Surface anisotropy and particle size influence on hysteresis loops in La2/3Ca1/3MnO3 nanoparticles : A simulation approach

Thermal and hysteretic magnetic properties of La2/3Ca1/3MnO3 nanoparticles were studied using Monte Carlo simulations, with emphasis on the influence of anisotropy. In this work, several nanoparticle sizes ranging from 2.32 to 11.58 nm were analyzed and their properties were compared to those of the bulk material. The magnetic behavior of the material was modeled using the three dimensional Heisenberg model with nearest neighbor interactions. Furthermore, both uniaxial and Néel anisotropies were considered for core and surface magnetic sites respectively. Deviations in the critical temperature and coercive field were observed for nanoparticles when compared with those of the bulk material. In addition to these properties, the special spin configurations that arise from the competition between the exchange, anisotropy and external magnetic field were also studied. All these effects are interpreted in terms of the surface properties such as the Néel anisotropy and the decrease in the coordination number

Optimal phase space sampling for Monte Carlo simulations of Heisenberg spin systems

We present an adaptive algorithm for the optimal phase space sampling in Monte Carlo simulations of 3D Heisenberg spin systems. Based on a golden rule of the Metropolis algorithm which states that an acceptance rate of 50% is ideal to efficiently sample the phase space, the algorithm adaptively modifies a cone-based spin update method keeping the acceptance rate close to 50%. We have assessed the efficiency of the adaptive algorithm through four different tests and contrasted its performance with that of other common spin update methods. In systems at low and high temperatures and anisotropies, the adaptive algorithm proved to be the most efficient for magnetization reversal and for the convergence to equilibrium of the thermal averages and the coercivity in hysteresis calculations. Thus, the adaptive algorithm can be used to significantly reduce the computational cost in Monte Carlo simulations of 3D Heisenberg spin systems

Scaling Out Evidence-Based Interventions Outside the U.S. Mainland: Social Justice or Trojan Horse?

Global health disparities continue to widen as professional standards for effectiveness of mental health services provision become more precise and difficult to achieve across varied economic and social contexts. Within the U.S., health disparities are evident in Latinx populations. Globally, the health disparities are also evident in Latin America as compared to the U.S. and other economically affluent nations. The diversification of psychology in content and persons has led to a unique opportunity to build bridges that can help reduce disparities in- and outside of the U.S. mainland. Collaborations can be of great use in addressing health disparities internationally but also are of critical importance in testing the ecological validity of existing interventions. It is imperative that researchers approach these exchanges as truly collaborative and power even, as researchers in all locations stand to learn and grow from the partnership, otherwise U.S.-based researchers can unwittingly engage intellectual colonization and advance cultural imperialism. U.S.-based researchers must be particularly thoughtful about disparities in both resources and consequences for success and failures in research contexts. We discuss specific failures, recoveries, and successes that may be useful to other researchers engaged, or seeking to engage in, international collaborations

Drainage And Sedimentary Response Of The Northern Andes And The Pebas System To Miocene Strike-slip Tectonics: A Source To Sink Study Of The Magdalena Basin

Miocene strike-slip tectonics was responsible for creating and closing short-lived (ca. 6 Ma) passages and the emergence of isolated topography in the Northern Andes. These geological events likely influenced the migration and/or isolation of biological populations. To better understand the paleogeography of the Miocene hinterland and foreland regions in the Northern Andes, we conducted a source-to-sink approach in the Magdalena Basin. This basin is located between the Central and Eastern Cordilleras of Colombia and contains an ample Miocene record, which includes Lower Miocene fine-grained strata and Middle Miocene to Pliocene coarsening-up strata. Our study presents a new data set that includes detrital U–Pb zircon ages (15 samples), sandstone petrography (45 samples) and low-temperature thermochronology from the Southern Central Cordillera (19 dates); which together with previously published data were used to construct a paleogeographical model of the Miocene hinterland and foreland regions in the Northern Andes. The evolution of the Magdalena Basin during the Miocene was characterized by playa and permanent lake systems at ca. 17.5 Ma, which may be related to a marine incursion into NW South America and western Amazonia. The appearance of Eocene to Miocene volcanic sources in the Honda Group after ca. 16 Ma suggests the development of fluvial passages, which connected the Pacific with the western Amazonia and Caribbean regions. These passages were synchronous with a time of Miocene exhumation and topographic growth (ca. 16 to 10 Ma) in the Central Cordillera and the transition from lacustrine to fluvial deposition in the Magdalena Basin. Middle to Late Miocene strike-slip deformation promoted by oblique plate convergence and the oblique collision of the Panamá-Chocó Block likely explains the synchronous along-strike fragmentation and exhumation in the Central Cordillera

Parenting, mental health and economic pathways to prevention of violence against children in South Africa.

BACKGROUND: Parenting programs based on social learning theory have increasing empirical evidence for reducing violence against children. Trials are primarily from high-income countries and with young children. Globally, we know little about how parenting programs work to reduce violence, with no known studies in low or middle-income countries (LMICs). This study examines mechanisms of change of a non-commercialized parenting program, Parenting for Lifelong Health for Teens, designed with the World Health Organization and UNICEF. A cluster randomized trial showed main effects on parenting and other secondary outcomes. We conducted secondary analysis of trial data to investigate five potential mediators of reduced violence against children: improved parenting, adolescent behaviour, caregiver mental health, alcohol/drug avoidance, and family economic strengthening. METHODS: The trial was implemented in rural South Africa with 40 sites, n = 552 family dyads (including adolescents aged 10-18 and primary caregivers). Intervention sites (n = 20) received the 14-session parenting program delivered by local community members, including modules on family budgeting and savings. Control sites (n = 20) received a brief informational workshop. Emotional and physical violence against children/adolescents and each potential mediator were reported by adolescents and caregivers at baseline and 9-13 months post-randomisation. Structural equation modelling was used to test simultaneous hypothesized pathways to violence reduction. RESULTS: Improvements in four pathways mediated reduced violence against children: 1) improved parenting practices, 2) improved caregiver mental health (reduced depression), 3) increased caregiver alcohol/drug avoidance and 4) improved family economic welfare. Improved child behaviour was not a mediator, although it was associated with less violence. CONCLUSIONS: Simultaneously bolstering a set of family processes can reduce violence. Supporting self-care and positive coping for caregivers may be essential in challenging contexts. In countries with minimal or no economic safety nets, linking social learning parenting programs with economic strengthening skills may bring us closer to ending violence against children

Caracterización de las pequeñas, medianas y grandes empresas localizadas en la ciudad de Pereira y sus necesidades de capacitación en normas internacionales de contabilidad / ., ., .,.,

T 657.9 C151; 96 p.En la ciudad de Pereira, encontramos 1049 empresas divididas en pequeñas, medianas y grandes, desarrollando actividades comerciales, de servicios, industriales y agropecuarias. Sobresalen esencialmente las empresas cuya actividad es la comercialización. Resulta importante conocer cuáles empresas tienen la obligación de aplicar la normatividad estipulada en la Ley 1314 de 2009, y cuáles de ellas estarían dispuestas a capacitar a su personal para la implementación de tal convergencia.Universidad Libre de Pereir

Has land use pushed terrestrial biodiversity beyond the planetary boundary? A global assessment

Land use and related pressures have reduced local terrestrial biodiversity, but it is unclear how the magnitude of change relates to the recently proposed planetary boundary (“safe limit”). We estimate that land use and related pressures have already reduced local biodiversity intactness—the average proportion of natural biodiversity remaining in local ecosystems—beyond its recently proposed planetary boundary across 58.1% of the world’s land surface, where 71.4% of the human population live. Biodiversity intactness within most biomes (especially grassland biomes), most biodiversity hotspots, and even some wilderness areas is inferred to be beyond the boundary. Such widespread transgression of safe limits suggests that biodiversity loss, if unchecked, will undermine efforts toward long-term sustainable development

Spread of a SARS-CoV-2 variant through Europe in the summer of 2020.

Following its emergence in late 2019, the spread of SARS-CoV-21,2 has been tracked by phylogenetic analysis of viral genome sequences in unprecedented detail3–5. Although the virus spread globally in early 2020 before borders closed, intercontinental travel has since been greatly reduced. However, travel within Europe resumed in the summer of 2020. Here we report on a SARS-CoV-2 variant, 20E (EU1), that was identified in Spain in early summer 2020 and subsequently spread across Europe. We find no evidence that this variant has increased transmissibility, but instead demonstrate how rising incidence in Spain, resumption of travel, and lack of effective screening and containment may explain the variant’s success. Despite travel restrictions, we estimate that 20E (EU1) was introduced hundreds of times to European countries by summertime travellers, which is likely to have undermined local efforts to minimize infection with SARS-CoV-2. Our results illustrate how a variant can rapidly become dominant even in the absence of a substantial transmission advantage in favourable epidemiological settings. Genomic surveillance is critical for understanding how travel can affect transmission of SARS-CoV-2, and thus for informing future containment strategies as travel resumes. © 2021, The Author(s), under exclusive licence to Springer Nature Limited