Energy consumption and economic growth: The experience of African countries revisited

The aim of this paper is to re-examine the causal relationship between energy consumption and economic growth for seventeen African countries in a multivariate framework by including labor and capital as additional variables. We apply the variance decomposition analysis due to Pesaran and Shin [Pesaran M.H. and Shin, Y. Generalised impulse response analysis in linear multivariate models, Economics Letters, 1998; 58; 17–29.] to evaluate how important is the causal impact of energy consumption on economic growth relative to labor and capital. The results of our multivariate modified Granger causality analysis due to Toda and Yamamoto [Toda, H.Y. and Yamamoto, T. Statistical inference in vector autoregressions with possibly integrated process, Journal of Econometrics, 1995; 66; 225–250.] tend to reject the neutrality hypothesis for the energy–income relationship in fifteen out of the seventeen countries. In contrast, results of our variance decomposition analyses show that in eleven out of the seventeen countries, energy is no more than a contributing factor to output growth and not an important one when compared to capital and labor. Labor and capital are the most important factors in output growth in fifteen out of the seventeen countries. However, these results should be interpreted with care as they may not be sufficiently robust enough to support the inference that energy consumption plays a minor role in the economic growth of African countries.     

Levels of essential and non-essential metals in leaves of the tea plant (Camellia sinensis L.) and soil of Wushwush farms,Ethiopia

Five tea clones of the Camellia assamica variety grown in Wushwush tea plantation farms, Ethiopia, were analyzed for their contents of essential, non-essential and toxic metals (K, Ca, Mg, Fe, Mn, Cu, Zn, Na, Cd and Pb) by atomic absorption flame emission spectroscopy. Both the tea leaves and the soils of the study farms showed similar accumulation patterns in their contents of the studied macronutrients. Among the macronutrient metals, K was the most abundant element in the tea leaves (17.7–24.8 mg/g) and the soils (7.14–9.73 mg/g). Mn was the predominant micronutrient heavy metal in the tea leaf tissues ranging between 501 and 1281 mg/kg. Level of Fe (29.6–100 mg/kg) in the leaf tissue was found to be the second most abundant micronutrient next to Mn whereas concentrations of Cu and Co were relatively lower both in the soil and tea samples. The toxic heavy metals Pb and Cd in the leaf tissues were present at levels too low to be detected by the analytical technique used in this study. The soils were found to be acidic (pH 5.04–5.49) with high organic matter (5.48–6.02%). Fe was the most abundant metal followed by Mn, Na and Zn in the soils. Unlike the tea leaves, the soils were found to contain traces of the toxic metal, Cd (0.02–1.10 mg/kg). The levels of most of the metals determined in this study compared well with those reported for tea leaves from some other parts of the world.     

Bounds test approach to cointegration and causality between nuclear energy consumption and economic growth in India

This paper attempts to examine the dynamic relationship between economic growth, nuclear energy consumption, labor and capital for India for the period 1969–2006. Applying the bounds test approach to cointegration developed by Pesaran et al. (2001) we find that there was a short- and a long-run relationship between nuclear energy consumption and economic growth. Using four long-run estimators we also found that nuclear energy consumption has a positive and a statistically significant impact on India's economic growth. Further, applying the Toda and Yamamoto (1995) approach to Granger causality and the variance decomposition approach developed by Pesaran and Shin (1998), we found a positive and a significant uni-directional causality running from nuclear energy consumption to economic growth without feedback. This implies that economic growth in India is dependent on nuclear energy consumption where a decrease in nuclear energy consumption may lead to a decrease in real income. For a fast growing energy-dependent economy this may have far-reaching implications for economic growth. India's economic growth can be frustrated if energy conservation measures are undertaken without due regard to the negative impact they have on economic growth.     

Prevalence of goiter in children 6 to 12 years of age in Ethiopia

BACKGROUND: Iodine-deficiency disorders are a major public health problem in Ethiopia. In conjunction with implementing control programs, baseline information needs to be established. OBJECTIVE: To investigate the distribution and degree of severity of iodine-deficiency disorders in terms of goiter prevalence, urinary iodine excretion (UIE) levels, and proportion of households with iodated salt in Ethiopia. METHODS: A nationwide, community-based, cross-sectional study was conducted from February to May 2005 among 10,965 children aged 6 to 12 years. A multistage, proportional-to-population-size sampling method was used. Goiters were classified by the method recommended by the World Health Organization/UNICEF/International Council for the Control of Iodine Deficiency Disorders (WHO/UNICEF/ICCIDD), in which the thyroid gland is graded as 0 (normal), 1 (palpable goiter), or 2 (visible goiter); urinary iodine was determined by the wet digestion method; and salt samples were analyzed by a rapid test kit. RESULTS: The national total goiter weighted prevalence rate among children aged 6 to 12 years was 39.9% (95% confidence interval, 38.6% to 41.2%), representing more than 4 million children. The median UIE was 2.45 microg/ dL; 45.8% of children had UIE values of 2 microg/dL or less, and 22.8% had UIE values of 2.01 to 5.0 pg/dL. Only 4.2% of the households had iodated salt. CONCLUSIONS: According to the WHO/UNICEF/ ICCIDD classification, both goiter prevalence and UIE levels indicate that the whole country appears to be severely affected by iodine deficiency. Furthermore, the virtual absence of iodated salt in the households shows that currently there is no salt iodization program in the country. Dietary sources of iodine in Ethiopia are not dependable, and hence a sustainable universal salt iodization program needs to be implemented without delay.     

Fabrication of micro-gas chromatograph columns for fast chromatography

Gas chromatography (GC) is one of the most widespread techniques used in laboratories as a way to separate and analyze complex mixtures of volatile and semi-volatile compounds. The main advantage of miniaturization of these systems is the increased performance due to the reduced time for analysis and reduced fabrication cost of the complex pneumatic flow system. In this paper advanced design ideas and fabrication processes to facilitate integration of the sample concentrator and the column will be presented. Using the LIGA process, 0.5- and 2-m-long, 50-μm-wide, and up to 600-μm-high aspect ratio metal GC separation columns with on-chip integrated sample injection and detection were fabricated. Initial experiments of coating these high aspect ratio columns show promising results when compared to simple tubular columns.     

Coal consumption and economic growth revisited

This paper revisits the causal relationship between coal consumption and real GDP for six major coal consuming countries for the period 1965–2005 within a vector autoregressive (VAR) framework by including capital and labour as additional variables. Applying a modified version of the Granger causality test due to Toda and Yamamoto [Toda HY, Yamamoto T. Statistical inference in vector autoregressions with possibly integrated process. J Econom 1995;66:225–50], we found a unidirectional causality running from coal consumption to economic growth in India and Japan while the opposite causality running from economic growth to coal consumption was found in China and South Korea. In contrast there was a bi-directional causality running between economic growth and coal consumption in South Africa and the United States. Variance decomposition analysis seems to confirm our Granger causality results. The policy implication is that measures adopted to mitigate the adverse effects of coal consumption may be taken without harming economic growth in China and South Korea. In contrast, for the remaining four countries conservation measures can harm economic growth.     

Modeling the clay minerals–enzyme binding by fusion fluorescent proteins and under atomic force microscope

In the present study, binding of cellulase protein to different clay minerals were tested using fluorescent–protein complex and microscopic techniques. Cellulase gene (Cel5H) was cloned into three fluorescent vectors and expressed as fusion enzymes. Binding of Cel5H–mineral particles was confirmed by confocal microscopy, and enzyme assay. Among the Cel5H–fusion enzymes, green–fusion enzyme showed higher intensity compared with other red and yellow fusion–proteins. Intensity of fusion–proteins was dependent on the pH of the medium. Confocal microscopy revealed binding of the all three fusion proteins with different clay minerals. However, montmorillonite displayed higher binding capacity than kaolinite clay. Likewise, atomic force microscopy (AFM) image profile analysis showed proteins appeared globular molecules in free‐state on mica surface with an average cross sectional diameter of 110 ± 2 nm and rough surface of montmorillonite made protein appear flattened due to structural alteration. Even surface of kaolinite also exerted some strain on protein molecular conformation after binding to surface. Our results provide further evidence for 3D visualization of enzyme–soil complex and encourage furthering study of the force involved interactions. Therefore, our results indicate that binding of proteins to clay minerals was external and provides a molecular method to observe the interaction of clay minerals–enzyme complex.     

Technology transfer of hand pumps in rural communities of Swaziland: Towards sustainable project life cycle management

The research summarised in this paper explored the reasons behind the high failure rates of hand pumps from a technology transfer perspective, by examining the existing hand pump technology transfer practices and procedures in Swaziland where over 3000 hand pumps were installed and about 60% are not working. The research determined that there is a lack of proper, structured and sustainable knowledge sharing practices among the main stakeholders, suppliers, providers, users, and the government. It was observed that operations and maintenance, knowledge management, and the integration of a project life cycle management approach were crucial elements for the sustainability of hand pump-based rural water supply projects. Users have little involvement throughout the project life cycle; they do not know where and how to access parts, the majority of the areas do not have trained technicians, and government does not have stock for parts. There is poor communication between the users and suppliers, which is critical for product improvement and product support. It is therefore necessary to have a balanced focus on resource allocation for a hard and soft technology transfer process. A maintenance model resulting from the study aims to provide for practical co-ordination involving all the major stakeholders. Its objective is to establish a sustainable institutional support system through a public/private partnership.     

Electricity consumption and economic growth: a time series experience for 17 African countries

While the availability of electricity by itself is not a panacea for the economic and social problems facing Africa, the supply of electricity is nevertheless believed to be a necessary requirement for Africa's economic and social development. This paper tests the long-run and causal relationship between electricity consumption per capita and real gross domestic product (GDP) per capita for 17 African countries for the period 1971–2001 using a newly developed cointegration test proposed by Pesaran et al. (2001) and using a modified version of the Granger causality test due to Toda and Yamamoto (1995). The advantage of using these two approaches is that they both avoid the pre-testing bias associated with conventional unit root and cointegration tests. The empirical evidence shows that there was a long-run relationship between electricity consumption per capita and real GDP per capita for only 9 countries and Granger causality for only 12 countries. For 6 countries there was a positive uni-directional causality running from real GDP per capita to electricity consumption per capita; an opposite causality for 3 countries and bi-directional causality for the remaining 3 countries. The result should, however, be interpreted with care as electricity consumption accounts for less than 4% of total energy consumption in Africa and only grid-supplied electricity is taken into account.     

Effects of excessive speeding and falling asleep while driving on crash injury severity in Ethiopia: A generalized ordered logit model analysis

The severity of injury from vehicle crash is a result of a complex interaction of factors related to drivers’ behavior, vehicle characteristics, road geometric and environmental conditions. Knowing to what extent each factor contributes to the severity of an injury is very important. The objective of the study was to assess factors that contribute to crash injury severity in Ethiopia. Data was collected from June 2012 to July 2013 on one of the main and busiest highway of Ethiopia, which extends from the capital Addis Ababa to Hawassa. During the study period a total of 819 road crashes was recorded and investigated by trained crash detectors. A generalized ordered logit/partial proportional odds model was used to examine factors that might influence the severity of crash injury. Model estimation result suggested that, alcohol use (Coef. = 0.5565; p-value = 0.017), falling asleep while driving (Coef. = 1.3102; p-value = 0.000), driving at night time in the absence of street light (Coef. = 0.3920; p-value = 0.033), rainfall (Coef. = 0.9164; p-value = 0.000) and being a minibus or vans (Coef. = 0.5065; p-value = 0.013) were found to be increased crash injury severity. On the other hand, speeding was identified to have varying coefficients for different injury levels, its highest effects on sever and fatal crashes. In this study risky driving behaviors (speeding, alcohol use and sleep/fatigue) were a powerful predictor of crash injury severity. Therefore, better driver licensing and road safety awareness campaign complimented with strict police enforcement can play a pivotal role to improve road safety. Further effort needed as well to monitor speed control strategies like; using the radar control and physical speed restraint measures (i.e., rumble strips).