Depressed youth, suicidality and antidepressants

The document attached has been archived with permission from the editor of the Medical Journal of Australia. An external link to the publisher’s copy is included.Robert D Goldney, Peter R Mansfield, Melissa K Raven, Jon N Jureidini, Joseph M Rey, Michael J Dudley, Duncan Toplis

Robust interferometer for the routing of light beams carrying orbital angular momentum

We have developed an interferometer requiring only minimal angular alignment for the routing of beams carrying orbital angular momentum. The Mach–Zehnder interferometer contains a Dove prism in each arm where each has a mirror plane around which the transverse phase profile is inverted. One consequence of the inversions is that the interferometer needs no alignment. Instead the interferometer defines a unique axis about which the input beam must be coupled. Experimental results are presented for the fringe contrast, reaching a maximum value of 93±1%

Asymptotic enumeration of incidence matrices

We discuss the problem of counting {\em incidence matrices}, i.e. zero-one matrices with no zero rows or columns. Using different approaches we give three different proofs for the leading asymptotics for the number of matrices with $n$ ones as $n\to\infty$. We also give refined results for the asymptotic number of $i\times j$ incidence matrices with $n$ ones.Comment: jpconf style files. Presented at the conference "Counting Complexity: An international workshop on statistical mechanics and combinatorics." In celebration of Prof. Tony Guttmann's 60th birthda

Fueling climate (in)action:How organizations engage in hegemonization to avoid transformational action on climate change

This study examines how organizations avoid the urgent need for transformational action on climate change by engaging in a hegemonization process. To show how this unfolds, we draw from Laclau and Mouffe’s discourse theory, focusing on the case of BP and its engagement with the climate change debate from 1990 to 2015. Our study takes a longitudinal approach to illustrate how BP defended its core business of producing and selling fossil fuel products by enacting three sequential hegemonization strategies. These included: adopting new signifiers; building ‘win-win’ relationships; and adapting nodal points. In doing so, we demonstrate how hegemonic construction enables organizations to both incorporate and evade various types of stakeholder critique, which, we argue, reproduces business-as-usual. Our study contributes to organization studies literature on hegemony by highlighting how the construction of hegemony operates accumulatively over an extended period of time. We also contribute more broadly to conversations around political contests and the natural environment by illustrating how the lack of effective climate responses is shaped by temporal dynamics

On the modulation instability development in optical fiber systems

Extensive numerical simulations were performed to investigate all stages of modulation instability development from the initial pulse of pico-second duration in photonic crystal fiber: quasi-solitons and dispersive waves formation, their interaction stage and the further propagation. Comparison between 4 different NLS-like systems was made: the classical NLS equation, NLS system plus higher dispersion terms, NLS plus higher dispersion and self-steepening and also fully generalized NLS equation with Raman scattering taken into account. For the latter case a mechanism of energy transfer from smaller quasi-solitons to the bigger ones is proposed to explain the dramatical increase of rogue waves appearance frequency in comparison to the systems when the Raman scattering is not taken into account.Comment: 9 pages, 54 figure

Nonlinear wavelength conversion in photonic crystal fibers with three zero dispersion points

In this theoretical study, we show that a simple endlessly single-mode photonic crystal fiber can be designed to yield, not just two, but three zero-dispersion wavelengths. The presence of a third dispersion zero creates a rich phase-matching topology, enabling enhanced control over the spectral locations of the four-wave-mixing and resonant-radiation bands emitted by solitons and short pulses. The greatly enhanced flexibility in the positioning of these bands has applications in wavelength conversion, supercontinuum generation and pair-photon sources for quantum optics

Influence of turbulence on the dynamo threshold

We use direct and stochastic numerical simulations of the magnetohydrodynamic equations to explore the influence of turbulence on the dynamo threshold. In the spirit of the Kraichnan-Kazantsev model, we model the turbulence by a noise, with given amplitude, injection scale and correlation time. The addition of a stochastic noise to the mean velocity significantly alters the dynamo threshold. When the noise is at small (resp. large) scale, the dynamo threshold is decreased (resp. increased). For a large scale noise, a finite correlation time reinforces this effect

Fuller\u27s First Fifty - No. 03

A monthly historical newsletter published for the Fuller community during the fiftieth anniversary year. The School of World Mission: a new school for a new movement -- Donald A. McGavran: beginning again at 67 -- George Eldon Ladd: an appreciatio