Critical behavior in a cross-situational lexicon learning scenario

The associationist account for early word learning is based on the co-occurrence between referents and words. Here we introduce a noisy cross-situational learning scenario in which the referent of the uttered word is eliminated from the context with probability gamma, thus modeling the noise produced by out-of-context words. We examine the performance of a simple associative learning algorithm and find a critical value of the noise parameter gamma(c) above which learning is impossible. We use finite-size scaling to show that the sharpness of the transition persists across a region of order tau(-1/2) about gamma(c), where tau is the number of learning trials, as well as to obtain the learning error (scaling function) in the critical region. In addition, we show that the distribution of durations of periods when the learning error is zero is a power law with exponent -3/2 at the critical point. Copyright (C) EPLA, 2012

A structural model of emotions of cognitive dissonances

Cognitive dissonance is the stress that comes from holding two conflicting thoughts simultaneously in the mind, usually arising when people are asked to choose between two detrimental or two beneficial options. In view of the well-established role of emotions in decision making, here we investigate whether the conventional structural models used to represent the relationships among basic emotions, such as the Circumplex model of affect, can describe the emotions of cognitive dissonance as well. We presented a questionnaire to 34 anonymous participants, where each question described a decision to be made among two conflicting motivations and asked the participants to rate analogically the pleasantness and the intensity of the experienced emotion. We found that the results were compatible with the predictions of the Circumplex model for basic emotions. (C) 2012 Elsevier Ltd. All rights reserved.

Effect of external fields in Axelrod's model of social dynamics

The study of the effects of spatially uniform fields on the steady-state properties of Axelrod's model has yielded plenty of counterintuitive results. Here, we reexamine the impact of this type of field for a selection of parameters such that the field-free steady state of the model is heterogeneous or multicultural. Analyses of both one- and two-dimensional versions of Axelrod's model indicate that the steady state remains heterogeneous regardless of the value of the field strength. Turning on the field leads to a discontinuous decrease on the number of cultural domains, which we argue is due to the instability of zero-field heterogeneous absorbing configurations. We find, however, that spatially nonuniform fields that implement a consensus rule among the neighborhood of the agents enforce homogenization. Although the overall effects of the fields are essentially the same irrespective of the dimensionality of the model, we argue that the dimensionality has a significant impact on the stability of the field-free homogeneous steady state.

Arquitectura antidesertización. Fluidez, biodiversidad, hidrofilia y transpirabilidad

La escasez de recursos, la desertización creciente y el previsible calentamiento global forman un escenario físico sin precedentes que urge la revisión de las relaciones entre arquitectura y agua en la urbanización de los paisajes secos, donde la aridez es el factor limitante principal. Cuestionar la idea de escasez, la de residuo o la de confort es el punto de partida para analizar la hidrología urbana. La condición ubicua y dinámica del agua, sus continuos cambios de estado y las implicaciones energéticas y ambientales involucradas argumentan a favor de un entendimiento integral, holístico, que aborda el diseño en relación a lo paisajístico, lo infraestructural y lo ambiental como un único ámbito de investigación, planteado en términos no solo de materia o de escasez, sino de energía. Este trabajo se interesa por el rol de la arquitectura en este proyecto conjunto, integral, del espacio físico con el ciclo hidrológico donde lo orgánico, lo geológico y lo atmosférico están ligados, y donde las categorías de lo hidrológico y lo hidráulico se confunden. Las profundas implicaciones culturales en la construcción de la naturaleza urbana y en la relación con el cuerpo humano adquieren especial notoriedad en los modelos de paisaje y de espacio público adoptados, importados desde las geografías húmedas, y en la estigmatización del agua desde los presupuestos del higienismo decimonónico, que conduce al hidrofugado general de una ciudad aséptica y estéril, que se extiende hasta las envolventes de fachadas estancas y los interiores blancos y satinados. La búsqueda de referentes salta la modernidad hacia contextos de baja energía como el oasis tradicional de las tierras áridas, que concilia la formación de un ecosistema productivo con la climatización de un espacio público exterior, o los ambientes aislados de la investigación aeroespacial, con ciclos cerrados de materia. Las condiciones del ciclo del agua, como la vinculación con el suelo y el territorio, la capacidad de disolver, de mezclarse y de lavar, su volumen variable y su papel como termorregulador señalan el interés que características físicas como la fluidez, la biodiversidad, la hidrofilia y la transpirabilidad tienen para una arquitectura con competencias hidráulicas y un espacio urbano transparente a los procesos del agua. La morfología y localización, la elección de escalas, jerarquías y relaciones entre espacios y la reformulación de los sistemas constructivos aparecen como herramientas y categorías propias desde las que proponer mejores respuestas a problemas como la deshidratación, la erosión y la contaminación. Una urbanización permeable e hidrófila que absorba el agua como un recurso valioso, nuevos ensamblajes para la bioquímica urbana (que introduzcan una idea de limpieza más próxima a fertilidad que a la desinfección), y el diseño de las condiciones atmosféricas a través de una arquitectura transpirable, que se empapa y rezuma frescor, son las claves de este nuevo proyecto. La ciudad se piensa como una síntesis multiescalar de espacios hidráulicos que aporta mayor resiliencia frente a la desertificación y las condiciones climáticas extremas, y mayor visibilidad en la escena pública al agua y a las inevitables conexiones entre ecología y economía. Pero también es una oportunidad para revisar las categorías disciplinares, para renovar las consistencias materiales, las calidades ambientales y las relaciones entre el cuerpo y el espacio. ABSTRACT The shortage of resources, foreseeable global warming and increasing desertification create an unprecedented prospect that question the existing relationships between water and architecture, in the urbanization of the arid lands. The awareness of the huge volumes of water that pierce unnoticed through urban space, their impact on the landscape as well as on environmental qualities, promote a design field where cultural, social and political considerations intersect, related to the body and the physical experience of space within the built environment. Fluidity and ubiquity, solution ability, variability and cyclical processes are characteristic of water as material, directly related with the fields of potential, chemical and thermal energy and the reality of its mass, as it occupies a changing volume in space. These are also the imposing cross sections that water introduces into the project, that argue in favor of a comprehensive and holistic understanding, of addressing design in relationship to landscape, infrastructure and environmental issues as a one single area of research. This work attempts to investigate how architecture, with its specific tools, can partake in the design of water cycle in the space, linking the organic, geological, and atmospheric, blurring the lines between hydrology and hydraulic. It aims to identify issues, within the continuous query associated with water, that deal with the architectural project and may have here better results. The deep cultural implications in the construction of urban nature and the relationship with the body, acquire special notoriety in the models of landscape and public space adopted, imported from humid geographies. Also in the stigmatization of water from the premises of nineteenth- century hygienics, which lead to the entire waterproofing of an aseptic and sterile city, to the sealed facades and white and polished interiors. The search for alternative references goes beyond modernity towards a mindset of low energy, as the traditional oasis of arid lands, which aims to reconcile the formation of a productive ecosystem with the conditioning of an outdoor public space, or the controlled environments of aerospace research, with closed cycles of matter. Fluidity, biodiversity, hydrophilicity and breathability are characteristic of an architecture with hydraulic competences. The distributing phenomenon of water, its necessary connectivity to the ground and to small cycles in the ecosystems, shows strong affinities with an infrastructural architecture, as an alternative to large-scale centralized networks. Its volume has approximated to the dimensions of the built space, promoting a new found condition of coexistence. A permeable and hydrophilic urbanization absorbs water as a valuable resource; new assemblies for urban biochemistry introduce an idea of sanitation closer to fertility than to disinfection; a breathable architecture that soaks and exudes freshness design the atmospheric conditions: these are the essential components of this new project. The city is understood as a synthesis of multi-scale hydraulic spaces that provides greater resilience against desertification and increases the visibility of water and the linkages between ecology and economy in the public scene. It is also an opportunity to review the disciplinary categories of architecture, the material consistencies, the environmental qualities and the relationship between body and space.

Bibliography on solid lubricants, with indexes.

"Material for this bibliography was selected by Aerospace Research Applicants Center (ARAC) University of Indiana."

A technical report on analytical-experimental correlation of radiation loss from an argon arcjet.

At head of title: Dept. of the Air Force. Office of Aerospace Research. Aeronautical Research Laboratory. Thermomechanics Branch. Contract AF 33(657)-9962.

Air Force surveys in geophysics.

Some numbers issued as the Laboratories' AFCRC-TR and AFCRC-TN.

Impact tests of a near-production air cushion restraint.

Mode of access: Internet.

A computer-controlled graphical display processor /

"This report reproduces a thesis of the same title submitted to the Department of Electrical Engineering, Massachusetts Institute of Technology, in partial fulfillment of the requirements for the degree of Master of Science."--p. v

Proceedings of the Workshop on Methods of Obtaining Winds and Densities from Radar Meteor Trail Returns : held at the Charter House Motor Hotel, Waltham, Massachusetts, 16-19 August 1966 /

At head of title: Meteorology Laboratory, Project 8628.

Investigation of the dynamics of ionized media (plasmas)

"ARL 65-91."

Monte Carlo calculations of gamma ray penetration /

"Task No. 70717"

Proceedings of the Air Force Science and Engineering Symposium, 8-10 October, 1963 /

"Sponsored by Office of Aerospace Research, Air Force Systems Command, United States Air Force."

Helium injection into the boundary layer at an axisymmetric stagnation point

"Contract no. AF 33(616)-7661, Project no. 7064, Task no. 70169."

OAR directory.

Mode of access: Internet.