Solitary waves and their stability in colloidal media: semi-analytical solutions

Spatial solitary waves in colloidal suspensions of spherical dielectric nanoparticles are considered. The interaction of the nanoparticles is modelled as a hard-sphere gas, with the Carnahan-Starling formula used for the gas compressibility. Semi-analytical solutions, for both one and two spatial dimensions, are derived using an averaged Lagrangian and suitable trial functions for the solitary waves. Power versus propagation constant curves and neutral stability curves are obtained for both cases, which illustrate that multiple solution branches occur for both the one and two dimensional geometries. For the one-dimensional case it is found that three solution branches (with a bistable regime) occur, while for the two-dimensional case two solution branches (with a single stable branch) occur in the limit of low background packing fractions. For high background packing fractions the power versus propagation constant curves are monotonic and the solitary waves stable for all parameter values. Comparisons are made between the semi-analytical and numerical solutions, with excellent comparison obtained.Comment: Paper to appear in Dynamics of Continuous, Discrete and Impulsive Systems, Series

Changes in maternal and newborn health care in Ethiopia

This IDEAS study of interactions between families and frontline workers and coverage of critical interventions for mothers and newborns was conducted between May-June 2012 and May-June 2015 across four regions of Ethiopia. The aim was to estimate changes in maternal and newborn health care in areas where implementation projects funded by the Bill & Melinda Gates Foundation were operating. In 2012 the study methods were defined to include a sub-set of areas where the Last Ten Kilometers (L10K) project was operating, run by John Snow Incorporated. Over the last two decades maternal, newborn and child survival has improved from very high levels of mortality. The maternal mortality ratio declined from an estimated 1,400 maternal deaths per 100,000 live births in 1990 to 420/100,000 in 2014, although this falls short of the 2015 target of 350/100,000. Child mortality rates declined from 204 child deaths per 1,000 live births in 1990 to 59/1,000 in 2015, meeting 2015 targets. And neonatal mortality declined from 61 deaths in the first 28 days of life per 1,000 live births in 1990 to 28/1,000 in 2015. The country has set ambitious goals to build on these gains even further. Key Messages -While improvements are still needed, access to antenatal and intrapartum health care has increased on a large scale in Ethiopia. Simultaneously, there have been improvements in the readiness of the health system to provide quality care - The data collection period coincided with a period of remarkable activity in the Ethiopian health system with government led health system strengthening being implemented throughout the country - Across the continuum of care we observe large gains in coverage of life saving interventions being made amongst the most poor women, with coverage among all sub-groups increasing - Yet, coverage of postnatal checks for the mother and the newborn remain extremely low and represent a problem needing urgent attentio

Changes in maternal and newborn health care in Uttar Pradesh, India

'Interactions between families and frontline workers – their frequency, quality, and equity – and coverage of interventions for mothers and newborns'. This IDEAS study of the interactions between families and frontline workers and coverage of critical interventions for mothers and newborns was conducted between November 2012 and November 2015 in the State of Uttar Pradesh, India. It is one of three country-specific reports, along with Ethiopia and North Eastern Nigeria. It follows from the 2013 Baseline findings from Uttar Pradesh, India. The aim was to estimate changes in maternal and newborn health care in areas where Bill & Melinda Gates Foundation implementation projects were operating, with three active projects in the region: Manthan; Better Birth; The Community Mobilisation Project. The main body of this report focuses on change in indicators that were expected to improve as a result of the specific implementation activities in place in the study area. This study was not designed to reflect progress of individual projects, but to understand changes arising as a result of investments made by the Bill & Melinda Gates Foundation strategy for maternal and newborn health. Key Messages: (1) Some, but not all, indicators that had been targeted by projects were observed to have increased between the surveys (2) Coverage of at least one antenatal care visit with a skilled provider increased so that three quarters of women reported this in 2015. But there was no change in coverage of at least four antenatal care visits with only one quarter of women having the recommended four visits in 2015. (3) Postnatal care for the mother within two days of birth increased from half of women receiving a check, to two-thirds of women in 2015. This large change was driven by an increase in the number of postnatal checks for women who delivered at home. (4) Postnatal care for the newborn remained very low at just 15% in 2015 and Indicators of interaction quality showed no evidence of change (5) There was very little change in the coverage of life saving interventions for newborns (6) Over three-quarters of women with a recent birth had been visited at home by a frontline worker in 2015. Citation Marchant, T; (2016). Change in maternal and newborn health care: Interactions between families and front line workers – their frequency, quality, and equity – and coverage of interventions for mothers and newborns. Report from six-district surveys in Uttar Pradesh, India, 2012-2015. IDEAS Project Report. London School of Hygiene & Tropical Medicine. Acknowledgement The IDEAS team wishes to acknowledge the work of Sambodhi Research and Communications Pvt. Ltd who implemented the surveys, and the cooperation of the grantees in Uttar Pradesh throughout the development and implementation process. We are grateful to the State officials in Lucknow who provided support to the survey implementation, and to all households, facilities and individuals surveyed

Maternal and newborn health care. Baseline findings from Ethiopia. Interactions between families and frontline workers (their frequency, quality, and equity), and coverage of interventions for mothers and newborns.

The IDEAS baseline study of interactions between families and frontline workers and coverage of critical interventions for mothers and newborns was conducted in 2012 in Ethiopia. Its aim was to gather information about the frequency, quality, and equity of interactions that women have with frontline workers during pregnancy, delivery, and in the first 28 days after birth, and to estimate the coverage of life saving interventions that frontline workers are able to deliver to mothers and newborns. In the context of Ethiopia, frontline workers include the Health Development Army, Community Health Promoters and Traditional Birth Attendants working in communities, Health Extension Workers working at health posts and in communities, and nurses, midwives and doctors working in primary health centres. The findings represent a descriptive analysis of interactions and intervention coverage along the continuum of care. At least two years after baseline, an endline survey will be carried out to investigate the extent to which innovations implemented in the study area that aim to enhance family and frontline worker interactions (by making them more frequent, better quality, and more equitable) result in measurable increases in intervention coverage

Changes in maternal and newborn health care in Gombe State, Nigeria

Interactions between families and frontline workers – their frequency, quality, and equity – and coverage of interventions for mothers and newborns This IDEAS report studies the interactions between families and frontline workers and coverage of critical interventions for mothers and newborns was conducted between June 2012 and June 2015 in Gombe State, Nigeria. IDEAS focuses on the changes in indicators that were expected to improve as a result of the specific implementation activities. The aim was to estimate changes in maternal and newborn health care in areas where Bill & Melinda Gates Foundation implementation projects were operating. In this region, the project was implemented by the Society for Family Health. This is one of three country-specific reports, along with Ethiopia and Uttar Preadesh, India. It follows from the 2013 Baseline findings from Gombe State, Nigeria. The survey results suggest that while coverage of routine care across the continuum did not increase, more women who needed emergency care at the time of birth were able to access it. Important improvements in the coverage of some newborn interventions were observed, especially those that relied on the behaviours of caregivers such as delayed bathing, although none became universal. The unfinished agenda for change in Gombe State needs the continued promotion of maternal and newborn health issues amongst communities, mechanisms to improve the care provided to mother and baby immediately after birth, enhancing the supply of quality care in facilities, and an urgent agenda to address the considerable and persistent inequity in the state. This publication was written by Tanya Marchant and produced by the IDEAS project led by Professor Joanna Schellenberg at the London School of Hygiene Tropical Medicine. The IDEAS team wishes to acknowledge the work of Health Hub Ltd and Data Research and Mapping Consult Ltd. who implemented the surveys in 2012 and 2015 respectively, and the cooperation and contributions by the implementing partners in the state, Society for Family Health and PACT throughout the development and implementation process. We are also grateful to state officials in Gombe for their input and support, and to all households, facilities and individuals surveyed. The short URL for this report is bit.ly/mnh-nigeri

Evidence to improve maternal and newborn health in Ethiopia, North East Nigeria and Uttar Pradesh, India

IDEAS aims to improve the health and survival of mothers and babies through generating evidence to inform policy and practice. IDEAS uses measurement, learning and evaluation to find out what works, why and how in maternal and newborn health. IDEAS is funded between 2010 and 2015 by a grant from the Bill & Melinda Gates Foundation to the London School of Hygiene & Tropical Medicine. One research question is"Do enhanced interactions lead to increased coverage of interventions?

Common envelope ejection in massive binary stars - Implications for the progenitors of GW150914 and GW151226

The recently detected gravitational wave signals (GW150914 and GW151226) of the merger event of a pair of relatively massive stellar-mass black holes (BHs) calls for an investigation of the formation of such progenitor systems in general. We analyse the common envelope (CE) stage of the "traditional" formation channel in binaries where the first-formed compact object undergoes an in-spiral inside the envelope of its evolved companion star and ejects the envelope in that process. We calculate envelope binding energies of donor stars with initial masses between 4 and 115 Msun for metallicities of Z=Zsun/2 and Z=Zsun/50, and derive minimum masses of in-spiralling objects needed to eject these envelopes. We find that CE evolution, besides from producing WD-WD and NS-NS binaries, may, in principle, also produce massive BH-BH systems with individual BH component masses up to ~50-60 Msun, in particular for donor stars evolved to giants. However, the physics of envelope ejection of massive stars remains uncertain. We discuss the applicability of the energy-budget formalism, the location of the bifurcation point, the recombination energy and the accretion energy during in-spiral as possible energy sources, and also comment on the effect of inflated helium cores. Massive stars in a wide range of metallicities and with initial masses up to at least 115 Msun may possibly shed their envelopes and survive CE evolution, depending on their initial orbital parameters, similarly to the situation for intermediate mass and low-mass stars with degenerate cores. We conclude that based on stellar structure calculations, and in the view of the usual simple energy budget analysis, events like GW150914 and GW151226 could possibly be produced from the CE channel. Calculations of post-CE orbital separations, however, and thus the estimated LIGO detection rates, remain highly uncertain. [Abridged]Comment: 13 pages, 7 figures, A&A accepte

Measuring skilled attendance at birth using linked household, health facility, and health worker surveys in Ethiopia, North-East Nigeria, and Uttar Pradesh, India

Background: The measurement of key intervention coverage to improve maternal health is complex. Large scale household surveys provide high-quality estimates of the number of women who have skilled attendance at birth, but most provide little or no detail about the quality of care women receive. For example, information on the preparedness of the skilled birth attendant to manage labour is not included. Here we describe measurement of key intervention coverage for mothers using linked household data, health facility and health worker data. Methods: In 2012, linked household, health facility and health worker survey data were collected to ascertain the relationship between women having interactions with health workers, and the population level coverage of key interventions for mothers and newborns. Data from each source was linked at the level of the household cluster: sub-villages. All women living in the sub-village were interviewed with a special module for women who had a birth in the previous 12 months. The health facility providing services to these women was surveyed to determine preparedness to provide care, and frontline health workers in the village were interviewed. The number and quality of interactions taking place, and the extent to which this translated into coverage of key interventions, was explored. Findings: Health facility, health worker and household data were all needed to estimate the six intra-partum interventions that usually fall under the proxy indicator ‘skilled attendance at birth’. Data is presented to illustrate measurement complexities, and the gap between coverage of skilled birth attendance, quality of care, and the coverage of the six key intra-partum interventions. Interpretation: Measurement across the continuum of care requires linking multiple data collection approaches. Developing methods to unpack key interventions for mothers, and for their newborns, is of critical importance to develop strategies for improved survival

Asteroseismic test of rotational mixing in low-mass white dwarfs

We exploit the recent discovery of pulsations in mixed-atmosphere (He/H), extremely low-mass white dwarf precursors (ELM proto-WDs) to test the proposition that rotational mixing is a fundamental process in the formation and evolution of low-mass helium core white dwarfs. Rotational mixing has been shown to be a mechanism able to compete efficiently against gravitational settling, thus accounting naturally for the presence of He, as well as traces of metals such as Mg and Ca, typically found in the atmospheres of ELM proto-WDs. Here we investigate whether rotational mixing can maintain a sufficient amount of He in the deeper driving region of the star, such that it can fuel, through HeII-HeIII ionization, the observed pulsations in this type of stars. Using state-of-the-art evolutionary models computed with MESA, we show that rotational mixing can indeed explain qualitatively the very existence and general properties of the known pulsating, mixed-atmosphere ELM proto-WDs. Moreover, such objects are very likely to pulsate again during their final WD cooling phase.Comment: accepted for publication in A&A Letter