The Geometrical Trinity of Gravity

The geometrical nature of gravity emerges from the universality dictated by the equivalence principle. In the usual formulation of General Relativity, the geometrisation of the gravitational interaction is performed in terms of the spacetime curvature, which is now the standard interpretation of gravity. However, this is not the only possibility. In these notes we discuss two alternative, though equivalent, formulations of General Relativity in flat spacetimes, in which gravity is fully ascribed either to torsion or to non-metricity, thus putting forward the existence of three seemingly unrelated representations of the same underlying theory. Based on these three alternative formulations of General Relativity, we then discuss some extensions.Comment: 22 pages, 2 figure

Flocking Behaviour: Agent-Based Simulation and Hierarchical Leadership

We have studied how leaders emerge in a group as a consequence of interactions among its members. We propose that leaders can emerge as a consequence of a self-organized process based on local rules of dyadic interactions among individuals. Flocks are an example of self-organized behaviour in a group and properties similar to those observed in flocks might also explain some of the dynamics and organization of human groups. We developed an agent-based model that generated flocks in a virtual world and implemented it in a multi-agent simulation computer program that computed indices at each time step of the simulation to quantify the degree to which a group moved in a coordinated way (index of flocking behaviour) and the degree to which specific individuals led the group (index of hierarchical leadership). We ran several series of simulations in order to test our model and determine how these indices behaved under specific agent and world conditions. We identified the agent, world property, and model parameters that made stable, compact flocks emerge, and explored possible environmental properties that predicted the probability of becoming a leader.Flocking Behaviour; Hierarchical Leadership; Agent-Based Simulation; Social Dynamics

Spatial Behavior in Groups: an Agent-Based Approach

We present an agent-based model with the aim of studying how macro-level dynamics of spatial distances among interacting individuals in a closed space emerge from micro-level dyadic and local interactions. Our agents moved on a lattice (referred to as a room) using a model implemented in a computer program called P-Space in order to minimize their dissatisfaction, defined as a function of the discrepancy between the real distance and the ideal, or desired, distance between agents. Ideal distances evolved in accordance with the agent\'s personal and social space, which changed throughout the dynamics of the interactions among the agents. In the first set of simulations we studied the effects of the parameters of the function that generated ideal distances, and in a second set we explored how group macro-level behavior depended on model parameters and other variables. We learned that certain parameter values yielded consistent patterns in the agents\' personal and social spaces, which in turn led to avoidance and approaching behaviors in the agents. We also found that the spatial behavior of the group of agents as a whole was influenced by the values of the model parameters, as well as by other variables such as the number of agents. Our work demonstrates that the bottom-up approach is a useful way of explaining macro-level spatial behavior. The proposed model is also shown to be a powerful tool for simulating the spatial behavior of groups of interacting individuals.Spatial Behavior, Proxemics, Agent-Based Modeling, Minimum Dissatisfaction Model, Small Groups, Social Interaction

Our Roots: : Latinx Parents\u27 Language Ideologies Concerning Bilingualism

Language is a fundamental component of one\u27s identity, as well as a means of surviving in a globalizing world. This study draws upon sixteen narratives of first-generation Mexican and Puerto Rican parents in Central Florida to answer the research question: What are the language ideologies of Mexican and Puerto Rican immigrant parents towards the English Language acquisition and Spanish Language retention of their children? The information was gathered through semi-structured interviews and it aimed to learn how and if they value English and Spanish bilingualism and whether it was desired for their children. On the one hand, they are aware of the necessity of being fluent in English to properly navigate themselves in the United States and to secure better opportunities for education and careers. However, Spanish retention is just as important as a means to remember ones raices, or roots, which was a statement that was voiced throughout the respondents. Demographic information, language use in different contexts, access to resources, and whether they faced any forms of language discrimination are all factors that were also analyzed to determine a more holistic account of the parents\u27 language ideologies. My results reflect how Latinx family\u27s experiences in the United States have shaped their language ideologies and the language use outcomes of future generations. El lenguaje es un componente fundamental de nuestra identidad, y también un medio para sobrevivir en un mundo globalizado. Este estudio se basa en dieciséis narrativas de padres mexicanos y puertorriqueños de primera generación en Florida Central para responder a la pregunta de investigación: ¿Cuáles son las ideologías del idioma de los padres inmigrantes mexicanos y puertorriqueños hacia la adquisición de inglés y la retención de español de sus hijos? La información fue conseguido a través de entrevistas semiestructuradas, y el objetivo es para aprender cómo y si valoran el bilingüe (inglés y español), y si deseaban esta habilidad para sus hijos. Por un lado, los padres son conscientes de la necesidad de ser fluentes en inglés para navegar adecuadamente por los Estados Unidos y para asegurar mejores oportunidades para su educación y carreras. Sin embargo, la retención de español es importante como un medio para recordar los raices de su cultura; que fue una declaración que se expresó en todo los encuestados. La información demográfica, el uso del lenguaje en diferentes contextos, el acceso a los recursos y si se enfrentaron a alguna forma de discriminación del lenguaje son factores que también se analizaron para determinar un relato más holístico de las ideologías del idioma de los padres. Mis resultados reflejan cómo las experiencias de las familias Latinx en los Estados Unidos han dado forma a sus ideologías de lenguaje y al uso del lenguaje para las futuras generaciones

Clinical and magnetic resonance imaging characteristics of thoracolumbar intervertenral disk extrusions and protrusions in large breed dogs

It has recently been shown that the fat-derived hormone adiponectin has the ability to decrease hyperglycemia and to reverse insulin resistance. However, bacterially produced full-length adiponectin is functionally inactive. Here, we show that endogenous adiponectin secreted by adipocytes is post-translationally modified into eight different isoforms, as shown by two-dimensional gel electrophoresis. Carbohydrate detection revealed that six of the adiponectin isoforms are glycosylated. The glycosylation sites were mapped to several lysines (residues 68, 71, 80, and 104) located in the collagenous domain of adiponectin, each having the surrounding motif of GXKGE(D). These four lysines were found to be hydroxylated and subsequently glycosylated. The glycosides attached to each of these four hydroxylated lysines are possibly glucosylgalactosyl groups. Functional analysis revealed that full-length adiponectin produced by mammalian cells is much more potent than bacterially generated adiponectin in enhancing the ability of subphysiological concentrations of insulin to inhibit gluconeogenesis in primary rat hepatocytes, whereas this insulin-sensitizing ability was significantly attenuated when the four glycosylated lysines were substituted with arginines. These results indicate that full-length adiponectin produced by mammalian cells is functionally active as an insulin sensitizer and that hydroxylation and glycosylation of the four lysines in the collagenous domain might contribute to this activity.link_to_subscribed_fulltex

The Circumnuclear Ring of Ionized Gas in NGC3593

We present the results of narrow-band Halpha+NII imaging of the early-type spiral NGC3593 in combination with a study of the flux radial profiles of the NII (lambda: 654.80, 658.34 nm), Halpha, and SII (lambda: 671.65, 673.08 nm) emission lines along its major axis. The galaxy is known to contain two counterrotating stellar discs of different size and luminosity. We find that the Halpha emission mainly derives from a small central region of 57 arcsec x 25 arcsec. It consists of a filamentary pattern with a central ring. This has a diameter of about 17 arcsec (~ 0.6/h kpc) and it contributes about half of the total Halpha flux. The ring is interpreted as the result of the interaction between the acquired retrograde gas which later formed the smaller counterrotating stellar disc and the pre-existing prograde gas of the galaxy.Comment: Accepted for pubblication in Astronomy and Astrophysics; one latex file (corsini.tex), and 2 encapsulated postscript figures (corsini_fig1.ps,corsini_fig2.ps). To be compiled with aa.cls latex2e macro style (pslatex option): 6 pages after latex compilatio