Transaction costs: an empirical analysis of their relationship with investment and foreign direct investment

As stated by the New Institutional Economics theory, transaction costs play a relevant role in economics and, according to the extent of such costs, agents make investment decisions. Actually, transaction costs may represent a disincentive to entrepreneurship. This work aims to verify whether transaction costs are related to investment rate and foreign direct investment rate (FDI) in different business environments. The results suggest that foreign investors do not have precise information about other countries as domestic investors do; as it is observed, only the relation between transaction costs and investment rate is significant. Furthermore, there is evidence that the business environments of BRIC countries are less developed when compared to business environments of other countries in the study

Earnings management and economic crises in the brazilian capital market

The 2008 economic crisis challenged accounting, either demanding recognition and measurement criteria well adjusted to this scenario or even questioning its ability to inform appropriately entities' financial situation before the crisis occurred. So, our purpose was to verify if during economic crises listed companies in the Brazilian capital market tended to adopt earnings management (EM) practices. Our sample consisted in 3,772 firm-years observations, in 13 years - 1997 to 2009. We developed regression models considering discretionary accruals as EM proxy (dependent variable), crisis as a macroeconomic factor (dummy variable of interest), ROA, market-to-book, size, leverage, foreign direct investment (FDI) and sector as control variables. Different for previous EM studies two approaches were used in data panel regression models and multiple crises were observed simultaneously. Statistics tests revealed a significant relation between economic crisis and EM practices concerning listed companies in Brazil in both approaches used.

INTERNATIONALIZATION OF STATE-OWNED ENTERPRISES THROUGH FOREIGN DIRECT INVESTMENT

ABSTRACT State-owned enterprises (SOEs) are created to focus on domestic needs, and yet recent evidence points to increasing outward foreign direct investment by SOEs. Existing International Business (IB) theories focus on efficiency-based motives for internationalization; therefore, they do not fully capture SOEs' internalization dynamics, which are driven largely by political factors and social welfare considerations. We integrate public management and IB theories to develop propositions that combine these questions: why SOEs internationalize; what are their motivations; and what are the main managerial outcomes of SOEs' internationalization. Our findings suggest that SOEs display little hesitancy in entering international markets, and that SOE international expansion is not contradictory with the goals of state-ownership if the purpose is to adjust the company to changing institutional environments both in the domestic and international markets. Our propositions about SOE internationalization are based on an in-depth case study of the outward foreign direct investment conducted by Brazil's Petrobras over the past three decades.

The measurement by serological means of the impact of the Hong Kong/68 influenza virus on a population

In order to obtain evidence on the size of the impact of the Hong Kong/68 variant of influenza A2 virus on the population of São Paulo, Brazil, serum samples taken in 1967 before this variant appeared and during successive years after it appeared were examined for their antibody content. Haemagglutination-inhibition tests performed on a total of 2726 serum samples from adults showed a sharp decrease in 1969 of the proportion of sera without antibody to the Hong Kong/68 variant and a corresponding mercase in the proportion with high titres. It was concluded that about three-quarters of the adult population became infected at some time after the variant appeared, the majority in the first year of prevalence.

Direct Power Control of Matrix Converter Based Unified Power Flow Controllers

This paper presents the Direct Power Control of Three-Phase Matrix Converters (DPC-MC) operating as Unified Power Flow Controllers (UPFC). Since matrix converters allow direct AC/AC power conversion without intermediate energy storage link, the resulting UPFC has reduced volume and cost, together with higher reliability. Theoretical principles of DPC-MC method are established based on an UPFC model, together with a new direct power control approach based on sliding mode control techniques. As a result, active and reactive power can be directly controlled by selection of an appropriate switching state of matrix converter. This new direct power control approach associated to matrix converters technology guarantees decoupled active and reactive power control, zero error tracking, fast response times and timely control actions. Simulation results show good performance of the proposed system.

Power Electronics Didactic Modules for Direct Current Machine Control

Several didactic modules for an electric machinery laboratory are presented. The modules are dedicated for DC machinery control and get their characteristic curves. The didactic modules have a front panel with power and signal connectors and can be configurable for any DC motor type. The three-phase bridge inverter proposed is one of the most popular topologies and is commercially available in power package modules. The control techniques and power drives were designed to satisfy static and dynamic performance of DC machines. Each power section is internally self-protected against misconnections and short-circuits. Isolated output signals of current and voltage measurements are also provided, adding versatility for use either in didactic or research applications. The implementation of such modules allowed experimental confirmation of the expected performance.

Validation of a measurement scale for the relationship between the orientation to corporate social responsibility and other business strategic variables

The importance of Social Responsibility (SR) is higher if this business variable is related with other ones of strategic nature in business activity (competitive success that the company achieved, performance that the firms develop and innovations that they carries out). The hypothesis is that organizations that focus on SR are those who get higher outputs and innovate more, achieving greater competitive success. A scale for measuring the orientation to SR has defined in order to determine the degree of relationship between above elements. This instrument is original because previous scales do not exist in the literature which could measure, on the one hand, the three classics sub-constructs theoretically accepted that SR is made up and, on the other hand, the relationship between SR and the other variables. As a result of causal relationships analysis we conclude with a scale of 21 indicators, validated scale with a sample of firms belonging to the Autonomous Community of Extremadura and it is the first empirical validation of these dimensions we know so far, in this context.

Estudo da resposta de um dosímetro eletrónico individual

Introdução – A monitorização da exposição ocupacional a doses de radiação ionizante pode ser complementada por dosímetros eletrónicos individuais que permitem uma leitura direta da dose de radiação recebida. Dada a dependência energética e de débito de dose já reportada para estes dosímetros, este trabalho pretende determinar a linearidade da resposta de um dosímetro eletrónico individual e estudar o comportamento da sua resposta em função da energia de radiação e do débito de dose. Metodologia – Para estudar a dependência da energia da radiação do dosímetro eletrónico pessoal Vertec Bleeper Sv procedeu‑se à sua irradiação com um equivalente de dose individual, Hp(10), de 500 μSv de radiação gama do Cobalto – 60 (60C) e Césio – 137 (137Cs) e das qualidades de radiação X da série Narrow (N): N‑30, N‑40, N‑60, N‑80, N‑100 e N‑120. Para investigar a dependência da resposta em função do débito de dose aplicaram‑se à ampola de raios X as intensidades de corrente elétrica de 1 mA, 5 mA, 10 mA, 15 mA e 20 mA. Resultados – Não existe uma relação entre a resposta do detetor e a energia de radiação a que este é exposto. Ocorre uma subestimação superior a 50% na grandeza medida para energias inferiores a 33 keV, mas ostenta uma medida relativamente linear da grandeza Hp(10) para doses inferiores a 100 μSv. Também se constata que, à medida que o débito de dose aumenta, existe uma diminuição na resposta do dosímetro. O menor decréscimo na resposta deste dosímetro eletrónico individual dá‑se para as qualidades de radiação N‑30 (1,1%), N‑40 (4,1%) e N‑120 (20,0%). Conclusão – Verifica‑se que a resposta do dosímetro individual Vertec Bleeper Sv depende fortemente da energia da radiação e do débito de dose. ABSTRACT: Introduction – The measurement of occupational exposure to radiation doses can be completed with an electronic personal dosemeter that allows a direct reading and alarm function of the received radiation dose. Due to the energy and dose rate dependence already reported for this type of dosemeter, it is intended, with this work, to determine the response linearity of an Electronic Personal Dosemeter and to study its response behavior to the dose rate and radiation energy. Methodology – The electronic personal dosemeter Vertec Bleeper Sv energy dependency was evaluated by its irradiation with 500 μSv from the radionuclides Cobalt – 60 (60C) and Cesium – 137 (137Cs) as well as by the radiation qualities of the Narrow (N) series: N‑30, N‑40, N‑60, N‑80, N‑100 e N‑120. To investigate the dose rate dependency, the intensities of electric current of 1 mA, 5 mA, 10 mA, 15 mA and 20 mA were applied to the X‑ray tube. Results – There is no relationship between the response of the detector and the radiation energy. For energies below 33 keV there is an underestimation over 50% of the radiation dose measured but the detector presents a linear response for energies under 100 μSv. A dependency on the dose rate is perceived since as the dose rate increases, the response of the individual monitor decreases. There is a smaller decrease for the radiation qualities of N‑30 (1.1%), N‑40 (4.1%) and N‑120 (20.0%). Conclusion – It is concluded that there is a strong dependence of radiation energy and dose rate on the response of an electronic personal dosemeter.

A Flexible Architecture for the Computation of Direct and Inverse Transforms in H.264/AVC Video Codecs

A new high throughput and scalable architecture for unified transform coding in H.264/AVC is proposed in this paper. Such flexible structure is capable of computing all the 4x4 and 2x2 transforms for Ultra High Definition Video (UHDV) applications (4320x7680@ 30fps) in real-time and with low hardware cost. These significantly high performance levels were proven with the implementation of several different configurations of the proposed structure using both FPGA and ASIC 90 nm technologies. In addition, such experimental evaluation also demonstrated the high area efficiency of theproposed architecture, which in terms of Data Throughput per Unit of Area (DTUA) is at least 1.5 times more efficient than its more prominent related designs(1).

O desenvolvimento do conceito de área: um estudo com alunos do 3.º ano de escolaridade

O objetivo desta investigação é compreender como é que alunos do 3.º ano de escolaridade desenvolvem o conceito de área com ênfase em conhecimentos sobre figuras e propriedades geométricas. Para melhor objetivar o estudo, formulei três questões que orientaram a investigação. Pretendo (1) compreender como é que os alunos mobilizam conhecimentos sobre as propriedades das figuras geométricas no estudo da área de uma figura plana? A que estratégias recorrem? Que dificuldades sentem? (2) que compreensão é que os alunos têm sobre o processo de medição? e (3) que ideias e/ou experiências são relevantes no desenvolvimento do conceito de área? Este é um estudo que se insere no paradigma interpretativo e que segue uma abordagem qualitativa, pelo que não visa generalização de resultados, mas uma descrição compreensiva dos processos vivenciados, tendo em conta os contextos pessoais e sociais. Optei por realizar dois Estudos de Caso. Os dados foram recolhidos através de fontes diversificadas, donde se destacam a observação participante e a análise de registos audiovisuais e escritos dos alunos. A análise dos dados teve por referência categorias criadas com base em contributos da literatura de referência. As conclusões desta investigação centram-se numa análise acerca das estratégias a que os alunos em estudo tendencialmente mais recorrem, visando também algumas das suas dificuldades mais relevantes e sobre as quais importa refletir. Destaca-se que ambos os alunos foram capazes de recorrer a raciocínios baseados e não baseados na medida, embora seja evidente uma tendência para raciocínios baseados na medida. É igualmente importante referir que os dois alunos revelaram um bom conhecimento acerca do processo de medição, mesmo quando ele implicava a definição de uma unidade de medida adequada e/ou mudança de unidade. É dado, também, destaque às experiências matemáticas que devem ser proporcionadas aos alunos no sentido do desenvolvimento de um conhecimento amplo e flexível do conceito de área. - Abstract The purpose of this investigation is to understand the development of 3rd year students’ concept of area based on their knowledge of geometrical properties and figures. As means to orientate the present study, the following investigation questions were formulated: 1) how do students use their knowledge about geometrical properties in order to understand geometrical shape’s areas? Which strategies do they use? What do they struggle with? (2) What is their understanding about measurement? And (3) what are the most relevant mathematical reasonings and classroom tasks in the development of the concept of area? This is a study that follows a qualitative approach: it does not intend to be a generalization, but a fully comprehensive description of the witnessed learning processes, bearing in mind the social and personal contexts. As such, two study-cases were developed. The data were collected through various sources, such as direct observation and analysis of audiovisual records or written worksheets. The scrutiny of the generated data was undertaken following criteria based on the literature of reference. The conclusions of this investigation are centered on the most used strategies as well as the students’ difficulties upon which it is important to discuss. It was noticed that the two students were able to use both measurement and non measurement thinking – although, preferably, they tend to use the first one. On the other hand, it is equally demonstrated that the two students have shown good acquaintance about measurement, even if obliged to the establishment of a suitable unit of measurement and/or change of units. At last, it is also referred which mathematical classroom tasks are important to develop a sustained and comprehensive concept of area.

Direct multisearch for multiobjective optimization

In practical applications of optimization it is common to have several conflicting objective functions to optimize. Frequently, these functions are subject to noise or can be of black-box type, preventing the use of derivative-based techniques. We propose a novel multiobjective derivative-free methodology, calling it direct multisearch (DMS), which does not aggregate any of the objective functions. Our framework is inspired by the search/poll paradigm of direct-search methods of directional type and uses the concept of Pareto dominance to maintain a list of nondominated points (from which the new iterates or poll centers are chosen). The aim of our method is to generate as many points in the Pareto front as possible from the polling procedure itself, while keeping the whole framework general enough to accommodate other disseminating strategies, in particular, when using the (here also) optional search step. DMS generalizes to multiobjective optimization (MOO) all direct-search methods of directional type. We prove under the common assumptions used in direct search for single objective optimization that at least one limit point of the sequence of iterates generated by DMS lies in (a stationary form of) the Pareto front. However, extensive computational experience has shown that our methodology has an impressive capability of generating the whole Pareto front, even without using a search step. Two by-products of this paper are (i) the development of a collection of test problems for MOO and (ii) the extension of performance and data profiles to MOO, allowing a comparison of several solvers on a large set of test problems, in terms of their efficiency and robustness to determine Pareto fronts.

Fast optimum-predictive control and capacitor voltage balancing strategy for bipolar back-to-back NPC converters in high-voltage direct current transmission systems

Multilevel power converters have been introduced as the solution for high-power high-voltage switching applications where they have well-known advantages. Recently, full back-to-back connected multilevel neutral point diode clamped converters (NPC converter) have been used inhigh-voltage direct current (HVDC) transmission systems. Bipolar-connected back-to-back NPC converters have advantages in long-distance HVDCtransmission systems over the full back-to-back connection, but greater difficulty to balance the dc capacitor voltage divider on both sending and receiving end NPC converters. This study shows that power flow control and dc capacitor voltage balancing are feasible using fast optimum-predictive-based controllers in HVDC systems using bipolar back-to-back-connected five-level NPC multilevel converters. For both converter sides, the control strategytakes in account active and reactive power, which establishes ac grid currents in both ends, and guarantees the balancing of dc bus capacitor voltages inboth NPC converters. Additionally, the semiconductor switching frequency is minimised to reduce switching losses. The performance and robustness of the new fast predictive control strategy, and its capability to solve the DC capacitor voltage balancing problem of bipolar-connected back-to-back NPCconverters are evaluated.

Matrix Converter-Based Unified Power-Flow Controllers: Advanced Direct Power Control Method

This paper presents a direct power control (DPC) for three-phase matrix converters operating as unified power flow controllers (UPFCs). Matrix converters (MCs) allow the direct ac/ac power conversion without dc energy storage links; therefore, the MC-based UPFC (MC-UPFC) has reduced volume and cost, reduced capacitor power losses, together with higher reliability. Theoretical principles of direct power control (DPC) based on sliding mode control techniques are established for an MC-UPFC dynamic model including the input filter. As a result, line active and reactive power, together with ac supply reactive power, can be directly controlled by selecting an appropriate matrix converter switching state guaranteeing good steady-state and dynamic responses. Experimental results of DPC controllers for MC-UPFC show decoupled active and reactive power control, zero steady-state tracking error, and fast response times. Compared to an MC-UPFC using active and reactive power linear controllers based on a modified Venturini high-frequency PWM modulator, the experimental results of the advanced DPC-MC guarantee faster responses without overshoot and no steady-state error, presenting no cross-coupling in dynamic and steady-state responses.

Otimização de dose em mamografia

Mestrado em Radiações Aplicadas às Tecnologias da Saúde. Área de especialização: Imagem Digital com Radiação X.