Slum Tourism: Developments in a Young Field of Interdisciplinary Tourism Research

This paper introduces the Special Issue on slum tourism with a reflection on the state of the art on this new area of tourism research. After a review of the literature we discuss the breadth of research that was presented at the conference 'Destination Slum', the first international conference on slum tourism. Identifying various dimensions, as well as similarities and differences, in slum tourism in different parts of the world, we contest that slum tourism has evolved from being practised at only a limited number of places into a truly global phenomenon which now is performed on five continents. Equally the variety of services and ways in which tourists visit the slums has increased.The widening scope and diversity of slum tourism is clearly reflected in the variety of papers presented at the conference and in this Special Issue. Whilst academic discussion on the theme is evolving rapidly, slum tourism is still a relatively young area of research. Most papers at the conference and, indeed, most slum tourism research as a whole appears to remain focused on understanding issues of representation, often concentrating on a reflection of slum tourists rather than tourism. Aspects, such as the position of local people, remain underexposed as well as empirical work on the actual practice of slum tourism. To address these issues, we set out a research agenda in the final part of the article with potential avenues for future research to further the knowledge on slum tourism. © 2012 Copyright Taylor and Francis Group, LLC

Reframing urban tourism.

In a matter of weeks last year, discussions regarding tourism in cities changed from how to deal with overtourism to how to deal with ‘no tourism’. Shortly thereafter, a great number of posts on LinkedIn, websites, and blogs highlighted how the tourism crisis that resulted from the COVID-19 pandemic could help reinvent tourism, into something more equal, inclusive, and sustainable. And so, online – at leastin mypersonalonlinebubble – there seemedtobe a real momentum for proper, transformative changes in (urban) tourism. How can we rebuild urban tourism in a sustainable and resilient way

Movement disorders and eye movement disorders in late-onset inborn errors of metabolism:an unexplored area

This thesis is about late-onset inborn error of metabolism (IEM). IEMs are genetic disorders that cause disturbance of a biochemical process in the body. Some of these disorders are detected through neonatal screening, however, this is not available for the majority. For a long time, these disorders were considered to occur only in children, but after improvement of diagnostic methods, IEMs are found to be present in adolescents and adults as well. Unfortunately, it often takes a long time before these patients get the right diagnosis, which is a problem because some IEMs are treatable. In this thesis, tools to enhance the recognition of IEMs are provided. First, a new diagnostic approach is presented to improve the detection of late-onset IEMs presenting with a movement disorder, in which clinical phenotyping is the cornerstone. An underlying IEM should be suspected in patients with movement disorders, psychiatric symptoms, and cognitive impairment. Eye movement disorders are frequent too, and this thesis shows that they can be present early in the disease course and may be very characteristic. To aid non-neurologists to recognize movement disorders, which is important because they can serve as a clue in the diagnosis of an IEM and they impact quality of life, a diagnostic screening tool is presented.To conclude, this thesis contributes to a clearer view of late-onset IEMs. It gives tools to enhance clinical diagnosis and suggestions for improvement of care. This is both important in the light of the development of new treatments for IEMs

Geometric phase methods with Stokes theorem for a general viscous swimmer

The geometric phase techniques for swimming in viscous flows express the net displacement of a swimmer as a path integral of a field in configuration space. This representation can be transformed into an area integral for simple swimmers using the Stokes theorem. Since this transformation applies for any loop, the integrand of this area integral can be used to help design these swimmers. However, the extension of this Stokes theorem technique to more complicated swimmers is hampered by problems with variables that do not commute and by how to visualise and understand the higher-dimensional spaces. In this paper, we develop a treatment for each of these problems, thereby allowing the displacement of general swimmers in any environment to be designed and understood similarly to simple swimmers. The net displacement arising from non-commuting variables is tackled by embedding the integral into a higher-dimensional space, which can then be visualised through a suitability constructed surface. These methods are developed for general swimmers and demonstrated on three benchmark examples: Purcell's two-hinged swimmer, an axisymmetric squirmer in free space and an axisymmetric squirmer approaching a free interface. We show in particular that, for swimmers with more than two modes of deformation, there exists an infinite set of strokes that generate each net displacement. Hence, in the absence of additional restrictions, general microscopic swimmers do not have a single stroke that maximises their displacement

Analytical solutions to slender-ribbon theory

The low-Reynolds number hydrodynamics of slender ribbons is accurately captured by slender-ribbon theory, an asymptotic solution to the Stokes equation which assumes that the three length scales characterising the ribbons are well separated. We show in this paper that the force distribution across the width of an isolated ribbon located in a infinite fluid can be determined analytically, irrespective of the ribbon's shape. This, in turn, reduces the surface integrals in the slender-ribbon theory equations to a line integral analogous to the one arising in slender-body theory to determine the dynamics of filaments. This result is then used to derive analytical solutions to the motion of a rigid plate ellipsoid and a ribbon torus and to propose a ribbon resistive-force theory, thereby extending the resistive-force theory for slender filaments

Rotation of slender swimmers in isotropic-drag media.

The drag anisotropy of slender filaments is a critical physical property allowing swimming in low-Reynolds number flows, and without it linear translation is impossible. Here we show that, in contrast, net rotation can occur under isotropic drag. We first demonstrate this result formally by considering the consequences of the force- and torque-free conditions on swimming bodies and we then illustrate it with two examples (a simple swimmers made of three rods and a model bacterium with two helical flagellar filaments). Our results highlight the different role of hydrodynamic forces in generating translational versus rotational propulsion.This research was funded in part by the European Union through a Marie Curie CIG grant (EL) and by the Cambridge Trust (LK).This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by the American Physical Society

The boundary integral formulation of Stokes flows includes slender-body theory

The incompressible Stokes equations can classically be recast in a boundary integral (BI) representation, which provides a general method to solve low-Reynolds number problems analytically and computationally. Alternatively, one can solve the Stokes equations by using an appropriate distribution of flow singularities of the right strength within the boundary, a method particularly useful to describe the dynamics of long slender objects for which the numerical implementation of the BI representation becomes cumbersome. While the BI approach is a mathematical consequence of the Stokes equations, the singularity method involves making judicious guesses that can only be justified a posteriori. In this paper we use matched asymptotic expansions to derive an algebraically accurate slender-body theory directly from the BI representation able to handle arbitrary surface velocities and surface tractions. This expansion procedure leads to sets of uncoupled linear equations and to a single one-dimensional integral equation identical to that derived by Keller and Rubinow (1976) and Johnson (1979) using the singularity method. Hence we show that it is a mathematical consequence of the BI approach that the leading-order flow around a slender body can be represented using a distribution of singularities along its centreline. Furthermore when derived from either the single-layer or double-layer modified BI representation, general slender solutions are only possible in certain types of flow, in accordance with the limitations of these representations

Overtourism and Employment Outcomes for the Tourism Worker: Impacts to Labour Markets

This paper aims to undertake an ideal-typical analysis of the implications of overtourism on employment at the level of the destination