Organising a joint green European electricity market: the model ElGreen

In this paper, the features and the most important results of the computer model ElGreen will be presented. With the help of the computer model it is possible to simulate various promotion strategies for different technologies in all EU countries. Policies that can be selected are the most important price driven strategies (feed-in tariffs, investment subsidies, tax incentives), capacity driven instruments (tradable green certificates, national or international wide trading system) and a voluntary green pricing system.The following recommendations are derived:

(i)Regardless of which strategy is chosen credible sources must guarantee that the promotional strategy will survive a specified planning horizon;

(ii)The differences between either national trading, international trading or feed-in tariffs are very small if the design of the promotional system is optimised;

(iii)When introducing a TGC system it is of paramount importance that no mix up between existing and new capacities takes place.

     

Texture Assessment of Magnetically Processed Iron Titanate

Untextured and highly textured iron titanate specimens were produced by vacuum filtering iron titanate-ethanol suspensions in the absence and presence of a strong magnetic field, respectively. Crystallographic texture was assessed by measuring X-ray pole figures on surfaces parallel and perpendicular to the field direction for several peaks in each system. Morphological texture was assessed by measuring grain size as a function of angle to a reference direction. Results indicate that magnetic field processing imposes a strong, fiber-type texture on the order of 30 times random, with the b -axis parallel to the applied field. Additionally, morphological texturing is absent for the grain sizes studied in this work.     

Intracellular pH regulation in bovine aortic endothelial cells: evidence of both Na+/H+ exchange and Na+-dependent Cl-/HCO3- exchange

Regulation of intracellular pH (pHi) was studied in cultured bovine aortic endothelial cells, an important cell system for cardiovascular research. Suspended cells were acidified by the NH4Cl prepulse technique as well as by exposure to CO2/HCO3-. Subsequent rates of pHi recovery were monitored using the fluorescent dye 2',7'-bis(2-carboxyethyl)-5-(6)-carboxyfluorescein (BCECF). In HCO3(-)-free solutions, an EIPA-sensitive, Na+-dependent mechanism fully accounted for realkalinization, namely the Na+/H+ exchanger (NHE). In the presence of HCO3-, an additional acid efflux mechanism was found. This one was dependent on Na+ and intracellular Cl-, EIPA-insensitive but DIDS-sensitive, and therefore represented a Na+-dependent Cl-/HCO3- exchanger (NCBE). In summary, two acid-extruding mechanisms were identified in bovine aortic endothelial cells: NHE and NCBE.     

Effects of ginseng treatment on neutrophil chemiluminescence and immunoglobulin G subclasses in a rat model of chronic Pseudomonas aeruginosa pneumonia

OBJECTIVE: To examine the effect of different concentrations of calcium on the contractile responses of isolated strips of rabbit bladder detrusor to various forms of stimulation after 2 h incubation in the presence of substrate and oxygen depletion (in vitro ischaemia), followed by 1 h of recovery. The resultant contractile responses were correlated with the level of lipid peroxidation as determined by malonedialdehyde (MDA) concentration. MATERIALS AND METHODS: Isolated strips of rabbit bladder detrusor smooth muscle were incubated in Tyrode's solution containing different concentrations of calcium (0-5.4 mmol/L). The effect of 2 h of incubation in oxygen- and substrate-free medium (in vitro ischaemia), followed by a 1-h incubation in the presence of oxygen and substrate, on the contractile responses to field stimulation, carbachol and KCl were determined. The effects of repetitive stimulation (15 s of stimulation at 32 Hz applied every 5 min during the 2-h experimental period) were also assessed. RESULTS: The contractile responses to all stimuli increased as the extracellular calcium concentration was increased from 0.6 to 5.4 mmol/L. A 2 h exposure to in vitro ischaemia, followed by a return to normal solution, resulted in a diminished response to all stimuli. This contractile dysfunction was least in the presence of calcium chelator (EGTA) and greatest in the presence of 5.4 mmol/L calcium. Repetitive stimulation during in vitro ischaemia also exacerbated the contractile dysfunction. Lipid peroxidation increased during in vitro ischaemia in proportion to the calcium concentration and was enhanced by repetitive stimulation during this period. Regardless of the incubation conditions, the reduction in the contractile response was significantly greater for field-stimulated tissues than for those stimulated with carbachol or KCl. CONCLUSIONS: These results show that the magnitude of contractile dysfunction induced by incubation in the presence of substrate and oxygen depletion is reduced in the presence of low calcium concentrations, increased in the presence of high calcium levels and increased in the presence of repetitive stimulation. In addition, the level of lipid peroxidation after the recovery period was proportional to the magnitude of contractile dysfunction present.     

The effects of geometrical parameters on synaptic transmission: a Monte Carlo simulation study

Monte Carlo simulations of transmitter diffusion and its interactions with postsynaptic receptors have been used to study properties of quantal responses at central synapses. Fast synaptic responses characteristic of those recorded at glycinergic junctions on the teleost Mauthner cell (time to peak approximately 0.3-0.4 ms and decay time constant approximately 3-6 ms) served as the initial reference, and smaller contacts with fewer postsynaptic receptors were also modeled. Consistent with experimental findings, diffusion, simulated using a random walk algorithm and assuming a diffusion coefficient of 0.5-1.0 x 10(-5) cm2 s(-1), was sufficiently fast to account for transmitter removal from the synaptic cleft. Transmitter-receptor interactions were modeled as a two-step binding process, with the double-bound state having opened and closed conformations. Addition of a third binding step only slightly decreased response amplitude but significantly slowed both its rising and decay phases. The model allowed us to assess the sources of response variability and the likelihood of postsynaptic saturation as functions of multiple kinetic and spatial parameters. The method of nonstationary fluctuation analysis, typically used to estimate the number of functional channels at a synapse and single channel current, proved unreliable, presumably because the receptors in the postsynaptic matrix are not uniformly exposed to the same profile of transmitter concentration. Thus, the time course of the probability of channel opening most likely varies among receptors. Finally, possible substrates for phenomena of synaptic plasticity, such as long-term potentiation, were explored, including the diameter of the contact zone, defined by the region of pre- and postsynaptic apposition, the number and distribution of the receptors, and the degree of vesicle filling. Surprisingly, response amplitude is quite sensitive to the size of the receptor-free annulus surrounding the receptor cluster, such that expansion of the contact zone could produce an appreciable increase in quantal size, normally attributed to either the presence of more receptors or the release of more transmitter molecules.     

Subjective symptoms and sleep apnea among persons referred to a sleep center. A questionnaire survey

The aim of this study was to evaluate the relation between symptoms and clinical characteristics and the frequency of increased apnoea and hypopnoea activity. The study population consisted of 135 persons referred to a sleep centre. One hundred and fifteen patients (85%) completed a questionnaire and were subsequently monitored during one night's sleep. Fifty-two persons (45%) had an Apnoea Hypopnoea Index (AHI = the mean number of apnoea and hypopnoea episodes per hour of sleep) > or = 10. Forty-one (36%) had an Apnoea Index (AI = the mean number of apnoea per hour of sleep) > or = 10. Symptoms and clinical characteristics had no significant correlation to increased apnoea activity; however, there was a significant relationship between self-reported frequent breathing pauses during sleep and increased AHI and AI. Symptoms and clinical characteristics are not capable of identifying persons with increased apnoea activity.     

Masters of harmony

Faber Birren, the well known color consultant and writer, has, over a considerable time period, researched and pondered unusual and novel aspects of color as they are related to art and harmony. He is in the process of preparing a comprehensive review in book form on this subject. He has been kind enough to offer three chapters in advance to our readers.     

Uber ein chemisches verfahren zur herstellung von elektrochemisch aktivem blei-IV-oxid

There are experiments described where it is possible to produce active electrode mass due to direct influence of ozone. Ni-II-hydroxide can be turned into NiOOH when it is dry. MnO₂ can be precipitated by passing O₃ into a Mn-II-salt solution. Only for PbO₂ the situation is not so easy to handle. Within pure lead-II-salt solutions below pH 3 there will be no precipitation. Only at a higher pH and a suitable buffering PbO₂ appears as a reaction product. Technically economic procedures are reached by slurrying lead powder or low valent lead oxides under alkaline circumstances. Some detailed results of an extensive research program are being presented, which have been made in order to pursue the relation between chemical synthesis, structure and electrochemical activity of the PbO₂. Specific capacity of max. 567 coul/g of PbO₂-material have been measured. The molecular water content (presence of protons) within the solid structure plays, similar to the former tested MnO₂, but in a much more sensitive way, an important role for the electrochemical properties of the gained substances. The life of a PbO₂-particle in the positive electrode of the lead battery becomes more understandable due to the recognized results.     

A Sense of Illumination. Remarks on a New Approach to Color Expression

Color in art is traced from the Renaissance to the present. Much in the past has been taken from nature, with emphasis on optical effects involving visual appearances. Principles based on modern studies of perception offer new incentives to the artist, and new modes of expression in which brain reactions supplement visual ones.