What is the potential for biogas digesters to improve soil carbon sequestration in Sub-Saharan Africa? Comparison with other uses of organic residues

Acknowledgments We are very grateful to the UK Department for International Development (DFID) New and Emerging Technologies Research Call for funding this work. PS is a Royal Society-Wolfson Research Merit Award holder.Peer reviewedPostprin

What is the potential for biogas digesters to improve soil fertility and crop production in Sub-Saharan Africa?

Acknowledgements We are very grateful to the UK Department for International Development (DFID) New and Emerging Technologies Research Call for funding this work. PS is a Royal Society-Wolfson Research Merit Award holder.Peer reviewedPostprin

Can biogas digesters help to reduce deforestation in Africa?

Acknowledgements The authors are grateful for financial support for this work in part from the UK Department for International Development (DFID) New and Emerging Technologies Research Call, and in part from the EU under the REDD-ALERT (Reducing Emissions from Deforestation and Degradation from Alternative Land Uses in Rainforests of the Tropics) project, Grant agreement number 226310. The authors thank Dr Hoang Viet Anh, Dr Suyanto and Mr. Gamma Galudra for their input on the manuscript.Peer reviewedPostprin

Bacterial isolates and their antimicrobial susceptibility pattern among patients with external ocular infections at Borumeda hospital, Northeast Ethiopia

Background: Bacteria are major cause of ocular infections and possible loss of vision. The emergence of antimicrobial resistant bacteria increases the risk of treatment failure with potentially serious consequences. The aim of this study was to determine the prevalence of bacterial isolates and their antimicrobial susceptibility pattern among patients with external ocular infections. Methods: A cross sectional study was conducted among 160 patients with external ocular infections at Borumeda hospital, Northeast Ethiopia. Socio-demographic and clinical data were collected using structured questionnaire. External ocular specimens were collected using sterile swabs and inoculated on MacConkey agar, Chocolate agar and Blood agar culture Medias. Presumptive isolates were further identified by a series of biochemical tests. The antimicrobial susceptibility patterns of the isolates were determined by disk diffusion method. Result: The overall prevalence of bacterial pathogens among external ocular samples was 59.4 %. The majority of the isolates (93.7 %; 89/95) were Gram positive and the other 6.3 % (6/95) Gram negative bacteria. The proportion of coagulase negative Staphylococci among the Gram positive bacterial isolates was 53.7 % (n = 51/95). All Gram positive isolates were susceptible for vancomycin but 67.4 % (n = 60/95) of them were resistant against amoxicillin. Moreover, drug resistance to tetracycline, norfloxacylin, ceftriaxone and ciprofloxacin were observed among Gram negative bacteria isolates. Conclusion: The prevalence of bacterial pathogens among external ocular samples was high and the predominant isolate was coagulase negative Staphylococci. Exceptionally high amoxicillin resistance was observed among Gram positive bacterial isolates that may dictate to conduct drug susceptibility test routinely.Birtukan Shiferaw, Baye GelawEmail author, Abate Assefa, Yared Assefa and Zelalem Addi

Mechanical Property of Plastic Lumber Produced from Recycled High Density Polyethylene (HDPE)

Recycling is a strategy to combat environmental pollution due to plastic wastes. Of the many plastic wastes, researchers confirmed the possibility to produce plastic lumber from used HDPE plastics. The aim of this study is to experimentally determine the mechanical property of the plastic lumber produced from pure HDPE and its composite with wood to proof usability and applicability for different purpose. The experiment considered different conditions. Pure plastic lumber and wood plastic composite lumber is initially produced and examined under room temperature and below room temperature. Under each condition, bending, tensile and impact strength were examined. For each test eight specimens were prepared based on international standards and the experiments were conducted using standard testing machines. The result shows that pure plastic lumber has demonstrated superior load carrying capability, tensile load resistance capability and impact load resistance at room temperature. Moreover, the pure plastic lumber has an elastic nature and the wood composite has a brittle nature. In both cases the mechanical property of the plastic lumber permits to use for different applications. This has been also tested and resulted in similar phenomena at 20C below room temperature

A Coupled Remote Sensing and Simplified Surface Energy Balance Approach to Estimate Actual Evapotranspiration from Irrigated Fields

Accurate crop performance monitoring and production estimation are critical for timely assessment of the food balance of several countries in the world. Since 2001, the Famine Early Warning Systems Network (FEWS NET) has been monitoring crop performance and relative production using satellite-derived data and simulation models in Africa, Central America, and Afghanistan where ground-based monitoring is limited because of a scarcity of weather stations. The commonly used crop monitoring models are based on a crop water-balance algorithm with inputs from satellite-derived rainfall estimates. These models are useful to monitor rainfed agriculture, but they are ineffective for irrigated areas. This study focused on Afghanistan, where over 80 percent of agricultural production comes from irrigated lands. We developed and implemented a Simplified Surface Energy Balance (SSEB) model to monitor and assess the performance of irrigated agriculture in Afghanistan using a combination of 1-km thermal data and 250-m Normalized Difference Vegetation Index (NDVI) data, both from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. We estimated seasonal actual evapotranspiration (ETa) over a period of six years (2000-2005) for two major irrigated river basins in Afghanistan, the Kabul and the Helmand, by analyzing up to 19 cloud-free thermal and NDVI images from each year. These seasonal ETa estimates were used as relative indicators of year-to-year production magnitude differences. The temporal water-use pattern of the two irrigated basins was indicative of the cropping patterns specific to each region. Our results were comparable to field reports and to estimates based on watershed-wide crop water-balance model results. For example, both methods found that the 2003 seasonal ETa was the highest of all six years. The method also captured water management scenarios where a unique year-to-year variability was identified in addition to water-use differences between upstream and downstream basins. A major advantage of the energy-balance approach is that it can be used to quantify spatial extent of irrigated fields and their water-use dynamics without reference to source of water as opposed to a water-balance model which requires knowledge of both the magnitude and temporal distribution of rainfall and irrigation applied to fields