Sustainable valorisation of organic urban wastes : insights from African case studies

Understanding the problems and potentials of the organic waste stream is perhaps the single most important step that city authorities in Africa could take in moving towards sustainable, affordable, effective and efficient waste management. This publication presents four examples of recent attempts to manage organic waste sustainably in the African context. The participants in the ‘Nairobi organic urban waste’ project have structured this case exercise in order to use the case studies as object lessons, to harvest genuine insights into the feasibility of a variety of ways to successfully and sustainably valorise urban organic waste streams. Three contemporary case examples of compost production are presented. These include composting by a community-based organisation in the Kenyan private sector and by a public-private partnership in Malawi. In all three cases, the project and case study focus is on the relations between city waste and the agricultural supply chain. A fourth case study describes the technical and economic potential to produce and use biogas from urban organic waste

Reexamining Participant Satisfaction With the Mission Continues Fellowship Program for Post-9/11 Veterans

Reexamining Participant Satisfaction With the Mission Continues Fellowship Program for Post-9/11 Veteran

Network Inference via the Time-Varying Graphical Lasso

Many important problems can be modeled as a system of interconnected entities, where each entity is recording time-dependent observations or measurements. In order to spot trends, detect anomalies, and interpret the temporal dynamics of such data, it is essential to understand the relationships between the different entities and how these relationships evolve over time. In this paper, we introduce the time-varying graphical lasso (TVGL), a method of inferring time-varying networks from raw time series data. We cast the problem in terms of estimating a sparse time-varying inverse covariance matrix, which reveals a dynamic network of interdependencies between the entities. Since dynamic network inference is a computationally expensive task, we derive a scalable message-passing algorithm based on the Alternating Direction Method of Multipliers (ADMM) to solve this problem in an efficient way. We also discuss several extensions, including a streaming algorithm to update the model and incorporate new observations in real time. Finally, we evaluate our TVGL algorithm on both real and synthetic datasets, obtaining interpretable results and outperforming state-of-the-art baselines in terms of both accuracy and scalability

The Mission Continues: Reexamining Engagement of Post-9/11 Veterans in Civic Service

The Mission Continues: Reexamining Engagement of Post-9/11 Veterans in Civic Servic

Reexamining Impacts of the Mission Continues Fellowship Program on Post-9/11 Veterans, Their Families, and Their Communities

Reexamining Impacts of the Mission Continues Fellowship Program on Post-9/11 Veterans, Their Families, and Their Communitie

Locally responsive intervention to improve municipal solid waste collection coverage in Accra, Ghana

The paper reports on a process that engaged stakeholders to assess the strengths and weaknesses of the city of Accra’s approach to raising solid waste collection coverage. Stakeholders, working with researchers, have made the evaluation using a combination of benchmark indicators, analysis of franchise agreements, process flow diagramming of collection trends, and statistical analysis of user answers to a survey. Informal services are growing while formal services are shrinking. A logistic regression model suggests that regular collection and affordable user charges significantly increases the levels of user satisfaction. The use of a participatory approach has led to an unusual alliance: formal service providers have agreed to work with informal providers as subcontractors and support them to formalize and increase collection coverage. The positive experience of participation leads the authors to advocate institutionalizing the use of a participatory approach through stakeholder platforms to evaluate interventions and develop plans for service improvement