Are Superhumps Good Measures of the Mass Ratio for AM CVn Systems?

We extend recent work that included the effect of pressure forces to derive the precession rate of eccentric accretion discs in cataclysmic variables to the case of double degenerate systems. We find that the logical scaling of the pressure force in such systems results in predictions of unrealistically high primary masses. Using the prototype AM CVn as a calibrator for the magnitude of the effect, we find that there is no scaling that applies consistently to all the systems in the class. We discuss the reasons for the lack of a superhump period to mass ratio relationship analogous to that known for SU UMa systems and suggest that this is because these secondaries do not have a single valued mass-radius relationship. We highlight the unreliability of mass-ratios derived by applying the SU UMa expression to the AM CVn binaries.Comment: 7 pages, 2 tables, to appear in Monthly Notices of the Royal Astronomical Societ

Don’t get involved: an examination of how public sector organisations in England are involving disabled people in the Disability Equality Duty

The Disability Equality Duty (DED) came into force in December 2006. It stipulated that all public sector organisations were to develop policies to promote the equality of disabled people as staff members, consumers or visitors. Its emergence comes as part of a network of social policies developed over the last 20 years to promote disability rights and citizenship in the UK. However unlike previous legislation, the DED set in place the need for organisations to be pro-active in their policies and work with disabled people to move towards change in public sector cultures and working practices. This article reports on this early stage of implementation in England. Findings show that whilst some progress has been made in securing change, practice varied greatly. Therefore if a fundamental change in the culture of work and service provision is to be secured, this key requirement will need to be given a higher priority by organisations

The rocks from space initiative and the space safari

This paper reports the successes of a new initiative in the UK using electronic resources, such as virtual learning environments and e-classrooms, for planetary and space science public engagement activities

Differentiation and Replication of Spots in a Reaction Diffusion System with Many Chemicals

The replication and differentiation of spots in reaction diffusion equations are studied by extending the Gray-Scott model with self-replicating spots to include many degrees of freedom needed to model systems with many chemicals. By examining many possible reaction networks, the behavior of this model is categorized into three types: replication of homogeneous fixed spots, replication of oscillatory spots, and differentiation from `m ultipotent spots'. These multipotent spots either replicate or differentiate into other types of spots with different fixed-point dynamics, and as a result, an inhomogeneous pattern of spots is formed. This differentiation process of spots is analyzed in terms of the loss of chemical diversity and decrease of the local Kolmogorov-Sinai entropy. The relevance of the results to developmental cell biology and stem cells is also discussed.Comment: 8 pages, 12 figures, Submitted to EP

An in-depth examination of the implementation of the Disability Equality Duty in England

This seven-month study examined the implementation of the Disability Equality Duty (DED) in England. The DED, introduced through the Disability Discrimination Act 2005, applies to public authorities in England, Wales and Scotland

Role of Landau-Rabi quantization of electron motion on the crust of magnetars within the nuclear energy density functional theory

Magnetic fields of order $10^{15}$ G have been measured at the surface of some neutron stars, and much stronger magnetic fields are expected to be present in the solid region beneath the surface. The effects of the magnetic field on the equation of state and on the composition of the crust due to Landau-Rabi quantization of electron motion are studied. Both the outer and inner crustal regions are described in a unified and consistent way within the nuclear-energy density functional theory.Comment: 23 pages, 11 figure

Prolactin delays hair regrowth in mice

Mammalian hair growth is cyclic, with hair-producing follicles alternating between active (anagen) and quiescent (telogen) phases. The timing of hair cycles is advanced in prolactin receptor (PRLR) knockout mice, suggesting that prolactin has a role in regulating follicle cycling. In this study, the relationship between profiles of circulating prolactin and the first post-natal hair growth cycle was examined in female Balb/c mice. Prolactin was found to increase at 3 weeks of age, prior to the onset of anagen 1 week later. Expression of PRLR mRNA in skin increased fourfold during early anagen. This was followed by upregulation of prolactin mRNA, also expressed in the skin. Pharmacological suppression of pituitary prolactin advanced dorsal hair growth by 3.5 days. Normal hair cycling was restored by replacement with exogenous prolactin for 3 days. Increasing the duration of prolactin treatment further retarded entry into anagen. However, prolactin treatments, which began after follicles had entered anagen at 26 days of age, did not alter the subsequent progression of the hair cycle. Skin from PRLR-deficient mice grafted onto endocrine-normal hosts underwent more rapid hair cycling than comparable wild-type grafts, with reduced duration of the telogen phase. These experiments demonstrate that prolactin regulates the timing of hair growth cycles in mice via a direct effect on the skin, rather than solely via the modulation of other endocrine factors