Using Different Approaches to Evaluate Individual Social Equity in Transport

Inequalities not only exist in the field of economics in relation to income and wealth, but also in other areas, such as the transport sector, where access to and use of different transport modes varies markedly across population groups, and which provides the means to access everyday living activities. A key concern within the transport sector is that inequality has extended beyond the traditional measures of travel, and now covers a wide range of effects relating to social exclusion, freedom, well-being and being able to access reasonable opportunities and resources. In order to address the aforementioned issues, an important question to resolve is what type of methods can be used to measure inequalities in transport most effectively. Therefore, this study aims to apply different approaches, including the Capabilities Approach (CA) and a further six inequality indices, namely the Gini coefficient, the Atkinson index, the Palma ratio, the Pietra ratio, the Schutz coefficient and the Theil index, to the case study using the relatively migrant-rich lower-income neighbourhood of Tuqiao, in Beijing, in order to assess individual transport-related social inequity issues. The findings suggest that the CA is useful in assessing transport-related inequalities where there are significant barriers to the take up of accessibility, for example where there are high levels of disadvantaged groups and disaggregated analysis can be undertaken. The Palma ratio appears to have a larger effect than the Gini coefficient and the other inequality indices when measuring transport-related social inequity. In addition, we also found that most income inequality methods adapted from econometrics may be better suited to measuring transport-related social inequity between different regions, cities or countries, or within the same area, but at different points in time, rather than to measuring a single neighbourhood as a whole. Finally, we argue that to what extent politicians or transport planners can use appropriate management tools to measure transport-related social inequalities may be significant in terms of the progress that can be made in the fight against social inequity in the transport field

Electronic state and superconductivity of YBa2Cu3-xO7-y (M=Al,Zn and Sn) systems

A series of YBa2Cu(3-x)MxO(7-y) (M=Al,Zn and Sn) single phase samples were prepared, and the measurements of the crystal structure, oxygen content, electric resistivity, thermoelectric power, Mossbauer spectrum, XPS and superconductivity were performed. The experimental results of X ray powder diffraction, Mossbauer spectrum and oxygen content show that the Zn(2+) and the Al(3+) occupy the Cu(2) site in Cu-O planes and the Cu(1) site in Cu-O chains respectively, but the Sn(4+) occupies both the Cu(1) sites. As regards the properties in superconducting state, both the Zn(2+) and the Al(3+) depress T(sub c) strongly, but the Sn(4+) does not. As for the electronic transport properties in normal state, the system doped by Al(3+) displays a rapid increase of resistivity and some electron localization-like effects, and the thermoelectric power enhances obviously; the series contained Zn(2+) almost shows no changes of electric resistivity but the sign of the thermoelectric power is reversed. Other results are given and briefly discussed

The structural, mechanical, electronic, optical and thermodynamic properties of t-X3_{3}As4_{4} (X == Si, Ge and Sn) by first-principles calculations

The structural, mechanical, electronic, optical and thermodynamic properties of the t-X$_{\mathrm{3}}$As$_{\mathrm{4}}$ (X $=$ Si, Ge and Sn) with tetragonal structure have been investigated by first principles calculations. Our calculated results show that these compounds are mechanically and dynamically stable. By the study of elastic anisotropy, it is found that the anisotropic of the t-Sn$_{\mathrm{3}}$As$_{\mathrm{4}}$ is stronger than that of t-Si$_{\mathrm{3}}$As$_{\mathrm{4}}$ and t-Ge$_{\mathrm{3}}$As$_{\mathrm{4}}$. The band structures and density of states show that the t-X$_{\mathrm{3}}$As$_{\mathrm{4}}$ (Si, Ge and Sn) are semiconductors with narrow band gaps. Based on the analyses of electron density difference, in t-X$_{\mathrm{3}}$As$_{\mathrm{4}}$ As atoms get electrons, X atoms lose electrons. The calculated static dielectric constants, $\varepsilon_{1} (0)$, are 15.5, 20.0 and 15.1 eV for t-X$_{\mathrm{3}}$As$_{\mathrm{4}}$ (X $=$ Si, Ge and Sn), respectively. The Dulong-Petit limit of t-X$_{\mathrm{3}}$As$_{\mathrm{4}}$ is about 10 J mol$^{\mathrm{-1}}$K$^{\mathrm{-1}}$. The thermodynamic stability successively decreases from t-Si$_{\mathrm{3}}$As$_{\mathrm{4}}$ to t-Ge$_{\mathrm{3}}$As$_{\mathrm{4}}$ to t-Sn$_{\mathrm{3}}$As$_{\mathrm{4}}$.Comment: 14 pages, 10 figures, 6 table

Anomalous Currents on Closed Surfaces: Extended Proximity, Partial Quantization, and Qubits

Motivated by the surface of topological insulators, the Dirac anomaly's discontinuous dependence on sign of the mass, $m/|m|$, is investigated on closed topologies when mass terms are weak or only partially cover the surface. It is found that, unlike the massive Dirac theory on an infinite plane, there is a smoothly decreasing current when the mass region is not infinite; also, a massive finite region fails to exhibit a Hall current edge--exerting an extended proximity effect, which can, however, be uniformly small--and oppositely orientated Hall phases are fully quantized while accompanied by diffuse chiral modes. Examples are computed using Dirac energy eigenstates on a flat torus (genus one topology) and closed cap cylinder (genus zero topology) for various mass-term geometries. Finally, from the resulting the properties of the surface spectra, a potential application for a flux-charge qubit is presented.Comment: 22 pages, 13 figures. References and focus updated. Added effective action arguments. Same text as published versio

Modified Bethe-Peierls boundary condition for ultracold atoms with Spin-Orbit coupling

We show that the Bethe-Peierls (BP) boundary condition should be modified for ultracold atoms with spin-orbit (SO) coupling. Moreover, we derive a general form of the modified BP boundary condition, which is applicable to a system with arbitrary kind of SO coupling. In the modified BP condition, an anisotropic term appears and the inter-atomic scattering length is normally SO-coupling dependent. For the special system in the current experiments, however, it can be proved that the scattering length is SO-coupling independent, and takes the same value as in the case without SO coupling. Our result is helpful for the study of both few-body and many-body physics in SO-coupled ultracold gases.Comment: 8 pages, significant improvement is made in the current versio

Helium Recombination Lines as a Probe of Abundance and Temperature Problems

The paper presents a simplified formula to determine an electron temperature, Te(He I), for planetary nebulae (PNe) using the He I 7281/6678 line flux ratio. In our previous studies of Te(He I) (Zhang et al. 2005), we used the He I line emission coefficients given by Benjamin et al. (1999). Here we examine the results of using more recent atomic data presented by Porter et al. (2005). A good agreement is shown, suggesting that the effect of uncertainties of atomic data on the resultant Te(He I) is negligible. We also present an analytical formula to derive electron temperature using the He I discontinuity at 3421 A. Our analysis shows that Te(He I) values are significantly lower than electron temperatures deduced from the Balmer jump of H I recombination spectra, Te(H I), and that inferred from the collisionally excited [O III] nebular-to-auroral forbidden line flux ratio, Te([O III]). In addition, Te(H I) covers a wider range of values than either Te(He I) or Te([O III]). This supports the two-abundance nebular model with hydrogen-deficient material embedded in diffuse gas of a ``normal'' chemical composition (i.e. ~solar).Comment: 5 pages, 3 figures. To appear in the RevMexAA proceedings of "The Ninth Texas-Mexico Conference on Astrophysics