The effects of disjunct sampling and averaging time on maximum mean wind speeds

Conventionally, the 50-year wind is calculated on basis of the annual maxima of consecutive 10-min averages. Very often, however, the averages are saved with a temporal spacing of several hours. We call it disjunct sampling. It may also happen that the wind speeds are averaged over a longer time period before being saved. In either case, the extreme wind will be underestimated. This paper investigates the effects of the disjunct sampling interval and the averaging time on the attenuation of the extreme wind estimation by means of a simple theoretical approach as well as measurements. The measurements include climates dominated by extratropical lows, as well as more complicated, wind climate types. For both, the investigations are done for omni-directional and sector-wise situations. The theory assumes the time series is a Gaussian Markov chain and it performs adequately for sites in the extratropical regions. The sector-wise situation is more complicated. The attenuation of the extreme mean winds for a sector shows a dependency on the frequency of occurrence from that sector.     

Die Innovationstätigkeit der deutschen Softwareindustrie

In this article we present the results of two empirical studies focusing on the structure and extent of the innovation activities of the German Software Industry and analyze distinctive features of Software Innovations. We distinguish the activities of the primary (core) Software Industry and secondary industries such as Mechanical and Electrical Engineering, Motor Industry and Telecommunications. A special focus is put on the question if innovations in Software are sequential, on the role of Open Source Software and the importance of interoperability.     

Uremia: pathophysiologic sequelae and indications for kidney replacement therapy

Mortality in intensive care unit patients with acute renal failure is still high. The reasons for this are not fully understood. Renal failure without other failing organs does not lead to death if treatment is adequate. Uremia is therefore thought to prevent spontaneous recovery from and impedes the treatment of other organ failures. The reasons for this have been elucidated only partially. Of main importance are different kinetics and dynamics of endo- and xenobiotics in uremia. The mechanisms that lead to altered kinetics in such patients are quite clearly understood, while in the field of altered dynamics many questions are open. It is also unclear which accumulating metabolites are responsible for the different dynamics. This is the reason why parameters that would indicate when to start a dialysis procedure in acute renal failure are still lacking. Exceptions are substances known to lead to death if they are present in high concentrations. These substances are mainly potassium, salt and water.     

Amyloid Beta-Mediated Changes in Synaptic Function and Spine Number of Neocortical Neurons Depend on NMDA Receptors

Onset and progression of Alzheimer’s disease (AD) pathophysiology differs between brain regions. The neocortex, for example, is a brain region that is affected very early during AD. NMDA receptors (NMDARs) are involved in mediating amyloid beta (Aβ) toxicity. NMDAR expression, on the other hand, can be affected by Aβ. We tested whether the high vulnerability of neocortical neurons for Aβ-toxicity may result from specific NMDAR expression profiles or from a particular regulation of NMDAR expression by Aβ. Electrophysiological analyses suggested that pyramidal cells of 6-months-old wildtype mice express mostly GluN1/GluN2A NMDARs. While synaptic NMDAR-mediated currents are unaltered in 5xFAD mice, extrasynaptic NMDARs seem to contain GluN1/GluN2A and GluN1/GluN2A/GluN2B. We used conditional GluN1 and GluN2B knockout mice to investigate whether NMDARs contribute to Aβ-toxicity. Spine number was decreased in pyramidal cells of 5xFAD mice and increased in neurons with 3-week virus-mediated Aβ-overexpression. NMDARs were required for both Aβ-mediated changes in spine number and functional synapses. Thus, our study gives novel insights into the Aβ-mediated regulation of NMDAR expression and the role of NMDARs in Aβ pathophysiology in the somatosensory cortex.     

A Simple Method Using Tracer Gas to Identify the Main Airflow and Contaminant Paths within a Room

The main airflow and contaminant paths or the spatial distribution of the age of air (or contaminant) in a room are of great interest in estimating venrilation efficiency. A simple meusurement method is presented which consists of injecting one or more tracer gases at locations of interest and analysing the concentration at several other locations, carefully chosen for best accuracy. Response functions can be fitted to these measurements, which are the age of the tracers or of the air or the concentration of the tracers as a function of the location. The salient paths, such as the dead zones, are also determined from these functions. The paper presents the method, its application and validation in a well controlled test room.     

Effect of a changed temperature regime on the benthos of a norwegian regulated river

The lowermost 20 km of the River Surna, north-western Norway receives cool water during summer from a hypolimnetic release mountain reservoir. The benthic fauna is completely dominated by insects. Benthic densities immediately below the power station are much lower than at all other localities. Although benthic densities increase downstream of the power station, they never exceed the densities above. The dominant insect group, chironomids, can be divided into four categories according to their abundance and distribution above and below the power station: (1) rare or absent above, but common or abundant below; (2) abundant or common above but rare or absent below; (3) slightly less abundant below; (4) unchanged abundance. No major differences in the species composition were recorded for stonefilies, mayflies and caddisflies.