R&D, innovation and productivity, and the CIS: sampling, specification and comparability issues

We construct and estimate a modified version of the Crépon, Duguet and Mairesse (1998) model to investigate the links between R&D, innovation output and productivity. We propose a model specification that, among other features, aims to better capture the variance component of the cooperation and obstacles to innovation variables. Results based on Finnish CIS data support this alternative specification and highlight the role of process innovations. We also address comparability over time within the same country, by comparing Finnish CIS3 and CIS4 estimates. Despite CIS harmonisation, both sample selection issues and nuances in the specification of the variables prove to have a profound effect on the results, and question the validity of this currently popular comparison exercises

Circadian Variation in the Onset of Acute Ischemic Stroke

Background: To evaluate the relation of circadian variation on onset of acute ischemic stroke.Methods: In this descriptive study 181patients with ischemic stroke were included. The time of onset of symptoms to determine the circadian variation was noted. In order to determine the frequency of acute ischemic stroke associated with circadian variation, the time of day was divided into four equal intervals of 6 hours each. Time of stroke onset was noted and each patient was bracketed in a particular six hour time period. These six hour periods were 0-6, 6:01-12, 12:01-18, and 18:01-24 hours.Results : Out of 181 patients, majority (44.8%) had acute ischemic stroke during 6:00-12:00 hours. Mean age of the study population was 69.09 +12.607 with age range from 36 to 97 years . Majority (74.6%) were male.Conclusion: Incidence of ischemic stroke is significantly increased in the morning 6:01-12:00 hours