Further investigation of the uncertain trend in U.S. GDP

The presence of deterministic or stochastic trend in U.S. GDP has been a continuing debate in the literature of macroeconomics. Ben-David and Papell (1995) found evindence in favor of trend stationarity using the secular sample of Maddison (1995). More recently, Murray and Nelson (2000) correctly criticized this nding arguing that the Maddison data are plagued with additive outliers (AO), which bias inference towards stationarity. Hence, they propose to set the secular sample aside and conduct inference using a more homogeneous but shorter time-span post-WWII sample. In this paper we re-visit the Maddison data by employing a test that is robust against AO s. Our results suggest the U.S. GDP can be modeled as a trend stationary process.

Common cycles in macroeconomic aggregates

Reduced form estimation of multivariate data sets currently takes into account long-run co-movement restrictions by using Vector Error Correction Models (VECM' s). However, short-run co-movement restrictions are completely ignored. This paper proposes a way of taking into account short-and long-run co-movement restrictions in multivariate data sets, leading to efficient estimation of VECM' s. It enables a more precise trend-cycle decomposition of the data which imposes no untested restrictions to recover these two components. The proposed methodology is applied to a multivariate data set containing U.S. per-capita output, consumption and investment Based on the results of a post-sample forecasting comparison between restricted and unrestricted VECM' s, we show that a non-trivial loss of efficiency results whenever short-run co-movement restrictions are ignored. While permanent shocks to consumption still play a very important role in explaining consumption’s variation, it seems that the improved estimates of trends and cycles of output, consumption, and investment show evidence of a more important role for transitory shocks than previously suspected. Furthermore, contrary to previous evidence, it seems that permanent shocks to output play a much more important role in explaining unemployment fluctuations.

Measuring core inflation as the common trend of prices

In recent years, many central banks have adopted inflation targeting policies starting an intense debate about which measure of inflation to adopt. The literature on core inflation has tried to develop indicators of inflation which would respond only to "significant" changes in inflation. This paper defines a measure of core inflation as the common trend of prices in a multivariate dynamic model, that has, by construction, three properties: it filters idiosyncratic and transitory macro noises, and it leads the future leveI of headline inflation. We also show that the popular trimmed mean estimator of core inflation could be regarded as a proxy for the ideal GLS estimator for heteroskedastic data. We employ an asymmetric trimmed mean estimator to take account of possible skewness of the distribution, and we obtain an unconditional measure of core inflation.

Trend following performance with size and liquidity: evidence from US, Brazil and Portugal

Neste trabalho, eu analiso a eficiência de se aplicar estratégias que identificam tendências em mercados de capitais, em três países diferentes, usando um conjunto de variáveis macroeconómicas. Em cada país, a estratégia é testada contra os índices de grande capitalização, pequena capitalização e o índice principal. Eu concluo que, ao combinar os sinais diários obtidos pela estratégia, é possível alcançar retornos ajustados ao risco superiores e reduzir as perdas possíveis do portfólio. No geral, enfatizo os benefícios de usar estratégias que exploram tendências para investidores avessos ao risco, obtendo retornos característicos de capitais próprios com a volatilidade característica de obrigações.

Botão "Play"

Ilustração componente do jogo “Responda se puder", desenvolvido pela equipe do Laboratório de Objetos de Aprendizagem da Universidade Federal de São Carlos (LOA/UFSCar).

Botão "Play"

Imagem componente do jogo “DigesTower (http://www.loa.sead.ufscar.br/digestower.php)” desenvolvido pela equipe do Laboratório de Objetos de Aprendizagem da Universidade Federal de São Carlos (LOA/UFSCar).

Encaminhamento óptimo do tráfego em redes Triple Play

A Internet é responsável pelo surgimento de um novo paradigma de televisão – IPTV (Televisão sobre IP). Este serviço distingue-se de outros modelos de televisão, pois permite aos utilizadores um elevado grau de interactividade, com um controlo personalizado sobre os conteúdos a que pretende assistir. Possibilita ainda a oferta de um número ilimitado de canais, bem como o acesso a conteúdos de Vídeo on Demand (VoD). O IPTV apresenta diversas funcionalidades suportadas por uma arquitectura complexa e uma rede convergente que serve de integração a serviços de voz, dados e vídeo. A tecnologia IPTV explora ao máximo as características da Internet, com a utilização de mecanismos de Qualidade de Serviço. Surge ainda como uma revolução dentro do panorama televisivo, abrindo portas a novos investimentos por parte das empresas de telecomunicações. A Internet também permite fazer chamadas telefónicas sobre a rede IP. Este serviço é denominado VoIP (Voz sobre IP) e encontra-se em funcionamento já há algum tempo. Desta forma surge a oportunidade de poder oferecer ao consumidor final, um serviço que inclua os serviços de Internet, de VoIP e de IPTV denominado serviço Triple Play. O serviço Triple Play veio obrigar a revisão de toda a rede de transporte de forma a preparar a mesma para suportar este serviço de uma forma eficiente (QoS), resiliente (recuperação de falhas) e optimizado (Engenharia de tráfego). Em redes de telecomunicações, tanto a quebra de uma ligação como a congestão nas redes pode interferir nos serviços oferecidos aos consumidores finais. Mecanismos de sobrevivência são aplicados de forma a garantir a continuidade do serviço mesmo na ocorrência de uma falha. O objectivo desta dissertação é propor uma solução de uma arquitectura de rede capaz de suportar o serviço Triple Play de uma forma eficiente, resiliente e optimizada através de um encaminhamento óptimo ou quase óptimo. No âmbito deste trabalho, é realizada a análise do impacto das estratégias de encaminhamento que garantem a eficiência, sobrevivência e optimização das redes IP existentes, bem como é determinado o número limite de clientes permitido numa situação de pico de uma dada rede. Neste trabalho foram abordados os conceitos de Serviços Triple Play, Redes de Acesso, Redes Núcleo, Qualidade de Serviço, MPLS (Multi-Protocolo Label Switching), Engenharia de Tráfego e Recuperação de falhas. As conclusões obtidas das simulações efectuadas através do simulador de rede NS-2.33 (Network Simulator versão 2.33) serviram para propor a solução da arquitectura de uma rede capaz de suportar o serviço Triple Play de uma forma eficiente, resiliente e optimizada.

Play behaviour in nonhuman animals and the animal welfare issue

The mission of defining animal welfare indicators is methodologically difficult, limited, and possibly impossible. A promising alternative, however, to evaluate suitable environmental conditions is the assessment of play behaviour. In the present review, we summarise the general aspects of play behaviour in nonhuman animals and propose its use as a potential indicator of animal welfare. Play behaviour probably occurs in most vertebrates and some invertebrates, but predominately in mammals. It is also more frequent in young males and is associated with the environmental context in which animals find themselves. Animals play if they are healthy and well-fed, but not if they are under stressful conditions or if they are in a stressful state. We can therefore use the prevalence of play behaviour as an indicator of suitable environmental conditions, considering the specificity associated with the above-mentioned modifying factors.

Pycnoscelus surinamensis (Linnaeus, 1758) (Blaberoidea: Blaberidae), a cockroach with a possible association with the ant Brachymyrmex cordemoyi Forel, 1895 (Hymenoptera: Formicidae) and which may be exhibiting a domiciliation trend.

In the present paper, we report on the occurrence of the cockroach Pycnoscelus surinamensis (Linnaeus, 1758) in Brachymyrmex cordemoyi Forel, 1895 nests, indicating a possible symbiosis between these two species. Also, the finding of intradomicile P. surinamensis nymphs may indicate this species is extending its habitat to human habitations, i.e. changing its ecological category from peridomestic to domestic.

O Trabalho e o labirinto da responsabilidade socioempresarial:a experiência da cidadania empresarial do Banco do Brasil

In the current systemic crisis, economic policy is directed to correct the consequences of the functioning of this metabolism, but within the limits of the capital. From this perspective, decision makers propose trade policies, agricultural and industrial to ensure conditions for economic growth. However, as a dead end, there is failure of the State in giving efficacy to the operation of all segments of the economy, especially given the budget constraint. Public managers are forced to seek external resources, resuming the cycle of political allegiance to the interests of international financial and banking representatives, installed in so-called multilateral. The complex ideological capital comes into play in trying to convince society that the paths taken by governments are inevitable, and that capitalism can be "humanized", even with the realization of the growing inequalities caused by historical irrationalism of the production process of capital . In this sense, emerging concepts that attempt to demonstrate the compatibility of the system to real human needs. This ideological offensive is intended to legitimize the capital. The so-called third sector has a special highlight with the concept of corporate social responsibility. It creates a political environment in which the inevitable mix-up with new illusions offered by and often funding the metabolism of capital in order to perpetuate this system. In this context, political elites, and considerable portions of the academy, embark on "waves of capitalist optimism," while the sociometabolismo capital expands its historical limits, driving forces postponing their collapse, but that cause human suffering and ecological stress. Wars are disseminated to strengthen the deadly war industry and the automobile industry; and devastating the environment of which depends the capital system. In this scenario disassemble, propositions emerge around a "new social pact" in order to minimize the adverse effects of the dynamics of reproduction of capital. The business class is called to exercise its role through the discourse that appeals to social responsibility programs, in order to intervene directly in the "social question". The core of this research is precisely this point. Although there is considerable scholarship on the phenomenon of Social Responsibility and Corporate Citizenship, there is also an evident lack of this approach focused on the banking sector in Brazil. The importance of rentier capital increased ownership of shares in the wealth produced by all of Brazilian society, justifies a sociological research project on Social Responsibility in the domestic financial sector. In this sense, it was decided to perform a dynamic approach to the "Corporate Citizenship" in the banking industry, specifically in the Bank of Brazil. As this is a key institution, is important analyze of the impacts of this strategy fetish of capitalist reproduction, in order to evaluate the social legitimization of rentier capital in Brazil. In this scenario of the abundance of the discourse on social responsibility there exist a progressive impoverishment of professional work in this segment in Brazil. There is a dramatic mismatch between rhetoric and practice because of the trend of deepening vulnerability of the working conditions of the Brazilian bank worker, from the 1990's. In the specific case of the Bank of Brazil, the first initiative of the institution was to conform to the principles of the UNO and the Ethos Institute, aiming to align their domestic policies to this new strategy of domination of capital. The purpose is to place the Bank in the ideological sphere of corporate social responsibility, just as with its partners in the private financial intercapitalist competition. Indeed, in the internal ambit of the Bank of Brazil, there is a policy to adjust its functional segments to the doctrine of Social Corporate Responsibility. The concepts of this doctrine is presented as something inexorable. There are no alternatives. The Bank of Brazil operates in a highly competitive market, the segment featuring the dominance of financial capital accumulation today. For this reason it can not fail to incorporate the technological advances organizational. For employees there is no alternative but to adapt to this new set of ideas proposed by the metabolism of capital