Magnetism and topological phases in an interacting decorated honeycomb lattice with spin-orbit coupling

We study the interplay between spin-orbit coupling (SOC) and Coulomb repulsion in a Hubbard model on a decorated honeycomb lattice which leads to a plethora of phases. While a quantum spin hall insulator is stable at weak Coulomb repulsion and moderate SOC, a semimetallic phase emerges at large SOC in a broad range of Coulomb repulsion. This semimetallic phase has topological properties not observed in conventional metals such as a finite, non-quantized spin Hall conductivity. At large Coulomb repulsion and negligible spin-orbit coupling, electronic correlations stabilize a resonance valence bond (RVB) spin liquid state in contrast to the classical antiferromagnetic state predicted by mean-field theory. Under sufficiently strong SOC, such RVB state is transformed into a magnetic insulator consisting on S~3/2 localized moments on a honeycomb lattice with antiferromagnetic order and topological features.Comment: 13 pages, 10 figure

The Relationship Between Sleep Deprived College Students and Internalizing Symptoms Caused by Perceived Academic Workload

A recent trend among college students shows that students are willingly depriving themselves of sleep, in exchange for longer hours of studying, as a means for optimizing academic performance (Pilcher & Odle-Dusseau, 2004). That said, the effects of sleep deprivation are known to make students susceptible to mental health disorders, especially internalizing symptoms (i.e., depression & anxiety). However, less is known about the purpose and rationale behind this behavior, which often prompts students to willingly deprive themselves of sleep. The purpose of this study is to investigate the connection between sleep deprived college students and the negative indirect effect of internalizing symptoms caused by increased amounts of perceived academic workload. A cross-sectional survey was employed among N = 300 matriculated college students, to analyze the effects of sleep deprivation on cognitive performance and on internalizing symptoms related to perceived workload. It is hypothesized that sleep deprived college students are likely to experience internalizing symptoms due to increased amounts of perceived academic workload. Results were recorded in the form of a self-reported online survey, using the FIU licensed survey software, Qualtrics. It is hoped that this study helps bring awareness and insight to both the public and educational institutions, on the ideal amount of academic workload assigned to students

MotoStudent, un paradigma de emprendimiento y educación no formal en la universidad

(SPA)Muchas instituciones de educación superior de todo el mundo llevan tiempo dinamizando sus enseñanzas a fin de transmitir a sus egresados las nuevas competencias que demanda la sociedad del siglo XXI. Afortunadamente en España también existe una fuerte apuesta por la flexibilización de la educación superior, que se materializa en iniciativas tales como la competición internacional MotoStudent. (ENG)A lot of educational superior institutions around the world have been dynamized their teaching methods trying to transmit to their graduates the new abilities that demands the XX’s century society. Fortunately in Spain it also exist a hard bet for the flexibility of the high education, materialized in initiatives as the international “MotoStudent” contest

Ushahidi

(SPA)Ushahidi es el programa africano de mayor difusión mundial, que permite mapear información vital, desde el punto de vista social, en zonas de catástrofe o de conflicto. Originalmente concebida para reunir las múltiples denuncias de fraude en relación a las elecciones kenianas, ha sido utilizada posteriormente en todo el mundo en centenares de situaciones diversas, generalmente relacionadas con situaciones de amenazas, crisis, ayuda humanitaria, etc. Este artículo presenta el fenómeno Ushahidi y sus aplicaciones, a fin de entender su alcance y sus posibles repercusiones. También se introducen temas de gran interés para el desarrollo humano como el Crowdsourcing, la GeoWeb, la Neogeografía y la Información Geográfica Voluntaria, dada su estrecha relación con el objeto del trabajo. (ENG) Ushahidi is the African program of global outreach greater, which allows to map vital information from the social point of view, in areas of disaster or conflict. Originally designed to meet the multiple allegations of fraud in relation to the Kenyan elections, has since been used worldwide in hundreds of different situations, usually related to situations of threat, crisis, humanitarian aid, etc. This paper presents the Ushahidi phenomenon and its applications, in order to understand its scope and possible implications. Topics of great interest to human development, as Crowdsourcing, the GeoWeb, the Neogeography and Volunteered Geographic Information, given its close relationship with the object of labor are also introduced

Leflunomide derivative FK778 inhibits production of antibodies in an experimental model of alloreactive T-B cell interaction

El pdf es el artículo en full text.-- et al.[Objectives]: The contribution of humoral immune response in allograft and xenograft rejection has been clearly demonstrated in recent years. For this reason, inhibition of alloantibody production has become essential in managing transplanted patients. Here, we assessed the effects of the leflunomide derivative FK778 (FK778) in the control of antibody production resulting from semiallogeneic cognate T-B-cell interactions. [Materials and Methods]: BALB/c mice were tolerized at birth with semiallogeneic spleen cells from (BALB/c × C57BL/6) F1 mice, with or without overexpression of human bcl-2 transgene in B cells. These tolerized mice were treated with different dosages of FK778, either from birth, or from the third week of age, when autoantibody production was detected. The production of autoantibodies, used as markers of semiallogeneic cognate T-B-cell interactions, was evaluated at different time points during drug administration or after the interruption of treatment. [Results]: FK778 treatment started at birth inhibited the production of semiallogeneic-driven antibodies in a dose-dependent manner. In addition, FK778 also reduced the levels of preformed circulating autoantibodies in adult mice, although the dosage required was 4 times higher than that used in neonates. However, the levels of IgG antibodies in these tolerized mice increased after FK778 withdrawal, indicating that FK778 failed to induce tolerance to semiallogeneic host CD4+ Th2 and/or donor B cells. [Conclusions]: Our results demonstrate the efficacy of FK778 in the control of antibody production resulting from semiallogeneic cognate T-B-cell interactions. © Başkent University 2009. All Rights Reserved.This work was supported by REDINREN RD06/0016 and PI070683 grants from the “Instituto de Salud Carlos III, Ministerio de Sanidad y Consumo” (Spain) to MA, by grant No. SAF2005-00811 from the “Ministerio de Educación y Ciencia,” and a grant from the “Fundación Ramón Areces” (Spain) to RM, by grants No. SAF2006-012520-C02-02 from the “Ministerio de Educación y Ciencia,” and grant No. API07/08 from the “Fundación Marqués de Valdecilla” (Spain) to JM, and MAR-B is the recipient of a postdoctoral fellowship from the “Instituto Reina Sofía de la Fundación Renal Iñigo Alvarez de Toledo,” Spain. IS is funded by the “Fundación Marqués de Valdecilla, API06/07” (Spain).Peer Reviewe

México: partida de ajedrez. Mario Pani

Se ensaya aquí cómo construye su mirada el arquitecto Mario Pani Darqui (México, D.F., 1911-1993), cuya visión es la del jugador de ajedrez: estratégica, cenital y transversal, profunda y extrañada, inci- siva y extensa, mimética y contrapuesta. Todo al mismo tiempo. Con base en esta reconstrucción de su forma de ver ―crucial para el entendimiento de la arquitectura y el urbanismo de México en el si- glo XX― se plantea una acción conceptual en el entorno del río Manzanares en Madrid. Un paisaje espiritual, silente, que a través de tres situaciones radicales obliga a quien lo contempla a un ejercicio instantáneo de meditación. Se ejecuta y se cartografía, dando como resultado una aproximación sen- sible sobre cómo intervenir en el paisaje y su registro

El legado gráfico arquitectónico de Armando Sol

A lo largo de la historia de la arquitectura salvadoreña, han existido personajes que han dejado huella a través de sus diseños y construcciones, que reflejan soluciones creativas, inmersas en un contexto social, económico y cultural de una época. Tal es el caso de Armando Sol, uno de los primeros arquitectos salvadoreños graduados en el exterior y que aportara al país, no sólo un legado arquitectónico, sino también un legado artístico que pocos conocen y que es necesario valorarlo, conservarlo y difundirlo, con la intensión de que la sociedad, pero sobretodo las nuevas generaciones de arquitectos en formación aprendan a respetar y a proteger nuestro patrimonio cultural edificado.Universidad Tecnológica de El Salvado

Deception as cooperation

I develop a rate-distortion analysis of signaling games with imperfect common interest. Sender and receiver should be seen as jointly managing a communication channel with the objective of minimizing two independent distortion measures. I use this analysis to identify a problem with 'functional' theories of deception, and in particular Brian Skyrms's: there are perfectly cooperative, non-exploitative instances of channel management that come out as manipulative and deceptive according to those theories

Can education policy make children happier? A comparative study in 33 countries

There is an increasing academic and policy interest in subjective well-being (SWB). However, the questions of whether and how public policy can promote children’s SWB remain understudied. This thesis aims to reduce this gap by studying the association between education policy and students’ SWB, with a focus on life satisfaction (LS). To quantitatively study this question, this thesis analyses data on 15-year-old students in 33 countries that participated in the 2015 Programme for International Student Assessment (PISA) study. The analysis draws on Bronfenbrenner’s ecological model of child development and it is conducted by using a range of advanced quantitative methods, mainly multilevel regression. This thesis presents analysis demonstrating an association between several education policy-relevant factors and students´ LS, which is particularly prominent –and observed in almost all countries- for schoolwork-related anxiety, bullying and parents’ emotional support in relation to school. Results also indicate that schools may play an important role in shaping students’ LS. This is supported by evidence that these associations tend to vary by school, by evidence on the existence of school effects in almost all countries, and by the finding that a proportion - substantial in some countries- of the variation in students’ LS is explained by differences between schools. Moreover, findings suggest that school type and school peers’ characteristics can be important to students’ LS too. In addition, in many countries, the links between schools and education policy and students’ LS differ for girls and boys and for students of different socio-economic status. Finally, in all the analyses described above, there are significant differences across countries. Overall, this thesis makes key contributions to our understanding of whether and how children´s SWB can be influenced by schools and education policy, supporting calls that education policy should also be assessed in terms of its impact in children´s SWB