Flow Injection Spectrophotometric Determination of Total Polyphenols in Black Tea Processed and Marketed in Ethiopian

The present study proposes an alternative flow injection spectrophotometric method for the quantification of total polyphenols in tea samples. The method was based on the reaction between polyphenols and 4-aminoantipyrine (4-AAP) in the presence of hexacyanoferrate in alkaline medium. A reddish-brown coloured product is formed as a result of a reaction between polyphenols and 4-AAP in the presence of oxidizing reagent, hexacyanoferrate, in alkaline medium which was detected at a wavelength of 520 nm. Standard gallic acid solutions prepared in the range of 10- 500 mg/L was used to plot a calibration graph. A good linear calibration graph (r= 0.997, n= 5) was obtained by plotting A (520nm) values versus gallic acid standards solutions (10- 500mg/L). The effect of several experimental conditions such as the effect of pH, reaction coil length, flowrate, the concentration of 4-AAP and concentration of hexacyanoferrate (HCF) were optimized and applied to flow injection analytical system. The proposed method was applied for the quantification of total polyphenol in selected tea samples and the result obtained are given as gallic acid equivalent (GAE) mg/L with RSD < 5. Keywords: Flow Injection, Amino-Antipyrine, Total-Polypheno

HETEROGENEOUS CONSTRAINTS, INCENTIVES AND INCOME DIVERSIFICATION STRATEGIES IN RURAL AFRICA

A burgeoning recent literature emphasizes "livelihood" diversification among smallholder populations (Chambers and Conway 1992, Davies 1993, Ellis 1998, Bryceson 1999, Ellis 2000, Little et al. 2001). While definitions vary within this literature, the concept of livelihoods revolves around the opportunity set afforded an individual or household by their asset endowment and their chosen allocation of those assets across various activities to generate a stream of benefits, most commonly measured as income. This holistic perspective has the potential to enhance our understanding of the strategies that farm households pursue to ensure food and income security given the natural and economic environment in which they operate. Diversification patterns reflect individuals' voluntary exchange of assets and their allocation of assets across various activities so as to achieve an optimal balance between expected returns and risk exposure conditional on the constraints they face (e.g., due to missing or incomplete markets for credit, labor, or land). Because it offers a glimpse as to what people presently consider their most attractive options, given the incentives and constraints they face, the study of diversification behavior offers important insights as to what policy or project interventions might effectively improve either the poor's asset holdings or their access to higher return or lower risk uses of the assets they already possess. Since diversification is not an end unto itself, it is essential to connect observed livelihood strategies back to resulting income distributions and poverty. Not all diversification into off-farm or non-farm income earning activities offers the same benefits and not all households have equal access to the more lucrative diversification options. Yet the livelihoods literature offers little documentation or explanation of important differences between observed diversification strategies. This paper addresses that gap by offering a comparative analysis using data from three different countries, Cote d'Ivoire, Kenya and Rwanda. Like Dercon and Krishnan (1996) and Omamo (1999), we emphasize that interhousehold heterogeneity in constraints and incentives must factor prominently in any sensible explanation of observed diversification behaviors. Indeed, section 4 demonstrates that at a very fundamental level - the choice of basic livelihood strategy - households would prefer locally available livelihood strategies other than those they choose, were they not constrained from doing so. A simple appeal to the principle of revealed preference thus suggests that heterogeneous constraints and incentives play a fundamental role in determining livelihood diversification patterns manifest in income diversification data. The plan for the remainder of this paper is as follows. The next section presents the basic conceptual foundation from which we operate. Section 3 then introduces the data sets and definitions employed in the analysis. Section 4 presents findings relating to the observed variation in income sources across the income distribution, to distinct livelihood strategies pursued by rural African households, to the determinants of strategy choice, and to the effects of alternative livelihood strategies on income dynamics. These findings point especially to significant rural markets failures - especially with respect to finance and land - that force poorer subpopulations to select strategies offering demonstrably lower returns while wealthier subpopulations are able to enjoy higher return strategies to which entry is at least partly impeded by fixed costs and lower marginal costs of participation. Section 5 concludes.Labor and Human Capital, O & Q12,

Physicochemical Characterization of Distillery Effluent from One of the Distilleries Found in Addis Ababa, Ethiopia

Effluents released from distillery industries are known for the damage they cause to the natural ecosystem if proper pretreatment procedure is not performed. A study is required to assess the physicochemical property of the effluent such as colour, odour, total dissolved solid (TDS), chemical oxygen demand (COD), pH, biochemical oxygen demand (BOD), electrical conductivity, and heavy metals which are considered as the mostly reported parameters to indicate the level of pollution from industrial effluents. The present study was conducted to investigate the physicochemical characteristic of one of the distillery effluent found in Addis Ababa, Ethiopia. In our investigation lower pH, higher temperature, higher concentration of chemical oxygen demand (COD) and biochemical oxygen demand (BOD) have been recorded. Keywords: Physicochemical, Distillery-Effluent, Total Dissolved Soli

Sand Filtration as an Alternative Technique for the Treatment of Distillery Effluent

Distilleries produce large volume of wastewater which poses a considerable environmental impact by polluting water and soil bodies. The present study was conducted to find a simple and economical way for wastewater treatment. Wastewater released from distilleries was filtered by using different ratio of sand and clay soil with some amount of wood ash and charcoal. The result revealed that there was a significant reduction in parameters as: pH, COD, BOD, TDS, EC and heavy metal concentrations. Maximum percentage reduction in all parameter was obtained for the filtration with 3:1 sand and clay soil with some amount of crushed wood charcoal. Minimum reduction in all parameter was recorded for the filtration with 3:1 sand and clay soil. Keywords: Wastewater, Physicochemical, Filtration-Be

Insecticidal Activity of Prosopis Juliflora Seed Oil against Termite (Odontotermes obesus) and Cockroach (Blattella germanica)

Plant produces large number of compounds as secondary metabolites with complex structure and diversity with a potent insecticidal activity. Large number of plants has been identified so far for their insecticidal property and can be used as an alternative pest management for synthetic pesticides. The present investigation was conducted to evaluate the insecticidal activity of prosopis juliflora against termite (Odontotermes obesus) and cockroach (Blattella germanica). The n-hexane extract of the proposed plant showed higher percentage mortality at 10 % concentration in 30 and 42 hours against termite and cockroach respectively. The LD50 was determined to be 0.472% and 1.07% for termite and cockroach, respectively after 23 hours. The proposed plant showed significant insecticidal activity at 0.005% level of confidence. From the present investigation it can be suggested that prosopis juliflora can be used as potential insecticide. Keywords: Insecticidal, prosopis juliflora, Bio-degradabl

Strukturní vývoj a U/Pb datování hammerské jednotky (východoafrický orogen)

in English Studied parts of the Hammar Domain and Adola-Moyale Belt is situated at the junction of the Arabian Nubian Shield (ANS) and Mozambique Belt (MB) as a crucial area where to study the overall imprint of the East-African Orogeny in Ethiopia. Based on detailed field geological mapping, morphotectonic analysis of Digital Elevation Model, detailed structural analysis and U/Pb dating results of biotite orthogneiss from the Hammar Domain the overall tectonic evolution associated with the East-African Orogeny is interpreted. The structural evolution of the northern Hammar Domain and northwestern tip of the Adola- Moyale Belt could be defined into four deformation phases D1 to D4 resulted in origin of: (a) Relict compositional banding (S1) of flat-lying orientation defining the primary contacts of high- to medium grade lithologies, (b) superimposed steeply to moderately dipping ~N-S to ~NW-SE trending compressional foliation (S2) due to a regional ~E-W oriented compression and (c) later sub-horizontal to gently NW dipping foliation (S3) associated with well-developed NW plunging lineation. Furthermore, the localized tectonic activity was concentrated in form of narrow brittle-ductile to brittle ~N-S to ~NW-SE trending shear zones, commonly accompanied by hydrothermal mineralization. New...(v českém jazyce) Studované části hammarské domény a pásu Adola-Moyale se nachází na pomezí Arabsko- núbijského štítu (ANS) a mosambického pásu (MB). Jedná se o důležité oblasti kde lze studovat záznam východoafrických orogenenních procesů v Etiopii. Na základě podrobného terénního geologického mapování, morfotektonické analýzy digitálního modelu reliéfu, strukturní analýzy a výsledků U/Pb datování biotitické ortoruly z hammarské domény byl interpretován celkový tektonický vývoj oblasti spojený s východoafrickou orogenní fází. Výsledky morfotektonické analýzy digitálního modelu reliéfu reprezentují jak širší spektrum zlomových struktur, které byly aktivní od období neoproterozoika až po součastnost, tak i výrazná litologická rozhraní. Strukturní vývoj severní části hammarské domény a severozápadní části pásu Adola-Moyale lze definovat ve čtyřech deformačních fází D1 až D4, jehož výsledkem je: (a) tvorba reliktního kompozičního páskování (S1), které definuje primární litologické kontakty, (b) superponovaná strmě orientovaná kompresní foliace (S2) s-j. až sz-jv. průběhu, jejíž vznik je důsledkem regionální ~V-Z orientované komprese a (c) superpozice subhorizontální až mírně k ~SZ updající foliace (S3) s výraznými lineacemi. Dále, lokalizovaná tektonická aktivita byla koncentrována ve formě úzkých...Ústav petrologie a strukturní geologieInstitute of Petrology and Structural GeologyFaculty of SciencePřírodovědecká fakult