An Isolated Stellar-Mass Black Hole Detected Through Astrometric Microlensing

We report the first unambiguous detection and mass measurement of an isolated stellar-mass black hole (BH). We used the Hubble Space Telescope (HST) to carry out precise astrometry of the source star of the long-duration (t_E ~ 270 days), high-magnification microlensing event MOA-2011-BLG-191/OGLE-2011-BLG-0462, in the direction of the Galactic bulge. HST imaging, conducted at eight epochs over an interval of six years, reveals a clear relativistic astrometric deflection of the background star's apparent position. Ground-based photometry shows a parallactic signature of the effect of the Earth's motion on the microlensing light curve. Combining the HST astrometry with the ground-based light curve and the derived parallax, we obtain a lens mass of 7.1 +/- 1.3 M_Sun and a distance of 1.58 +/- 0.18 kpc. We show that the lens emits no detectable light, which, along with having a mass higher than is possible for a white dwarf or neutron star, confirms its BH nature. Our analysis also provides an absolute proper motion for the BH. The proper motion is offset from the mean motion of Galactic-disk stars at similar distances by an amount corresponding to a transverse space velocity of ~45 km/s, suggesting that the BH received a modest natal 'kick' from its supernova explosion. Previous mass determinations for stellar-mass BHs have come from radial-velocity measurements of Galactic X-ray binaries, and from gravitational radiation emitted by merging BHs in binary systems in external galaxies. Our mass measurement is the first ever for an isolated stellar-mass BH using any technique

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Impact assessment in complex contexts of rural livelihood transformations in Africa. Part 2- Interview data

Qualitative interview resulting from semi-structured household interviews and focus group discussions that aimed to assess the impact of development activities that are intended to benefit poor men, women and children; and how their income and food security is changing. The study took place in four rural village sites: Masumbankhunda and Karonga areas in Malawi and Tigray and Oromia areas in Ethiopia

Impact assessment in complex contexts of rural livelihood transformations in Africa. Part 1- Longitudinal household income data

The individual household method (IHM) was developed by Evidence for Development as a reliable, standardised method of collecting and using household income data that is suitable for operational use. IHM work involves both in-person data collection and the use of specialised analytical software, open-IHM, which can be used to manage complex household data and produce reports, models and predictions to inform policy-making. This data set includes anonymised data from project areas Masumbankunda, Malawi; Karonga, Malawi; Tigray, Ethiopia; Assela, Ethiopia. Please also see related file on Qualitative Impact Assessment (QUIP) data which includes some qualitative data collected from a sub-sample of the same households included in this study (only Round 2 files - Round 1 households were not from the same sample set)

Risk factors for symptoms of gastrointestinal illness in rural town Isiolo, Kenya

This study assesses risk factors for food-borne gastrointestinal illness indicated by diarrhoea and/or vomiting using 14-day recalls among children and young adults. The study was set in Isiolo, a rural town of Kenya, inhabited mainly by pastoralists of different ethnic groups. The preparation methods of milk at the household level were also investigated. The study was cross-sectional and involved 900 participants from randomly selected households. They were interviewed using a structured questionnaire. An unmatched nested case-control study was constructed by randomly selecting three controls for each case. Potential risk factors for gastrointestinal illness were analysed using both univariate and multivariate logistic regression models with random effect on ethnic groups. The study results showed that consumption of mutton, carrots, Irish potatoes, raw camel milk, boiled camel milk and fermented camel milk were important risk factors for diarrhoea and/or vomiting, whereas the consumption of boiled goat milk, boiled cow milk, spinach, washing of hands with soap and the presence of proper drainage system had protective effects (odds ratio > 1). We conclude that in this setting, primarily vegetables and the camel milk market chain pose the greatest risks for symptoms of food-borne gastrointestinal illnes