741 research outputs found
The science of greenhouse gases:Uncertainties in sources and sinks, and implications for verification
Our present knowledge about the carbon cycle, governing the sources and sinks of the most important anthropogenically influenced greenhouse gas CO2 is still far from satisfactory in the quantitative sense. This statement holds on all scales, from global to local. Therefore, long-term atmospheric measurements, on many locations, are absolutely needed, both to improve our quantitative knowledge of the carbon cycle, and to create a firm verification basis for mitigation measures. Yet, it is an illusion to think that source/sink characterisation by these atmospheric measurements will get to the detail that Kyoto Protocol actions can be surveyed and verified on a national level in the coming years (if ever !). Therefore, a combination of validation (on project basis) and verification (on a continental scale) is proposed. Mitigation measures through mere sink enhancement (afforestation) are at best a temporary solution. Therefore, not much (political) effort should be invested into this option.</p
The science of greenhouse gases:Uncertainties in sources and sinks, and implications for verification
Our present knowledge about the carbon cycle, governing the sources and sinks of the most important anthropogenically influenced greenhouse gas CO2 is still far from satisfactory in the quantitative sense. This statement holds on all scales, from global to local. Therefore, long-term atmospheric measurements, on many locations, are absolutely needed, both to improve our quantitative knowledge of the carbon cycle, and to create a firm verification basis for mitigation measures. Yet, it is an illusion to think that source/sink characterisation by these atmospheric measurements will get to the detail that Kyoto Protocol actions can be surveyed and verified on a national level in the coming years (if ever !). Therefore, a combination of validation (on project basis) and verification (on a continental scale) is proposed. Mitigation measures through mere sink enhancement (afforestation) are at best a temporary solution. Therefore, not much (political) effort should be invested into this option.</p
Development and application of a sensitive, high precision weighing lysimeter for use in greenhouses
A high precision weighing lysimeter for measuring evapotranspiration in greenhouses was developed. The instrument has a measurement of sensitivity of one part in 106, that is one order of magnitude better than any other so far described in the literature. With it, evaporation rates in a greenhouse, even at night, can be measured on a one minute time scale. Development and construction of the instrument are described and measurements of the transpiration of a tomato crop in a greenhouse are used to demonstrate its capabilities
Towards a computational model for stimulation of the Pedunculopontine nucleus
The pedunculopontine nucleus (PPN) has recently been suggested as a new therapeutic target for deep brain stimulation (DBS) in patients suffering from Parkinson's disease, particularly those with severe gait and postural impairment [1]. Stimulation at this site is typically delivered at low frequencies in contrast to the high frequency stimulation required for therapeutic benefit in the subthalamic nucleus (STN) [1]. Despite real therapeutic successes, the fundamental physiological mechanisms underlying the effect of DBS are still not understood. A hypothesis is that DBS masks the pathological synchronized firing patterns of the basal ganglia that characterize the Parkinsonian state with a regularized firing pattern. It remains unclear why stimulation of PPN should be applied with low frequency in contrast to the high frequency stimulation of STN. To get a better understanding of PPN stimulation we construct a computational model for the PPN Type I neurons in a network
Why Would Anyone Like To Share His Knowledge?
Why do workers within organizations, or organizations in a network share information and knowledge? This question reverses the logic in some of the knowledge management literature, which addresses impediments and problems in information and knowledge sharing. According to property rights theory, information sharing can be explained in terms of self-interest, maximizing behavior, indispensability of groups and complementarity of assets. Based on this line of reasoning and on empirical evidence presented in this paper, we conclude that the ownership structure of information and knowledge systems matters. In building knowledge management systems, developers should take into account that the intuitive wisdom, indicating that central control is better control, should be interpreted with great caution
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