424 research outputs found
Deforestation and apparent extinctions of endemic forest beetles in Madagascar
Madagascar has lost about half of its forest cover since 1953 with much regional variation, for instance most of the coastal lowland forests have been cleared. We sampled the endemic forest-dwelling Helictopleurini dung beetles across Madagascar during 2002–2006. Our samples include 29 of the 51 previously known species for which locality information is available. The most significant factor explaining apparent extinctions (species not collected by us) is forest loss within the historical range of the focal species, suggesting that deforestation has already caused the extinction, or effective extinction, of a large number of insect species with small geographical ranges, typical for many endemic taxa in Madagascar. Currently, roughly 10% of the original forest cover remains. Species–area considerations suggest that this will allow roughly half of the species to persist. Our results are consistent with this prediction
Smart Containers With Bidding Capacity: A Policy Gradient Algorithm for Semi-Cooperative Learning
Smart modular freight containers -- as propagated in the Physical Internet
paradigm -- are equipped with sensors, data storage capability and intelligence
that enable them to route themselves from origin to destination without manual
intervention or central governance. In this self-organizing setting, containers
can autonomously place bids on transport services in a spot market setting.
However, for individual containers it may be difficult to learn good bidding
policies due to limited observations. By sharing information and costs between
one another, smart containers can jointly learn bidding policies, even though
simultaneously competing for the same transport capacity. We replicate this
behavior by learning stochastic bidding policies in a semi-cooperative multi
agent setting. To this end, we develop a reinforcement learning algorithm based
on the policy gradient framework. Numerical experiments show that sharing
solely bids and acceptance decisions leads to stable bidding policies.
Additional system information only marginally improves performance; individual
job properties suffice to place appropriate bids. Furthermore, we find that
carriers may have incentives not to share information with the smart
containers. The experiments give rise to several directions for follow-up
research, in particular the interaction between smart containers and transport
services in self-organizing logistics.Comment: 15 page
Adapted motivational interviewing to improve the uptake of treatment for glaucoma in Nigeria: study protocol for a randomized controlled trial.
BACKGROUND: Glaucoma is a chronic eye disease associated with irreversible visual loss. In Africa, glaucoma patients often present late, with very advanced disease. One-off procedures, such as laser or surgery, are recommended in Africa because of lack of or poor adherence to medical treatment. However, acceptance of surgery is usually extremely low. To prevent blindness, adherence to treatment needs to improve, using acceptable, replicable and cost-effective interventions. After reviewing the literature and interviewing patients in Bauchi (Nigeria) motivational interviewing (MI) was selected as the intervention for this trial, with adaptation for glaucoma (MIG). MI is designed to strengthen personal motivation for, and commitment to a specific goal by eliciting and exploring a person's reasons for change within an atmosphere of acceptance and compassion. The aim of this study is to assess whether MIG increases the uptake of laser or surgery amongst glaucoma patients where this is the recommended treatment. The hypothesis is that MIG increases the uptake of treatment. This will be the first trial of MI in Africa. METHODS: This is a hospital based, single centre, randomized controlled trial of MIG plus an information sheet on glaucoma and its treatment (the latter being "standard care") compared with standard care alone for glaucoma patients where the treatment recommended is surgery or laser.Those eligible for the trial are adults aged 17Â years and above who live within 200Â km of Bauchi with advanced glaucoma where the examining ophthalmologist recommends surgery or laser. After obtaining written informed consent, participants will be randomly allocated to MIG plus standard care, or standard care alone. Motivational interviewing will be delivered in Hausa or English by one of two MIG trained personnel. One hundred and fifty participants will be recruited to each arm. The primary outcome is the proportion of participants undergoing laser or surgery within two months of the date given to re attend for the procedure. MIG quality will be assessed using the validated MI treatment integrity scale. DISCUSSION: Motivational interviewing may be an important tool to increase the acceptance of treatment for glaucoma. The approach is potentially scalable and may be useful for other chronic conditions in Africa. TRIAL REGISTRATION: ISRCTN79330571 (Controlled-Trials.com)
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