Subordinated hedonic games

Hedonic games are simple models of coalition formation whose main solution concept is that of core-partition. Several conditions guaranteeing the existence of core-partitions have been proposed so far. In this paper, we explore hedonic games where a reduced family of coalitions determines the development of the game. We allow each coalition to select a subset of it so as to act as its set of representatives (a distribution). Then, we introduce the notion of subordination of a hedonic game to a given distribution. Subordination roughly states that any player chosen as a representative for a coalition has to be comfortable with this decision. With subordination we have a tool, within hedonic games, to compare how a "convenient" agreement reached by the sets of representatives of dierent groups of a society is "valued" by the rest of the society. In our approach, a "convenient" agreement is a core-partition, so this paper is devoted to relate the core of a hedonic game with the core of a hedonic game played by the sets of representatives. Thus we have to tackle the existence problem of core-partitions in a reduced game where the only coalitions that matter are those prescribed by the distribution as a set of representatives. We also study how a distribution determines the whole set of core-partitions of a hedonic game. As an interesting example, we introduce the notion of hedonic partitioning game, which resembles partitioning games studied in the case where a utility, transferable or not, is present. The existence result obtained in this new class of games is later used to provide a non constructive proof of the existence of a stable matching in the marriage model.Fil: Cesco, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - San Luis. Instituto de Matemática Aplicada de San Luis; Argentina

The effect of copper toxicity on synergisms and antagonisms between nutrients in grapevine plants

Copper (Cu) accumulation in soils can induce toxicity and nutrient imbalances in several plant species. The aim of this work was thus to evaluate the effect of Cu toxicity on two grapevine rootstocks, Fercal and 196.17, and to elucidate if intercropping with oat can alleviate grapevine Cu toxicity using hydroponic trials and rhizobox experiments. The hydroponic trial revealed that Cu-induced root exudation was correlated with genes expression (VvPEZlike); furthermore the ionome analysis revealed that both mono- and intercropped L96.t7 rootstocks display a synergistic effect on Zn and Mn in the root tissues at high Cu concentrations. An increase of Zn and Mn in roots was also reported for the intercropped FercaJ rootstock at high Cu concentrations while an antagonistic relation was observed for root Zn in the monocropped Fercal rootstock. The rhizobox experiments further confirmed these results showing a different nutrient concentration depending on the rootstock and on the soil characteristics. lndeed, Cu availability is shaped by rhizosphere processes, which depend on soil properties and/or the co-cultivation of different plant species. The soil-based experiments revealed that nutrient availability and dissolved organic carbon including root exudates differ depending on soil properties and the rootstock rather than on the cultivation system, ln particular, we did not observe any apparent competition between the two plant species in the alkaline soil; on the other hand, in the acid soil, the intercropping revealed a beneficial etfect reducing the available Cu in the rhizosphere. Our results revealed that Fercal rootstock is able to take advantage from oat, while 196.17 seems disadvantaged by the intercropping system. Yet, even though the intercropping system seems to be a valuable tool to counteract grapevine Cu toxicity, the application of this agricultural practice has shown to be species and mostly soil type dependent and should be evaluated for each rootstock

Reglas proporcionales en problemas de árboles de mínimo costo

En este trabajo se presenta una nueva familia de reglas de distribución para problemas de árboles  de mínimo costo. Se utilizan criterios de proporcionalidad para estas reglas y a través de un ejemplo clásico se observa un mejor comportamiento que las reglas de Bird, Kar y Dutta-Kar. Se prueban algunas propiedades que cumplen estas reglas proporcionales y se concluye que comparativamente, desde el punto de vista de las propiedades que cumplen, se encuentran bien posicionadas.Fil: Cesco, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; ArgentinaFil: Pepa Risma, Eliana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; ArgentinaFil: Quintas, Luis Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentin

Followers are not followed: observed group interactions modulate subsequent social attention

We asked whether previous observations of group interactions modulate subsequent social attention episodes. Participants first completed a learning phase with two conditions. In the ‘leader’ condition one of three identities turned her gaze first, followed by the two other faces. In the ‘follower’ condition, one of the identities turned her gaze after the two other faces had first shifted their gaze. Thus, participants observed that some individuals were consistently ‘leaders’ and others ‘followers’ of others’ attention. In the test phase, the faces of ‘leaders’ and ‘followers’ were presented in a gaze cueing paradigm. Remarkably, the ‘followers’ did not elicit gaze cueing. Our data demonstrate that individuals who do not guide group attention in exploring the environment are ineffective social attention directors in later encounters. Thus, the role played in previous group social attention interactions modulates the relative weight assigned to others’ gaze: we ignore the gaze of group followers

Characterization of humic fractions in leachates from soil under organic and conventional management and their interactions with the root zone

Humic fractions were shown to be closely involved in gene expression and promotion of different PM H+-ATPase isoforms, as well as in lateral root development, indicating an enhanced nutrient absorption capacity of the plant root system. HPLC-SEC confirmed that water-soluble humic substances (WSHS) correspond to a subfraction of the fulvic fraction of humic substances. This was supported by E465/E665 ratios higher than 8.5. These ratios generally increased over the growing season in cultivated soils but showed significant differences between conventionally and organically managed bare soils. FTIR data and the analytical quantification of carboxyls confirmed relevant structural changes in bare soil under both organic and conventional farming management. Absorption intensities ratios at 1,590–1,570 cm-1 and 1,440–1,380 cm-1 showed the predominant aliphatic character of these molecules

Ejemplos de Guiones para radionovela

Texto explicativo e com exemplos de scripts de uma radionovel