Testing Modified Newtonian Dynamics with Rotation Curves of Dwarf and Low Surface Brightness Galaxies

Dwarf and low surface brightness galaxies are ideal objects to test modified Newtonian dynamics (MOND), because in most of these galaxies the accelerations fall below the threshold below where MOND supposedly applies. We have selected from the literature a sample of 27 dwarf and low surface brightness galaxies. MOND is successful in explaining the general shape of the observed rotation curves for roughly three quarters of the galaxies in the sample presented here. However, for the remaining quarter, MOND does not adequately explain the observed rotation curves. Considering the uncertainties in distances and inclinations for the galaxies in our sample, a small fraction of poor MOND predictions is expected and is not necessarily a problem for MOND. We have also made fits taking the MOND acceleration constant, a_0, as a free parameter in order to identify any systematic trends. We find that there appears to be a correlation between central surface brightness and the best-fit value of a_0, in the sense that lower surface brightness galaxies tend to have lower a_0. However, this correlation depends strongly on a small number of galaxies whose rotation curves might be uncertain due to either bars or warps. Without these galaxies, there is less evidence of a trend, but the average value we find for a_0 ~ 0.7*10^-8 cm s^-2 is somewhat lower than derived from previous studies. Such lower fitted values of a_0 could occur if external gravitational fields are important.Comment: 12 pages, accepted for publication in Ap

Over ‘sexed’ regulation and the disregarded worker: an overview of the impact of sexual entertainment policy on lap-dancing club workers

In England and Wales, with the introduction of Section 27 of the Policing and Crime Act 2009, lap-dancing clubs can now be licensed as Sexual Entertainment Venues. This article considers such, offering a critique of Section 27, arguing that this legislation is not evidence-based, with lap-dancing policy, like other sex-work policies, often associated with crime, deviance and immorality. Furthermore, it is argued that sex-work policies are gradually being homogenised as well as increasingly criminalised. Other criticisms relate to various licensing loopholes which lead to some striptease venues remaining unlicensed and unregulated, potentially impacting on the welfare of erotic dancers. In addition, restrictions on the numbers of lap-dancing venues may exacerbate dancer unemployment, drawing these women into poverty. Finally, The Policing and Crime Act reflects how the political focus is being directed away from the exploitation of workers, on to issues relating to crime and deviance, despite limited evidence to support this focus

Training, Task Flexibility and Low-Skilled Workers' Employability

In this paper we analyse whether the training participation and task flexibility of low-skilled workers contribute to their firm-internal and external mobility. We find that both workers’ training participation and task flexibility merely contribute to workers’ firm-internal employability. However, the workers’ participation in training plays a much more explicit role in workers’ firm-internal careers than their task flexibility as it appears to be an important means to enhance their opportunities on the firm-internal labour market. Both workers’ participation in training and their task flexibility do not contribute to the external employability of the low-skilled workers. Task flexible low-skilled workers even less often expect to be externally employable than non-task flexible workers. The focus of low-skilled workers on their firm-internal employability can be explained by the fact that they usually have more opportunities to improve their position in the firm-internal labour market than on the external labour market.education, training and the labour market;

Nonzero Classical Discord

Quantum discord is the quantitative difference between two alternative expressions for bipartite mutual information, given respectively in terms of two distinct definitions for the conditional entropy. By constructing a stochastic model of shared states, classical discord can be similarly defined, quantifying the presence of some stochasticity in the measurement process. Therefore, discord can generally be understood as a quantification of the system's state disturbance due to local measurements, be it quantum or classical. We establish an operational meaning of classical discord in the context of state merging with noisy measurement and thereby show the quantum-classical separation in terms of a negative conditional entropy.Comment: Replaced by the published versio

Quantum Encodings in Spin Systems and Harmonic Oscillators

We show that higher-dimensional versions of qubits, or qudits, can be encoded into spin systems and into harmonic oscillators, yielding important advantages for quantum computation. Whereas qubit-based quantum computation is adequate for analyses of quantum vs classical computation, in practice qubits are often realized in higher-dimensional systems by truncating all but two levels, thereby reducing the size of the precious Hilbert space. We develop natural qudit gates for universal quantum computation, and exploit the entire accessible Hilbert space. Mathematically, we give representations of the generalized Pauli group for qudits in coupled spin systems and harmonic oscillators, and include analyses of the qubit and the infinite-dimensional limits.Comment: 4 pages, published versio