Inventering av plantskog med laserscanning och digitalt flygfoto

Referat av artikeln: Korpela, I., Tuomola, T., Tokola, T. & Dahlin, B. 2008. Appraisal of seedling stand vegetation with airborne imagery and discrete-return LiDAR - an exploratory analysis. Silva Fennica 42 (5) : 753-772.

The Regulation of Skeletal and Cardiac Muscle Blood Flow in Humans. Studies by positron emission tomography with special reference to exercise, adenosine and nitric oxide

Virtually every cell and organ in the human body is dependent on a proper oxygen supply. This is taken care of by the cardiovascular system that supplies tissues with oxygen precisely according to their metabolic needs. Physical exercise is one of the most demanding challenges the human circulatory system can face. During exercise skeletal muscle blood flow can easily increase some 20-fold and its proper distribution to and within muscles is of importance for optimal oxygen delivery. The local regulation of skeletal muscle blood flow during exercise remains little understood, but adenosine and nitric oxide may take part in this process. In addition to acute exercise, long-term vigorous physical conditioning also induces changes in the cardiovasculature, which leads to improved maximal physical performance. The changes are largely central, such as structural and functional changes in the heart. The function and reserve of the heart’s own vasculature can be studied by adenosine infusion, which according to animal studies evokes vasodilation via it’s a_2A receptors. This has, however, never been addressed in humans in vivo and also studies in endurance athletes have shown inconsistent results regarding the effects of sport training on myocardial blood flow. This study was performed on healthy young adults and endurance athletes and local skeletal and cardiac muscle blod flow was measured by positron emission tomography. In the heart, myocardial blood flow reserve and adenosine A_2A receptor density, and in skeletal muscle, oxygen extraction and consumption was also measured. The role of adenosine in the control of skeletal muscle blood flow during exercise, and its vasodilator effects, were addressed by infusing competitive inhibitors and adenosine into the femoral artery. The formation of skeletal muscle nitric oxide was also inhibited by a drug, with and without prostanoid blockade. As a result and conclusion, it can be said that skeletal muscle blood flow heterogeneity decreases with increasing exercise intensity most likely due to increased vascular unit recruitment, but exercise hyperemia is a very complex phenomenon that cannot be mimicked by pharmacological infusions, and no single regulator factor (e.g. adenosine or nitric oxide) accounts for a significant part of exercise-induced muscle hyperemia. However, in the present study it was observed for the first time in humans that nitric oxide is not only important regulator of the basal level of muscle blood flow, but also oxygen consumption, and together with prostanoids affects muscle blood flow and oxygen consumption during exercise. Finally, even vigorous endurance training does not seem to lead to supranormal myocardial blood flow reserve, and also other receptors than A_2A mediate the vasodilator effects of adenosine. In respect to cardiac work, atheletes heart seems to be luxuriously perfused at rest, which may result from reduced oxygen extraction or impaired efficiency due to pronouncedly enhanced myocardial mass developed to excel in strenuous exercise.

Comparing service contract prices of outsourcing partner

The main objective of this Master’s thesis is to find out which one of the two pricing models is the most cost-effective. In this thesis there are two companies that have made an outsourcing contract, in which they have a possibility to choose between two different pricing models. The first model is so called FTE (Full Time Employee) -based. The total cost will be based on the amount of outsourced person-workyears. The second pricing model is the transaction-based, in which the price will be formed according to the amount of transactions. Changing the pricing model from FTE-based to the transaction-based will also incur other costs. It is very important that these other costs are also taken into consideration, so that it is possible to determine the total costs of the pricing models. These other costs are direct costs, indirect costs and performance related costs of outsourcing. Activity based-costing (ABC) was used in order to find out the trues indirect costs of the outsourced processes. Performance related costs are related to quality, so Pareto-analysis was used to analyse the costs. Based on all of that, a framework for service related cost analysis was developed. Quality costs were almost impossible to quantify, so quality had to be taken into consideration in a qualitative way. Furthermore, considering only the indirect and direct costs in a quantitative way and quality costs in a qualitative way, it was possible to find a conditional solution for the research question.

Kognitiivinen haaste uskonnontutkimukselle

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