Entrepreneurship, management services and economic growth

We model the joint production of entrepreneurs and workers where the former provide both entrepreneurial (strategic) and managerial (coordination, motivation) services, and management services are shared with individual workers in an output maximizing way. The static equilibrium of the model determines the endogenous share of entrepreneurs in the economy in a given moment of time. The time dynamics of the solution implies that a given growth rate in quality of entrepreneurial services contributes to productivity growth proportionally to the share of entrepreneurs at the start of the period and improvement in quality of entrepreneurial services is convergence enhancing. Model predictions are tested with data from OECD countries in the period 1970-2002. We find that improvements in quality of entrepreneurial services over time explain up to 100% of observed average productivity growth in these countries.

Cooperative Transmission and Radio Resources Management for Wireless Networks

Report for the scientific sojourn at the Multimedia Communications Laboratory, University of Texas at Dallas, USA, from September to December 2005. The cooperative transmission has been analyzed taking a broadcast relay channel which assumes a scenario with one source and multiple destinations. Moreover, in order to improve the performance in terms of mutual information, it has been considered that for each destination there is another nearby terminal (called relay) which will help to improve the performance of the destination. This scheme combines different types of channels considered in the information theory, such as the relay channel, broadcast channel and interference channel (if the relays transmit information intended only to its associated destination). In this work, the author has studied the optimal way to encode the signals for the different users, known as capacity region (i.e. related to radio resources management ), of the broadcast relay channel.

Explaining Variation in Organizational Change: The Reform of Human Resource Management in the European Commission and the OECD

In this article we investigate the reforms of human resource management in the European Commission and the OECD by analyzing comparatively to what extent both organizations have adjusted their respective structures towards the ideal type of the so-called New Public Management (NPM). The empirical findings show that reforms towards NPM are more pronounced in the Commission than in the OECD. These findings are surprising for two reasons: First, it seems rather paradoxical that the OECD as central promoter of NPM at the international level lags behind the global trend when it comes to reforming its own structures. Second, this result is in contradiction with theoretical expectations, as they can be derived from theories of institutional isomorphism. To nevertheless account for the surprising results, it is necessary to modify and complement existing theories especially with regard to the scope conditions of their causal mechanisms.

Fiscal insurance and debt management in OECD economies

Assuming the role of debt management is to provide hedging against fiscal shocks we consider three questions: i) what indicators can be used to assess the performance of debt management? ii) how well have historical debt management policies performed? and iii) how is that performance affected by variations in debt issuance? We consider these questions using OECD data on the market value of government debt between 1970 and 2000. Motivated by both the optimal taxation literature and broad considerations of debt stability we propose a range of performance indicators for debt management. We evaluate these using Monte Carlo analysis and find that those based on the relative persistence of debt perform best. Calculating these measures for OECD data provides only limited evidence that debt management has helped insulate policy against unexpected fiscal shocks. We also find that the degree of fiscal insurance achieved is not well connected to cross country variations in debt issuance patterns. Given the limited volatility observed in the yield curve the relatively small dispersion of debt management practices across countries makes little difference to the realised degree of fiscal insurance.

Diagnosing pulmonary embolism in outpatients with clinical assessment, D-dimer measurement, venous ultrasound, and helical computed tomography: a multicenter management study.

PURPOSE: To evaluate a diagnostic strategy for pulmonary embolism that combined clinical assessment, plasma D-dimer measurement, lower limb venous ultrasonography, and helical computed tomography (CT). METHODS: A cohort of 965 consecutive patients presenting to the emergency departments of three general and teaching hospitals with clinically suspected pulmonary embolism underwent sequential noninvasive testing. Clinical probability was assessed by a prediction rule combined with implicit judgment. All patients were followed for 3 months. RESULTS: A normal D-dimer level (<500 microg/L by a rapid enzyme-linked immunosorbent assay) ruled out venous thromboembolism in 280 patients (29%), and finding a deep vein thrombosis by ultrasonography established the diagnosis in 92 patients (9.5%). Helical CT was required in only 593 patients (61%) and showed pulmonary embolism in 124 patients (12.8%). Pulmonary embolism was considered ruled out in the 450 patients (46.6%) with a negative ultrasound and CT scan and a low-to-intermediate clinical probability. The 8 patients with a negative ultrasound and CT scan despite a high clinical probability proceeded to pulmonary angiography (positive: 2; negative: 6). Helical CT was inconclusive in 11 patients (pulmonary embolism: 4; no pulmonary embolism: 7). The overall prevalence of pulmonary embolism was 23%. Patients classified as not having pulmonary embolism were not anticoagulated during follow-up and had a 3-month thromboembolic risk of 1.0% (95% confidence interval: 0.5% to 2.1%). CONCLUSION: A noninvasive diagnostic strategy combining clinical assessment, D-dimer measurement, ultrasonography, and helical CT yielded a diagnosis in 99% of outpatients suspected of pulmonary embolism, and appeared to be safe, provided that CT was combined with ultrasonography to rule out the disease.

Diarrhées aiguës: propositions de prise en charge ambulatoire [Acute diarrhea: proposal for outpatient management]

Dans la majorité des cas, les diarrhées aiguës sont bénignes et d'évolution spontanément favorable. Il faut cependant savoir reconnaître les situations pouvant mener à des complications, en l'occurrence identifier les diarrhées invasives, inflammatoires, caractérisées par la présence de fièvre, de douleurs abdominales, de ténesmes, de mucus et, ou de sang dans les selles. Celles-ci sont à distinguer des diarrhées sécrétoires, non invasives, non inflammatoires, sans fièvre, généralement aqueuses et volumineuses. En cas de doute diagnostique, l'identification de leucocytes par microscopie ou test à la lactoferrine dans les selles permet d'évoquer une gastroentérite invasive. Les indications à une antibiothérapie empirique dans l'attente du résultat de la coproculture sont la présence d'un syndrome dysentérique (T > 38°C, > 6 selles/24 heures, douleurs abdominales, diarrhées mucopurulentes), l'âge avancé, des comorbidités significatives, une immunosuppression et la présence d'une prothèse endovasculaire. In the majority of the cases, an acute diarrhea is mild and of spontaneously favorable evolution. It is however necessary to know how to recognize the situations being able to lead to complications, in particular to identify the invasive, inflammatory diarrheas, characterized by the presence of fever, abdominal pains, mucus and\or blood. The identification of leukocytes by microscopy or lactoferrine test is helpful. Empiric quinolones treatment is recommended in the presence of dysenteric syndrome (T > 38 degrees C, > 6 stods/24 h 00, abdominal pain muco-purulent diarrhea), advanced age, significant comorbidities, immunosuppression or presence of an endovascular prothesis