The potential predictors of ischemic heart disease mortality were studied for 931 male foundry workers in Finland who participated in a health examination in 1973. These workers were followed up to 1993 through registers and by using a questionnaire. In 1973, the systolic and diastolic blood pressures of workers exposed to carbon monoxide (CO) were slightly higher than those of unexposed workers. The prevalence of angina pectoris showed a clear dose-response relation to CO exposure. Electrocardiogram (ECG) findings indicating past myocardial infarction or suggesting coronary artery disease as a function of smoking and/or CO exposure were not evident. In the 1987 follow-up, the rate ratio for ischemic heart disease mortality was estimated as 4.4 for CO-exposed smokers compared with unexposed nonsmokers. Ischemic heart disease mortality in 1973-1993 was analyzed by using the Cox proportional hazards model. The statistically significant predictors were age, pathologic ECG findings in 1973, regular CO exposure, and abundant alcohol drinking. Of the ECG findings, changes in Q or QS and ST-J or ST waves and in ventricular extrasystoles were statistically significant. The risk of mortality from ischemic heart disease was increased by working in iron foundries, by hypertension, and by smoking.
The data produced by cut-to-length harvesters provide new large-scale data source for event-based update of national forest stand inventory by Finnish Forest Centre. This study aimed to automate geoprocessing, which generates delineations of operated areas from harvester location data. Automated algorithms were developed and tested with a dataset of 455 harvested objects, recorded during harvestings. In automated stand delineation, the location points are clustered, the stand points are identified and external strip roads are separated. Then, stand polygons are produced. To validate the results, automatic delineations were compared to 57 observed delineations from field measurements and aerial images. A detailed comparison method was developed to study the correspondence. Stand polygonization parameter was adjusted and areal correspondence with 1% error on average was obtained for stands over 0.75 ha. Good stand shape agreement was observed. Overall, the automated method worked well, and the operative stand delineations were found suitable for updating the forest inventory data. To modify the operative stands towards forest inventory stands, a balancing algorithm is introduced to create a solid, unique stand boundary between overlapping stands. This algorithm is beneficial for upkeep of stand networks. In addition, the Global Navigation Satellite System (GNSS) accuracy of the harvesters was examined and estimated numerically.
No abstract
In this study, timber trade scenarios are considered in a wood procurement region of Finland. This multiple objective decision-making situation includes the timber purchase from forest owners and the lumber sales from sawmill to abroad. The situation is further complicated by a number of stem bucking instructions of sawmill during different periods. In practice, this decision problem has been solved by applying single-objective stem bucking instructions in harvesters. Due to the complex nature of the problem, single-objective solution can't be directly used to support the timber trade in a manner that it is techno-economically relevant to the forest owners and industries. In this study, stand parameters and timber trade attributes were measured in local wood procurement conditions to improving the bucking instructions. Three scenarios of how the simulation system works based on the real stem diameters and optional monetary value of logs are investigated in the timber-trade process. The Finnish timber trade market is subjected to agreements regarding stem bucking regulations. These agreements could be made on the basis of the three criteria suggested in this study accounting for the effects of stand classification on the timber sales of forest owners and the lumber sales of export companies. Keywords-cut-to-length method, forest industry, forest owner, multi-criteria analysis, stem bucking, wood procurement. I.
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