Grundlegende Prozesse betreffend Hydraulik, Sedimenttransport und Flussmorphologie an der Donau

Im Rahmen des Pilotprojektes Bad Deutsch-Altenburg wurde vor, während und nach der gleichzeitigen Umsetzung mehrerer Maßnahmen (Buhnenumbau, Granulometrische Sohlverbesserung GSV, Uferrückbau und Gewässervernetzung) ein umfassendes Monitoringprogramm durchgeführt. Ziel war es, neben der Ist-Zustandserfassung, Begleitung und Dokumentation der Bauphase und der Erfassung der Entwicklung nach Bau auch die zugrunde liegenden Prozesse hinsichtlich Hydraulik, Sedimenttransport und Flussmorphologie zu analysieren. Erstmals wurde dabei die zeitliche Schwankung der Sohlschubspannung direkt gemessen. Die auftretenden Sohlschubspannungen folgten dabei in Abhängigkeit von der Turbulenzintensität einer Log-Normal- oder einer Normalverteilung. Diese Schwankungen sind mit ein Grund, weshalb schon bei Niederwasser ein nennenswerter Geschiebetransport gemessen wurde. Der effektive Durchfluss des Geschiebetransportes liegt dabei im Bereich von 2000 und 2200 m3/s. 50% Prozent des Geschiebes wird bei Durchflüssen bis 2300 m3/s transportiert, mit Jahresfrachten von 306.000 bis 594.000 t für die Jahre 2006 bis 2014. Bei Betrachtung des Transportverhaltens einzelner Tracersteine in 3 Größenklassen durchwanderten 74% der Steine die 3 km lange Strecke in einem Jahr, mit Geschwindigkeiten von 6,2 bis 10,6 m/d. Kleine Steine bewegten sich häufiger und weiter als mittlere und große, welche ein ähnliches Transportverhalten aufwiesen. Die erstmalig an der Donau beschriebenen Kiesdünen erreichten im Vergleich wesentlich höhere Geschwindigkeiten mit 2,5 bis 9 m/h. Ein Abgleich mit Fangkorbmessungen zeigte, dass Kiesdünen, wenn sie auftreten, den überwiegenden Teil des Geschiebetransportprozesses bestimmen.In the scope of the Pilotproject Bad Deutsch-Altenburg a comprehensive monitoring program was conducted, prior, during and after the implementation of several measures (groyne reconstruction, granulometric bed improvementGBI, river bank restoration and side arm reconnection). Beside the documentation of the current status, during the construction works and after the implementation of the measures, description and analyses of the underlying processes concerning hydrodynamics, sediment transport and morphology were a main objective. For the first time the instantaneous bed shear stress was measured directly in a gravel bed river. The probability distributions of the occurring bed shear stress, showed a dependency on the turbulence intensity, either following a log-normal or a normal distribution. Those fluctuations seem to be one of the reasons for a notable bed load transport, measured during low flow conditions in the Danube. The effective discharge lies in a discharge range from 2000 to 2200 m3/s, with 50% of the bed load being transported at discharges up to 2300 m3/s and an annual bed load transport between 306,000 and 594,000 tons for the years 2006 to 2014. Regarding the transport behaviour of single tracer stones 74% passed the 3 km long reach within one year, with a virtual velocity between 6,2 and 10,6 m/d. Small stones moved more frequent and farther, compared to the medium and big stones, who showed a comparable transport behaviour. In comparison gravel dunes moving with 2,59 m/h have a substantially higher velocity, and tend to dominate the bed load transport process when occurring.(VLID)136346

Tripropylendiaminchromasalze

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Activation of Slo2.1 channels by niflumic acid

Slo2.1 channels conduct an outwardly rectifying K+ current when activated by high [Na+]i. Here, we show that gating of these channels can also be activated by fenamates such as niflumic acid (NFA), even in the absence of intracellular Na+. In Xenopus oocytes injected with <10 ng cRNA, heterologously expressed human Slo2.1 current was negligible, but rapidly activated by extracellular application of NFA (EC50 = 2.1 mM) or flufenamic acid (EC50 = 1.4 mM). Slo2.1 channels activated by 1 mM NFA exhibited weak voltage dependence. In high [K+]e, the conductance–voltage (G-V) relationship had a V1/2 of +95 mV and an effective valence, z, of 0.48 e. Higher concentrations of NFA shifted V1/2 to more negative potentials (EC50 = 2.1 mM) and increased the minimum value of G/Gmax (EC50 = 2.4 mM); at 6 mM NFA, Slo2.1 channel activation was voltage independent. In contrast, V1/2 of the G-V relationship was shifted to more positive potentials when [K+]e was elevated from 1 to 300 mM (EC50 = 21.2 mM). The slope conductance measured at the reversal potential exhibited the same [K+]e dependency (EC50 = 23.5 mM). Conductance was also [Na+]e dependent. Outward currents were reduced when Na+ was replaced with choline or mannitol, but unaffected by substitution with Rb+ or Li+. Neutralization of charged residues in the S1–S4 domains did not appreciably alter the voltage dependence of Slo2.1 activation. Thus, the weak voltage dependence of Slo2.1 channel activation is independent of charged residues in the S1–S4 segments. In contrast, mutation of R190 located in the adjacent S4–S5 linker to a neutral (Ala or Gln) or acidic (Glu) residue induced constitutive channel activity that was reduced by high [K+]e. Collectively, these findings indicate that Slo2.1 channel gating is modulated by [K+]e and [Na+]e, and that NFA uncouples channel activation from its modulation by transmembrane voltage and intracellular Na+

Rhegmatogenous retinal detachment in Scotland: research design and methodology

<p>Abstract</p> <p>Background</p> <p>Rhegmatogenous retinal detachment (RRD) is a potentially blinding condition and a common cause of ocular morbidity. Establishing an accurate estimate of disease incidence and distribution is an important first step in assessing the healthcare burden related to this condition and in subsequent planning and provision of treatment strategies. The aim of this study is to obtain a first estimate incidence of RRD in Scotland, to estimate the incidence of familial RRD and to describe the known associations of RRD within the study population.</p> <p>Methods/Design</p> <p>We have established a national prospective observational study seeking to identify and recruit all incident cases of RRD in the Scottish population over a 2 year period. After fully informed consent, all participants will have a blood sample taken and a full medical history and clinical examination performed including visual acuity, refraction, slit-lamp examination, intra-ocular pressure measurement and detailed fundal examination. We describe the study design and protocol.</p> <p>Conclusion</p> <p>This study will provide the first estimate of the annual incidence of RRD in Scotland. The findings of this study will be important in estimating the burden of disease and in the planning of future health care policy related to this condition. This study will also establish a genetic resource for a genome wide association study to investigate if certain genetic variants predispose to RRD.</p

Klein Venedig : Landhaus bei Zürich

gez. v. Haimann ; [D.A. Schmid del.

Supervision : concepts and practices of management

411 p. : 25 cm