The living standards of families with children reporting low incomes

The Government has high-profile child poverty targets which are assessed using a measure of income, as recorded in the Household Below Average Income series (HBAI). However, income is an imperfect measure of living standards. Previous analysis suggests that some children in households with low income do not have commensurately low living standards. This report aims to document the extent to which this is true, focusing on whether children in low-income households have different living standards depending on whether their parents are employed, self-employed, or workless

A two-fluid model for tissue growth within\ud a dynamic flow environment

We study the growth of a tissue construct in a perfusion bioreactor, focussing on its response to the mechanical environment. The bioreactor system is modelled as a two-dimensional channel containing a tissue construct through which a flow of culture medium is driven. We employ a multiphase formulation of the type presented by G. Lemon, J. King, H. Byrne, O. Jensen and K. Shakesheff in their study (Multiphase modelling of tissue growth using the theory of mixtures. J. Math. Biol. 52(2), 2006, 571–594) restricted to two interacting fluid phases, representing a cell population (and attendant extracellular matrix) and a culture medium, and employ the simplifying limit of large interphase viscous drag after S. Franks in her study (Mathematical Modelling of Tumour Growth and Stability. Ph.D. Thesis, University of Nottingham, UK, 2002) and S. Franks and J. King in their study (Interactions between a uniformly proliferating tumour and its surrounding: Uniform material properties. Math. Med. Biol. 20, 2003, 47–89).\ud \ud The novel aspects of this study are: (i) the investigation of the effect of an imposed flow on the growth of the tissue construct, and (ii) the inclusion of a mechanotransduction mechanism regulating the response of the cells to the local mechanical environment. Specifically, we consider the response of the cells to their local density and the culture medium pressure. As such, this study forms the first step towards a general multiphase formulation that incorporates the effect of mechanotransduction on the growth and morphology of a tissue construct. The model is analysed using analytic and numerical techniques, the results of which illustrate the potential use of the model to predict the dominant regulatory stimuli in a cell population

Detecting suicidality on Twitter

Twitter is increasingly investigated as a means of detecting mental health status, including depression and suicidality, in the population. However, validated and reliable methods are not yet fully established. This study aimed to examine whether the level of concern for a suicide-related post on Twitter could be determined based solely on the content of the post, as judged by human coders and then replicated by machine learning. From 18th February 2014 to 23rd April 2014, Twitter was monitored for a series of suicide-related phrases and terms using the public Application Program Interface (API). Matching tweets were stored in a data annotation tool developed by the Commonwealth Scientific and Industrial Research Organisation (CSIRO). During this time, 14,701 suicide-related tweets were collected: 14% were randomly (n = 2000) selected and divided into two equal sets (Set A and B) for coding by human researchers. Overall, 14% of suicide-related tweets were classified as ‘strongly concerning’, with the majority coded as ‘possibly concerning’ (56%) and the remainder (29%) considered ‘safe to ignore’. The overall agreement rate among the human coders was 76% (average κ = 0.55). Machine learning processes were subsequently applied to assess whether a ‘strongly concerning’ tweet could be identified automatically. The computer classifier correctly identified 80% of ‘strongly concerning’ tweets and showed increasing gains in accuracy; however, future improvements are necessary as a plateau was not reached as the amount of data increased. The current study demonstrated that it is possible to distinguish the level of concern among suicide-related tweets, using both human coders and an automatic machine classifier. Importantly, the machine classifier replicated the accuracy of the human coders. The findings confirmed that Twitter is used by individuals to express suicidality and that such posts evoked a level of concern that warranted further investigation. However, the predictive power for actual suicidal behaviour is not yet known and the findings do not directly identify targets for intervention.This project was supported in part by funding from the NSW Mental Health Commission and the NHMRC John Cade Fellowship 1056964. PJB and ALC are supported by the NHMRC Early Career Fellowships 1035262 and 1013199

Ytterbium-doped tantalum pentoxide waveguide lasers

We have demonstrated a Yb:Ta2O5 waveguide laser fabricated by RF magnetron sputtering on oxidised silicon. The waveguide laser was end-pumped with a laser diode at 977 nm and lasing was observed between 1015 and 1020 nm. The launched pump power threshold and slope efficiency were measured to be ~25 mW and 1.78 %, respectively

The interplay between tissue growth and scaffold degradation in engineered tissue constructs

In vitro tissue engineering is emerging as a potential tool to meet the high demand for replacement tissue, caused by the increased incidence of tissue degeneration and damage. A key challenge in this field is ensuring that the mechanical properties of the engineered tissue are appropriate for the in vivo environment. Achieving this goal will require detailed understanding of the interplay between cell proliferation, extracellular matrix (ECM) deposition and scaffold degradation.\ud \ud In this paper, we use a mathematical model (based upon a multiphase continuum framework) to investigate the interplay between tissue growth and scaffold degradation during tissue construct evolution in vitro. Our model accommodates a cell population and culture medium, modelled as viscous fluids, together with a porous scaffold and ECM deposited by the cells, represented as rigid porous materials. We focus on tissue growth within a perfusion bioreactor system, and investigate how the predicted tissue composition is altered under the influence of (i) differential interactions between cells and the supporting scaffold and their associated ECM, (ii) scaffold degradation, and (iii) mechanotransduction-regulated cell proliferation and ECM deposition.\ud \ud Numerical simulation of the model equations reveals that scaffold heterogeneity typical of that obtained from μCT scans of tissue engineering scaffolds can lead to significant variation in the flow-induced mechanical stimuli experienced by cells seeded in the scaffold. This leads to strong heterogeneity in the deposition of ECM. Furthermore, preferential adherence of cells to the ECM in favour of the artificial scaffold appears to have no significant influence on the eventual construct composition; adherence of cells to these supporting structures does, however, lead to cell and ECM distributions which mimic and exaggerate the heterogeneity of the underlying scaffold. Such phenomena have important ramifications for the mechanical integrity of engineered tissue constructs and their suitability for implantation in vivo

Field observations of the evolution of plunging-wave shapes

© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in O’Dea, A., Brodie, K., & Elgar, S. Field observations of the evolution of plunging-wave shapes. Geophysical Research Letters, 48(16), (2021): e2021GL093664, https://doi.org/10.1029/2021GL093664.There are few high-resolution field observations of the water surface during breaking owing to the difficulty of collecting spatially dense measurements in the surf zone, and thus the factors influencing breaking-wave shape in field conditions remain poorly understood. Here, the shape and evolution of plunging breakers is analyzed quantitatively using three-dimensional scans of the water surface collected at high spatial and temporal resolution with a multi-beam terrestrial lidar scanner. The observed internal void shapes in plunging breakers agree well with previously developed theoretical shapes at the onset of breaking, and become more elongated and less steep as breaking progresses. The normalized void area increases as the local bottom slope steepens and as the breaking depth decreases. The void shape becomes more circular as the local bottom slope and the ratio of breaking water depth to wavelength increase, as well as in conditions with opposing winds.Funding was provided by the U.S. Department of Defense (DoD) Laboratory University Collaboration Initiative program, the U.S. Army ERDC Military Engineering Basic Research Program from the Assistant Secretary of the Army for Acquisition, Logistics, and Technology, the Vannevar Bush Faculty Fellowship program, the National Science Foundation, and the U.S. Coastal Research Program. This project was supported in part by an appointment to the Research Participation Program at the DoD, administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the U.S. Department of Energy and the DoD