Influence of excited electron lifetimes on the electronic structure of carbon nanotubes

We have studied the dynamics of electrons in single wall carbon nanotubes using femtosecond time-resolved photoemission. The lifetime of electrons excited to the pi* bands is found to decrease continuously from 130 fs at 0.2 eV down to less than 20 fs at energies above 1.5 eV with respect to the Fermi level. This should lead to a significant lifetime--induced broadening of the characteristic van Hove singularities in the nanotube DOS.Comment: 6 pages, 4 figure

Physisorption of molecular oxygen on single-wall carbon nanotube bundles and graphite

We present a study on the kinetics of oxygen adsorption and desorption from single-wall carbon nanotube (SWNT) and highly oriented pyrolytic graphite (HOPG) samples. Thermal desorption spectra for SWNT samples show a broad desorption feature peaked at 62 K which is shifted to significantly higher temperature than the low-coverage desorption feature on HOPG. The low-coverage O2 binding energy on SWNT bundles, 18.5 kJ/mol, is 55% higher than that for adsorption on HOPG, 12.0 kJ/mol. In combination with molecular mechanics calculations we show that the observed binding energies for both systems can be attributed to van der Waals interactions, i.e. physisorption. The experiments provide no evidence for a more strongly bound chemisorbed species or for dissociative oxygen adsorption.Comment: 7 pages, 5 figures, 1 tabl

Iraq and Afghanistan veterans’ experiences living with their parents after separation from the military

When military service members separate from the military, many return to their families of origin, living with their parents for a period of several weeks to years. While research with veterans and their spouses has documented the particular strain of this reintegration period on veterans and their partners, little research to date has examined veterans’ experiences living with their parents. The present study sought to fill this research gap by investigating veterans’ experiences living with their parents using qualitative, in-depth interviews with Iraq and Afghanistan veterans in California. Overall, veterans appreciated the instrumental and emotional support their parents provided when they separated. However, in some cases, living with parents also produced conflict and strain. In situations where adult veteran children had difficulty with the transition to civilian life or returned with mental health problems, parents were often the first to identify these problems and to support their children in accessing appropriate care. We analyze these findings in light of family systems theory, identifying ways in which adult veteran children continue a process of differentiation while living with their parents and maintaining emotional connectedness. We suggest ways that clinicians can better support veterans and their parents through the reintegration period and recommend that programming for military families explicitly include parents of service members in addition to conjugal families

Killing for Trophies: An Analysis of Global Trophy Hunting Trade

As the trophy hunting industry has grown over the last few decades, governments, conservationists, and animal welfare advocates are keen to understand its global economic and conservation impacts with data as supporting evidence. Unfortunately, little credible research had been done to understand the global trophy industry's extent and impact..This report is a result of a comprehensive analysis of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) Trade Database. This analysis can serve as a baseline for more study on how trophy hunting is changing and how the global industry ultimately affects animals and their populations, both regionally and globally

Dynamical signatures of topological order in the driven-dissipative Kitaev chain

We investigate the effects of dissipation and driving on topological order in superconducting nanowires. Rather than studying the non-equilibrium steady state, we propose a method to classify and detect dynamical signatures of topological order in open quantum systems. Bulk winding numbers for the Lindblad generator $\hat{\mathcal{L}}$ of the dissipative Kitaev chain are found to be linked to the presence of Majorana edge master modes -- localized eigenmodes of $\hat{\mathcal{L}}$. Despite decaying in time, these modes provide dynamical fingerprints of the topological phases of the closed system, which are now separated by intermediate regions where winding numbers are ill-defined and the bulk-boundary correspondence breaks down. Combining these techniques with the Floquet formalism reveals higher winding numbers and different types of edge modes under periodic driving. Finally, we link the presence of edge modes to a steady state current.Comment: Submission to SciPost. 29 pages, 8 figure

Marc H. Lerner, A Laboratory of Liberty. The Transformation of Political Culture in Republican Switzerland, 1750-1848. (Studies in Central European Histories, Vol. 54.) Leiden/Boston, Brill 2012

DBP 121