Optimization of digital signal processing routines for high speed coherent transmissions

Alcuni moduli di un ricevitore coerente per trasmissioni ottiche vengono analizzati e ottimizzati per ridurre il tempo di esecuzione e migliorare le perfomances.ope

Flow Based Load Balancing: Optimizing Web Servers Resource Utilization

The expansion of the Internet has caused a growth on the number of users requesting services through the network, as well as the number of servers and the amount of services they offer. In order to minimize this problem, web servers have started to use a distributed architecture implementation, however with only one external interface for receiving requests from users. In this paper, we propose an approach towards flow-oriented load balancing, using the OpenFlow technology. Thus, each data flow is directed to a server, according to the policy being employed. We evaluate three load balancing techniques: random choice, time slice based choice and weighted balancing, each of them with its advantages and disadvantages.Through our measurements, weighted balancing achieved the best results over the other policies. More over, random choice and time slice based choice are capable of distributing the load in an acceptable way among nodes, considering the average load of each server.Keywords: load balancing, OpenFlow, flow based load balancing

The Coexistence of asthma and Chronic Ostructive Pulmonary Disease (COPD): prevalence and risk factors in young, middle-aged and elderly people from the general population

Background: The joint distribution of asthma and chronic obstructive pulmonary disease (COPD) has not been well described. This study aims at determining the prevalence of self-reported physician diagnoses of asthma, COPD and of the asthma-COPD overlap syndrome and to assess whether these conditions share a common set of risk factors. Methods: A screening questionnaire on respiratory symptoms, diagnoses and risk factors was administered by mail or phone to random samples of the general Italian population aged 20–44 (n = 5163) 45–64 (n = 2167) and 65–84 (n = 1030) in the frame of the multicentre Gene Environment Interactions in Respiratory Diseases (GEIRD) study. Results: A physician diagnosis of asthma or COPD (emphysema/chronic bronchitis/COPD) was reported by 13% and 21% of subjects aged &lt;65 and 65–84 years respectively. Aging was associated with a marked decrease in the prevalence of diagnosed asthma (from 8.2% to 1.6%) and with a marked increase in the prevalence of diagnosed COPD (from 3.3% to 13.3%). The prevalence of the overlap of asthma and COPD was 1.6% (1.3%–2.0%), 2.1% (1.5%–2.8%) and 4.5% (3.2%–5.9%) in the 20–44, 45–64 and 65–84 age groups. Subjects with both asthma and COPD diagnoses were more likely to have respiratory symptoms, physical impairment, and to report hospital admissions compared to asthma or COPD alone (p&lt;0.01). Age, sex, education and smoking showed different and sometimes opposite associations with the three conditions. Conclusion: Asthma and COPD are common in the general population, and they coexist in a substantial proportion of subjects. The asthma-COPD overlap syndrome represents an important clinical phenotype that deserves more medical attention and further research.</br

Pactuando e Impactando: O Efeito dos Acordos de Acionistas no Valor de Mercado da Firma

Some countries admit the presence of pacts that allow to change the relations and balance of power control exercised by the shareholders. Known as shareholder agreements, these pacts are contracts between two or more partners whose goal is to agree on the direction of the relationship between its members. Empirical results suggest that shareholder’ agreements play an important role in low legal protection markets because they inhibit the ability of the majority shareholder to extract benefits in detriment of minority shareholder. This paper aims to analyze the effect of shareholders' agreements in the market value of Brazilian companies from 1999 to 2013. The sample is composed by 472 companies, including 86 companies with shareholder’ agreements. The empirical strategy comprises the fixed effects method on a panel data model. The results show that the effect on firm value is positive as the degree of protection of minority shareholders is higher. However, the regressions tested with the indirect ownership structure have not been able to provide evidence to that effect.Alguns países admitem a convenção de pactos capazes de alterar as relações e o equilíbrio do poder de controle exercido pelos acionistas. Denominados acordos de acionistas, trata-se de contratos celebrados entre dois ou mais sócios, cujo objetivo é convencionar a direção do relacionamento entre seus membros. Resultados empíricos sugerem que os acordos desempenham um papel importante em mercados de baixa proteção legal porque inibem a inclinação do maior acionista em extrair benefícios em detrimento dos minoritários. Este trabalho propõe analisar o efeito dos acordos no valor de mercado das firmas brasileiras no período de 1999 até 2013. A composição da amostra é de 472 companhias, sendo 86 com acordos firmados. A estratégia empírica compreende o método de dados em painel com controle de efeitos fixos. Os resultados apontam que o efeito no valor da firma é positivo à medida que o grau de proteção aos acionistas minoritários é maior. No entanto, as regressões efetuadas com a estrutura de propriedade indireta não foram capazes de prover indícios nesse sentido

Avaliação do Desempenho no Setor Público: Uma Análise da Literatura

O presente artigo tem por objetivo identificar as abordagens da literatura internacional sobre o tema da avaliação de desempenho do setor público. Dentro de uma abordagem qualitativa, esta pesquisa aplica o método ProKnow-C para selecionar um portfólio bibliográfico (BP). Revelou-se um arcabouço teórico que demonstra a evolução da avaliação de desempenho no setor público. Em seguida, são relatadas, especificamente, as etapas da revisão, o que também contribui, como guia, para o aprimoramento das revisões da literatura científica em geral. Neste manuscrito, 39 trabalhos de pesquisa foram selecionados a partir de um banco bruto de 2228 artigos. Foram realizadas análises bibliométricas básicas e avançadas para identificar algumas particularidades da área de pesquisa, como autores, artigos e periódicos mais citados, além das preocupações específicas da avaliação de desempenho no setor público, como a necessidade de avaliação de desempenho promovendo a estratégia organizacional

Latitude variation in the prevalence of asthma and allergic rhinitis in Italy: results from the GEIRD study

BACKGROUND: Earlier studies have pointed out a great variability in the prevalence of asthma and asthma-like symptoms in different geo-climatic areas. AIM: To test the association between latitude and prevalence of asthma and allergic rhinitis in Italian young adults. METHODS: In the frame of Gene-Environment Interaction in Respiratory Diseases study, a postal screening questionnaire on respiratory health and exposure to environmental factors was administered to 18,357 randomly selected subjects aged 20-44 years in 7 centres: 3 in Northern (Torino, Pavia, Verona), 2 in Central (Ancona, Perugia) and 2 in Southern Italy (Salerno, Sassari). RESULTS: 10,494 (57.2%) subjects responded to the questionnaire. The prevalence of self-reported doctor-diagnosed asthma and allergic rhinitis in the lifespan was 10.2% and 26.9%, respectively, and was significantly different across the centres (p&lt;0.05). After adjusting for sex, age, potential risk factors for respiratory diseases and design confounders, the prevalence of asthma (OR: 1.07 per 1°latitude decrease, p&lt;0.001), asthma-like symptoms (wheezing, chest tightness, asthma attacks: OR ranging from 1.04 to 1.06, p&lt;0.05) and allergic rhinitis (OR: 1.03, p=0.04) showed a significant north-to-south trend. Similarly, a 1°C increment in temperature was significantly associated with asthma (OR: 1.10, p&lt;0.001) and asthma-like symptoms (OR from 1.07 to 1.10, p&lt;0.05), but not with allergic rhinitis (OR=1.02, p=0.190). CONCLUSION: The prevalence of asthma and allergic rhinitis increased moving southwards in Italy, suggesting that prolonged exposure to different geo-climatic conditions may affect the onset of asthma and allergic respiratory diseases

Environmental enrichment modulates the response to chronic stress in zebrafish

Several studies have shown that manipulations to the housing environment modulate susceptibility to stress in laboratory animals, mainly in rodents. Environmental enrichment (EE) is one such manipulation that promotes neuroprotection and neurogenesis, besides affecting behaviors such as drug self-administration. Zebrafish are a popular and useful animal model for behavioral neuroscience studies; however, studies evaluating the impact of housing conditions in this species are scarce. In this study, we verified the effects of EE on behavioral (novel tank test) and biochemical [cortisol and reactive oxygen species (ROS)] parameters in zebrafish submitted to unpredictable chronic stress (UCS). Consistent with our previous findings, UCS increased anxiety-like behavior, cortisol and ROS levels in zebrafish. EE for 21 or 28 days attenuated the effects induced by UCS on behavior and cortisol, and prevented the effects on ROS levels. Our findings reinforce the idea that EE exerts neuromodulatory effects across species, reducing vulnerability to stress and its biochemical impact. Also, these results indicate that zebrafish is a suitable model animal to study the behavioral effects and neurobiological mechanisms related to EE