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We have observed and investigated random telegraph noise in the photoluminescence (PL) from small InP quantum dots (QDs) in GaInP. Very few of the QDs exhibit switching between two states, which have similar total intensities, but distinctly different spectra. Usually, one of the states dominates at low excitation power and the other at high excitation power. The switching occurs on the time scale
Variation in transpiration and conductance between individual trees of Scots pine and Norway spruce was investigated in a mixed 50-year-old stand in central Sweden. Daily transpiration rates were measured by the tissue heat balance method on five trees of each species during a dry, warm growing season. Daytime averages of sapflow, climatic variables and soil water content were used to fit an empir
This article outlines an experimental and numerical study of moisture in concrete subjected to air, water or sealed curing. For this purpose columns of eight qualities of concrete were studied at 3 different ages each over a period of 450 days. Parallel studies of hydration, internal relative humidity, self-desiccation and strength were carried out. Finally the article presents an analysis of the
PURPOSE: To study endovascular graft attachment with self-expanding Gianturco Z-stents and balloon-expanded Palmaz stents and the effect of these devices on the renal ostia. METHODS: Ten stent-grafts were constructed, 5 with Gianturco Z-stents and 5 with Palmaz stents. The endografts were implanted under fluoroscopic guidance into the abdominal aorta of 10 pigs so that the uncovered portion of the
Recently, it has been suggested that at least somekinds of mental representation are strongly context-dependent. Not only what is represented, but also how, depends on the context and the subject's interaction with it. Theories about situated cognition stress the importance of the subject's bodily presence and physical activity in the environment for representing and thinking. What does this mean
Purpose: We report tong-term effects of vagus nerve stimulation (VNS) on epileptiform activity in 15 children, and how these changes are related to activity stage and to clinical effects on seizure reduction, seizure severity (NHS3) and quality of life (QOL). Methods: Initially, and after 3 and 9 months of VNS-treatment, 15 children were investigated with 24 h ambulatory EEG monitoring for spike d
The influence of experimental errors on the determination of flux control coefficients from transient metabolite concentrations with the method proposed by Delgado and Liao [(1992) Biochem. J. 282, 919-927] has been investigated by using Monte Carlo simulations. The method requires least-squares fitting of the transient metabolite concentrations. Three different fitting methods have been evaluated
The level crossing method has been used for the investigation of the hyperfine structure of the 6p2P3/2 and 7p2P3/2 levels of the isotopes Cs133, Cs135, and Cs137. For the hyperfine coupling constants a and b and for the lifetimes ? we find: a(6p Cs133)=50.72(3) gJ/-1.345, b(6p Cs133)=-0.38(18) gJ/-1.345 a(7p Cs133)=16.610(6) gJ/-1.3349, b(7p Cs133)=-0.15(3) gJ/-1.3349 a(6p Cs135)=53.64(4) gJ/-1.3
We present an ab initio study of the n --> pi(*) electronic excitation energy together with the corresponding oscillator strength and rotatory strength tensor for two optically active cyclopropanone related structures: S,S-dimethylcyclopropanone and R,R-t-butylcyclopropanone. We discuss and compare the available experimental data for the n --> pi(*) electronic excitation energy and rotatory streng
The number-size distribution and hygroscopic growth of submicrometer aerosol particles were measured in central Amazonia during the first Cooperative LBA Airborne Regional Experiment (CLAIRE) wet season experiment in March-April 1998. This was the first time ever that these types of measurements were performed in the Amazon rain forest. A Differential Mobility Particle Sizer (DMPS) was used to mea
An easy and rapid hollow-fibre supported liquid membrane method (HFSLM) has been developed to extract and determinate the total concentration of four dinitrophenols in environmental water at ng L-1 level. This extraction method provides a high selectivity, short extraction time and very low cost for real samples. It is a three-phase system, aqueous-organic-aqueous, where the organic solvent is hel
The effect of preganglionic sympathetic nerve stimulation on mucociliary activity in the rabbit maxillary sinus was investigated in vivo. Response to nerve stimulation was recorded photoelectrically and expressed as a percentage of the basal mucociliary activity prior to stimulation. Nerve stimulation (15 V, 5 ms) for 60 s at 2, 10 and 20 Hz stimulated mucociliary activity, the maximum increase be
