Flume studies were carried out to investigate flow structure above flexible vegetation. A new data set of mean velocity profiles and turbulence characteristics is reported from experiments with ...wheat. The flow above the wheat reasonably followed the log law. Maximum values of the turbulence intensity
u
rms and Reynolds stress
−
u
′
w
′
¯
were found approximately at the level of the maximum observed deflected plant height. A recent approach for describing vertical velocity profiles above aquatic vegetation Stephan, U., 2002. Zum Fließwiderstandsverhalten flexibler Vegetation. Wiener Mitteilungen 180. Doctoral Thesis. Institute of Hydraulics, Hydrology and Water Resources Management, Faculty of Civil Engineering, Technical University of Vienna. was evaluated with these new data, which represent a different vegetal roughness type. The approach proved to be successful beyond the original scope. However, a new definition for the shear velocity based on the deflected plant height is suggested. The benefit of this modification is that complex turbulence measurements can be avoided, which enhances the practical applicability of the approach.
AbstractThe correct parameterization of vegetation using measurable plant characteristics is essential for reliable flow resistance estimates. This paper focuses on the impact of density and ...distribution of the leaf mass on the drag force. Direct drag force measurements on flexible artificial plants were conducted in a stand. The experiments were novel in that the leaf area index (LAI) was varied in two ways: (1) the distances between the plants were altered, and (2) the leaf area of the plants was doubled and tripled. In addition, the vertical leaf area distribution was examined. The drag forces depended on the leaf mass in a similar fashion regardless of the horizontal distribution of the leaf mass, but the vertical distribution had a more significant impact. Shading of the leaves slightly reduced resistance for bushy plants because the leaf mass hidden behind the frontal projected area exerted drag. The experiments confirmed LAI to be a useful measure in estimating vegetative resistance.
Abstract The effects of a prolonged seizure, i.e. status epilepticus (SE), on neurogenesis of dentate granule cells (DGCs) in the immature dentate gyrus (DG) and possible changes in the phenotypes of ...the newborn neurons have remained incompletely characterized. We have now studied neurogenesis of DGCs in 9-day-old (postnatal, P9) rats 1 week after kainate (KA)-induced SE using 5-bromo-2-deoxyuridine (BrdU) immunostaining. The phenotype characterization of the newborn cells was carried out by immunofluorescence double labeling using doublecortin (DCX) and nestin as markers for immature cells, and glial fibrillary acid protein (GFAP) as a marker for glial cells. Newborn GABAergic neurons were further identified with antibodies for parvalbumin, glutamate decarboxylase 67 (GAD67), and the GABAA receptor α1 subunit, and mRNA expression of GABAergic and immature neurons was measured with quantitative real-time PCR (qPCR) in the DG. Our results show that the number of newborn as well as GABAergic neurons was significantly decreased after SE in the superior blade of the septal DG. The majority of the newborn BrdU-stained neurons co-expressed DCX, but neither nestin nor GFAP. In both experimental groups, newborn neurons were frequently localized in close contact, but not co-localized, with the cells positively stained for the GABAergic cell markers. Nestin and calretinin mRNA expression were significantly increased after SE. Our results suggest that SE-induced disruption of DGC neurogenesis and decreased number of GABAergic neurons could modify the connectivity between these cells and disturb the maturation of the GABAergic neurotransmission in the immature DG at the early epileptogenic phase.
Objectives
Improvement of health‐related quality of life (HRQoL) is one of the primary objectives of symptomatic therapies in Parkinson's disease (PD). The aim of this observational study was to ...investigate possible changes in generic HRQoL in relation to changed PD pharmacotherapy in the clinical setting.
Materials & methods
A total of 219 outpatients with mild to moderate PD (median H&Y score = 2.0), treated with oral antiparkinsonian medications, were investigated twice with a 6‐month interval. At baseline, PD medication dose was increased for 82 patients for clinical reasons (median increase of 100 mg levodopa equivalent daily dose or 31.9%), whereas medication remained unchanged for 137 patients. Two generic HRQoL questionnaires, EQ‐5D and 15D, were used at baseline and at 6 months, and the baseline and delta HRQoL values were compared between the treatment groups.
Results
In the entire sample, the EQ‐VAS score decreased during the study period, indicating a general decline in HRQoL (P = 0.04). There were no differences in the baseline HRQoL values or delta values between the treatment groups as measured with EQ‐5D or 15D (levodopa dose elevated vs dopamine agonist/MAO‐B inhibitor dose elevated vs no change in medication).
Conclusions
An approximately 1/3 increase in antiparkinsonian medication dose did not have an impact on generic HRQoL. Disease‐specific QoL may be more sensitive to pharmacotherapy‐related changes in PD.
Background
Patients with type 1 diabetes have shown an increase in circulating cytokines, altered lipoprotein metabolism and signs of vascular dysfunction in response to high‐fat meals. Intestinal ...alkaline phosphatase (IAP) regulates lipid transport and inflammatory responses in the gastrointestinal tract. We therefore hypothesized that changes in IAP activity could have profound effects on gut metabolic homeostasis in patients with type 1 diabetes.
Methods
Faecal samples of 41 nondiabetic controls and 46 patients with type 1 diabetes were analysed for IAP activity, calprotectin, immunoglobulins and short‐chain fatty acids (SCFAs). The impact of oral IAP supplementation on intestinal immunoglobulin levels was evaluated in C57BL/6 mice exposed to high‐fat diet for 11 weeks.
Results
Patients with type 1 diabetes exhibited signs of intestinal inflammation. Compared to controls, patients with diabetes had higher faecal calprotectin levels, lower faecal IAP activities accompanied by lower propionate and butyrate concentrations. Moreover, the amount of faecal IgA and the level of antibodies binding to oxidized LDL were decreased in patients with type 1 diabetes. In mice, oral IAP supplementation increased intestinal IgA levels markedly.
Conclusion
Deprivation of protective intestinal factors may increase the risk of inflammation in the gut – a phenomenon that seems to be present already in patients with uncomplicated type 1 diabetes. Low levels of intestinal IgA and antibodies to oxidized lipid epitopes may predispose such patients to inflammation‐driven complications such as cardiovascular disease and diabetic nephropathy. Importantly, oral IAP supplementation could have beneficial therapeutic effects on gut metabolic homeostasis, possibly through stimulation of intestinal IgA secretion.
In this paper we studied the use of common electronic semiconductor diodes in temperature measurements at cryogenic atmosphere. The motivation for this is the high price of calibrated cryogenic ...temperature sensors since there are some applications, like quench detection, in which a cheaper and a less accurate sensor would suffice. We measured the forward voltage as a function of temperature, Vf(T), of several silicon rectifier diodes to determine the accuracy and interchangeability of the diodes. The experimental results confimed that Vf(T) of common rectifier diodes are similar to cryogenic sensor diodes, but the variability between two samples is much larger. The interchangeability of the diodes proved to be poor if absolute temperatures are to be measured. However for sensing changes in temperature they proved to be adequate and thus can be used to measure e.g. quench propagation or sense quench ignition at multiple locations with cheap price.
We show by modelling that the quench propagation velocity is not constant in HTS coils but it changes during the quench. Due to the large temperature margin between the operation and the current ...sharing temperatures, the normal zone does not propagate with the temperature front. This means that the temperature will rise in a considerably larger volume when compared to the quenched volume. Thus, the evolution of the temperature distribution below current sharing temperature
T
c
s
after the quench onset affects the normal zone propagation velocity in HTS more than in LTS coils. This can be seen as an acceleration of the quench propagation velocities while the quench evolves when margin to
T
c
s
is high. In this paper, we scrutinize quench propagation in a stack of YBCO cables with an in-house finite element method software which solves the heat diffusion equation. We compute the longitudinal and transverse normal zone propagation velocities at various distances from the hot spot to demonstrate the distance-variation of these velocities. According to the results in our particular simulation case, the longitudinal normal zone propagation velocity is 30 % higher far away from the quench origin compared to its immediate vicinity when
T
op
=4.2 K and
T
c
s
=15 K.
Flow resistance of natural grasses, sedges and willows was studied in a laboratory flume. The objective was to investigate, how type, density and placement of vegetation, flow depth and velocity ...influence friction losses. The plants were studied in various combinations under nonsubmerged and submerged conditions in a total of 350 test runs. The results show large variations in the friction factor,
f, with depth of flow, velocity, Reynolds number, and vegetative density. The friction factor was dependent mostly on (1) the relative roughness in the case of grasses; (2) the flow velocity in the case of willows and sedges/grasses combined; and (3) the flow depth in the case of leafless willows on bare bottom soil. Leaves on willows seemed to double or even triple the friction factor compared to the leafless case despite the fact that the bottom was growing sedges in both cases. For the leafless willows,
f appeared to increase with depth almost linearly and independently of velocity. Unexpectedly, different spacing of the same number of leafless willows with grasses did not have any significant effect on
f. Based on the experimental work, a better understanding of flow resistance due to different combinations of natural stiff and flexible vegetation under nonsubmerged and submerged conditions was gained.
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