147 resultados para First Coalition, War of the, 1792-1797
Resumo:
The nitrogen-vacancy (NV) center is a paramagnetic defect in diamond with applications as a qubit. Here, we investigate its electronic structure by using ab initio density functional theory for five different NV center models of two different cluster sizes. We describe the symmetry and energetics of the low-lying states and compare the optical frequencies obtained to experimental results. We compute the major transition of the negatively charged NV centers to within 25–100 meV accuracy and find that it is energetically favorable for substitutional nitrogens to donate an electron to NV0. The excited state of the major transition and the NV0 state with a neutral donor nitrogen are found to be close in energy.
Resumo:
We present near-infrared linear spectropolarimetry of a sample of persistent X-ray binaries, Sco X-1, Cyg X-2, and GRS 1915+105. The slopes of the spectra are shallower than what is expected from a standard steady state accretion disk, and can be explained if the near-infrared flux contains a contribution from an optically thin jet. For the neutron star systems, Sco X-1 and Cyg X-2, the polarization levels at 2.4 mu m are 1.3% +/- 0.10% and 5.4% +/- 0.7%, respectively, which is greater than the polarization level at 1.65 mu m. This cannot be explained by interstellar polarization or electron scattering in the anisotropic environment of the accretion flow. We propose that the most likely explanation is that this is the polarimetric signature of synchrotron emission arising from close to the base of the jets in these systems. In the black hole system GRS 1915+105 the observed polarization, although high (5.0% +/- 1.2% at 2.4 mu m), may be consistent with interstellar polarization. For Sco X-1 the position angle of the radio jet on the sky is approximately perpendicular to the near-infrared position angle (electric vector), suggesting that the magnetic field is aligned with the jet. These observations may be a first step toward probing the ordering, alignment, and variability of the outflow magnetic field in a region closer to the central accreting object than is observed in the radio band.
Resumo:
Charting the enduring export appeal of policing models from (Northern) Ireland, this article sheds some light on the processes by which policing models are communicated and actively promoted to the global policing environment. The authors demonstrate how the transplantation of the Irish colonial model (ICM) represents an early example of the globalization of policing. The legacy of counterinsurgency expertise embedded within the ICM remains a historical constant and is a key factor in relation to the increasing commodification of the contemporary Northern Irish policing model, a model that successfully blends counterterrorism experience with a template for democratic policing reform. By juxtaposing these models, the authors provide a conceptual framework through which to assess the contemporary substance of policing transfer. The authors conclude by suggesting that the seductiveness of these policing models is largely attributable to lessons in counterinsurgency and notions of "Ireland as the solution" to a host of complex security scenarios.