33 research outputs found

    Job Selection in a Network of Autonomous UAVs for Delivery of Goods

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    This article analyzes two classes of job selection policies that control how a network of autonomous aerial vehicles delivers goods from depots to customers. Customer requests (jobs) occur according to a spatio-temporal stochastic process not known by the system. If job selection uses a policy in which the first job (FJ) is served first, the system may collapse to instability by removing just one vehicle. Policies that serve the nearest job (NJ) first show such threshold behavior only in some settings and can be implemented in a distributed manner. The timing of job selection has significant impact on delivery time and stability for NJ while it has no impact for FJ. Based on these findings we introduce a methodological approach for decision-making support to set up and operate such a system, taking into account the trade-off between monetary cost and service quality. In particular, we compute a lower bound for the infrastructure expenditure required to achieve a certain expected delivery time. The approach includes three time horizons: long-term decisions on the number of depots to deploy in the service area, mid-term decisions on the number of vehicles to use, and short-term decisions on the policy to operate the vehicles

    Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

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    [This corrects the article DOI: 10.1186/s13054-016-1208-6.]

    Finishing the euchromatic sequence of the human genome

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    The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

    Methodological Review and Revision of the Global Hunger Index

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    The Global Hunger Index (GHI) is a multidimensional measure of hunger that considers three dimensions: (1) inadequate dietary energy supply, (2) child undernutrition, and (3) child mortality. The initial version of the index included the following three, equally weighted, non-standardized (i.e. unscaled) indicators that are expressed in percent: the proportion of the population that is calorie deficient (FAO's prevalence of undernourishment); the prevalence of underweight in children under five; and the under-five mortality rate. Several decisions regarding the original formulation of the GHI are reconsidered in light of recent discussions in the nutrition community and suggestions by other researchers, namely the choice of the prevalence of child underweight for the child undernutrition dimension, the use of the under-five mortality rate from all causes for the child mortality dimension, and the decision not to standardize the component indicators prior to aggregation. Based on an exploration of the literature, data availability and comparability across countries, and correlation analyses with indicators of micronutrient deficiencies, the index is revised as follows: (1) The child underweight indicator is replaced with child stunting and child wasting; (2) The weight of one third for the child undernutrition dimension is shared equally between the two new indicators; and (3) The component indicators of the index are standardized prior to aggregation, using fixed thresholds set above the maximum values observed in the data set. The under-five mortality rate from all causes is retained, because estimating under-five mortality attributable to nutritional deficiencies would be very costly and make the production of the GHI dependent on statistics about cause-specific mortality rates by country and year that are published irregularly, while the expected benefits are limited

    Social Safety Nets for Food and Nutritional Security in India

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    This paper brings together existing literature on the Mahatma Gandhi National Rural Employment Guarantee Act (MGNRGEA) and the Public Distribution System (PDS) in India, offering a narrative review of the evidence on impacts on food security, health and nutrition of beneficiaries. Both programs operate on a large scale and have the capacity to impact the factors leading to undernutrition. It is evident that despite the deficiencies in implementation, both the MGNREGA and the PDS are inclusive and reach the poor and the marginalized who are likely to also experience greater undernutrition and poor health. Data challenges have however prevented researchers from conducting studies that assess the ultimate impact of these two large-scale programs on health and nutrition. The evidence that exists suggests largely positive impacts indicating a clear potential to make these programs more nutrition sensitive not just by incorporating elements that would explicitly address nutritional concerns but also by directing specific attention to innovations that strengthen critical complementarities and synergies that exist between the two programs

    Harvesting Solar Power in India

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