Charge Transfer in Partition Theory

The recently proposed Partition Theory (PT) [J.Phys.Chem.A 111, 2229 (2007)] is illustrated on a simple one-dimensional model of a heteronuclear diatomic molecule. It is shown that a sharp definition for the charge of molecular fragments emerges from PT, and that the ensuing population analysis can be used to study how charge redistributes during dissociation and the implications of that redistribution for the dipole moment. Interpreting small differences between the isolated parts' ionization potentials as due to environmental inhomogeneities, we gain insight into how electron localization takes place in H2+ as the molecule dissociates. Furthermore, by studying the preservation of the shapes of the parts as different parameters of the model are varied, we address the issue of transferability of the parts. We find good transferability within the chemically meaningful parameter regime, raising hopes that PT will prove useful in chemical applications.Comment: 12 pages, 16 figure

Competition between polar and nonpolar lattice distortions in oxide quantum wells: new critical thickness at polar interfaces

Two basic lattice distortions permeate the structural phase diagram of oxide perovskites: antiferrodistortive (AFD) rotations and tilts of the oxygen octahedral network and polar ferroelectric modes. With some notable exceptions, these two order parameters rarely coexist in a bulk crystal, and understanding their competition is a lively area of active research. Here we demonstrate, by using the LaAlO₃/SrTiO₃ system as a test case, that quantum confinement can be a viable tool to shift the balance between AFD and polar modes and selectively stabilize one of the two phases. By combining scanning transmission electron microscopy (STEM) and first-principles-based models, we find a crossover between a bulklike LaAlO₃ structure where AFD rotations prevail, to a strongly polar state with no AFD tilts at a thickness of approximately three unit cells; therefore, in addition to the celebrated electronic reconstruction, our work unveils a second critical thickness, related not to the electronic properties but to the structural ones. We discuss the implications of these findings, both for the specifics of the LaAlO₃/SrTiO₃ system and for the general quest towards nanoscale control of material properties

Coupled Mg/Ca and clumped isotope analyses of foraminifera provide consistent water temperatures

The reliable determination of past seawater temperature is fundamental to paleoclimate studies. We test the robustness of two paleotemperature proxies by combining Mg/Ca and clumped isotopes (Δ47) on the same specimens of core top planktonic foraminifera. The strength of this approach is that Mg/Ca and Δ47 are measured on the same specimens of foraminifera, thereby providing two independent estimates of temperature. This replication constitutes a rigorous test of individual methods with the advantage that the same approach can be applied to fossil specimens. Aliquots for Mg/Ca and clumped analyses are treated in the same manner following a modified cleaning procedure of foraminifera for trace element and isotopic analyses. We analysed eight species of planktonic foraminifera from coretop samples over a wide range of temperatures from 2 to 29°C. We provide a new clumped isotope temperature calibrations using subaqueous cave carbonates, which is consistent with recent studies. Tandem Mg/Ca–Δ47 results follow an exponential curve as predicted by temperature calibration equations. Observed deviations from the predicted Mg/Ca-Δ47 relationship are attributed to the effects of Fe-Mn oxide coatings, contamination, or dissolution of foraminiferal tests. This coupled approach provides a high degree of confidence in temperature estimates when Mg/Ca and Δ47 yield concordant results, and can be used to infer the past δ18O of seawater (δ18Osw) for paleoclimate studies

Urban Climate Action. The urban content of the NDCs: Global review 2022

This report was prepared by United Nations Human Settlement Programme (UN-Habitat) and the UNESCO Chair on Urban Resilience at the University of Southern Denmark (SDU.Resilience). It offers a global analysis of the urban content of 193 Nationally Determined Contributions (NDCs) submitted to the Secretariat of the United Nations Framework Convention on Climate Change (UNFCCC) before the 19th of June 2022. For this report, more than 200 indicators were used to analyse external data (e.g., Human Development Index and income categorisation) and data within the NDCs, including climate mitigation and adaptation challenges and responses, as well as specific sectors. This analysis is instrumental to supporting Parties’ efforts in further integrating national climate policies and urban climate actions, which is considered fundamental to raising ambition and developing adequate and timely actions as required by the current climate emergency. This review can be instrumental for advocacy and direct support to countries by partner organisations. The work was supported by a group of experts from bilateral and multilateral organisations and academia. Three expert group meetings were convened, and a peer review was organised for the final report

Uso del residuo industrial “yeso rojo” como sustituto del yeso natural para la fabricación de cementos comerciales

The main objective of this research has been the valorisation of a waste from the TiO2 production process (sulphate method), called red gypsum, in the production of cements. This waste is mainly formed by di-hydrate calcium sulphate and iron hydroxides. To cover this objective it has been necessary to perform the physico-chemical characterisation of the red gypsum as well as the main components in the production of cements and of the new cements generated. Moreover, for the red gypsum, has been analyzed its radioactive content because it is generated in a NORM (Naturally Occurring Radioactive Materials) industry. Finally, the most important properties of the obtained cements with different proportions of red gypsum in their composition have been studied by comparing them with the standard ones obtained in a Portland cement. Lastly, we have demonstrated that the new cements fulfil all the quality tests imposed by the European legislation.El objetivo de esta investigación ha sido analizar la valorización de un residuo generado en el proceso de producción de dióxido de titanio (vía sulfato), denominado yeso rojo, en la producción de cementos. Dicho residuo está compuesto fundamentalmente por sulfato de calcio di-hidratado e hidróxidos de hierro. Para ello, ha sido necesaria la caracterización físico-química del yeso rojo, así como la de los otros componentes fundamentales en la fabricación de cementos y de los cementos generados con el mencionado residuo. Además, en el caso del yeso rojo, se ha analizado su contenido radiactivo al generarse éste en una industria NORM (Natural Occurring Radioactive Materials). Posteriormente, se han estudiado las propiedades más importantes de los cementos producidos con diferentes porcentajes de yeso rojo añadido, comparando estas mezclas con las propiedades de un cemento Portland comercial, comprobándose que se cumplen todas las normas Europeas de calidad exigibles

Perfiles de inteligencia emocional y conducta social en adolescentes españoles

Este trabajo tuvo dos objetivos, por una parte, identificar diferentes perfiles de inteligencia emocional (IE) y, por otra parte, comprobar si entre los perfiles identificados existen diferencias estadísticamente significativas respecto a la conducta social. Participaron 1.071 adolescentes españoles (50,2% chicas) españoles con edades de 14 a 17 años, a los que se les administró la “Escala de inteligencia emocional percibida” (Trait Meta-Mood Scale-24, TMMS-24) y la “Batería de socialización BAS-3”. El análisis de conglomerados identificó cuatro perfiles de IE: un grupo de adolescentes con un perfil de baja IE, un grupo con puntuaciones altas en percepción, un grupo con predominio de elevada regulación emocional y un último grupo de adolescentes con alta IE. Los resultados también indicaron diferencias estadísticamente significativas entre los perfiles en los patrones de comportamiento social, destacando los estudiantes de los grupos con alta IE generalizada y alta puntuación en regulación emocional, los cuales muestran mayores puntuaciones en conductas sociales positivas. Los descubrimientos se discuten en términos de sus implicaciones prácticas con adolescentes españoles.This work had two objectives. First, to identify different profiles of emotional intelligence (EI), and second, to verify the existence of significant statistical differences between the profiles identified in relation to social behavior. The participants were 1071 Spanish adolescents (50.2% girls), ranging in age from 14 to 17 years, who completed the Trait Meta-Mood Scale-24 (TMMS-24) and the Socialization Battery BAS-3. Cluster analysis identified four EI profiles: a group of adolescents with a low EI profile, a group with high scores in perception, a group with predominantly high emotional regulation, and a group of adolescents with high EI. The results also indicated statistically significant differences in the profiles in most of social behaviors. The students from the groups with high general EI scores and high scores in emotional regulation also show higher scores in several positive social behaviors. Findings are discussed in terms of their practical implications for Spanish adolescents.Este trabajo ha sido realizado a través del Proyecto con Ref: EDU2009-10316 perteneciente al Plan Nacional de Investigación Científica, Desarrollo de Innovación Tecnológica del Ministerio de Innovación y Ciencia, y fondos FEDER, concedido al primer autor

Storing magnetic information in IrMn/MgO/Ta tunnel junctions via field-cooling

In this paper, we demonstrate that in Ta/MgO/IrMn tunneling junctions, containing no ferromagnetic elements, distinct metastable resistance states can be set by field cooling the devices from above the Néel temperature (TN) along different orientations. Variations of the resistance up to 10% are found upon field cooling in applied fields, in-plane or out-of-plane. Well below TN, these metastable states are insensitive to magnetic fields up to 2 T, thus constituting robust memory states. Our work provides the demonstration of an electrically readable magnetic memory device, which contains no ferromagnetic elements and stores the information in an antiferromagnetic active layer

Triple oxygen and hydrogen isotopes of gypsum hydration water for quantitative paleo-humidity reconstruction

© 2017 Elsevier B.V. Atmospheric relative humidity is an important parameter affecting vegetation yet paleo-humidity proxies are scarce and difficult to calibrate. Here we use triple oxygen (δ17O and δ18O) and hydrogen (δD) isotopes of structurally-bound gypsum hydration water (GHW) extracted from lacustrine gypsum to quantify past changes in atmospheric relative humidity. An evaporation isotope-mass-balance model is used together with Monte Carlo simulations to determine the range of climatological conditions that simultaneously satisfy the stable isotope results of GHW, and with statistically robust estimates of uncertainty. We apply this method to reconstruct the isotopic composition of paleo-waters of Lake Estanya (NE Spain) and changes in normalized atmospheric relative humidity (RHn) over the last glacial termination and Holocene (from ∼15 to 0.6 cal. kyrs BP). The isotopic record indicates the driest conditions occurred during the Younger Dryas (YD; ∼12–13 cal. kyrs BP). We estimate a RHnof ∼40–45% during the YD, which is ∼30–35% lower than today. Because of the southward displacement of the Polar Front to ∼42°N, it was both windier and drier during the YD than the Bølling–Allerød period and Holocene. Mean atmospheric moisture gradually increased from the Preboreal to Early Holocene (∼11 to 8 cal. kyrs BP, 50–60%), reaching 70–75% RHnfrom ∼7.5 cal. kyrs BP until present-day. We demonstrate that combining hydrogen and triple oxygen isotopes in GHW provides a powerful tool for quantitative estimates of past changes in relative humidity

The Influence of Emotional Intelligence on Resilience, Test Anxiety, Academic Stress and the Mediterranean Diet. A Study with University Students

The academic transition to university is a turning point in young people’s lifestyles. However, studies to date have focused on student behaviour within the classroom context, rather than on the consequences it may have on their lifestyle. This study aims to analyze the influence of emotional intelligence of university students on their resilience, academic stress, exam anxiety, and eating habits related to the Mediterranean diet at the university stage. This study was carried out with the participation of 733 male and 614 female students from the University of Almeria, aged between 19 and 27. A structural equation model was made to explain the causal relationships between the variables. The results showed emotional intelligence positively predicted resilience. In turn, test anxiety and academic stress were negatively predicted by resilience. Finally, test anxiety and academic stress were negatively predicted by the Mediterranean diet. In short, the results of the present study have shown that academic transfer to university and grading pressure can generate maladaptive consequences for food consumption