An Optimal Control Formulation for Inviscid Incompressible Ideal Fluid Flow

In this paper we consider the Hamiltonian formulation of the equations of incompressible ideal fluid flow from the point of view of optimal control theory. The equations are compared to the finite symmetric rigid body equations analyzed earlier by the authors. We discuss various aspects of the Hamiltonian structure of the Euler equations and show in particular that the optimal control approach leads to a standard formulation of the Euler equations -- the so-called impulse equations in their Lagrangian form. We discuss various other aspects of the Euler equations from a pedagogical point of view. We show that the Hamiltonian in the maximum principle is given by the pairing of the Eulerian impulse density with the velocity. We provide a comparative discussion of the flow equations in their Eulerian and Lagrangian form and describe how these forms occur naturally in the context of optimal control. We demonstrate that the extremal equations corresponding to the optimal control problem for the flow have a natural canonical symplectic structure.Comment: 6 pages, no figures. To appear in Proceedings of the 39th IEEEE Conference on Decision and Contro

Eimeria tenella protein trafficking: differential regulation of secretion versus surface tethering during the life cycle

Eimeria spp. are intracellular parasites that have a major impact on poultry. Effective live vaccines are available and the development of reverse genetic technologies has raised the prospect of using Eimeria spp. as recombinant vectors to express additional immunoprotective antigens. To study the ability of Eimeria to secrete foreign antigens or display them on the surface of the sporozoite, transiently transfected populations of E. tenella expressing the fluorescent protein mCherry, linked to endogenous signal peptide (SP) and glycophosphatidylinositol-anchor (GPI) sequences, were examined. The SP from microneme protein EtMIC2 (SP2) allowed efficient trafficking of mCherry to cytoplasmic vesicles and following the C-terminal addition of a GPI-anchor (from surface antigen EtSAG1) mCherry was expressed on the sporozoite surface. In stable transgenic populations, mCherry fused to SP2 was secreted into the sporocyst cavity of the oocysts and after excystation, secretion was detected in culture supernatants but not into the parasitophorous vacuole after invasion. When the GPI was incorporated, mCherry was observed on the sporozites surface and in the supernatant of invading sporozoites. The proven secretion and surface exposure of mCherry suggests that antigen fusions with SP2 and GPI of EtSAG1 may be promising candidates to examine induction of protective immunity against heterologous pathogens

Viral proteins expressed in the protozoan parasite Eimeria tenella are detected by the chicken immune system

BACKGROUND: Eimeria species are parasitic protozoa that cause coccidiosis, an intestinal disease commonly characterised by malabsorption, diarrhoea and haemorrhage that is particularly important in chickens. Vaccination against chicken coccidiosis is effective using wild-type or attenuated live parasite lines. The development of protocols to express foreign proteins in Eimeria species has opened up the possibility of using Eimeria live vaccines to deliver heterologous antigens and function as multivalent vaccine vectors that could protect chickens against a range of pathogens. RESULTS: In this study, genetic complementation was used to express immunoprotective virus antigens in Eimeria tenella. Infectious bursal disease virus (IBDV) causes Gumboro, an immunosuppressive disease that affects productivity and can interfere with the efficacy of poultry vaccination programmes. Infectious laryngotracheitis virus (ILTV) causes a highly transmissible respiratory disease for which strong cellular immunity and antibody responses are required for effective vaccination. Genes encoding the VP2 protein from a very virulent strain of IBDV (vvVP2) and glycoprotein I from ILTV (gI) were cloned downstream of 5’Et-Actin or 5’Et-TIF promoter regions in plasmids that also contained a mCitrine fluorescent reporter cassette under control of the 5’Et-MIC1 promoter. The plasmids were introduced by nucleofection into E. tenella sporozoites, which were then used to infect chickens. Progeny oocysts were sorted by FACS and passaged several times in vivo until the proportion of fluorescent parasites in each transgenic population reached ~20 % and the number of transgene copies per parasite genome decreased to < 10. All populations were found to transcribe and express the transgene and induced the generation of low titre, transgene-specific antibodies when used to immunise chickens. CONCLUSIONS: E. tenella can express antigens of other poultry pathogens that are successfully recognised by the chicken immune system. Nonetheless, further work has to be done in order to improve the levels of expression for its future use as a multivalent vaccine vector. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13071-016-1756-2) contains supplementary material, which is available to authorized users

On the numeric integration of dynamic attitude equations

We describe new types of numerical integration algorithms developed by the authors. The main aim of the algorithms is to numerically integrate differential equations which evolve on geometric objects, such as the rotation group. The algorithms provide iterates which lie on the prescribed geometric object, either exactly, or to some prescribed accuracy, independent of the order of the algorithm. This paper describes applications of these algorithms to the evolution of the attitude of a rigid body

Classroom Demonstrations: Learning Tools Or Entertainment?

We compared student learning from different modes of presenting classroom demonstrations to determine how much students learn from traditionally presented demonstrations, and whether learning can be enhanced by simply changing the mode of presentation to increase student engagement. We find that students who passively observe demonstrations understand the underlying concepts no better than students who do not see the demonstration at all, in agreement with previous studies. Learning is enhanced, however, by increasing student engagement; students who predict the demonstration outcome before seeing it, however, display significantly greater understanding

'An Apotheosis of Well-Being': Durkheim on austerity and double-dip recessions

This article is an attempt to contribute a view on the economic crisis from classical sociology, a voice often missing from the sociological response to the crisis. The work of Émile Durkheim provides a unique perspective here centred on morality and inequality produced in a historical context akin to our neoliberal times. It is argued there are four key points to take from Durkheim’s work. Firstly, that the initial credit crunch can be more fully understood with reference to the economic anomie which Durkheim sees as ‘chronic’ in a time of marketization. Secondly, that this creates an antagonistic relationship between a supposedly self-dependent rich and lazy poor. Thirdly, this conception of self-dependency and individual initiative makes any attempt to regulate the economy akin to sacrilege. Finally, the state is unwilling to intervene due to the emergence of ‘pseudo-democracies’. Therefore, Durkheim’s theory accounts for the initial crisis, austerity and double-dip recessions in a sociological framework. The article concludes by returning to the centrality of morality to the crisis for Durkheim and highlighting the omission of this in contemporary debates

On the making and taking of professionalism in the further education workplace

This paper examines the changing nature of professional practice in English further education. At a time when neo-liberal reform has significantly impacted on this under-researched and over-market-tested sector, little is known about who its practitioners are and how they construct meaning in their work. Sociological interest in the field has tended to focus on further education practitioners as either the subjects of market and managerial reform or as creative agents operating within the contradictions of audit and inspection cultures. In challenging such dualism, which is reflective of wider sociological thinking, the paper examines the ways in which agency and structure combine to produce a more transformative conception of the further education professional. The approach contrasts with a prevailing policy discourse that seeks to re-professionalise and modernise further education practice without interrogating either the terms of its professionalism or the neo-liberal practices in which it resides

Existence of solutions for a higher order non-local equation appearing in crack dynamics

In this paper, we prove the existence of non-negative solutions for a non-local higher order degenerate parabolic equation arising in the modeling of hydraulic fractures. The equation is similar to the well-known thin film equation, but the Laplace operator is replaced by a Dirichlet-to-Neumann operator, corresponding to the square root of the Laplace operator on a bounded domain with Neumann boundary conditions (which can also be defined using the periodic Hilbert transform). In our study, we have to deal with the usual difficulty associated to higher order equations (e.g. lack of maximum principle). However, there are important differences with, for instance, the thin film equation: First, our equation is nonlocal; Also the natural energy estimate is not as good as in the case of the thin film equation, and does not yields, for instance, boundedness and continuity of the solutions (our case is critical in dimension $1$ in that respect)

Belligerent broadcasting, male anti-authoritarianism and anti-environmentalism: the case of Top Gear (BBC, 2002–2015)

This article considers the format and cultural politics of the hugely successful UK television program Top Gear (BBC 2002–2015). It analyzes how—through its presenting team—it constructed an informal address predicated around anti-authoritarian or contrarian banter and protest masculinity. Regular targets for Top Gear presenter’s protest—curtailed by broadcast guidelines in terms of gender and ethnicity—are deflected onto the “soft” targets of government legislation on environmental issues or various forms of regulation “red tape. Repeated references to speed cameras, central London congestion charges and “excessive” signage are all anti-authoritarian, libertarian discourses delivered through a comedic form of performance address. Thus, the BBC’s primary response to complaints made about this program was to defend the program’s political views as being part of the humor. The article draws on critical discourse analysis and conversation analysis to consider how the program licensed a particular form of engagement that helped it to deflect criticisms, and considers the limits to such discursive positioning. We conclude by examining the controversies that finally led, in 2015, to the removal of the main presenter, Jeremy Clarkson, and the ending of this version of the program through the departure of the team to an on-demand online television service