Revisiting the manganese dimer on the base of first-principles theory.

Manganese is one of the most intriguing elements showing multiple magnetic phases. In order to shed some light on the complex behavior, the manganese dimer has been the focus of extensive interest in theoretical research. Various quantum techniques have been utilized to comprehend the characteristics of the Mn dimer.

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Objetivo: Estimar el riesgo de morir por SARS-CoV-2 en el periodo febrero de 2020 a junio de 2022, en función de las desigualdades socioterritoriales existentes en la Ciudad de México. Material y métodos. Análisis retrospectivo de los datos de defunciones por SARS-CoV-2 en la población de la Ciudad de México entre febrero de 2020 y junio de 2022, según la colonia de residencia clasificada en muy bajo, bajo, medio, alto y muy alto desarrollo social, a partir del Índice de Desarrollo Social (IDS) propuesto por el Consejo de Evaluación de la Ciudad de México.

Electronic, Vibrational, and Structural Properties of the Natural Mineral Ferberite (FeWO): A High-Pressure Study.

This paper reports an experimental high-pressure study of natural mineral ferberite (FeWO) up to 20 GPa using diamond-anvil cells. First-principles calculations have been used to support and complement the results of the experimental techniques. X-ray diffraction patterns show that FeWO crystallizes in the wolframite structure at ambient pressure and is stable over a wide pressure range, as is the case for other wolframite AWO (A = Mg, Mn, Co, Ni, Zn, or Cd) compounds.

Exploring the crystal structure and properties of ytterbium orthoantimonate under high pressure.

The crystal structure of YbSbO was determined from powder X-ray diffraction data using the Rietveld method. YbSbO is found to be monoclinic and isostructural to α-PrSbO. We have also tested the influence of pressure on the crystal structure up to 22 GPa by synchrotron powder X-ray diffraction.

First-principles study of Mn adsorbed on Au(111) and Cu(111) surfaces.

A theoretical study of the Mn trimer adsorbed on the noble metal surfaces Au(111) and Cu(111) is reported. The calculations were performed using first-principles methods within the density functional theory and the generalized gradient approximation in the collinear and non-collinear magnetic phases. The system was modeled by considering a surface unit cell of 25 atoms to improve the trimer's isolation on the surface.

High-pressure characterization of multifunctional CrVO.

The structural stability and physical properties of CrVOunder compression were studied by x-ray diffraction, Raman spectroscopy, optical absorption, resistivity measurements, andcalculations up to 10 GPa. High-pressure x-ray diffraction and Raman measurements show that CrVOundergoes a phase transition from the ambient pressure orthorhombic CrVO-type structure (Cmcm space group, phase III) to the high-pressure monoclinic CrVO-V phase, which is proposed to be isomorphic to the wolframite structure. Such a phase transition (CrVO-type → wolframite), driven by pressure, also was previously observed in indium vanadate.

Precise Characterization of the Rich Structural Landscape Induced by Pressure in Multifunctional FeVO.

We have studied the high-pressure behavior of FeVO by means of single-crystal X-ray diffraction (XRD) and density functional theory (DFT) calculations. We have found that the structural sequence of FeVO is different from that previously assumed. In particular, we have discovered a new high-pressure phase at 2.

First-principles study of Ni adatom migration on graphene with vacancies.

A theoretical study based on first-principles calculations about the interaction and diffusion of Ni atoms on pristine graphene and graphene with a single vacancy is presented. In the first case, we explored the structural changes due to the adsorption of Ni on graphene and the effects on the electronic structure. In the case of graphene with a vacancy, we analyzed the impact of the adsorbed Ni atom on the distortion of the graphene structure and how it depends on the distance from the graphene defect.

Anharmonic contribution to the stabilization of Mg(OH) from first principles.

Geometrical and vibrational characterization of magnesium hydroxide was performed using density functional theory. Four possible crystal symmetries were explored: P3[combining macron] (No. 147, point group -3), C2/m (No.

Stability of FeVO under Pressure: An X-ray Diffraction and First-Principles Study.

The high-pressure behavior of the crystalline structure FeVO has been studied by means of X-ray diffraction using a diamond-anvil cell and first-principles calculations. The experiments were carried out up to a pressure of 12.3 GPa, until now the highest pressure reached to study an FeVO compound.

Fe/Ni core/shell nanowires and nanorods: a combined first-principles and atomistic simulation study.

In recent years, construction and characterization of core-shell structures have attracted great attention because of their unique functional properties and their integration into technological devices. However, some aspects of their basic physics still remain to be explored. In this study, we report on an extensive hierarchical multiscale modeling methodology applied to Fe-Ni core/shell nanostructures of technological interest.

First-Principles Study of InVO under Pressure: Phase Transitions from CrVO- to AgMnO-Type Structure.

First-principles calculations have been carried out to study the InVO compound under pressure. In this work, total energy calculations were performed in order to analyze the structural behavior of the experimentally known polymorphs of InVO: α-MnMoO-type (I), CrVO-type (III), and wolframite (V). In addition, in this paper we present our results about the stability of this compound beyond the pressures reached by experiments.

First-principles study of pressure-induced structural phase transitions in MnF.

In this work we report a complete structural and magnetic characterization of crystalline MnF under pressure obtained using first principle calculations. Density functional theory was used as the theoretical framework, within the generalized gradient approximation plus the Hubbard formalism (GGA+U) necessary to describe the strong correlations present in this material. The vibrational, the magnetic exchange couplings and the structural characterization of MnF in the rutile ground state structure and potential high pressure phases are reported.

Atomic and molecular oxygen adsorbed on (111) transition metal surfaces: Cu and Ni.

Density functional theory is used to investigate the reaction of oxygen with clean copper and nickel [111]-surfaces. We study several alternative adsorption sites for atomic and molecular oxygen on both surfaces. The minimal energy geometries and adsorption energies are in good agreement with previous theoretical studies and experimental data.

Polymorphs of CaSeO4 under pressure: a first-principles study of structural, electronic, and vibrational properties.

In this paper we report a theoretical study of the CaSeO4 compound at ambient pressure and under pressure. Here we made a structural analysis of its three known polymorphs--orthorhombic (Cmca), monoclinic monazite, and tetragonal scheelite--where direct comparison with experimental measurements is done. Besides, the electronic and vibrational structures are reported for the first time for those structures.

Pressure control of magnetic clusters in strongly inhomogeneous ferromagnetic chalcopyrites.

Room-temperature ferromagnetism in Mn-doped chalcopyrites is a desire aspect when applying those materials to spin electronics. However, dominance of high Curie-temperatures due to cluster formation or inhomogeneities limited their consideration. Here we report how an external perturbation such as applied hydrostatic pressure in CdGeP₂:Mn induces a two serial magnetic transitions from ferromagnet to non-magnet state at room temperature.

High-pressure structural behaviour of HoVO4: combined XRD experiments and ab initio calculations.

We report a high-pressure experimental and theoretical investigation of the structural properties of zircon-type HoVO4. Angle-dispersive x-ray diffraction measurements were carried out under quasi-hydrostatic and partial non-hydrostatic conditions up to 28 and 23.7 GPa, respectively.

[Organization of the drug supply chain in state health services: potential consequences of the public-private mix].

Objective: To assess the consequences of private outsourcing on the overall supply and filling of prescriptions in state health services.

Material And Methods: The research was conducted using quantitative and qualitative techniques in 13 states. The information was collected through interviews and direct observation.

[Changes in perceived health in war-displaced population, Ayacucho, Peru: 1980-2004].

The current study aims to show the individual and familiar changes in health patterns suffered by indigenous communities which were displaced from their Andean communities to Ayacucho city, Peru, for war-related political reasons, during the period of 1980 and 2004. Information about health self-perception was collected from displaced farmers living in Ayacucho city, and analyzed by using ethnographic research tools in: origin communities; during the displaced process to town, and during the integration process once the war was over in 1993. It was found out that these poor Andean communities had traditionally lived under severe social exclusion conditions, and were characterized by low access to health services and high childhood and maternal mortality rates.

[Socioeconomic inequality and mental health: a Latin American literature review].

This study provides a review of the scientific output in Latin America concerning the impact of socioeconomic status (SES) on mental disorders and drug use or addiction. International and regional databases were analyzed. According to the majority of the studies, adults and adolescents with low SES showed increased risk of mental disorders, and alcohol consumption was higher among individuals with high SES, while low SES was associated with alcohol abuse and addiction, although the evidence was less conclusive.

[Displaced people's healthcare use in Bucaramanga, Colombia].

Objective: Analysing the factors and barriers associated with the population displaced by armed conflict using medical services in Bucaramanga, Colombia.

Material And Methods: Data from the "Diagnosing the health of both displaced and non-displaced populations in Bucaramanga and its metropolitan area" study, designed and executed by the Industrial University of Santander and financed by the Pan-American Health Organisation, analysed medical service use in individuals aged over 15 years. This agreed with Andersen and Newman's model and evaluated the effect of associated factors by means of multiple logistical regression.

[The role of epidemiology in mental disorder research].

Mental disorders, including substance abuse, are part of the Mexican epidemiologic scenario and will remain so during several decades. They may even become more prominent as causes of disease, disability, and death in our country. It is thus imperative to frame appropriate management strategies to curb these problems without delay.

[Prenatal care at the first level of care: characteristics of providers that affect users' satisfaction].

Objective: To assess the satisfaction level attained by prenatal care users in primary health services in Mexico, and to compare the level of satisfaction according to characteristics of the provider and the service.

Material And Methods: A cross-sectional survey was conducted to analyze data from 217 care provider-user pairs. Interviews were carried out in 95 primary care units in eight Mexican states.