $\gtrsim 10^{16} \, \mathrm{G}$, the feedback from the magnetic evolution on the thermal evolution is negligible. Thus, as the core passively cools, the Urca reactions quickly become inefficient at restoring chemical equilibrium, so the magnetic field evolves very little, and the Grad-Shafranov equilibrium is not attained in this regime. Therefore, any substantial evolution of the core magnetic field must occur later, in the cooler "weak-coupling" regime ($T\lesssim 5\times 10^8 \, \mathrm{K}$), in which Urca reactions are effectively frozen and ambipolar diffusion becomes relevant.Comment: 19 pages, 12 figures, submitted to MNRA

Benchmarking seeding strategies for spreading processes in social networks: an interplay between infuencers, topologies and sizes

The explosion of network science has permitted an understanding of how the structure of social networks affects the dynamics of social contagion. In community-based interventions with spill-over effects, identifying influential spreaders may be harnessed to increase the spreading efficiency of social contagion, in terms of time needed to spread all the largest connected component of the network. Several strategies have been proved to be efficient using only data and simulation-based models in specific network topologies without a consensus of an overall result. Hence, the purpose of this paper is to benchmark the spreading efficiency of seeding strategies related to network structural properties and sizes. We simulate spreading processes on empirical and simulated social networks within a wide range of densities, clustering coefficients, and sizes. We also propose three new decentralized seeding strategies that are structurally different from well-known strategies: community hubs, ambassadors, and random hubs. We observe that the efficiency ranking of strategies varies with the network structure. In general, for sparse networks with community structure, decentralized influencers are suitable for increasing the spreading efficiency. By contrast, when the networks are denser, centralized influencers outperform. These results provide a framework for selecting efficient strategies according to different contexts in which social networks emerge

Educational differences in diabetes mortality among hispanics in the United States : an epidemiological analysis of vital statistics data (1989–2018)

Background: Diabetes accounted for approximately 10% of all-cause mortality among those 20–79 years of age worldwide in 2019. In 1986–1989, Hispanics in the United States of America (USA) represented 6.9% of the national population with diabetes, and this proportion increased to 15.1% in 2010–2014. Recently published findings demonstrated the impact of attained education on amenable mortality attributable to diabetes among Non-Hispanic Whites (NHWs) and Non-Hispanic Blacks (HNBs). Previous cohort studies have shown that low education is also a detrimental factor for diabetes mortality among the Hispanic population in the USA. However, the long-term impact of low education on diabetes mortality among Hispanics in the USA is yet to be determined. Aims and methods: The aim of this study was to measure the impact of achieving a 12th-grade education on amenable mortality due to diabetes among Hispanics in the USA from 1989 to 2018. We used a time-series designed to analyze death certificate data of Hispanic-classified men and women, aged 25 to 74 years, whose underlying cause of death was diabetes, between 1989 and 2018. Death certificate data from the USA National Center for Health Statistics was downloaded, as well as USA population estimates by age, sex, and ethnicity from the USA Census Bureau. The analyses were undertaken using JointPoint software and the Age–Period–Cohort Web Tool, both developed by the USA National Cancer Institute. Results: The analyses showed that between 1989 to 2018, age-and sex-standardized diabetes mortality rates among the least educated individuals were higher than those among the most educated individuals (both sexes together, p = 0.036; males, p = 0.053; females, p = 0.036). The difference between the least and most educated individuals became more pronounced in recent years, as shown by independent confidence intervals across the study period. Sex-based analyses revealed that the age-adjUSAted diabetes mortality rate had increased to a greater extent among the least educated males and females, respectively, than among the most educated. Conclusions: The results of the analyses demonstrated a powerful effect of low education on amenable mortality attributable to diabetes among the Hispanic population in the USA. As an increasing prevalence of diabetes among the least educated Hispanics has been reported, there is a great need to identify and implement effective preventive services, self-management, and quality care practices, that may assist in reducing the growing disparity among those most vulnerable, such as minority populations

Orbital Nature of Carboionic Monoradicals Made from Diradicals

The electronic, optical, and solid state properties of a series of monoradicals, anions and cations obtained from starting neutral diradicals have been studied. Diradicals based on s-indacene and indenoacenes, with benzothiophenes fused and in different orientations, feature a varying degree of diradical character in the neutral state, which is here related with the properties of the radical redox forms. The analysis of their optical features in the polymethine monoradicals has been carried out in the framework of the molecular orbital and valence bond theories. Electronic UVVis-NIR absorption, X-ray solid-state diffraction and quantum chemical calculations have been carried out. Studies of the different positive-/negative-charged species, both residing in the same skeletal π-conjugated backbone, are rare for organic molecules. The key factor for the dual stabilization is the presence of the starting diradical character that enables to indistinctively accommodate a pseudo-hole and a pseudoelectron defect with certainly small reorganization energies for ambipolar charge transport.The authors thank the Spanish Ministry of Science and Innovation (projects MINECO/FEDER PGC2018-098533-B-100 and PID2021-127127NB-I00) and the Junta de Andalucía, Spain (UMA18FEDERJA057 and Proyecto de Excelencia PROYEXCEL- 00328). We also thank the Research Central Services (SCAI) of the University of Málaga and the US National Science Foundation (CHE-1954389 to M.M.H., CHE-2003411 to M.A. P.). F.N and Y.D. acknowledge support from “Valutazione della Ricerca di Ateneo” (VRA)-University of Bologna. Y.D. acknowledges Ministero dell’Università e della Ricerca (MUR) for her Ph.D. fellowship. Funding for open access charge: Universidad de Málaga / CBU

System identification analysis for an air compressor system and enhancement proposal by sensors based in nanostructures

An Air Compressor System is an equipment (mechanical system) which can transmit energy due to increase air pressure level of air flow that through it. This energy can be used in many applications, such as in drills for mining, adding air to tires on vehicles, spraying crops, etc. Therefore, it is necessary to know the mathematical model of an Air Compressor System to study all the thermodynamical variables: “Temperature, Pressure, Air Flow” which let to get a formalized explanation of the energy transfer through this equipment. Furthermore it is described that Air Compressor System can be enhanced while it uses sensors/actuators based in nanostructures

Quid: observatorio de medios

En la primera parte de la obra se aborda el tema de medios y las elecciones de 2009; en la segunda, la transparencia y la rendición de cuentas, y en la tercera parte los medios de comunicación y el periodismo. Al final se presentan sembalnzas de Rigo Mora, Álvaro González de Mendoza y David “el Negro” Guerrero, quienes desde el cine y la radiodifusión, dejaron momentos memorables a la comunidad tapatía.ITESO, A.C

BRIQUITAS TABANIC

Seminario Desarrollo de Emprendedores. 2010. Carrera Administración de Empresas. Docente Lic. Alejandro Dávila Rueda..Briquetas Tabanic, es una empresa que estará ubicada en el departamento de Estelí, por la gran actividad económica que se presenta en relación al tabaco, porque esto contribuirá en gran medida a que se realice la elaboración de briquetas a base de residuos de tabaco, enfocado en la conservación del medio ambiente y también en la reducción de la tala de los bosques del país, ofreciendo un producto bajo en costos y con altos estándares de calidad. Con la intención de posicionarse en el mercado de forma acelerada gracias a una gran ventaja en competitividad de precios en relación a empresas productoras y vendedoras de carbón, además la calidad, resistencia y durabilidad del producto se señalan como algo comprobado, también mencionando que es producto que evita la deforestación en Nicaragua

Corn price volatility and producer income protection

Objective: To estimate the indicator of the risk of the future price of yellow corn #2 of the Chicago Futures Exchange in the United States to the spot price of white corn in the main white corn producing regions of Mexico through the financial volatility indicator. Methodology: The research used the returns of the monthly time series for the period January 1998 to December 2020 corresponding to the spot price of white corn for five producer-consumer regions of Mexico and the futures price of yellow corn #2 listed on the Chicago Stock Exchange. To quantify volatility, the generalized autoregressive conditional heteroskedasticity model of order (1,1) was estimated. Results: The volatility indicator for yellow corn turned out to be 0.9870 for the futures price of quality 2 yellow corn. In the case of the spot price of white corn in Mexico, the volatility was 0.0.7977 for the national price; 0.3385 for the central region; 0.3206 for the western region and 0.0078 for the southeastern region, respectively. Implications: The high volatility of yellow corn #, close to unity, shows that the international market for this commodity is riskier than the national market or the regional markets in Mexico. Conclusions: The national white corn market showed to be more risky than the western, central and southeastern regional markets, showing a higher volatility indicator.O Objective: To estimate the risk indicator of the future price of yellow corn #2 at the Chicago Futures Exchange (USA) regarding the spot price of white corn in the main producing regions in Mexico through the financial volatility indicator. Methodology: The research used the returns of the monthly time series corresponding to the spot price of white corn from January 1998 to December 2020, considering five producer-consumer regions of Mexico and the future price of yellow corn #2 as listed on the Chicago Stock Exchange. To quantify volatility, the generalized autoregressive conditional heteroskedasticity model of order (1,1) was estimated. Results: The yellow corn #2 volatility indicator was 0.9870 (future price). In the case of the spot price of white corn in Mexico, the volatility was 0.7977 for the national price, 0.3385 for the central region, 0.3206 for the western region, and 0.0078 for the southeast region. Implications: The high volatility of yellow corn #2 (close to unity) shows that the international market for this commodity is riskier than the national market or regional markets in Mexico. Conclusions: The national white corn market proved to be riskier than the west, center, and southeast regional markets, which have a higher volatility indicator

Metabolomic profile of cancer stem cell-derived exosomes from patients with malignant melanoma

Malignant melanoma (MM) is the most aggressive and life-threatening form of skin cancer. It is characterized by an extraordinary metastasis capacity and chemotherapy resistance, mainly due to melanoma cancer stem cells (CSCs). To date, there are no suitable clinical diagnostic, prognostic or predictive biomarkers for this neoplasia. Therefore, there is an urgent need for new MM biomarkers that enable early diagnosis and effective disease monitoring. Exosomes represent a novel source of biomarkers since they can be easily isolated from different body fluids. In this work, a primary patient-derived MM cell line enriched in CSCs was characterized by assessing the expression of specific markers and their stem-like properties. Exosomes derived from CSCs and serums from patients with MM were characterized, and their metabolomic profile was analysed by highresolution mass spectrometry (HRMS) following an untargeted approach and applying univariate and multivariate statistical analyses. The aim of this study was to search potential biomarkers for the diagnosis of this disease. Our results showed significant metabolomic differences in exosomes derived from MM CSCs compared with those from differentiated tumour cells and also in serum-derived exosomes from patients with MM compared to those from healthy controls. Interestingly, we identified similarities between structural lipids differentially expressed in CSC-derived exosomes and those derived from patients with MM such as the glycerophosphocholine PC 16:0/0:0. To our knowledge, this is the first metabolomic-based study aimed at characterizing exosomes derived from melanoma CSCs and patients’ serum in order to identify potential biomarkers for MM diagnosis. We conclude that metabolomic characterization of CSC-derived exosomes sets an open door to the discovery of clinically useful biomarkers in this neoplasia.MICIU FPU15/03682 FPU15/02350Ministerio de Ciencia, Innovación y Universidades (MICIU) MAT2015-62644.C2.2.R RTI2018-101309-BC2Instituto de Salud Carlos III PIE16-00045Junta de Andalucía SOMM17/6109/UGR (UCE-PP2017-3)European Union (EU) SOMM17/6109/UGR (UCE-PP2017-3)Chair 'Doctors Galera-Requena in cancer stem cell research' CMC-CTS963Fundación MEDIN