A mathematical model for LH release in response to continuous and pulsatile exposure of gonadotrophs to GnRH

In a previous study, a model was developed to investigate the release of luteinizing hormone (LH) from pituitary cells in response to a short pulse of gonadotropin-releasing hormone (GnRH). The model included: binding of GnRH to its receptor (R), dimerization and internalization of the hormone receptor complex, interaction with a G protein, production of inositol 1,4,5-trisphosphate (IP(3)), release of calcium from the endoplasmic reticulum (ER), entrance of calcium into the cytosol via voltage gated membrane channels, pumping of calcium out of the cytosol via membrane and ER pumps, and release of LH. The extended model, presented in this paper, also includes the following physiologically important phenomena: desensitization of calcium channels; internalization of the dimerized receptors and recycling of some of the internalized receptors; an increase in G(q )concentration near the plasma membrane in response to receptor dimerization; and basal rates of synthesis and degradation of the receptors. With suitable choices of the parameters, good agreement with a variety of experimental data of the LH release pattern in response to pulses of various durations, repetition rates, and concentrations of GnRH were obtained. The mathematical model allows us to assess the effects of internalization and desensitization on the shapes and time courses of LH response curves

A Perfect Script? Manchester United's Class of ‘92

The Class of ’92 is a documentary film featuring six Manchester United F.C. players who recount their time during a pivotal period for the club, English football and English society. The documentary claims to offer a commentary on Britain in the 1990s, but appears, without acknowledging the fact, to be a promotional vehicle to establish the six men as a brand labeled the Class of ’92 (CO92). Creating this brand necessarily involved presenting a selective account of their time and places with the film being little more than an advertisement, masquerading as an observational documentary. The film draws freely upon the symbolic capital held by the club and the city of Manchester and uses the Busby Babes/Munich chapter and the more recent “Madchester scene” to forge the Class of ’92 brand by editing out those elements that did not accord with this project. The article argues that a more complete representation of ’90s Britain, while disrupting the intended narrative, would acknowledge the significant structural and commercial changes experienced by the club, the sport, and the city in the last decade of the 20th century. We suggest that the Class of ’92 invites the viewer to consider how the documentary film genre can contribute to brand development and promotion

Major Substructure in the M31 Outer Halo: the South-West Cloud

We undertake the first detailed analysis of the stellar population and spatial properties of a diffuse substructure in the outer halo of M31. The South-West Cloud lies at a projected distance of ~100 kpc from the centre of M31, and extends for at least ~50 kpc in projection. We use Pan-Andromeda Archaeological Survey photometry of red giant branch stars to determine a distance to the South-West Cloud of 793 +/- 45 kpc. The metallicity of the cloud is found to be [Fe/H] = -1.3 +/- 0.1. This is consistent with the coincident globular clusters PAndAS-7 and PAndAS-8, which have metallicities determined using an independent technique of [Fe/H] = -1.35 +/- 0.15. We measure a brightness for the Cloud of M_V = -12.1 mag; this is ~75 per cent of the luminosity implied by the luminosity-metallicity relation. Under the assumption that the South-West Cloud is the visible remnant of an accreted dwarf satellite, this suggests that the progenitor object was amongst M31's brightest dwarf galaxies prior to disruption.Comment: 13 pages, 9 figures, accepted for publication in MNRA

Mirror-Descent Methods in Mixed-Integer Convex Optimization

In this paper, we address the problem of minimizing a convex function f over a convex set, with the extra constraint that some variables must be integer. This problem, even when f is a piecewise linear function, is NP-hard. We study an algorithmic approach to this problem, postponing its hardness to the realization of an oracle. If this oracle can be realized in polynomial time, then the problem can be solved in polynomial time as well. For problems with two integer variables, we show that the oracle can be implemented efficiently, that is, in O(ln(B)) approximate minimizations of f over the continuous variables, where B is a known bound on the absolute value of the integer variables.Our algorithm can be adapted to find the second best point of a purely integer convex optimization problem in two dimensions, and more generally its k-th best point. This observation allows us to formulate a finite-time algorithm for mixed-integer convex optimization

Sports mega-events – three sites of contemporary political contestation

This article discusses the contemporary politics of sports mega-events, involving the Olympic Games and Fédération Internationale de Football Association (FIFA) Men’s Football World Cup Finals as well as other lower ‘order’ sports megas, taking two main forms: the promotional and the protest. There is a politics in, and a politics of, sports mega-events. The former focuses on the internal politics of the organizing bodies, such as the International Olympic Committee and FIFA. This form of politics has been written about elsewhere, and hence, there is no detailed discussion in this article about it. Instead this article offers a brief discussion of the range and number of sports mega-events since 2000, an assessment of the contemporary politics of sports mega-events, a focus on three main sites of political contestation – rights, legacy and labour, and finally, it offers conclusions about research into the politics of sports mega-events

Dust Properties in the FUV in Ophiuchus

We have derived the albedo ($a$) and phase function asymmetry factor ($g$) of interstellar dust grains at 1100 \AA ~ using archival {\it Voyager} observations of diffuse radiation in Ophiuchus. We have found that the grains are highly forward scattering with $g =$ 0.55 $\pm$ 0.25 and $a =$ 0.40 $\pm$ 0.10. Even though most of the gas in this direction is in the Ophiuchus molecular cloud, the diffuse FUV radiation is almost entirely due to scattering in a relatively thin foreground cloud. This suggests that one cannot assume that the UV background is directly correlated with the total amount of gas in any direction.Comment: 11 pages, 7 figures, 2 tables, ApJ, accepte

‘Trust me I am a Football Agent’. The discursive practices of the players’ agents in (un)professional football

While the public and media attention is largely focused on the corruption scandals of high-ranking officials in international football, FIFA’s decision in April 2015 to deregulate football agents raises further concerns about its ability for self-regulation and governance. FIFA’s introduction (2006) and subsequent updating (2008, 2015) of its regulations and legal frameworks governing the activity of agents in professional football has important implications on the inner workings of international football. In this regard, FIFA’s decision to deregulate the industry is perhaps a reflection of the neoliberal influences surrounding the organisation to let the agents govern themselves and deal with the wrongdoings of the alleged bribery, exploitation and trafficking of young players. However, the deregulation of agents by FIFA can also be seen as the organisation’s inefficiency to maintain the primacy of self-regulation and self-governance in serious matters of the industry, such as agents’ global leadership and regulation of practices. This paper, using qualitative data collected from players, agents and managers from professional football leagues in the UK and Ireland, aims to uncover the unethical, extremely complex and deceptive sides of the agents’ industry. By doing so, it aims to emphasise the need for gold standards of practice and leadership in the regulation of international football, which desperately needs to restore its integrity. Two key issues are unpacked: (i) the alleged (un)ethical behaviour of football agents that provokes so much hostility in the football world; (ii) the power shift(s) from clubs and managers to agents and players and the implications these may have on the ethics of the business practices in football