Carbon 1s photoelectron spectra for 2-butyne (CH3C CCH3) measured in the photon energy range from threshold to 150 eV above threshold show oscillations in the intensity ratio C2,3/C1,4. Similar oscillations have been seen in chloroethanes, where the effect has been attributed to EXAFS-type scattering from the substituent chlorine atoms. In...
The relationship between the index of refraction and the porosity of a material is that the index decreases with respect to the porosity. This property can be used to change the index of refraction of films which allows control of the reflection of the material. This is important because being...
The fact that measuring a quantum system reduces it to apparently classical behavior, eliminating the interference patterns that are a hallmark of quantumness, cries out for an explanation. That explanation has been provided by the recognition of decoherence,whereby the interference is destroyed by the very interaction that acquires information.We begin...
Coastal dunes are dynamic and unique ecosystems. On the Pacific coast, dunes are generally dominated by the beach grasses, Ammophila breviligulata and Ammophila arenaria, two invasive species introduced in the early 1900’s to stabilize sand and create foredunes that serve to protect people who live behind them. Recently, a novel...
Re-occlusion of arteries following percutaneous transluminal coronary angioplasty (PTCA) remains a post-operative issue in the treatment of artery blockage. This re-narrowing of the luminal cavity, a condition called restenosis, has been attributed to the injury induced by PTCA balloon insertion. While arterial recoil can be completely prevented by a coronary...
X-ray photoemission spectroscopy is used in a great variety of research fields; one observable is the sample's stoichiometry. The stoichiometry can be deduced based on the expectation that the ionization cross sections for innershell orbitals are independent of the molecular composition. Here we used chlorine-substituted ethanes in the gas phase...
Measurements of helium isotopes in particles separated from polar ice demonstrate that extraterrestrial ³He dominates the ³He flux at the GISP2 (Greenland) and Vostok (Antarctica) ice core sites. Replicate measurements of late Holocene ice samples yield ³He fluxes of 0.62±0.27×10⁻¹² cm³ STP cm⁻² ka⁻¹ (GISP2) and 0.77 ± 0.25 ×...
Mountain environments are currently among the ecosystems least invaded by non-native
species; however, mountains are increasingly under threat of non-native plant invasion.
The slow pace of exotic plant invasions in mountain ecosystems is likely due to a combination
of low anthropogenic disturbances, low propagule supply, and extreme/steep environmental
gradients. The...