Biographien und Alltag von Spitzenmusikern

Die erste Untersuchung aus dem Projekt "Peak Performance" ist abgeschlossen, und an anderer Stelle ausführlicher beschrieben (ERICSSON, KRAMPE & TESCH-RÖMER, 1990). Die Autoren skizzieren in diesem Beitrag ihre Untersuchungsmethode und berichten einige Ergebnisse, die wichtige Aspekte ihres theoretischen Modells überprüfbar machen. (DIPF/Orig.

Laser-induced periodic surface structures:Fingerprints of light localization

The finite-difference time-domain (FDTD) method is used to study the inhomogeneous absorption of linearly polarized laser radiation below a rough surface. The results are first analyzed in the frequency domain and compared to the efficacy factor theory of Sipe and coworkers. Both approaches show that the absorbed energy shows a periodic nature, not only in the direction orthogonal to the laser polarization, but also in the direction parallel to it. It is shown that the periodicity is not always close to the laser wavelength for the perpendicular direction. In the parallel direction, the periodicity is about lambda/Re((n) over tilde), with (n) over tilde being the complex refractive index of the medium. The space-domain FDTD results show a periodicity in the inhomogeneous energy absorption similar to the periodicity of the low-and high-spatial-frequency laser-induced periodic surface structures depending on the material's excitation

Specific In Vivo Staining of Astrocytes in the Whole Brain after Intravenous Injection of Sulforhodamine Dyes

Fluorescent staining of astrocytes without damaging or interfering with normal brain functions is essential for intravital microscopy studies. Current methods involved either transgenic mice or local intracerebral injection of sulforhodamine 101. Transgenic rat models rarely exist, and in mice, a backcross with GFAP transgenic mice may be difficult. Local injections of fluorescent dyes are invasive. Here, we propose a non-invasive, specific and ubiquitous method to stain astrocytes in vivo. This method is based on iv injection of sulforhodamine dyes and is applicable on rats and mice from postnatal age to adulthood. The astrocytes staining obtained after iv injection was maintained for nearly half a day and showed no adverse reaction on astrocytic calcium signals or electroencephalographic recordings in vivo. The high contrast of the staining facilitates the image processing and allows to quantify 3D morphological parameters of the astrocytes and to characterize their network. Our method may become a reference for in vivo staining of the whole astrocytes population in animal models of neurological disorders

Rapid Acoustic Survey for Biodiversity Appraisal

Biodiversity assessment remains one of the most difficult challenges encountered by ecologists and conservation biologists. This task is becoming even more urgent with the current increase of habitat loss. Many methods–from rapid biodiversity assessments (RBA) to all-taxa biodiversity inventories (ATBI)–have been developed for decades to estimate local species richness. However, these methods are costly and invasive. Several animals–birds, mammals, amphibians, fishes and arthropods–produce sounds when moving, communicating or sensing their environment. Here we propose a new concept and method to describe biodiversity. We suggest to forego species or morphospecies identification used by ATBI and RBA respectively but rather to tackle the problem at another evolutionary unit, the community level. We also propose that a part of diversity can be estimated and compared through a rapid acoustic analysis of the sound produced by animal communities. We produced α and β diversity indexes that we first tested with 540 simulated acoustic communities. The α index, which measures acoustic entropy, shows a logarithmic correlation with the number of species within the acoustic community. The β index, which estimates both temporal and spectral dissimilarities, is linearly linked to the number of unshared species between acoustic communities. We then applied both indexes to two closely spaced Tanzanian dry lowland coastal forests. Indexes reveal for this small sample a lower acoustic diversity for the most disturbed forest and acoustic dissimilarities between the two forests suggest that degradation could have significantly decreased and modified community composition. Our results demonstrate for the first time that an indicator of biological diversity can be reliably obtained in a non-invasive way and with a limited sampling effort. This new approach may facilitate the appraisal of animal diversity at large spatial and temporal scales

Identification of alleles of carotenoid pathway genes important for zeaxanthin accumulation in potato tubers

We have investigated the genetics and molecular biology of orange flesh colour in potato (Solanum tuberosum L.). To this end the natural diversity in three genes of the carotenoid pathway was assessed by SNP analyses. Association analysis was performed between SNP haplotypes and flesh colour phenotypes in diploid and tetraploid potato genotypes. We observed that among eleven beta-carotene hydroxylase 2 (Chy2) alleles only one dominant allele has a major effect, changing white into yellow flesh colour. In contrast, none of the lycopene epsilon cyclase (Lcye) alleles seemed to have a large effect on flesh colour. Analysis of zeaxanthin epoxidase (Zep) alleles showed that all (diploid) genotypes with orange tuber flesh were homozygous for one specific Zep allele. This Zep allele showed a reduced level of expression. The complete genomic sequence of the recessive Zep allele, including the promoter, was determined, and compared with the sequence of other Zep alleles. The most striking difference was the presence of a non-LTR retrotransposon sequence in intron 1 of the recessive Zep allele, which was absent in all other Zep alleles investigated. We hypothesise that the presence of this large sequence in intron 1 caused the lower expression level, resulting in reduced Zep activity and accumulation of zeaxanthin. Only genotypes combining presence of the dominant Chy2 allele with homozygosity for the recessive Zep allele produced orange-fleshed tubers that accumulated large amounts of zeaxanthin

Microstructural characterization of surface damage through ultra-short laser pulses

Electron back-scatter diffraction (EBSD) technique, commonly used to study the microstructural characteristics of materials, was employed for the investigation of the surface damage induced through ultra-short laser pulses. Single-crystal silicon surface was irradiated with an Ytterbium-doped YAG (Trumpf-TruMicro 5050) laser source generating laser pulses of 6.7 ps duration, a 1030 nm wavelength and linear polarization. The laser fluence level was set to values lower than the single-pulse modification threshold of the material. The laser pulses were delivered on the surface at conditions of lateral displacement, i.e. a train of laser pulses with a partial overlap (laser track). This approach made it possible to investigate the early stages of modification of the surface. Scanning electron microscope equipped with a field emission gun (Philips XL30 SEM FEG) and EDAX-TSL EBSD system was used for inspection of the surface modifications initiated with pulsed laser radiation. Depth of the generation of back-scattered electrons at different acceleration voltages of the primary beam was estimated by the use of Monte-Carlo simulation. Trajectories of primary and back-scattered electrons in a flat Si surface were generated at an angle of 74° from the surface normal, which is the angle used for the EBSD observations. High sensitivity of EBSD signal allows an estimate of the depth and intensity of the laser induced damage to the crystal lattice. It is found that the thickness of amorphous layer increases gradually with a distance from the feature center. The similarity of surface damage profiles observed at different accelerating voltages of the primary beam indicates that the damage is formed via a gradual crystal damage accumulation in subsurface layer and via the formation and growth of an amorphous layer from the surface.<br/