Mid-infrared broadband modulation instability and 50 dB Raman assisted parametric gain in silicon photonic wires

Abstract: We demonstrate broadband modulation instability, > 40 dB parametric amplification with on-chip gain bandwidth > 580 nm, and narrowband Raman-assisted peak on-chip gain exceeding 50 dB, using mid-infrared dispersion-engineered silicon nanophotonic wires

Widely tunable silicon mid-infrared optical parametric oscillator

A synchronously-pumped mid-infrared optical parametric oscillator is demonstrated using unprecedented large parametric gain in silicon photonic wires. The output wavelength is tunable over a 75-nm bandwidth, with a maximum output pulse energy of 1.62 pJ

Socioeconomic disadvantage and childhood growth: A review of the literature focusing on the mediatory roles of birth weight, maternal age and parity

In this paper we review the literature on the relationship between maternal social disadvantage and childhood growth. We focus particularly on the potential mediatory roles played by birth weight, maternal age, and parity, and on studies of UK populations. We find convincing evidence of social inequalities of growth, both in terms of stature (height) and adiposity/overweight. Maternal age, parity and, particularly, birth weight are plausible mediators of the association between socioeconomic disadvantage and growth due to the acknowledged relationships between each of these factors. However, few studies have considered such mediation explicitly. Further work is required in this area

Global Civic Activism in Flux

Civil society around the world is in flux. New forms of civic activism have taken shape, ranging from protest movements to community-level forums and online campaigns by individual activists.This analysis charts how civic activism is evolving across eight countries:* Brazil* Egypt* India* Kenya* Thailand* Tunisia* Turkey* Ukraine.These case studies reveal crosscutting themes relevant to the future of civil society support:* While there is a global wave of new protests and innovative citizen movements, many civic struggles are increasingly rooted in specific national issues.* New and older forms of civic activism coexist and intertwine in a variety of ways.* Some new activism is highly political and confrontational; some is very practical and pragmatic about trying to circumvent the shortcomings of mainstream politics.* New civic activism includes groups espousing an increasingly wide range of ideological positions.* While the new activism has been effective on some specific issues, it is mostly struggling to hold at bay resurgent authoritarian and illiberal government responses

Assessing health literacy among migrants and associated socioeconomic factors

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Sample size calculations for cluster randomised controlled trials with a fixed number of clusters

Background\ud Cluster randomised controlled trials (CRCTs) are frequently used in health service evaluation. Assuming an average cluster size, required sample sizes are readily computed for both binary and continuous outcomes, by estimating a design effect or inflation factor. However, where the number of clusters are fixed in advance, but where it is possible to increase the number of individuals within each cluster, as is frequently the case in health service evaluation, sample size formulae have been less well studied. \ud \ud Methods\ud We systematically outline sample size formulae (including required number of randomisation units, detectable difference and power) for CRCTs with a fixed number of clusters, to provide a concise summary for both binary and continuous outcomes. Extensions to the case of unequal cluster sizes are provided. \ud \ud Results\ud For trials with a fixed number of equal sized clusters (k), the trial will be feasible provided the number of clusters is greater than the product of the number of individuals required under individual randomisation ($n_i$) and the estimated intra-cluster correlation ($\rho$). So, a simple rule is that the number of clusters ($\kappa$) will be sufficient provided: \ud \ud $\kappa$ > $n_i$ x $\rho$\ud \ud Where this is not the case, investigators can determine the maximum available power to detect the pre-specified difference, or the minimum detectable difference under the pre-specified value for power. \ud \ud Conclusions\ud Designing a CRCT with a fixed number of clusters might mean that the study will not be feasible, leading to the notion of a minimum detectable difference (or a maximum achievable power), irrespective of how many individuals are included within each cluster. \ud \u