Status and Potential of Spate Irrigation in Ethiopia

This article discusses spate irrigation in Ethiopia and aims to take stock of the current status of spate irrigation development. It summarizes experiences so far and formulates a number of recommendations on the development of this upcoming resource management system. It argues that raised weirs are useful mainly in areas where a large head for spate flow diversion is required, but that traditional earthen structures with conical stone/gabion reinforcements are cost-effective and technically adequate for floodwater distribution and management. It contends that the practical successes of sediment settling ponds (gravel traps) are at best mixed. Even where a small basin is justified, it can only ever trap a small proportion of the incoming sediment load. It is better to allow large floods with excessive sediment load (>100,000 ppm) to by-pass upstream intakes to be diverted lower down the system, and provide additional livelihood opportunities in downstream areas in the form of rangeland and agro-forestry development. This is particularly useful in the lowlands of Ethiopia with large pastoral community where spate irrigation is yet to make in-roads. The article further explains that water rights in spate are different from the sharing and allocation of perennial flows—they are dynamic and respond to a situation that differs from year to year as well as within a year and that a certain degree of inequity among users is inevitable. Keeping the command area compact can ensure two or more irrigation turns and this can highly increase productivity as crops are no longer in the ‘stress zone’. To transform spate irrigation in Ethiopia from subsistence to a business-oriented production system, the article proposes the promotion of cash crops including pulses and oil seeds as well as encouraging investors to go for bio-fuel development and agro-forestry in the lowland areas where huge potential exist. To avoid vehement conflicts that may arise among the settled agricultural and pastoral communities due to the implementation of the business-oriented production system, the traditional rights of the pastoral communities must be respected and their rangeland and water resources be safeguarded. For maximum yield, soil moisture conservation measures such as pre-irrigation land preparation, deep ploughing and mulching are essential as is the conjunctive use of spate flow and groundwater. Last, but most important, the article emphasizes that farmers need to be placed at the heart of any spate irrigation development programme as primary beneficiaries, managers and operators as well as part of the decision making institution.     

The prejudiced personality revisited: Personal need for structure and formation of erroneous group stereotypes.

Two studies explored the relation between personal need for structure (PNS) and a reasoning process through which stereotypes may form. Participants viewed information about the performance of group members on intelligence-related tasks and then indicated their inference strategies and impressions of the groups. Results indicated that high-PNS participants were more likely than low-PNS participants to form erroneous group stereotypes. Individual differences in attributional complexity and need for cognition also predicted stereotype formation under some conditions. The effects of PNS and other cognitive personality variables were weakened under conditions in which participants believed that they would have to justify their impressions publicly. Discussion focuses on processes underlying the relation between PNS and stereotype formation and on relations among personality, social context, and social inference. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of crop residues on grain yield response of sorghum (t Sorghum bicolor) (L.) to application of N and P fertilizer

A field experiment was conducted on two soil types for seven years (1988–1994) to investigate the effect of the presence of crop residue on grain yield response of sorghum to NP fertilizer applied every year or once only at the start of the experiment. Grain yield was increased by the NP fertilizer alone, but was not further significantly increased by application of both residues and NP fertilizer. During the study period yields decreased abruptly with decreasing rainfall after the first year particularly on the Typic Pellustert. Thus there was a difference according to soil type. This revised version was published online in August 2006 with corrections to the Cover Date.     

Longitudinal Proteomic Analysis of Plasma across Healthy Pregnancies Reveals Indicators of Gestational Age

Longitudinal changes in the blood proteome during gestation relate to fetal development and maternal homeostasis. Charting the maternal blood proteome in normal pregnancies is critical for establishing a baseline reference when assessing complications and disease. Using mass spectrometry-based shotgun proteomics, we surveyed the maternal plasma proteome across uncomplicated pregnancies. Results indicate a significant rise in proteins that govern placentation and are vital to the development and health of the fetus. Importantly, we uncovered proteome signatures that strongly correlated with gestational age. Fold increases and correlations between the plasma concentrations of ADAM12 (ρ = 0.973), PSG1 (ρ = 0.936), and/or CSH1/2 (ρ = 0.928) with gestational age were validated with ELISA. Proteomic and validation analyses demonstrate that the maternal plasma concentration of ADAM12, either independently or in combination with either PSG1 or CSH1/2, correlates with gestational age within ±8 days throughout pregnancy. These findings suggest that the gestational age in healthy pregnancies may be determined by referencing the concentration of select plasma proteins.     

Investigations with Drugs and Pesticides Revealed New Species- and Substrate-Dependent Inhibition by Elacridar and Imazalil in Human and Mouse Organic Cation Transporter OCT2

Multiple drugs are used to treat various indications as well as pesticides that are ingested unintentionally and enter the bloodstream. The residence time or bioavailability of these substances in circulation depends on several mechanisms, such as drug–drug interaction (DDI), drug–pesticide interaction, metabolizing enzymes and the hepatic and renal transport systems, involved in the elimination of the compounds from the body. One of these transporters is the Organic Cation Transporter 2 (OCT2) member of the solute carrier (SLC22) transporter family. OCT2 is highly expressed in the proximal tubule epithelial cells in human and mouse kidney, where it mediates the uptake of endogenous organic cations as well as numerous drugs and xenobiotics, and contributes to the first step of renal clearance. In this study, we examined OCT2 on two subjects: First, the transferability of data from mouse to human, since mice are initially examined in the development of new drugs to assess the renal excretion of organic cations. Second, to what extent the choice of substrate affects the properties of an inhibitor. For this purpose, the functional properties of hOCT2 and mOct2 were validated under the same experimental conditions with the known substrates metformin and 1-Methyl-4-phenylpyridinium iodide (MPP). While hOCT2 and mOct2 showed very low affinities for metformin with K_m values of 3.9 mM and 3.5 mM, the affinity of hOCT2 and mOct2 for MPP (62 and 40 µM) was 64- and 89-fold higher, respectively. For our positive control inhibitor decynium22, we determined the following IC₅₀ values for hOCT2 and mOct2: 2.2 and 2.6 µM for metformin uptake, and 16 and 6.9 µM for MPP uptake. A correlation analysis of the inhibitory effects of 13 drugs and 9 pesticides on hOCT2- and mOct2-mediated transport of metformin showed a correlation coefficient R² of 0.88, indicating good interspecies correlation. Nevertheless, the bioenhancer elacridar and the fungicide imazalil showed species-dependent inhibitory potentials. Concentration-dependent inhibition of hOCT2- and mOct2-mediated metformin uptake by elacridar showed IC₅₀ values of 20 µM and 1.9 µM and by imazalil 4.7 µM and 0.58 µM, respectively. In conclusion, although our data show comparable species-independent interactions for most compounds, there can be large species–specific differences in the interactions of individual compounds, which should be considered when extrapolating data from mice to humans. Furthermore, a comparison of the inhibitory potential of elacridar and imazalil on metformin uptake with that on MPP uptake reveals substrate-dependent differences in hOCT2 and mOct2 for both inhibitors. Therefore, it might be useful to test two different substrates in inhibition studies.     

Spatial variation in biodiversity, soil degradation and productivity in agricultural landscapes in the highlands of Tigray, northern Ethiopia

There is a growing concern about food security and sustainability of agricultural production in developing countries. However, there are limited attempts to quantify agro-biodiversity losses and relate these losses to soil degradation and crop productivity, particularly in Tigray, Ethiopia. In this study, spatial variation in agro-biodiversity and soil degradation was assessed in 2000 and 2005 at 151 farms in relation to farm, productivity, wealth, social, developmental and topographic characteristics in Tigray, northern Ethiopia. A significant decrease in agro-biodiversity was documented between 2000 and 2005, mainly associated with inorganic fertilizer use, number of credit sources and proximity to towns and major roads. Agro-biodiversity was higher at farms with higher soil fertility (available P and total N) and higher productivity (total caloric crop yield). Low soil organic matter, few crop selection criteria and steep slopes contributed to soil erosion. Sparsely and intensively cultivated land use types, as determined from satellite images, were associated with high and low agro-biodiversity classes, respectively, as determined during on-farm surveys in 2005. This study gives insight into the recent changes in and current status of agro-biodiversity and soil degradation at different spatial scales, which can help to improve food security through the maintenance of agro-biodiversity resources.

Prevalence of tobacco use in Eritrea: results from a noncommunicable disease risk factor survey.

The prevalence of noncommunicable diseases in Eritrea is increasing. Tobacco use is a recognized risk factor for most of these diseases, especially cardiovascular disease. No data have been published on tobacco use in Eritrea. The present study sought to establish the prevalence of tobacco smoking in Eritrea. The World Health Organization STEPwise approach was used for the survey, conducted in 2004 on a random national sample size of 2,460 subjects (response rate = 93.7%). The prevalence of tobacco smoking in the general population was 8.1%; the prevalence was 15% among men, compared with 0.6% among women. Prevalence rates were higher in those older than 45 years of age. The prevalence of tobacco smoking was higher among Muslims (11.4%) than Orthodox Christians (5.8%), and among alcohol drinkers (10.2%) than nondrinkers (6.6%). The majority of tobacco users (89.3%) used commercially available cigarettes. A study on knowledge, attitudes, and practices regarding tobacco use is needed to determine the behavioral factors leading to tobacco smoking among the vulnerable groups.     

An air–metal hydride battery using MmNi3.6Mn0.4Al0.3Co0.7 in the anode and a perovskite in the cathode

Hydrogen storage alloy MmNi_3.6Mn_0.4Al_0.3Co_0.7 (MH) was tested as anode material in a metal hydride–air cell. The cathode was a non-noble metal air electrode based on a mixture of perovskite and pyrolyzed macrocycles on carbon. Polarization and discharge capacities of the electrodes were measured and compared at 22 °C and 40 °C using air or oxygen at the cathode. Discharge capacity reaching 330 mAh/g MH with pure oxygen at 40 °C and 305 mAh/g MH with air at 22 °C were obtained. Power densities and/or energy densities were found to significantly depend on the increase of the electrode kinetics on both the ORR (oxygen reduction reaction) and HOR (hydrogen oxidation reaction). However, for air electrode, an increase of oxygen concentration by using pure oxygen gas plays a more important role than an 18 °C temperature increase.     

Research on bioorganic fuels as power sources

This paper deals with the kind of the bioorganic fuel cells that are equipped with or without ion exchange membranes. The bioorganic materials of interest are alcohols (methanol, ethanol) and glucose, which are obtained from renewable energy sources such as biomass. The operation temperatures of the direct fuel cells cover from room temperature up to 150 °C. The direct bioorganic fuel cells belong to the subject area of ‘Advanced fuel cells’ of the Working group 4 in the EU COST Action 543 among the collaborating Universities and Institutes. Bioorganic fuel cells are suitable for application in small portable power sources, such as backups, battery chargers and in electronic devices. A number of current and earlier works are summarised and advances are highlighted in this area with special emphasis on glucose as a fuel.