Influence of nanowire density on the shape and optical properties of ternary InGaAs nanowires

We have synthesized ternary InGaAs nanowires on (111)B GaAs surfaces by metal-organic chemical vapor deposition. Au colloidal nanoparticles were employed to catalyze nanowire growth. We observed the strong influence of nanowire density on nanowire height, tapering, and base shape specific to the nanowires with high In composition. This dependency was attributed to the large difference of diffusion length on (111)B surfaces between In and Ga reaction species, with In being the more mobile species. Energy dispersive X-ray spectroscopy analysis together with high-resolution electron microscopy study of individual InGaAs nanowires shows large In/Ga compositional variation along the nanowire supporting the present diffusion model. Photoluminescence spectra exhibit a red shift with decreasing nanowire density due to the higher degree of In incorporation in more sparsely distributed InGaAs nanowires.

Determination of the orientational distribution and orientation factor for transfer between membrane-bound fluorophores using a confocal microscope

Orientational fluorophores have been a useful tool in physical chemistry, biochemistry, and more recently structural biology due to the polarized nature of the light they emit and that fact that energy can be transferred between them. We present a practical scheme in which measurements of the intensity of emitted fluorescence can be used to determine limits on the mean and distribution of orientation of the absorption transition moment of membrane-bound. uorophores. We demonstrate how information about the orientation of. uorophores can be used to calculate the orientation factor k(2) required for use in FRET spectroscopy. We illustrate the method using images of AlexaFluor probes bound to MscL mechanosensitive transmembrane channel proteins in spherical liposomes.

The handbook of physical education

What is the current condition of the field of physical education? How has it adapted to the rise of kinesiology, sport and exercise science and human movement studies over the last thirty years? This Handbook provides an authoritative critical overview of the field and identifies future challenges and directions. The Handbook is divided in to six parts: - Perspectives and Paradigms in Physical Education Pedagogy Research; - Cross-disciplinary Contributions to Research on Physical Education; - Learners and Learning in Physical Education; - Teachers, Teaching and Teacher Education in Physical Education; - Physical Education Curriculum; - Difference and Diversity in Physical Education. This benchmark work is essential reading for educators and students in the field of physical education.

Using nitrogen stable isotope ratios ( d15N) of macroalgae to monitor changes in the extent of sewage impacts in Moreton Bay, Australia

During the past decade the use of stable isotopes to investigate transport pathways of nutrients in aquatic ecosystems has contributed new understanding and knowledge to many aspects of ecology; from the trophic structure of food webs to the spatial extent of nutrient discharges. At the same time aquatic monitoring programs around the world have become more interested in quantifying ecosystem health rather than simply measuring the physical and chemical properties of water (nutrients, pH, temperature and turbidity). A novel technique was initiated in 1998 as part of the development of the Ecosystem Health Monitoring Program in S.E. Queensland Australia (EHMP) using changes in the 15N value of the red macroalgae Catenella nipae, to indicate regions impacted by sewage nitrogen. Sewage plume mapping, using the 15N of C. nipae, has demonstrated that over the past 5 years there has been a large reduction in the magnitude and spatial extent of 15N enrichment at sites close to sewage treatment plants (STPs) discharging into Moreton Bay. This presentation will discuss how the 15N signatures of the C. nipae in the plume at the mouth of the Brisbane River have declined since it was first sampled in 1998 and will evaluate causes that may be responsible for these variations. A series of laboratory experiments were conducted to investigate how environmental conditions influence the 15N signature of C, nipae over the incubation period. These data will be used to discuss the observed in situ decline in 15N in an attempt to determine if the reduction can be attributed solely to improvements in the wastewater discharge.