The particle-hole transformation, supersymmetry and achiral boundaries of the open Hubbard model

We show that the particle-hole transformation in the Hubbard model has a crucial role in relating Shastry's R-matrix to the AdS/CFT S-matrix. In addition, we construct an achiral boundary for the open Hubbard chain which possesses twisted Yangian symmetry

Dreamt Spaces

Beyond a mere interdisciplinary relationship, the symbiosis of cinema, body and architecture conveys an illusion: showing a dreamt architecture. The vision of architecture through a cinematographic filter facilitates infinite possibilities, from creating habitability conditions in impossible spaces to endowing architecture with unimaginable attributes. Aspects such as movement or dematerialization, in principle far from classic architectural values, have a familiar ring due to experiences gained in cinema. Likewise, in recent decades architecture has dared to carry out spatial experiments whose only objective is experimentation on the interrelation between body and space. Despite the importance of this question to the perception of certain architecture, during many years architects absented themselves from this field of experimentation. In the majority of the cases, as mere spectators, they limited themselves exclusively to observe the proposals of some artists and film-makers who transformed space just in another plastic material. Many of these proposals of "space alteration" were left in the dust, however, some of them established a basis for certain events to come which would change forever the traditional ways of understanding space. This new perception emerging from cinematic images poses new processes of connectivity between body and space, as we may observe in some of the works of the US Americans Diller & Scofidio, intimately related to new technologies. Others, like Philippe Rahm, focus on the fusion of biological and sensorial aspects of life forms in determinate spaces. Some like the Fabric team propose a deliberate alteration of perceiving the interior-exterior interaction of habitable spaces by means of addition and fusion. None of the above is science fiction, but we can elaborate a new architectural map with clear cinematographic references

Overconfidence in a Career-Concerns Setting

We study the effects of overconfidence in a two-period investment-decision agency setting. Under common priors, agent risk aversion implies inefficiently low first-period investment. In our model, principal and agent disagree about the profitability of the investment decision conditional on a given public signal. An overconfident agent believes that the principal will update her beliefs upwards more often than not. As a consequence, the agent overestimates the benefits of learning from first-period investment. This implies that agent overconfidence mitigates the agency problems arising from the agent’s career concerns, even though an overconfident agent bears more project and reputational risk in equilibrium.overconfidence, heterogenous beliefs, career concerns

Ataques Especulativos: Un Enfoque de Incertidumbre e Información

Durante la década pasada hemos presenciado una proliferación de crisis cambiarias, tanto en Asia como en Europa y Latinoamérica, acompañada de abundante literatura acerca del tema. Es aceptado que, cuando las políticas monetaria y fiscal no son congruentes entre sí, habrá una crisis de balanza de pagos. La literatura reciente ha avanzado en varias direcciones para explicar los mecanismos de propagación de una crisis, que aplican aún cuando la política del gobierno es sostenible. No obstante, este tipo de modelos explica escasamente la iniciación de un ataque. El objetivo de este artículo es dar una explicación tentativa a esa iniciación. Se presenta un modelo donde la obtención de información es crucial para el inversionista y ésta se deteriora con el tiempo; en este marco, el ataque especulativo es un comportamiento óptimo para un inversionista que tenga la capacidad de llevarlo a cabo. Del modelo puede concluirse, entre otras cosas, que existe una relación inversa entre la frecuencia y la profundidad de los ataques. Además, el tamaño del agente relativo a la economía y la fuerza del efecto manada afectan de manera importante los costos del ataque y, de esta forma, afectan también la vulnerabilidad de cada economía a sufrir ataques especulativos.

State of the issue and new challenges of Social Work: reflections of recently graduated professionals from Peru and Spain

Currently the primacy of the market economy in most of the nations is constituted as a global phenomenon, which has direct consequences on the structure of the different states socio-political systems. In this framework, the way in which the relations between the market and each nation-state are materialized, including their intervention strategies, generate differential contexts with relevant implications in various areas, including education. These relationships deeply affect the social protection systems and especially the Public System of Social Services, traditionally associated with the most vulnerable and less economically solvent population. The discipline of Social Work is no stranger to this situation, living in recent years convulsive moments both in terms of the construction of own knowledge and in the practice of the profession. Given this situation, it is intended to obtain the discourse that social workers have on aspects as important as the relevance of the training model, the significance given to research, the social imaginary around the discipline or the adequacy of the available resources for the exercise of the profession.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Structure of supercritically dried calcium silicate hydrates (C-S-H) and structural changes induced by weathering

The nanostructure of supercritically dried calcium silicate hydrates was researched. This particular drying procedure was used to avoid nanostructure modifications due to conventional drying processes. Thus, in this study, the as-precipitated cementitious C-S-H structure was obtained for the first time. A specific surface area 20 % larger than conventionally dried C-S-H was measured. Given the importance of this nanostructured phase for the properties of hydrated cements, especially when in contact with CO2-rich environments, the supercritically dried C-S-H was weathered for 2 weeks. The structural effects of this weathering process on the C-S-H were researched and calcium carbonate microcrystal precipitation or the presence of silica by-product are reported. Calcite and aragonite polymorphs were observed, as well as nanoporous silica forming globular arrangements. In addition, 2 weeks of weathering was not enough to carbonate the entire C-S-H sample.Junta de Andalucía TEP11

Constraints on feedback processes during the formation of early-type galaxies

Galaxies are found to obey scaling relations between a number of observables. These relations follow different trends at the low- and the high-mass ends. The processes driving the curvature of scaling relations remain uncertain. In this letter, we focus on the specific family of early-type galaxies, deriving the star formation histories of a complete sample of visually classified galaxies from SDSS-DR7 over the redshift range 0.01<z<0.025, covering a stellar mass interval from 10^9 to 3 x 10^11 Msun. Our sample features the characteristic "knee" in the surface brightness vs. mass distribution at Mstar~3 x 10^10 Msun. We find a clear difference between the age and metallicity distributions of the stellar populations above and beyond this knee, which suggests a sudden transition from a constant, highly efficient mode of star formation in high-mass galaxies, gradually decreasing towards the low-mass end of the sample. At fixed mass, our early-type sample is more efficient in building up the stellar content at early times in comparison to the general population of galaxies, with half of the stars already in place by redshift z~2 for all masses. The metallicity-age trend in low-mass galaxies is not compatible with infall of metal-poor gas, suggesting instead an outflow-driven relation.Comment: 12 pages,3 figures, accepted for publication in ApJ