Mobile phone use is associated with higher smallholder agricultural productivity in Tanzania, East Africa.

Mobile phone use is increasing in Sub-Saharan Africa, spurring a growing focus on mobile phones as tools to increase agricultural yields and incomes on smallholder farms. However, the research to date on this topic is mixed, with studies finding both positive and neutral associations between phones and yields. In this paper we examine perceptions about the impacts of mobile phones on agricultural productivity, and the relationships between mobile phone use and agricultural yield. We do so by fitting multilevel statistical models to data from farmer-phone owners (n = 179) in 4 rural communities in Tanzania, controlling for site and demographic factors. Results show a positive association between mobile phone use for agricultural activities and reported maize yields. Further, many farmers report that mobile phone use increases agricultural profits (67% of respondents) and decreases the costs (50%) and time investments (47%) of farming. Our findings suggest that there are opportunities to target policy interventions at increasing phone use for agricultural activities in ways that facilitate access to timely, actionable information to support farmer decision making.

Assessment of Cardiopulmonary Responses to Treadmill Walking Following Gastric Bypass Surgery.

BACKGROUND: Studies that have evaluated cardiopulmonary responses to exercise within the first few months of bariatric surgery have utilized cycle ergometry. However, walking is the most commonly reported mode of both pre- and post-operative PA. The divergent cardiopulmonary responses and metabolic costs of weight-bearing (walking) and non-weight-bearing (cycling) exercises warrant examination of the effects of bariatric surgery on cardiopulmonary responses during walking. METHODS: Nine women completed a maximal cardiopulmonary exercise test on a treadmill 2 weeks before and 3 months after gastric bypass surgery (GBS). Heart rate (HR), oxygen uptake (VO2), oxygen pulse (O2-p), and time to fatigue were compared before and after surgery and between the GBS group and a comparison group of 12 normal-weight (NW) women who completed the same exercise testing protocol. RESULTS: Time to fatigue increased by ~140 s following GBS (p = 0.018). No other parameter improved during maximal exercise from pre- to post-surgery. Body weight- and fat-free mass-corrected VO2 and O2-p at peak exercise differed between the GBS and NW groups before surgery, while only weight-corrected values were different following surgery. These differences disappeared after controlling for body fat percentage. CONCLUSION: We have demonstrated that weight loss alone was not sufficient to improve select cardiopulmonary fitness measures during treadmill walking in obese females 3 months after GBS. However, we did observe a significant overall improvement in exercise capacity as the GBS group was able to exercise longer, presumably due to significant reductions in body mass and a subsequent reduced metabolic cost of walking.

Land management in the American southwest: a state-and-transition approach to ecosystem complexity.

State-and-transition models are increasingly being used to guide rangeland management. These models provide a relatively simple, management-oriented way to classify land condition (state) and to describe the factors that might cause a shift to another state (a transition). There are many formulations of state-and-transition models in the literature. The version we endorse does not adhere to any particular generalities about ecosystem dynamics, but it includes consideration of several kinds of dynamics and management response to them. In contrast to previous uses of state-and-transition models, we propose that models can, at present, be most effectively used to specify and qualitatively compare the relative benefits and potential risks of different management actions (e.g., fire and grazing) and other factors (e.g., invasive species and climate change) on specified areas of land. High spatial and temporal variability and complex interactions preclude the meaningful use of general quantitative models. Forecasts can be made on a case-by-case basis by interpreting qualitative and quantitative indicators, historical data, and spatially structured monitoring data based on conceptual models. We illustrate how science- based conceptual models are created using several rangeland examples that vary in complexity. In doing so, we illustrate the implications of designating plant communities and states in models, accounting for varying scales of pattern in vegetation and soils, interpreting the presence of plant communities on different soils and dealing with our uncertainty about how those communities were assembled and how they will change in the future. We conclude with observations about how models have helped to improve management decision-making.