Efficiency wage and union effects in labor demand and wage structure in Mexico - An application of quantile analysis

Applying quantile analysis to detailed firm-level data from Mexico, the authors study determinants of demand and wages for two classes of labor. Unions appear to have a strong impact on how much unskilled labor is employed but not on wages. This suggests an extreme example of"monopoly union"behavior. The impact on productivity is, by definition, negative, but unions could also be said to be forcing firms to use"appropriate technology"(less capital and more workers), increasing the total amount of labor employed in the economy. The only impact on wages appears for the tenth (lowest) quantile of unskilled workers, suggesting that unions prevent workers from being paid too far below the median for their skill level. The authors identify significant efficiency wage effects where firms pay above market clearing to prevent labor turnover both in labor demand and in the wage equations. Since minimum wages are not binding and the union impact on wages is small, this suggests that whatever segmentation exists emerges endogenously and is not due to union - or government - induced distortions. The authors offer the first use of quantile analysis to analyze labor demand at the firm level, and one of the first uses of correct standard errors in two-stage least-squares quantile regression.Labor Policies,Banks&Banking Reform,Public Health Promotion,Environmental Economics&Policies,Economic Theory&Research,Labor Management and Relations,Health Monitoring&Evaluation,Economic Theory&Research,Banks&Banking Reform,Environmental Economics&Policies

Towards a framework for investigating tangible environments for learning

External representations have been shown to play a key role in mediating cognition. Tangible environments offer the opportunity for novel representational formats and combinations, potentially increasing representational power for supporting learning. However, we currently know little about the specific learning benefits of tangible environments, and have no established framework within which to analyse the ways that external representations work in tangible environments to support learning. Taking external representation as the central focus, this paper proposes a framework for investigating the effect of tangible technologies on interaction and cognition. Key artefact-action-representation relationships are identified, and classified to form a structure for investigating the differential cognitive effects of these features. An example scenario from our current research is presented to illustrate how the framework can be used as a method for investigating the effectiveness of differential designs for supporting science learning

ESTIMATING PRIVATE DEMANDS FOR PUBLIC GOODS: A SURVEY

The main purpose of this paper is to present a methodology for the empirical study of individual preferences for public goods. We survey the literature annotating the main critiques to the now seminal paper of Bergstrom and Goodman (1973) and present some suggestions on the direction of future research.Este artigo propõe uma metodologia para estudos empíricos das preferências individuais para bens públicos. Através de uma revisão crítica da literatura, tomando como base o seminal artigo de Bergstrom e Goodman (1973), apontamos os componentes mínimo para estudos empíricos nessa área

Estudo comparativo da neoformação óssea entre parafuso de osso corticol bovino e enxerto ósseo aposicional

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde. Programa de Pós-Graduação em Odontologia.O objetivo deste estudo foi comparar o uso de parafuso de osso cortical bovino (POCB) com o enxerto ósseo autógeno aposicional (EOAA). Portanto, 18 cães Beagle fêmeas receberam 4 POCB e 1 EOAA. Os marcadores fluorcromáticos utilizados foram, alisarina, calceína e tetraciclina. Secções de amostras dos dois grupos foram analisadas por meio da microscopia de fluorescência aos 2, 4, e 6 meses pós-operatórios. Os resultados mostram presença de osso neoformado nos dois grupos analisados. O POCB foi gradativamente substituído por osso neoformado após integrar-se ao sítio receptor, indicando propriedade osseoindutora e osseocondutora. Adicionalmente, o osso estava contínuo com o sítio receptor. O EOAA também mostrou propriedades osseoindutora e osseocondutoras. No entanto, a velocidade de deposição óssea foi menor em comparação com a velocidade de degradação do EOAA. Nos intervalos de análise, o POCB mostrou formação óssea estatisticamente significativa comparado com o EOAA. Conclui-se que o POCB apresenta menor absorção óssea comparado com o EOAA. Sugere-se o uso do POCB como alternativa quando EOAA é indicada, devido à alta absorção do EOAO no sítio cirúrgico. Purpose: Compare newly formed bone after bovine cortical bone screw placement and onlay autogenous bone graft procedure. Methods and Materials: Eighteen female Beagle dog tibias received 4 bovine cortical bone screws and an onlay autogenous bone graft. Both augmentation techniques resulted in newly formed bone. Fluorchromatic bone markers were injected in the dogs in different time intervals. Sections of the samples were analyzed by fluorescence microscopy after 2, 4, and 6 months post-operatively. The fluorchrome markers were alizarin, calceíne and tetracycline. Results: Newly formed bone was observed in sections made of samples collected from both procedures. The bovine cortical bone screw was partially present in the samples and seemed to reduce in quantity as time intervals extended. Additionally, the bone was contiguous to the receptor site. This could be attributed to the bone neoformation. The autogenous onlay bone graft was gradationally substituted after integrated in the receptor site faster than the newly formed bone, suggesting an osseoinduction and osseoconduction characteristic. The newly formed bone was highly cellular, showing the presence of osteocytes and osteoclasts. Two months postoperatively, the cortical bovine bone screw technique showed statistically significant bone formation compared to the onlay bone graft. This finding was confirmed after 4 and 6 month interval analyses. Conclusion: The bovine cortical bone screw showed to be highly osteoinductive. The authors suggest its use compared to the onlay autogenous grafts for bone graft augmentation procedures. The bovine cortical screw used for bone augmentation showed to be a better solution in long terms compared to the onlay autogenous bone graft procedure, due to the higher bone resorption in the onlay graft surgical site

The effect of representation location on interaction in a tangible learning environment

Drawing on the 'representation' TUI framework [21], this paper reports a study that investigated the concept of 'representation location' and its effect on interaction and learning. A reacTIVision-based tangible interface was designed and developed to support children learning about the behaviour of light. Children aged eleven years worked with the environment in groups of three. Findings suggest that different representation locations lend themselves to different levels of abstraction and engender different forms and levels of activity, particularly with respect to speed of dynamics and differences in group awareness. Furthermore, the studies illustrated interaction effects according to different physical correspondence metaphors used, particularly with respect to combining familiar physical objects with digital--based table-top representation. The implications of these findings for learning are discussed

Amazon's Alexa critical genealogy through the imagery of women and machine in science fiction cinema

In order to better understand the phenomenon of genderization of consumer technologies, such as digital voice assistants (DVAs), present in the market today, this dissertation examines the possible sociocultural intersections between gender and technology present in the imaginary of science fiction cinema. To do so, a Foucauldian discourse analysis was conducted on ten feature films in this artistic genre, which is very dear to feminism, especially as of its third wave, drawing an intertextual parallel with the responses programmed into some of the most popular DVAs available today, such as Amazon’s Alexa and Apple’s Siri. This dissertation challenges the argument that the genderization of technology is a phenomenon as recent as these new technologies and that it can be explained only from a user experience point of view. With this objetive in mind, we trace a genealogy of Alexa based on the ideas proposed by Michel Foucault, in an attempt to expose the power games behind these gender constructions inside and outside of cinema. In this sense, we identified and examined three main categories of discourse analysis that are present and repeated not only in the filmic sample, but also in the DVAs used daily by millions of consumers around the world. The study points to the need to overcome gender barriers in not only technical, but also sociocultural, access to technologies in general.Com o objetivo de melhor compreender o fenômeno de genderização de tecnologias de consumo presentes hoje no mercado, como as digital voice assistants (DVAs), esta dissertação examina as possíveis interseções socioculturais entre gênero e tecnologia presentes no imaginário do cinema de ficção científica. Para isso, foi realizada uma análise de discurso foucauldiana em dez filmes de longa metragem deste gênero artístico, que é muito caro ao feminismo especialmente a partir da sua terceira onda, estabelecendo um paralelo intertextual a partir das respostas programadas em algumas das mais populares DVAs disponíveis atualmente, como Alexa, da Amazon, e Siri, da Apple. Esta dissertação desafia o argumento de que a genderização da tecnologia é um fenômeno tão recente quanto essas novas tecnologias e que pode ser explicado apenas do ponto de vista da experiência do usuário. Para este efeito, traça-se uma genealogia da Alexa com base nas ideias propostas por Michel Foucault, expondo os jogos de poder por detrás dessas construções de gênero dentro e fora do cinema. Nesse sentido, foram identificadas e examinadas três categorias principais de análise de discurso que estão presentes e se repetem não apenas na amostra fílmica, mas também nas DVAs utilizadas diariamente por milhões de consumidores ao redor do mundo. O estudo aponta para a necessidade de superação das barreiras de gênero no acesso não apenas técnico, mas também sociocultural, às tecnologias de forma geral

Combinação de Previsões de Volatilidade: Um Estudo

A avaliação de técnicas de combinação de previsões para previsão de valores esperados de uma série é um tópico bastante difundido, com a recomendação do uso de tais técnicas para previsão. Por outro lado, não há estudos comparativos do desempenho de combinação de previsões para previsão de volatilidade condicional, em relação a modelos individuais univariados. Comparando os modelos da família GARCH, de Alisamento Exponencial e o de Volatilidade Estocástica e técnicas de combinação por média aritmética, combinação de pesos fixos proposta por Granger e Ramanathan (1984) e a técnica de combinação com pesos móvel de Terui e Dijk (2002) para Ibovespa, Dow Jones e IGP-M, concluímos que os modelos de combinação de previsão apresentam melhores resultados em termos de MSE, MAPE e Theil-U para todas as séries, com destaque para o modelo de pesos fixos via regressão e o de pesos móveis.Volatilidade Condicional, Combinação de Previsões