1,228 research outputs found

    Idiopathic first seizure in adult life

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    This thesis is based on a prospective investigation of 226 patients aged 15 years and older, who were referred to one of the participating hospitals due to a possible idiopathic first seizure. Only those patients were admitted to the study in whom an obvious cause on clinical grounds for the occurrence of the seizure was lacking. A standard EEG, an EEG after partial sleep deprivation and a computerised tomography scan (CT scan) were obtained in all patients. None of the patients were treated with antiepileptic drugs, unless a second seizure occurred. Follow-up in all patients was 1 - 2 years

    A state space model for exponential smoothing with group seasonality

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    We present an approach to improve forecast accuracy by simultaneously forecasting a group of products that exhibit similar seasonal demand patterns. Better seasonality estimates can be made by using information on all products in a group, and using these improved estimates when forecasting at the individual product level. This approach is called the group seasonal indices (GSI) approach, and is a generalization of the classical Holt-Winters procedure. This article describes an underlying state space model for this method and presents simulation results that show when it yields more accurate forecasts than Holt-Winters.Common seasonality; demand forecasting; exponential smoothing; Holt-Winters; state space model.

    Regional geothermal aquifer architecture of the fluvial Lower Cretaceous Nieuwerkerk Formation – a palynological analysis

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    The primary challenge for efficient geothermal doublet design and deployment is the adequate prediction of the size, shape, lateral extent and thickness (or aquifer architecture) of aquifers. In the West Netherlands Basin, fluvial Lower Cretaceous sandstone-rich successions form the main aquifers for geothermal heat exploitation. Large variations in the thickness of these successions are recognised in currently active doublet systems that cannot be explained. This creates an uncertainty in aquifer thickness prediction, which increases the uncertainty in doublet lifetime prediction as it has an impact on net aquifer volume. The goal of this study was to improve our understanding of the thickness variations and regional aquifer architecture of the Nieuwerkerk Formation geothermal aquifers. For this purpose, new palynological data were evaluated to correlate aquifers in currently active doublet systems based on their chronostratigraphic position and regional Maximum Flooding Surfaces. Based on the palynological cuttings analysis, the fluvial interval of the Nieuwerkerk Formation was subdivided into two successions: a Late Ryazanian to Early Valanginian succession and a Valanginian succession. Within these successions trends were identified in sandstone content. In combination with seismic interpretation, maps were constructed that predict aquifer thickness and their lateral extent in the basin. The study emphasises the value of palynological analyses to reduce the uncertainty of fluvial hot sedimentary aquifer exploitation

    Fout na de oorlog: Fascistische en racistische organisaties in Nederland 1950-1990

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    Contains fulltext : 3777.pdf (publisher's version ) (Open Access

    Total factor productivity and the role of entrepreneurship

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    The absence of evidence in the scholarly literature for a tested long-term relationship between entrepreneurship and economic growth is at odds with the importance attributed to entrepreneurship in the policy arena. The present paper addresses this absence, introducing entrepreneurship using four different and accepted models explaining the total factor productivity of twenty OECD countries with data for the period 1969–2010. Traditionally, entrepreneurship is not addressed in these models. We show that in all models—as well as a joint one—entrepreneurship has a significant influence while the remaining effects largely stay the same. Entrepreneurship is measured as the business ownership rate (number of business owners per workforce) corrected for the level of economic development (GDP per capita)

    Economic effects of stimulating business R&D

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    The main question dealt with in this paper is: what are the economic effects of these financial government incentives? The answer is of particular importance with a view to the question whether the government should intensify, or conversely, cut down on its R&D incentives policy. The economic effects of these R&D incentives are determined by a multitude of factors; factors which also tend to interact. In addition to the spillover effects referred to above, the main decisive factors are: the extent to which the government incentives really do lead to an increase in business R&D, and the direct effects of this extra R&D on business performance. A total of 12 mechanisms are distinguished, all of which have an effect on the economic effects of R&D incentives. These twelve mechanisms are placed in a total framework in this paper. All in all, this paper shows that the economic effects of the government?s stimulation of business R&D are particularly beneficial. The paper also sets out the mechanisms that lead to this result, and which mechanisms are of particular importance in this respect

    Total factor productivity and the role of entrepreneurship

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    Total factor productivity of twenty OECD countries for a recent period (1971-2002) is explained using six different models based on the established literature. Traditionally, entrepreneurship is not dealt with in these models. In the present paper it is shown that when this variable is added - in all models there is a significant influence of entrepreneurship while the remaining effects mainly stay the same. Entrepreneurship is measured as the business ownership rate (number of business owners per workforce) corrected for the level of economic development (GDP per capita)

    Total Factor Productivity and the Role of Entrepreneurship

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    Total factor productivity of twenty OECD countries for a recent period (1971-2002) is explained using six different models based on the established literature. Traditionally, entrepreneurship is not dealt with in these models. In the present paper it is shown that – when this variable is added - in all models there is a significant influence of entrepreneurship while the remaining effects mainly stay the same. Entrepreneurship is measured as the business ownership rate (number of business owners per workforce) corrected for the level of economic development (GDP per capita)
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