Causas de variação nos preços de bovinos nelore elite no Brasil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

O impacto dos custos não-gerenciáveis na determinação das tarifas de energia elétrica: um estudo nas companhias distribuidoras do nordeste que tiveram revisão tarifária nos exercícios de 2003 e 2004

This work presents results derived from a study related to impact on non-controllable costs in the determination of energy taxes. This is done analyzing tax review practiced by concessionaries responsible for the distribution of electrical energy located in the Northeastern Region of Brazil, between 2003 and 2004. This Region was chosen as a study area due to the researcher s expectation in congregating companies that deliver services to markets that have similar social-economical profiles. A brief explanation related to the restructuring of the electrical sector in Brazil is presented, pointing out that there was privatization of the great majority of these companies. The study also points out the definition of regulating rules in service delivery process. The components of taxes that are practiced by these companies aimed at final consumers, as well as the market as a whole and the revision process that is executed by Agência Nacional de Energia Elétrica ANEEL for the definition of these taxes are demonstrated in the research. A brief historical of the concessionaires that were focus of the research is presented, totaling five companies. Some data used by ANEEL in the tax review process was analyzed as well as data on components of approved taxes. It is concluded that as a media 47, 49% of the components of taxes in the researched companies correspond to the non-controllable costs. These is done considering previous classification by ANEEL in the tax review process. Although, if it is considered that these companies since 2006, by the means of participation in energy auctions are able to negotiate energy prices for their own needs, it is concluded that these concession contracts guarantee the delivery of the service to the costumer in the total tribute. The percentage of non-controllable costs is 16, 27% average of the tax. This means, amongst other information, that the government has a great deal of responsibility in the formation of price practiced by these companies and its target markets

Valorização da reserva operativa em um ambiente competitivo para geradores hidrelétricos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

O 'Grupo Tapir'e a pintura de casarios (1960-1980)

Pós-graduação em Artes - IA

O investimento em transmissão de energia elétrica no Brasil: uma análise da atratividade das concessões por leilão

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeitos do peso vivo sobre a comercialização de bezerros de corte em leilões

Analisaram-se os efeitos da média de peso vivo de 1.880 lotes de bezerros comercializados em 13 leilões, no Rio Grande do Sul, sobre o valor de venda final por unidade de peso, e caracterizou-se a frequência dos lotes conforme a classe de peso durante as estações de outono e primavera, no período de 2004 a 2006. Os dados foram corrigidos pelo índice geral de preços - disponibilidade interna e analisados por meio de histogramas de frequência e análises de regressão e correlação. O peso vivo influenciou o preço dos bezerros, e a magnitude do efeito foi maior nos anos de grande demanda. Observou-se correlação negativa entre preço e peso dos bezerros na primavera, reflexo da oferta de animais mais pesados, devido aos efeitos de estação do ano ou à maior idade dos bezerros, comparados aos ofertados no outono. Não se observou maior liquidez dos bezerros comercializados no outono em relação aos da primavera. A conjuntura da cadeia da carne bovina e os preços de outras categorias têm grande relação com os preços pagos. A aquisição de animais de menor ou maior peso na ocasião da transação comercial pode auxiliar na redução dos custos que a reposição representa na produção.

Estudo da produção de hidrogênio eletrolítico a partir de fontes eólica, solar e hidrelétrica

Introduces technical, economic and environmentally competitive solutions in the energy market is a great challenge for society. This work examines each of these aspects considering the production of electrolytic hydrogen with energy from wind power, solar and hydropower, in order to ensure an overview of this energy carrier. Initially, an assessment of the technical aspects is made addressing existing electrolysers technologies, its main characteristics and differences. The geographical distribution of wind, solar and hydroelectric potential in Brazil is also mapped, and a configuration scheme of a hydrogen production system is discussed. Subsequently, the economic analysis calculates the cost of investment in the alkaline electrolyser of 60 Nm³ / h, similar to the Brazilian bus powered by hydrogen project, coordinated by EMTU. Since the main input of electrolysis is electricity, is analyzed the latest energy auctions of each primary source and it is calculated the cost of production of the wind, solar and hydropower hydrogen. Postponed to this, are investigated the intrinsic environmental impacts of electricity generation process, proposing a readjustment of an indicator of ecological efficiency for the production of hydrogen. Finally, the work discusses the concept of externalities and demonstrates how the incorporation of external costs can leverage the hydrogen economy. In short, it is evident that the wind and hydroelectric hydrogens are more promising compared to solar hydrogen, whether in the economic aspect, because it achieved lower costs, whether in the environmental aspect, because it reached the highest ecological efficiency

Modelo de leilão de energia multiperíodo com representação linearizada da transmissão e da coordenação com o médio prazo para sistemas hidrotérmicos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Meccanismi d'asta per on-line advertising: modelli, equilibri ed efficienza

Il seguente lavoro di tesi tratta l'argomento delle aste in modo tecnico, ovvero cerca di descriverne i modelli e le caratteristiche principali, spesso ignorate dagli stessi fruitori. Nel capitolo 1 si introduce brevemente il concetto di asta, descrivendone i principali elementi costitutivi. Si ripercorrono poi le origini di questa procedura ed alcuni suoi utilizzi. Nel capitolo 2 si presentano inizialmente le principali tipologie di aste conosciute e si accenna al processo di valutazione dell'oggetto d'asta. Si introduce poi il concetto di Private Value, analizzandolo per ogni tipo di asta e confrontando queste sotto l'aspetto della rendita. Si enuncia in seguito un principio fondamentale, quale quello dell'equivalenza delle rendite, rilassandone alcuni assunti basilari. Infine si passa al concetto di valori interdipendenti all'interno delle aste, valutandone equilibri, rendite ed efficienza, accennando nel contempo al problema denominato Winner's curse. Nel capitolo 3 si parla dei meccanismi di asta online, ponendo l'attenzione su un loro aspetto importante, ovvero la veridicità, ed analizzandoli attraverso l'analisi del caso peggiore e del caso medio in alcuni esempi costruiti ad-hoc. Nel capitolo 4 si descrivono in particolare le sponsored search auctions, narrandone inizialmente la storia, e successivamente passando all'analisi di equilibri, rendite ed efficienza; si presenta, infine, un modello di tali aste mettendone in rapporto la computabilità con quella dei meccanismi offline conosciuti.

A Multilevel Model with Time Series Components for the Analysis of Tribal Art Prices

In the present work we perform an econometric analysis of the Tribal art market. To this aim, we use a unique and original database that includes information on Tribal art market auctions worldwide from 1998 to 2011. In Literature, art prices are modelled through the hedonic regression model, a classic fixed-effect model. The main drawback of the hedonic approach is the large number of parameters, since, in general, art data include many categorical variables. In this work, we propose a multilevel model for the analysis of Tribal art prices that takes into account the influence of time on artwork prices. In fact, it is natural to assume that time exerts an influence over the price dynamics in various ways. Nevertheless, since the set of objects change at every auction date, we do not have repeated measurements of the same items over time. Hence, the dataset does not constitute a proper panel; rather, it has a two-level structure in that items, level-1 units, are grouped in time points, level-2 units. The main theoretical contribution is the extension of classical multilevel models to cope with the case described above. In particular, we introduce a model with time dependent random effects at the second level. We propose a novel specification of the model, derive the maximum likelihood estimators and implement them through the E-M algorithm. We test the finite sample properties of the estimators and the validity of the own-written R-code by means of a simulation study. Finally, we show that the new model improves considerably the fit of the Tribal art data with respect to both the hedonic regression model and the classic multilevel model.

Microneurography in rats: a minimally invasive method to record single C-fiber action potentials from peripheral nerves in vivo

Microneurography is a method suitable for recording intraneural single or multiunit action potentials in conscious subjects. Microneurography has rarely been applied to animal experiments, where more invasive methods, like the teased fiber recording technique, are widely used. We have tested the feasibility of microneurographic recordings from the peripheral nerves of rats. Tungsten microelectrodes were inserted into the sciatic nerve at mid-thigh level. Single or multiunit action potentials evoked by regular electrical stimulation were recorded, digitized and displayed as a raster plot of latencies. The method allows unambiguous recording and recognition of single C-fiber action potentials from an in vivo preparation, with minimal disruption of the nerve being recorded. Multiple C-fibers can be recorded simultaneously for several hours, and if the animal is allowed to recover, repeated recording sessions can be obtained from the same nerve at the same level over a period of weeks or months. Also, single C units can be functionally identified by their changes in latency to natural stimuli, and insensitive units can be recognized as 'silent' nociceptors or sympathetic efferents by their distinctive profiles of activity-dependent slowing during repetitive electrical stimulation, or by the effect on spontaneous efferent activity of a proximal anesthetic block. Moreover, information about the biophysical properties of C axons can be obtained from their latency recovery cycles. Finally, we show that this preparation is potentially suitable for the study of C-fiber behavior in models of neuropathies and nerve lesions, both under resting conditions and in response to drug administration.

Effiziente, operative Torbelegung mittels kombinatorischer Auktionen

Das operative Torbelegungsproblem (TBP) z. B. an einem Distributions- oder Cross-dockingzentrum ist ein logistisches Problem, bei dem es gilt, an- und abfahrende Fahrzeuge zeitlich und räumlich so auf die Warenein- und -ausgangstore zu verteilen, dass eine mög-lichst kostengünstige Abfertigung ermöglicht wird. Bisherige Arbeiten, die sich mit dem TBP beschäftigen, lassen Aspekte der Kooperation außer Acht. Dieser Beitrag stellt ein Verfahren vor, durch das der Nachteil einseitig optimaler Torbelegungen überwunden werden kann. Dabei wird auf das Mittel der kombinatorischen Auktionen zurückgegriffen und das TBP als Allokationsproblem modelliert, bei dem Frachtführer um Bündel konsekutiver Einheitszeit-intervalle an den Toren konkurrieren. Mittels eines Vickrey-Clarke-Groves-Mechanismus wird einerseits die Anreizkompatibilität, andererseits die individuelle Rationalität des Auk-tionsverfahrens sichergestellt. Das Verfahren wurde in ILOG OPL Studio 3.6.1 implemen-tiert und die durch Testdaten gewonnenen Ergebnisse zeigen, dass die Laufzeiten gering genug sind, um das Verfahren für die operative (kurzfristige) Planung einzusetzen und so transportlogistische Prozesse für alle Beteiligten wirtschaftlicher zu gestalten.

Reputation Formation and the Evolution of Cooperation in Anonymous Online Markets

Theoretical propositions stressing the importance of trust, reciprocity, and reputation for cooperation in social exchange relations are deeply rooted in classical sociological thought. Today’s online markets provide a unique opportunity to test these theories using unobtrusive data. Our study investigates the mechanisms promoting cooperation in an online-auction market where most transactions can be conceived as one-time-only exchanges. We first give a systematic account of the theoretical arguments explaining the process of cooperative transactions. Then, using a large dataset comprising 14,627 mobile phone auctions and 339,517 DVD auctions, we test key hypotheses about the effects of traders’ reputations on auction outcomes and traders’ motives for leaving feedback. Our statistical analyses show that sellers with better reputations have higher sales and obtain higher prices. Furthermore, we observe a high rate of participation in the feedback system, which is largely consistent with strong reciprocity—a predisposition to unconditionally reward (or punish) one’s interaction partner’s cooperation (or defection)—and altruism—a predisposition to increase one’s own utility by elevating an interaction partner’s utility. Our study demonstrates how strong reciprocity and altruism can mitigate the free-rider problem in the feedback system to create reputational incentives for mutually beneficial online trade.

Strategic Behavior in Day-Ahead and Real-Time Markets for Electricity: Offer Cost or Payment Cost Minimization?

This study compares the procurement cost-minimizing and productive efficiency performance of the auction mechanism used by independent system operators (ISOs) in wholesale electricity auction markets in the U.S. with that of a proposed alternative. The current practice allocates energy contracts as if the auction featured a discriminatory final payment method when, in fact, the markets are uniform price auctions. The proposed alternative explicitly accounts for the market clearing price during the allocation phase. We find that the proposed alternative largely outperforms the current practice on the basis of procurement costs in the context of simple auction markets featuring both day-ahead and real-time auctions and that the procurement cost advantage of the alternative is complete when we simulate the effects of increased competition. We also find that a trade-off between the objectives of procurement cost minimization and productive efficiency emerges in our simple auction markets and persists in the face of increased competition.

Concienciación para la conservación del patrimonio urbano : los instrumentos de gestión para la recuperación del barrio madrileño de Embajadores

La tesis trata la evolución de la conciencia de la conservación de los centros históricos y de los instrumentos de gestión utilizados en las políticas de rehabilitación del casco antiguo de Madrid, desde las primeras experiencias de los años ‘80 hasta el perfeccionamiento del complejo mecanismo contemporáneo. El proceso de rehabilitación ha demostrado ser extremadamente coherente en cuanto a los objetivos y en cuanto al tema de los instrumentos ha seguido la tendencia de diversificar y flexibilizar. En Madrid se ha utilizado el concepto de rehabilitación en sentido integral, abarca una amplia gama de acciones que implican por una parte, intervenciones directas sobre los edificios y por otra, la valorización del espacio público, de los edificios representativos, la introducción de dotaciones y también un componente social. El tema se analizará desde la perspectiva del barrio de Embajadores, un área muy especial del casco antiguo de la ciudad. Desde 1998 hasta la actualidad allí funciona el Área de Rehabilitación Integral con el nombre de Lavapiés. El barrio de Embajadores representa un caso de extrema complejidad dada su tradición, que mantiene hasta el momento, de barrio popular que ha tenido como consecuencia negativa un grave estado de deterioro de los edificios y de sus estructuras urbanas. Además, presenta una composición socio-cultural muy heterogénea ya que siempre ha alojado oleadas de inmigrantes que llegaban a la capital tanto de las provincias como del extranjero. Los ‘80 marcan en Madrid el inicio de la preocupación por la rehabilitación urbana y de los primeros intentos de definir unos mecanismos. Durante este período el barrio de Embajadores es escenario de los primeros proyectos piloto de rehabilitación. Se sientan las bases del sistema de subvenciones, que empujará hacia un modelo de rehabilitación generalizada. A principios de los años ‘90, la insatisfacción dejada por de los resultados obtenidos, la Administración decide reorganizar la estrategia y se procede a la rehabilitación integral por áreas, concentrando los esfuerzos geográfica y temporalmente. La idea ya se había utilizado diez años antes, pero sin encontrar nunca la voluntad política de aplicarla. En comparación con el casco antiguo, el barrio de Embajadores se dejó para el final del proceso para verificar los métodos en zonas más restringidas en cuanto a superficie y con menos problemas. Desde 1998 hasta hoy, período en que funciona el Área de Rehabilitación Integral de Lavapiés, los distintos tipos de actuaciones, de producción arquitectónica, urbanística y sociocultural, han mostrado su eficacia, de forma que los cambios que aportaron al barrio son evidentes para todos. Mientras que las Áreas de Rehabilitación del centro una vez alcanzados los objetivos, se preparan para su clausura, a nivel administrativo se están definiendo nuevas direcciones y nuevos objetivos para el casco antiguo: subastas para incentivar intervenciones de mejoramiento energético y del nivel de sostenibilidad de los edificios madrileños. La primera parte de la tesis establece las premisas presentando algunos puntos relevantes relativos al desarrollo histórico de los documentos y normativas más importantes que tendrán eco en el proceso de concienciación de la cultura de la conservación del patrimonio urbano de los centros históricos. Después, se habla de la experiencia de rehabilitación urbana en Europa, en España en general y en Madrid en particular, con referencia a los modelos de enfoque, al marco legislativo y a las experiencias relacionadas con el casco antiguo, y en definitiva a la creación de la conciencia de la rehabilitación y conservación de los centros de las ciudades. La segunda parte se centra en el caso de estudio, el barrio de Embajadores. En primer lugar, se presenta en detalle el barrio: ubicación, datos característicos, edificios representativos y flujos que generan, trama urbana, datos sobre la formación histórica, tipologías y características de construcción de los edificios y, para finalizar, algún dato demográfico para introducir la compleja problemática social. Más adelante se exponen las primeras experiencias de rehabilitación: dos proyectos piloto de intervención sobre las viviendas realizados en los años ‘80, uno privado y el otro público. La parte central del trabajo trata sobre la fase intensiva de rehabilitación, proceso puesto en marcha en el año ’98 y que corresponde al período en el que Embajadores es Área de Rehabilitación Integral. Se presentan y analizan los objetivos de la rehabilitación y luego los instrumentos de orden administrativo, normativo y legal que regulan las actuaciones en el barrio. Sucesivamente se afronta la rehabilitación de la parte residencial, en régimen privado y público, que fue el modelo principal que la Administración llevó a cabo. Se presenta todo el proceso, desde la decisión sobre el tipo de rehabilitación, las subvenciones y las soluciones técnicas adoptadas así como la rehabilitación de casos especiales de edificios, que por sus características, el alto nivel de degradación o porque ocupados por inquilinos con dificultades económicas, se realizó con intervención pública. Las enormes dificultades derivadas de la complicada gestión y de las incongruencias de las normativas también se analizan en este trabajo. El autor presenta un dosier de una veintena de trabajos llevados a cobo en el Barrio de Embajadores a lo largo de más de 15 años de experiencia profesional propia. Se intenta, en primer lugar, evaluar la actuación pública en comparación con la privada en cuanto a los modelos propuestos, a las problemáticas que generan y a los resultados obtenidos. Una segunda línea de argumentación se refiere a la relación que se establece entre los instrumentos que se promueven y los que obligan a la conservación y a la rehabilitación de los edificios. Quizás el elemento más interesante, por su conocida innovación, de la experiencia de la obligación de conservación a cargo de los propietarios y la introducción de una revisión periódica del estado de los edificios (ITE), que conduce a su mantenimiento permanente a lo largo del tiempo. El ultimo instrumento aparecido y de por si el más novedoso se refiere a la política de rehabilitación energética iniciada en los últimos años por el Ayuntamiento de Madrid. ABSTRACT Starting from the early experiences of the ‘80s and tackling the complex and improved contemporary techniques of development, the present thesis focuses on raising awareness of the conservation of urban heritage and deals with the evolution of rehabilitation policies adopted in the historical center of Madrid. The rehabilitation process has proven to be extremely coherent in terms of its objectives and, consequently, the subject of the instruments has forged ahead a trend of diversification and flexibility. Madrid has used the concept of rehabilitation in a comprehensive manner, encompassing a wide range of actions, which involved on the one hand, direct interventions on buildings and on the other, the appreciation of the public space with its representative edifices and endowments. Confident that the social components have not been neglected during the rehabilitation proceedings, the topic will be analysed in relation to the neighbourhood of Embajadores, an authentic area of the old town. From 1998 onwards, this quarter serves as a Comprehensive Rehabilitation Area under the name of Lavapies. Considering the tradition and popularity of the district, Embajadores represents a challenging case for rehabilitation projects, aiming to improve the severe state of deterioration of buildings and urban structures. Having a heterogeneous sociocultural dynamic, the neighbourhood has always hosted waves of immigrants who come to the capital both from other provinces and abroad. The 1980s in Madrid marked the beginning of concerns with urban regeneration and the first attempts to define feasible restoration techniques. During this period, the district of Embajadores has benefited from various pilot projects. The financial investments have significant effects on the overall environment, so the model of general rehabilitation has been encouraged throughout the years. In the early 90s, left by the dissatisfaction of the results obtained, the authorities proposed to reorganise the strategy and proceed to the full rehabilitation of areas, concentrating efforts geographically and temporally. The idea had already been used ten years before, but never encountered the political force to be implemented. Compared to the old town, the Embajadores neighbourhood has been left for the end of the process, which focused on verifying the methods in more restricted areas that caused fewer disruptions. For the Comprehensive Rehabilitation Area of Lavapies, the various types of administrative implementations from architectural to urban and socio-cultural productions have proved effective. The improvements experienced by the neighbourhood from 1998 are obvious to all. However, while the areas of rehabilitation of the city centre have achieved their objectives and prepare for closure, the administration is still generating new directions and new targets for the ancient surroundings: auctions to encourage the improvement of energy interventions and the sustainability level for the buildings of Madrid. Therefore, the first part of the thesis establishes the premises and introduces some relevant points concerning the entire city. It describes the historical development of urban projects, indicating the events that will echo in the rehabilitation process. This paper then turns to discuss the experience of urban regeneration in Spain, emphasising the case of Madrid with reference to models of approach, legislative frameworks and appreciation of the old structures. The second part reveals an in depth case study of the district of Embajadores. At first, the thesis provides insights into the neighbourhood: location, general data on representative buildings and propagated trends, urban, historical data on training, building typologies and characteristics. The section introduces some demographic data to complete the portrait of the elaborate social problems encountered in this district, also outlining the first experiences of rehabilitation: two pilot projects on housing intervention made in the 80s, one private and one public. The central part of the thesis deals with the intensive phase of rehabilitation developments launched in the year '98 when Embajadores joined the Comprehensive Rehabilitation Area. It analyses the goals of rehabilitation and the instruments of administrative, regulatory and governing legal proceedings of the neighbourhood. The following chapter addresses the privately and publicly founded plan of residential rehabilitation that constituted the main model conducted by the authorities. It describes the entire process: deciding the type of restoration, subsidies and technical solutions as well as the degree of rehabilitation for special buildings, which either have a high level of degradation or require public intervention when tenants face financial difficulties. The administrative difficulties caused by the enormous bureaucratic machinery and the inconsistencies in regulations are also discussed in this paper. Thus, a just evaluation of the public and private performances regarding the proposed models of rehabilitation, along with the problems they generate and the results obtained is desired throughout the thesis. A second line of argument concerns the relationship established between the instruments that are promoted and requiring conservation and the building restoration. Perhaps the most interesting and innovative element of the new rehabilitation policies is the owners' obligation to preserve their properties and the introduction of a periodic review for the state of the buildings (ITE). These thorough and meticulous regulations lead to an ongoing maintenance of constructions, preventing them from severe or sudden deteriorations.