Watching birds: observation, photography and the 'ethological eye'.

The article reflects upon the observational practices and methods developed by the early exponents of ethology committed to naturalistic field study and explores how their approaches and techniques influenced a wider field of popular natural-history filmmaking and photography. In doing so, my focus is upon three aspects of ethological field studies: the socio-technical devices used by ethologists to bring birds closer to them, the distinctive observational and representational practices which they forged, and the analogies they used to codify behaviour. This assemblage of elements included hides or screens from which to watch wild birds without disturbing them, optics to extend human vision, pens and paper to sketch and fix patterns of behaviour, watches to record timings, photography to capture action and freeze movement, and illustration and photographs to visualize behaviour. Carried through natural-history networks, the practices, methods and theories of ethologists like Huxley and Tinbergen influenced popular natural-history filmmaking and photography more broadly from the 1940s, driving a behavioural turn in these cultural practices. This popularization of the 'ethological eye' was further facilitated by the convergence of socio-technical devices, forms of observation and dramatization in the work of the early exponents of naturalistic field studies of birds and the popular filmmakers.

Nonlinear light behaviors near phase transition in non-parity-time-symmetric complex waveguides.

Many classes of non-parity-time (PT)-symmetric waveguides with arbitrary gain and loss distributions still possess all-real linear spectrum or exhibit phase transition. In this Letter, nonlinear light behaviors in these complex waveguides are probed analytically near a phase transition. Using multi-scale perturbation methods, a nonlinear ordinary differential equation (ODE) is derived for the light's amplitude evolution. This ODE predicts that a single class of these non-PT-symmetric waveguides supports soliton families and amplitude-oscillating solutions both above and below linear phase transition, in close analogy with PT-symmetric systems. For the other classes of waveguides, the light's intensity always amplifies under the effect of nonlinearity, even if the waveguide is below the linear phase transition. These analytical predictions are confirmed by direct computations of the full system.

Trouble at the National Trust: Post-war Recreation, the Benson Report and the Rebuilding of a Conservation Organization in the 1960s.

The growth of conservation organizations like the National Trust for England, Wales and Northern Ireland (NT), the Royal Society for the Protection of Birds and the county wildlife trusts was one of the more striking features of post-war social change. With their roots in late Victorian and Edwardian ideas of preservation and conservation, the membership of these organizations expanded sharply from the 1960s. The success of these groups, however, also brought its own problems. In particular the practical issues associated with their growth forced them to ask what kind of organizations they were and what kind of organizations they might become. The article focuses on the NT and the soul searching that it undertook in the late 1960s. It draws on but partly seeks to revise recent research on environmental and conservation organizations. In doing so, it documents how the transformation of the NT fits the professionalization thesis proposed within the existing historiographical literature, whilst seeking to draw attention to the influence of broader sociological changes associated with mass affluence and the growth of popular recreation. Given its patrician leadership, the NT was challenged by the democratizing effects of affluence and by the wider climate of cultural modernization. It was this set of cultural and social developments, rather than simply the inevitable logic of professionalization, which provided the conditions in which the Trust was impelled to reinvent itself and modernize its ways of working.

Pyramid diffraction in parity-time-symmetric optical lattices.

Nonlinear dynamics of wave packets in two-dimensional parity-time-symmetric optical lattices near the phase transition point are analytically studied. A fourth-order equation is derived for the envelope of these wave packets. A pyramid diffraction pattern is demonstrated in both the linear and nonlinear regimes. Blow-up is also possible in the nonlinear regime for both focusing and defocusing nonlinearities.

Nonlinear dynamics of wave packets in parity-time-symmetric optical lattices near the phase transition point.

Nonlinear dynamics of wave packets in parity-time-symmetric optical lattices near the phase-transition point is analytically studied. A nonlinear Klein-Gordon equation is derived for the envelope of these wave packets. A variety of phenomena known to exist in this envelope equation are shown to also exist in the full equation, including wave blowup, periodic bound states, and solitary wave solutions.

Dark solitons in mode-locked lasers.

Dark soliton formation in mode-locked lasers is investigated by means of a power-energy saturation model that incorporates gain and filtering saturated with energy, and loss saturated with power. It is found that general initial conditions evolve (mode-lock) into dark solitons under appropriate requirements also met in experimental observations. The resulting pulses are essentially dark solitons of the unperturbed nonlinear Schrödinger equation. Notably, the same framework also describes bright pulses in anomalous and normally dispersive lasers.

Building capacity for community-based participatory research for health disparities in Canada: the case of "Partnerships in Community Health Research".

Enthusiasm for community-based participatory research (CBPR) is increasing among health researchers and practitioners in addressing health disparities. Although there are many benefits of CBPR, such as its ability to democratize knowledge and link research to community action and social change, there are also perils that researchers can encounter that can threaten the integrity of the research and undermine relationships. Despite the increasing demand for CBPR-qualified individuals, few programs exist that are capable of facilitating in-depth and experiential training for both students and those working in communities. This article reviews the Partnerships in Community Health Research (PCHR), a training program at the University of British Columbia that between 2001 and 2009 has equipped graduate student and community-based learners with knowledge, skills, and experience to engage together more effectively using CBPR. With case studies of PCHR learner projects, this article illustrates some of the important successes and lessons learned in preparing CBPR-qualified researchers and community-based professionals in Canada.