Dynamics of one-dimensional electron systems

We investigate the separation of spin and charge in interacting one-dimensional fermion systems. Density matrix renormalisation group (DMRG) simulations on the Hubbard model in the time domain show this phenomenon explicitely in a transport scenario. The separation of internal degrees of freedom and charge even remains when extending the problem to SU(3) fermions. Additionally, identifying signatures for spinon and holon are found for the momentum-dependent spectral function in a magnetic field

Effect of High Dose Spironolactone and Chlorthalidone in Essential Hypertension: Relation to Plasma Renin Activity and Plasma Volume

The effect on blood pressure of high (400 mg/day-S400) and moderate dose (200 mg/day-S200) spironolactone and chlorthalidone (100 mg/day—C100), given in a random double-blind manner was related to plasma renin activity and plasma volume in 38 essential hypertensives. The fall in pressure from a control of 154/103 mm Hg was essentially the same after four weeks of each drug—S400 ABP 24/13 mm, S200 18/9 mm, C100 17/12 mm (all P < 0–001). Twelve of 37 patients (32%) had low initial renin, but this appeared as responsive to the chlorthalidone stimulus as that of the normal renin group. The anti-hypertensive effect of all regimens was unrelated to plasma renin activity. Plasma volume was significantly lowered at the end of each treatment period, but the decline could not be correlated with blood pressure effects. Patients with initially low plasma volume were more likely to respond to S400 ( r = 0.545, P < 0.01), whereas the anti-hypertensive effect of the S200 and C100 regimens was independent of this variable.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73411/1/j.1445-5994.1975.tb03249.x.pd

Real-time contour holography using BSO crystals

Contour holography can be a powerful tool for contactless measurements. Its application in real time is even more useful for the engineer. The BSO crystal was found to be appropriate for real-time contour holography using two wavelengths

Contribution to the automatic fringe analysis using Zernike polynomials

Bei der automatischen Messung und anschließenden analytischen Darstellung von Phasenfrontdifferenzen in Zweistrahlinterferometern erhebt sich das Problem der Verteilung der Meßpunkte über das Interferogramm. Die Anzahl und Anordnung der StützsteIlen beeinflußt stark die Varianz der Koeffizienten einer Zernike-Entwicklung der Phasenfront. Da zur Messung von Phasenfronten mit großen Gradienten &#948;&#968;/&#948;&#967; und &#948;&#967;/&#948;&#947; die Stützstellen sehr eng gelegt werden müssen, wird eine Kombination aus lokaler und globaler ausgleichender Interpolation vorgeschlagen, bei der die Entwicklungskoeffizienten mit hoher Genauigkeit bei kurzen Rechenzeiten ermittelt werden können.When measuring wavefront-differences in two-beam interferometers the distribution problem of the sampling points arises. The mean square of the coefficients of a Zernike polynomial fit is strongly influenced by the number and location of sampling points. Wavefronts with big gradients demand high density of sampling point distribution. A combination of local and global interpolation is proposed, where the coefficients are determined with high precision and short computing time

THE EFFECT OF PROPRANOLOL ON PLASMA RENIN ACTIVITY AND BLOOD PRESSURE IN MILD ESSENTIAL HYPERTENSION

Fourteen male patients with mild to moderate essential hypertension have been studied with regard to plasma renin activity (PRA) after acute and prolonged Β-adrenergic blockade with propranolol. Initial PRA was determined after four weeks of placebo treatment. Before propranolol was given PRA rose in response to 10 min of 45° head-up tilt from 151.7 ng/100 ml/h to 248.7 ng/100 ml/h ( p <0.01). After acute administration of propranolol 0.22 mg/kg b.wt. i.v. and following repeated tilt for 10 min PRA only rose to 204.7 ng/100 ml/h (n.s.). Following four weeks of oral propranolol treatment at 160–320 mg daily PRA after tilt was 39.0 ng/100 ml/h. Thus a significant reduction of PRA had taken place ( p < 0.005) to a level constituting only 15% of the initial PRA after tilt. The reduction of blood pressure (BP) after four weeks of propranolol treatment was also significant. Diastolic BP was reduced by 19 mmHg( p < 0.001). The changes in BP and tilted PRA were not significantly correlated ( r =0.449, p <0.10). These results indicate that propranolol causes a marked reduction of PRA in addition to its hypotensive effect. However, this does not necessarily imply that there is a direct causal relationship between the effect of propranolol on PRA and its effect on BP.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73325/1/j.0954-6820.1974.tb08159.x.pd

Doppelheterodyn-Interferometrie für hochgenaue Vermessung im Nahbereich

In diesem Aufsatz wurde ein Meßsystem vorgestellt, welches sich aus der Kombination der Zweiwellenlängen-Interferometrie mit dem intensitätsunabhängigen Heterodyn-Verfahren zusammensetzt. Die resultierende Doppelheterodyn-Interferometrie vereinigt die Vorteile der beiden Verfahren. Ein großer Eindeutigkeitsbereich entsprechend der effektiven Wellenlänge A entsteht, darüberhinaus sind optisch rauhe Oberflächen als Meßobjekte zulässig; reduzierte Empfindlichkeit gegenüber Vibrationen und Umwelteinflüssen, hohe Auflösung infolge elektronischer Phasenbestimmung sowie hochgenaue Abstandsmessung in Echtzeit sind weitere Vorteile. Das Doppelheterodyn-Interferometer wird in Zukunft zu einem effektiven und dynamischen Meßinstrument zur hochgenauen Entfernungsmessung im Mikrometerbereich bis hin zu Meßdistanzen von 100 m entwickelt werden, für das sich schon jetzt zahlreiche Einsatzmöglichkeiten abzeichnen