Non-emptiness of the alpha-core

We prove non-emptiness of the alpha-core for balanced games with non-ordered preferences, extending and generalizing in several aspects the results of Scarf (1971), Border (1984), Florenzano (1989), Yannelis (1991) and Kajii (1992). In particular we answer an open question in Kajii (1992) regarding the applicability of the non-emptiness results to models with infinite dimensional strategy spaces. We provide two models with Knightian and voting preferences for which the results of Scarf (1971) and Kajii (1992) cannot be applied while our non-emptiness result applies.

Existência e liberdade: a trans-descendência extática da vida no livro A religião e o nada de Nishitani Keiji

The dialog between the East philosophy and the Western thinking allow us to think the problems inherent to our time from several point of views. Nishitani Keiji, from the Kyoto School, sees the contemporaneity, or the time of the technic, for Heidegger, as derivation and as an immediate consequence of perspective introduced in the modern era form the Cartesian s cogito which creates a barrier that separates man and world. Scientific thinking that dominates our era was created from the thinking that ennobles human reason to the detriment of the others things in the world, determining that the knowledge just can be produced by the man himself and his set of rational powers. However, alerts us Nishitani, this point of view derived from modern thought which imposes subjectivity egocentric type besides not apprehend things in their truth, neither achieves the true self of man. In an attempt to overcome the abuses produced in modernity and that reverberates in our way of be until today, our philosopher will propose the point of view of the nothingness (śūnyatā) as a way to trans-descendance, that is, to overcome the traditional thinking overvalues the reason for the encounter with the original face of man, which by no longer impose its cognitive power can know all things in their true, in the tathatā

Application of hydrophobic resin adhesives to acid-etched dentin with an alternative wet bonding technique

Hydrophilic dentin adhesives are prone to water sorption that adversely affects the durability of resin-dentin bonds. This study examined the feasibility of bonding to dentin with hydrophobic resins via the adaptation of electron microscopy tissue processing techniques. Hydrophobic primers were prepared by diluting 2,2-bis[4(2-hydroxy-3-methacryloyloxy-propyloxy)-phenyl] propane/triethyleneglycol dimethacrylate resins with known ethanol concentrations. They were applied to acid-etched moist dentin using an ethanol wet bonding technique that involved: (1) stepwise replacement of water with a series of increasing ethanol concentrations to prevent the demineralized collagen matrix from collapsing; (2) stepwise replacement of the ethanol with different concentrations of hydrophobic primers and subsequently with neat hydrophobic resin. Using the ethanol wet bonding technique, the experimental primer versions with 40, 50, and 75% resin exhibited tensile strengths which were not significantly different from commercially available hydrophilic three-step adhesives that were bonded with water wet bonding technique. The concept of ethanol wet bonding may be explained in terms of solubility parameter theory. This technique is sensitive to water contamination, as depicted by the lower tensile strength results from partial dehydration protocols. The technique has to be further improved by incorporating elements of dentin permeability reduction to avoid water from dentinal tubules contaminating water-free resin blends during bonding. (c) 2007 Wiley Periodicals, Inc. J Biomed Mater Res 84A: 19-29, 2008.

The requirement of zinc and calcium ions for functional MMP activity in demineralized dentin matrices

The progressive degradation of resin-dentin bonds is due, in part, to the slow degradation of collagen fibrils in the hybrid layer by endogenous matrix metalloproteinases (MMPs) of the dentin matrix. In in vitro durability studies, the storage medium composition might be important because the optimum activity of MMPs requires both zinc and calcium. Objective. This study evaluated the effect of different storage media on changes in matrix stiffness, loss of dry weight or solubilization of collagen from demineralized dentin beams incubated in vitro for up to 60 days. Methods. Dentin beams (1 mm x 2 mm x 6 mm) were completely demineralized in 10% phosphoric acid. After baseline measurements of dry mass and elastic modulus (E) (3-point bending, 15% strain) the beams were divided into 5 groups (n = 11/group) and incubated at 37 degrees C in either media containing both zinc and calcium designated as complete medium (CM), calcium-free medium, zinc-free medium, a doubled-zinc medium or water. Beams were retested at 3, 7, 14, 30, and 60 days of incubation. The incubation media was hydrolyzed with HCl for the quantitation of hydroxyproline (HOP) as an index of solubilization of collagen by MMPs. Data were analyzed using repeated measures of ANOVA. Results. Both the storage medium and the storage time showed significant effects on E, mass loss and HOP release (p < 0.05). The incubation in CM resulted in relatively rapid and significant (p < 0.05) decreases in stiffness, and increasing amounts of mass loss. The HOP content of the experimental media also increased with incubation time but was significantly lower (p < 0.05) than in the control CM medium, the recommended storage medium. Conclusions. The storage solutions used to age resin-dentin bonds should be buffered solutions that contain both calcium and zinc. The common use of water as an aging medium may underestimate the hydrolytic activity of endogenous dentin MMPs. (c) 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

“Tia, você me adota?” : o abrigo e a escola na constituição subjetiva da criança sob tutela do Estado

O objetivo desta pesquisa foi discutir as interferências do acolhimento institucional e da educação escolar na constituição da subjetividade da criança que, por algum motivo, foi afastada da família e/ou responsável e se encontra sob tutela do Estado, aos cuidados de uma casa-lar, no município de Vila Velha. Para a leitura subjetiva das crianças que compuseram o cenário deste trabalho, a pesquisa ancorou-se na Perspectiva Histórico-Cultural do Desenvolvimento Humano, tendo como autores de base Lev Vigotski, Henri Wallon e Mikhail Bakhtin. A investigação ocorreu em dois espaços distintos: na “Casa-Lar Santa Cecília”, instituição que desenvolvia um programa de acolhimento institucional às crianças sob tutela pública; e numa escola de Ensino Fundamental, com crianças que estavam matriculadas no 3º ano. A metodologia utilizada nessa investigação foi o estudo de caso; trata-se, portanto, do estudo de caso de duas crianças sob tutela pública. Os procedimentos utilizados para o recolhimento do material empírico foram a observação participante e as entrevistas semiestruturadas com os profissionais do abrigo e da escola. O estudo teve enfoque em duas crianças – uma menina e um menino, ambos com dez anos de idade. O processo de destituição familiar e o acolhimento institucional sempre deixam marcas. Encontramos as marcas nas cicatrizes deixadas no corpo de Sofia em consequência dos maus-tratos; no seu silêncio, a dor por uma realidade vivida que não se desvanece. Nesse contexto, suas expectativas giravam em torno da adoção, de outro caminho, mas diferente do abrigamento. Deparamo-nos com a dor e a saudade, expressas por meio do choro, que Noah sentia de uma família que, ao longo do tempo, se foi desmembrando e se distanciando em decorrência da destituição familiar e da adoção dos irmãos; as dificuldades para elaborar esses acontecimentos e o sofrimento vivenciado diante do imenso vazio que se delineia com tantas perdas foram identificados nas manifestações de raiva, na intensificação da rispidez e da intolerância em relação, sobretudo, aos colegas de sala de aula. Por outro lado, a escola apresentou-se como um espaço significativo para essas duas crianças, que tinham, nessa instituição, a possibilidade de se constituir como alunos, da mesma forma que as outras crianças, e de vivenciar experiências no encontro com os outros que lhes traziam satisfação e, de certa forma, potencializavam o seu desenvolvimento. Encontramos indícios de ecos dos sentimentos dos outros na vida dessas crianças, bem como do impacto desses sentimentos na constituição subjetiva de cada uma delas; em outras palavras, o sentimento de pertencer a um grupo e de ter um lugar na vida de alguns membros da comunidade escolar, sobretudo, das outras crianças.

Do silêncio à acção.

From silence to action: silence taken as a foundational action that allows creative processes. It is a blankness that precedes the moment of creation but also stands for a search for perfection, the un-representable, the Sublime. The ‘art moment’ is that what is created from such emptiness, in the vertiginous abyss from nowhere to action. We will work this complex process of understanding if an action precedes the silence or if the silence precedes the action. Analyzing art process, considering its phases, from the tension between either to create or not to create will be related with the potency refereed by Agamben regarding Bartleby: starting with blankness, with the invisibility of potency, when communication is urgent. When “the blues” are called into participation, when the melancholic state installs the potency of the work both to grow or be doubted, of to do or not to do, how do we read agency? Is silence the action? Should the action rest in silence? What to do? Remain in the state of pure potency or prove the impossibility to create form? Nowadays, the pensive image counters the logic of the narrative action. On the one hand, the image extends the action on the other hand suspends any given presumption. The artistic process carries on, in its poetic freedom, a search without the enslavement of representational forms.

Saudade

Dissertação para obtenção do Grau de Mestre em Arte e Ciência do Vidro

Fairness under uncertainty with indivisibilities

I analyze an economy with uncertainty in which a set of indivisible objects and a certain amount of money is to be distributed among agents. The set of intertemporally fair social choice functions based on envy-freeness and Pareto efficiency is characterized. I give a necessary and sufficient condition for its non-emptiness and propose a mechanism that implements the set of intertemporally fair allocations in Bayes-Nash equilibrium. Implementation at the ex ante stage is considered, too. I also generalize the existence result obtained with envy-freeness using a broader fairness concept, introducing the aspiration function.

Stable coalition structures with fixed decision scheme

This paper studies the stability of a finite local public goods economy in horizontal differentiation, where a jurisdiction's choice of the public good is given by an exogenous decision scheme. In this paper, we characterize the class of decision schemes that ensure the existence of an equilibrium with free mobility (that we call Tiebout equilibrium) for monotone distribution of players. This class contains all the decision schemes whose choice lies between the Rawlsian decision scheme and the median voter with mid-distance of the two median voters when there are ties. We show that for non-monotone distribution, there is no decision scheme that can ensure the stability of coalitions. In the last part of the paper, we prove the non-emptiness of the core of this coalition formation game

Payoff-dependent balancedness and cores (revised version)

We prove the non-emptiness of the core of an NTU game satisfying a condition of payoff-dependent balancedness, based on transfer rate mappings. We also define a new equilibrium condition on transfer rates and we prove the existence of core payoff vectors satisfying this condition. The additional requirement of transfer rate equilibrium refines the core concept and allows the selection of specific core payoff vectors. Lastly, the class of parametrized cooperative games is introduced. This new setting and its associated equilibrium-core solution extend the usual cooperative game framework and core solution to situations depending on an exogenous environment. A non-emptiness result for the equilibrium-core is also provided in the context of a parametrized cooperative game. Our proofs borrow mathematical tools and geometric constructions from general equilibrium theory with non convexities. Applications to extant results taken from game theory and economic theory are given.

El Procés de la certificació energètica per edificació existent

Arran d’una part de la transposició a l’Estat espanyol de la Directiva 2002/91/CE sobre Eficiència Energètica d’Edificis mitjançant el Real Decret 47/2007, pel que s’aprova el Procediment bàsic per la certificació d’eficiència energètica d’edificis de nova construcció, la certificació energètica esdevé obligatòria per edificació nova, i es dóna de termini fins a 2009 per a l’obligatorietat en edificació existent. És en aquest buit de l’edificació existent on es presenta l’objectiu de l’estudi, que és precisament augmentar el coneixement i canvi d’actitud dels agents de l’habitatge social sobre solucions de la rehabilitació des d’una perspectiva de sostenibilitat ambiental, en el context de la certificació energètica per obra nova. Després d’un intens treball de recerca de dades, s’aplicà en un cas pràctic d’habitatge social la nova directiva sobre certificació energètica de l’edificació amb les eines oficials existents. S’aconseguí fer una avaluació energètica d’un habitatge com a eina de gestió per la definició d’estratègies, i solucions ambientals per aconseguir així una major eficiència dels mateixos. D’aquesta manera, s’ha demostrat el valor afegit de la certificació energètica, i les dades obtingudes de les diferents certificacions realitzades podran ajudar a desenvolupar eines i estratègies integrades d’aplicació de millores energètiques a nivell del parc d’edificis existent.

Declining prevalence of hepatitis A virus antibodies among children from low socioeconomic groups reinforces the need for the implementation of hepatitis A vaccination in Brazil

Age-related seroprevalence studies that have been conducted in Brazil have indicated a transition from a high to a medium endemicity of hepatitis A virus (HAV) infection in the population. However, most of these studies have focused on urban populations that experience lower incidence rates of HAV infection. In the current study, the prevalence of anti-HAV antibodies was investigated in children with a low socioeconomic status (SES) that live on the periphery of three capital cities in Brazil. A total of 1,162 dried blood spot samples were collected from individuals whose ages ranged from one-18 years and tested for anti-HAV antibodies. A large number of children under five years old (74.1-90%) were identified to be susceptible to HAV infection. The anti-HAV antibody prevalence reached ≥ 50% among those that were 10-14 years of age or older. The anti-HAV prevalence rates observed were characteristics of regions with intermediate level of hepatitis A endemicity. These data indicated that a large proportion of children with a low SES that live at the periphery of urban cities might be at risk of contracting an HAV infection. The hepatitis A vaccine that is currently offered in Brazil is only available for high-risk groups or at private clinics and is unaffordable for individuals with a lower SES. The results from this study suggest that the hepatitis A vaccine should be included in the Brazilian National Program for Immunisation.

The equity core and the Lorenz-maximal allocations in the equal division core

In this paper, we characterize the non-emptiness of the equity core (Selten, 1978) and provide a method, easy to implement, for computing the Lorenz-maximal allocations in the equal division core (Dutta-Ray, 1991). Both results are based on a geometrical decomposition of the equity core as a finite union of polyhedrons. Keywords: Cooperative game, equity core, equal division core, Lorenz domination. JEL classification: C71