Electron transport and recombination has been investigated in dye-sensitized electrochemical solar cells at varying TiO2 film thickness using experimental electrochemical potential technique. Photocurrent transients resulting from small-amplitude square wave modulation of the incident light were analyzed, and the effect of illumination intensity and film thickness studied. Photovoltage decay measurements were studied on solar cells when switched from short-circuit and under illumination to open circuit and dark at varying illumination intensity for different film thickness. The analysis was done for varying film thickness at constant illumination intensity and varying illumination intensity at constant film thickness. The varying film thicknesses in this study were 3.0 m, 6.0 m, 12.8 m, 23.5 m and 25.3 m while illumination intensities were 0.5, 1.2, 2.4, 5.1, 9.0 and 15.6 mWcm-2. The voltage decay measured (known as open circuit voltage, Vsc) was seen to first rise to a maximum value then followed by decay. The maximum Vsc (Vsc, max) increased with film thickness at constant prior illumination. On the other hand, Vsc, max was found to depend on the prior illumination and exhibited logarithmic increase with light intensity. The time (tmax) to attain Vsc, max varies exponentially with light intensity and closely matches the electron transport time measured by photocurrent decay measurements.

Influence of pore size on the optical and electrical properties of TiO2 thin films were studied. TiO2 thin films with different weight percentages (wt %) of carbon black were deposited by screen method on fluorine doped tin oxide (FTO) coated on glass substrate. Carbon black decomposed on annealing and artificial pores were created in the films. All the films were 3.2 µm thick as measured by a surface profiler. UV-VIS-NIR spectrophotometer was used to study transmittance and reflectance spectra of the films in the photon wavelength of 300-1500 nm while absorbance was studied in the range of 350-900 nm. Band gaps and refractive index of the films were studied using the spectra. Reflectance, absorbance and refractive index were found to increase with concentrations of carbon black. There was no significant variation in band gaps of films with change in carbon black concentrations. Transmittance reduced as the concentration of carbon black in TiO2 increased. Currents and voltages (I-V) characteristics of the films were measured by a 4 point-probe. Resistivity (

TiO2 nanofibres have been synthesized by a simple hydrothermal process in 10M NaOH. TEM images have shown that nanofibres measuring average length 500nm and diameter 10nm were formed by this method. XRD analysis indicated strong anatase peaks with crystal orientation in the direction (101) with slight rutile peaks appearing at 5000C calcinations temperature. Thin films prepared from the nanofibres had thickness varying from 4.5 – 5.5μm. The films were used to fabricate complete dye sensitised solar cells with Ruthenium complex dye as sensitizer. I-V characteristics yielded Voc and Jsc of 0.46V – 0.58V and 0.16mA/cm2 – 4.5mA/cm2 respectively under standard illumination of 100mW/cm2 (using a halogen lamp and data acquired using Keithley 2400 Source Meter® controlled by LabVIEW® software).

To establish the pattern of occurrence and the clinicopathological features of keratocystic odontogenic tumour (KCOT) over a 10-year period.

Objectives: To establish the types of E. coli isolates that are found in river water around Nairobi and to assess the potential risk of use of this water to human health. Design: Multiple stratified sampling was carried out. Surface sampling was used in the entire study. Setting: The study was carried out on river waters surrounding Nairobi, Kenya. Subjects: Forty Escherichia coli strains isolated from river water. Main outcome measures: Serotyping, toxin gene tests and susceptibility to tetracyclines, ampicillin, chloramphenicol and kanamycin were analysed. Results: None of the isolates could be specifically serotyped using the available antisera. Toxin gene production tests using the colony hybridisation technique revealed that nine (22.5 %) of the strains were positive for heat stable (ST) toxin, seven (17.5 0/0) to the heat labile (L T) toxin and two (5 0/0) to both. Using the Agar Disk Diffusion technique, eighty per cent of the strains were susceptible to all four antibiotics, while twenty per cent of the strains showed multiple resistance. None of the strains was resistant to all four antibiotics while no strain showed resistance to kanamycin. Conclusion: None of the E. coli isolates was serotypable and it was therefore not possible to determine whether serologically identical strains of ETEC were haboured by man or animals. Toxin gene tests results showed that there is some risk of infection by diarrhoea causing ETEC to man and animals. Toxin gene tests results showed that there is some risk of infection by diarrhoea causing ETEC to man and animals if they consume this water untreated and there is evidence to show resistance of bacteria to antibiotics, hence appropriate health measures should be adhered to.

The area of nanostructured materials for dye sensitized solar cells has gained great interest by scientists, especially after a breakthrough by Gratzel and coworkers in developing a solar cell from nanostructured oxide of titania gaining an overall efficiency of about 11%. Since then research has been going on with emphasis on improvement on this achievement.

TiO2 nanofibres measuring average length 500nm and diameter 10nm have been prepared by synthesis method using 10M NaOH and dispersed in alcohol. Thin films prepared from the nanofibres had thickness varying from 4.5 – 5.5μm. The films were used to fabricate complete dye sensitised solar cells with Ruthenium complex dye as sentizer. I-V characteristics yielded Voc and Isc of 0.41V – 0.58V and 0.18mA – to 1.1mA respectively under standard illumination of 100mW/cm2 (using a halogen lamp and data acquired using Keithley 2400 Source Metre® controlled by LabVIEW® software). XRD analysis indicated strong anatase peaks with crystal orientation in the direction (101). This showed that there was no lose of crystalline structure of the TiO2 during the synthesis process. However, as the sintering temperature was raised, the percentage crystal content of anatase reduced as the rutile structure slowly formed.

"

Sub-Saharan Africa, and more specifically the East African region, has the lowest rates of access to electricity in the world. On average, at most 15% of the rural population has access to electricity. Rural households and remote institutions use traditional energy sources such as charcoal, firewood, kerosene and diesel for generator sets, batteries and dry cell batteries. On the other hand, the region is one of the most promising in the world in economic development with growth levels being high and market saturation is a far away future problem. This growth has
however been hampered by several factors with lack of energy being one of them. Kenya being one of the countries
in the region faces a similar problem with the traditional sources of hydro facing weather related challenges. The
situation is more wanting in the rural setting having only achieved electrification rates of between 5 and 10%. The rural being where the majority of low-income earning groups reside is further compounded with large geographical imbalance in electricity demand and supply. The main challenge to adopting pv utilization however, is lack of local capacity to handle the uptake all the way from solar home systems to grid connected and hybrid systems. According to Kenya Renewable Energy Association (KEREA), it is estimated that between 800 and 1000 pv technicians have been in practice since this sector started in Kenya in the late eighties, majority of them having the basic skills but no formal training to provide the service. They however have been offering necessary service to end-users and are hence an important aspect in the pv sector as a whole. Currently the pv (mainly SHS) comprise an over the counter trade system which provides loopholes when it comes to quality of products and installation. To safeguard the quality and safety of installations, formal training has to be incorporated in the system.

We report investigation of effect of conduction band edge on the dye injection and transport by preparation of (Ti,Sn)O2 solid mixtures in ratios of 80:20 and 90:10 as possible applications in dye sensitized solar cells. SEM micrographs showed highly porous with nanometer sized particles of around 6 - 10μm diameter. X-ray diffraction patterns showed strong TiO2 anatase peaks with crystal orientation directions (101) being the strongest in both the solid mixtures and in pure TiO2. XPS studies have shown an apparent chemical shift for Ti 2p and O1s core level spectra with an energy difference between the unmodified and the solid mixture being 0.65eV. Initial I-V studies have shown high Voc but low short circuit photocurrent, showing a possible unfavorable band edge shift between the semiconductor and the dye LUMO level.

Atherosclerosis is a multifactorial and multipart progressive disease manifested by the focal development within the arterial wall of lesions – the atherosclerotic plaques – in response to various deleterious insults that affect the vessel wall’s cells. Among the risk factors, as identified by classical epidemiology, there are dyslipidemia, vasoconstrictor hormones incriminated in hypertension, products of glycoxidation associated with hyperglycemia, pro-inflammatory cytokines and smoking, out of which the first is a prerequisite for the initiation and progression of about half of arterial lesions. In other instances, an inflammatory reaction induced by putative antigens that stimulate T lymphocytes, certain heat shock proteins, components of plasma lipoproteins, and potentially, microbial structures induce atherosclerotic plaque in the absence of systemic hypercholesterolemia [1, 2]. Thus, the process is more complex than previously thought. The conventional view that stressed the role of dyslipidemia in the generation of atherosclerosis was rounded by extensive evidence that inflammation is a key contributor to all stages of this disease, from the initial lesion to the ruptured plaque [2]. In all cases, the atheroma formation entails a progressive process in which the gradual implication of various cells and their secretory products define a sequence of events that leads from the fatty streak to fibro-lipid plaque, and ultimately to plaque rupture and atherothrombosis.

Modern Problems in Insurance Mathematics. Springer, London, Chapter 20, pages 337 – 366, XIX, 387 pages.
Summary:
Risk is the uncertainty of an outcome and it can bring unexpected gains but can also cause unforeseen losses, even catastrophes. They are common and inherent in financial and commodity markets; for example; asset risk, interest rate risk, foreign exchange risk, credit risk, commodity risk. Investors have various attitudes towards risk, that is, risk aversion, risk seeking and risk neutral. Over the past few years financial derivatives have become increasingly important in the world of finance since they are kind of a risk management tool. A financial derivative is a financial instrument whose value depends on other fundamental financial assets, called underlying assets, such as stocks, indexes, currencies, commodities, bonds, mortgages and other derivatives (since we can have a derivative of a derivative). As an underlying asset one can also use a non-financial random phenomenon like for instance, weather conditions e.g. temperatures. Pricing derivatives accurately and quickly is important for risk management. This is important for both those who trade in derivatives and those who are willing to insure them. In this paper some lattice methods for pricing Asian options modeled using a jump diffusion process will be described. These methods can often be adapted to pricing of other derivatives or solving other types of problems in financial mathematics, for instance a jump diffusion process can be used to describe incoming claims to an insurance company, see [20].

Sarcoidosis is a disease of unknown etiology that is characterized by the generalized formation of granulomas and is accompanied by elevation in the serum in less than half the patients of angiotensin converting enzyme, a dipeptidyl carboxypeptidase that catalyzes the conversion of the decapeptide, angiotensin I, to the pressor octapeptide, angiotensin II, and L-histidyl-L-leucine. Mean activity of angiotensin converting enzyme was elevated generally more than 10-fold in granuloma-containing lymph nodes, but not in lung in which normally it is abundant, in 19 of 20 patients with sarcoidosis. Angiotensin converting enzyme in lymph nodes from subjects with sarcoidosis was similar to the enzyme from normal lung and lymph node with respect to activity as a function of pH, inhibition of activity by EDTA and o-phenanthroline, gel filtration on Sephadex G-200, and requirement for chloride for activity, but appeared to be more heat labile. The data suggest that the granulomas in sarcoidosis may be the source of the elevated serum enzyme and that cells of the granulomas, particularly the epitheloid cells which appear by electron microscopy to have active protein biosynthesis, may be actively synthesizing the enzyme.

Monocular eyelid closure in cats during a critical period in development produces both physiological plasticity, as indicated by a loss of responsiveness of primary visual cortical neurons to deprived eye stimulation, and morphological plasticity, as demonstrated by a decrease in the total length of individual geniculocortical arbors representing the deprived eye. Although the physiological plasticity appears maximal after 2 d of monocular deprivation (MD), the shrinkage of deprived-eye geniculocortical arbors is less than half-maximal at 4 d and is not maximal until 7 d of deprivation, at which time the deprived arbors are approximately half their previous size. To study this form of plasticity at the level of individual thalamocortical synapses rather than arbors, we developed a new double-label colocalization technique. First, geniculocortical afferent arbors serving either the deprived or nondeprived eye were labeled by injection of the anterograde tracer Phaseolus vulgaris leucoagglutinin into lamina A of the lateral geniculate nucleus. Then, using antibodies to synaptic vesicle proteins, we identified presynaptic terminals within the labeled arbors in layer IV of the primary visual cortex. Analysis of serial optical sections obtained using confocal microscopy allowed measurement of the numerical density of presynaptic sites and the relative amounts of synaptic vesicle protein in geniculocortical afferents after both 2 and 7 d of MD. We found that the density of synapses in geniculocortical axons was similar for deprived and nondeprived afferents, suggesting that this feature of the afferents is conserved even during periods in which synapse number is reduced by half in deprived-eye arbors. These results are not consistent with the hypothesis that a rapid loss of deprived-eye geniculocortical presynaptic sites is responsible for the prompt physiological effects of MD.

Description
A study conducted in the major grazing areas of Uasin Gishu involved twenty-eight (28) soils, twenty-eight (28) forage and forty-two (42) serum samples collected in six divisions at different sites. The purpose of the study was to determine the macro-and trace elements in soils, forages and animal serum, and compare to the recommended standards so as to identify those that could be presenting deficiencies in the area. Soils were extracted for available macro-minerals; Sodium (Na), Potassium (K), Calcium (Ca) magnesium (Mg) and trace elements; Iron (Fe), Manganese (Mn), Copper (Cu) and Zinc (Zn; the forage samples were assayed for the same elements plus phosphorus as total concentration on dry matter (DM) basis while blood serum was analyzed for the same forage elements plus molybdenum (Mo). Atomic absorption spectrophotometer (AAS) and UV/visible spectrophotometer were used to analyze the metal elements and molybdenum respectively. Soil and Forage analysis of samples from southern region including Kesses and Ainabkoi revealed lower levels in both macro and trace elements analyzed. Serum samples from grazing areas situated in southern region revealed similar deficiencies in most minerals. The factors responsible for the variations as soil pH, forage species and cattle breed were investigated using correlation analysis.

It has been established that H+ secretion can be maintained in frog stomach in the absence of exogenous CO2 by using a nutrient bathing fluid containing 25 mM H2PO4 (pH approximately equal to 4.5) or by lowering the pH of a nonbuffered nutrient solution to about 3.0-3.6. Exogenous CO2 in the presence of these nutrient solutions uniformly caused a marked decrease in H+ secretion, PD, adn short-circuit current (Isc) and an increase in transmucosal resistance (R). Elevation of nutrient [k+] to 83 mM reduced R significantly but transiently without change in H+ when nutrient pH less than 5.0, whereas R returned to base line and H+ increased when nutrient pH greater than 5.0. Acidification of the nutrient medium in the presence of exogenous CO2 results in inhibition of the secretory pump, probably by decreasing intracellular pH, and also interferes with conductance at the nutrient membrane. Removal of exogenous CO2 from standard bicarbonate nutrient solution reduced by 50% the H+, PD, and Isc without change in R; K+-free nutrient solutions reverse these changes in Isc and PD but not in H+. The dropping PD and rising R induced by K+-free nutrient solutions in 5% CO2 - 95% O2 are returned toward normal by 100% O2. Our findings support an important role for exogenous CO2 in maintaining normal acid-base balance in frog mucosa by acting as an acidifying agent.

A major risk factor for the spread of livestock diseases and their vectors is the uncontrolled transboundary movement of live animals for trade and grazing. Such movements constrain effective control of tick-transmitted pathogens, including Theileria parva. Only limited studies have been undertaken to identify ticks and tick-borne diseases (TTBDs) affecting cattle in central African countries, including Cameroon. We hereby report the collection of baseline data on the prevalence of T. parva in Cameroon through a countrywide cross-sectional survey, conducted in 2016, involving collection of blood samples from cattle from 63 sites across the five agro-ecological zones (AEZs) of the country. ELISA-based surveillance of infected cattle was performed on 479 randomly selected samples and revealed specific antibodies to T. parva in 22.7% and T. mutans in 41.1% of cattle. Screening of 1,340 representative DNA samples for the presence of T. parva identified 25 (1.86%) positives using a p104 antigen gene-based nested PCR assay. The positives were distributed across agro-ecological zones I, II, III and V. None of the p104 positive cattle exhibited clinical symptoms of East Coast fever (ECF). Using reverse line blot (RLB), 58 (4.3%) and 1,139 (85%) of the samples reacted with the T. parva and T. mutans oligonucleotide probes, respectively. This represents the first report of T. parva from Cameroon. Surprisingly, no Rhipicephalus appendiculatus ticks, the main vector of T. parva, were identified in a parallel study involving comprehensive morphological and molecular survey of tick species present in the country. Only two of the 25 p104 positive cattle were PCR-positive for the CD8+ T-cell target schizont-expressed antigen gene Tp1. Cloning and sequencing of Tp1 amplicons revealed sequence identity with the reference T. parva Muguga. This new finding raises serious concerns of a potential spread of ECF into the central African region.

Abstract:

This study reports the biosynthesis of narrow range diameter silver nanoparticles at optimum conditions using Eucalyptus corymbia as a reducing and stabilizing agent. Optimal conditions for biosynthesis of silver nanoparticles (AgNPs) were found to be; an extraction temperature of 90°C, pH of 5.7 a Silver Nitrate concentration of 1mM and AgNO3 to plant extract ratio of 4:1. UV-Visible spectroscopy monitored the formation of colloidal AgNPs. The UV-Visible spectrum showed a peak around 425 nm corresponding to the Plasmon absorbance of the AgNPs. The size and shape characterization of the AgNPs was done using Transmission Electron Microscopy (TEM) techniques which revealed narrow range diameter (18-20 nm), almost monodispersed AgNPs, spherical in nature and with minimal agglomeration. Energy Dispersive X-ray (EDX) results showed the presence of two peaks at 3.0 and 3.15 keV in the silver region. The Fourier Transform Infrared-Spectra (FTIR) of the plant extract and the AgNPs gave rise to vibrational peaks at 3260 and 1634 wavenumbers which are due to the presence of OH and –C=C-functional groups respectively.

Description
The effect of adding sodium dodecyl sulfate (SDS), a surface-active agent to acetate buffer solution containing penicillin V was investigated. The voltammetric responses of penicillin V on glassy carbon electrode was a function of the concentration of penicillin V, surfactant and pH. Addition of SDS to the penicillin V containing acetate buffer solution (ABS) was found to enhance the voltammetric oxidation current signal by about 10 times with insignificant shift of the oxidation potentials. With this electrochemical method, the optimal pH and SDS concentration were found to be pH 4.5 and 0.347 M respectively. Using cyclic voltammetry, the oxidation potential for penicillin V were found to be 1.61 V vs. Ag/AgCl in SDS/ABS, pH 4.5 and 1.55 V vs. Ag/AgCl in ABS, pH 4.5. Linear concentration range were also investigated using square wave voltammetry and found to lie in the range of 0.04–34.6 µM penicillin V in SDS/ABS, pH 4.5 and 3.5–14.0 µM penicillin V in ABS, pH 4.5. Limits of detection were also found to be 0.04 µM penicillin V in SDS/ABS, pH 4.5 and 3.5 µM penicillin V in ABS, pH 4.5 and limits of quantitation were 0.12 µM penicillin V in SDS/ABS, pH 4.5 and 14µM penicillin V in ABS, pH 4.5.

The debate on forest degradation in Kenya is mainly concerned with the utilization and exploitation of forest resources. Of particular interest is fuelwood, whose scarcity is a major forest degradation concern. Fuelwood gathered from the forested commons is the most important source of domestic energy in the rural areas of many developing countries. For the case of Kakamega, as shown by this study, there is a declining trend in the availability of fuelwood. Despite this state, rural households still depend largely on it for energy provision in the face of limited options constrained by low capital base. This study sought to examine how these households cope with the existing scarcity of fuelwood. The study employed both primary and secondary sources of data. For primary data, a total of 140 households were selected and interviewed using semi-structured questionnaires. Response mechanisms were analyzed through descriptive methods by looking at collection attributes, use patterns and fuel saving technologies applied by households. Majority of households in Kakamega have resorted to planting trees on their own farms to ease problems of fuelwood shortage. Findings further reveal that households in their endeavor to circumvent the problem of continued scarcity, have resorted to poorer quality tree/bushes for fuelwood, alongside other innovative methods of responding to the fuelwood scarcity. With improved economic well being, households become less reliant on forests for their livelihoods. Since reduced forest reliance is positively related with reduced demand for forest products, the findings suggest complementarities between strategies aimed at poverty alleviation and those towards forest conservation.

The ability of policies on biodiversity prospecting to contribute over the long term to economic development, conservation and the equitable sharing of genetic resources is examined. Consideration is given to: national innovation policy and biodiversity, the linkage of biotechnology to biodiversity, biotechnology transfer, technology assessment, and blind alleys and windows of opportunity. The discussion underlines that biodiversity prospecting will not contribute much to developing countries unless it helps them accumulate technological capacity through training programmes and technology development through scientific innovation. In order that national biotechnology policies enhance biodiversity prospecting much attention needs to be paid to human resource development, technological innovation, legal and institutional reforms, biotechnology regulation and intellectual property management. The experiences of INBio (Costa Rica's National Biodiversity Institute), a pilot technology transfer project, are discussed

This chapter analyses copyright in the context of e-commerce in Kenya. It explores whether the music industry in Kenya is sufficiently protected in the digital era by focusing on five interrelated themes. Part One explores the interrelationship between e-commerce and intellectual property in Kenya. It discusses e-commerce in the context of patent, trade mark, trade secret and domain names. Part Two, Copyright law in e-commerce. It introduces copyright law; copyright in musical works; music in the Internet; the music industry in Kenya; legal dimensions of online music; and the challenges facing the music industry in Kenya.. Part Three explores copyright enforcement in Kenya with respect to civil and criminal remedies for copyright infringement as well copyright management organizations. We conclude Part Four critically

Product counterfeiting and trade in counterfeit products, labels and packaging involve imitation of genuine products that are marketed under brand names.3 Counterfeit products are becoming a major problem to consumers, innovators and traders in Kenya and globally. Such imitations are usually clones or falsified products, labels and packaging designed to look like those of genuine products. The aim is to confuse or deceive consumers as to their quality, source, origin or legitimacy. Counterfeits are manufactured, processed or supplied by unscrupulous traders who infringe and unlawfully apply other corporations’ or individuals’ innovations and intellectual property (IP).4 The basic thesis in this Chapter is that although there are short-term gains to consumers and the Kenyan economy from counterfeiting, the medium and long-term losses are massive. This Chapter adopts a three-pronged strategy on combating counterfeiting in Kenya. First, I evaluate the nature and extent of counterfeit trade in Kenya in the context of trade liberalization and the development of an information society. I also assess the effects of counterfeit trade on the various economic players including consumers, innovators, traders, investors, and the Kenyan Government. Second, I evaluate the intellectual property regime in Kenya and how IP can combat counterfeiting. I then carefully examine the anti-counterfeiting law and enforcement mechanisms in Kenya, including their effectiveness in addressing the problem. Third, I explore how that law can be reformed to ensure sustainable development by protecting innovators, consumers and other stakeholders.

isolated from preterm neonates during the outbreak of gastroenteritis in hospital in Nairobi, Kenya, were resistance to trimethoprin-sulfathoxaxole, Chloramphenicol, oxytetracycline and ampicilin, but only a few strains were resistant to cefazolin, cefamandole, cefataximine, amikacin and nalidixic acid. Fourteen different antimicrobial resistance patterns were observed in the 229 strains of E.coli analyzed. Eighty-two percent of the EPEC strains belonged to two resistance patterns. There was no consistent relationship between palsmid profile group and antimicrobial resistance pattern, although one resistance pattern was more frequently observed in EAF-positive strins belonging to the dominant plasmid profile group. Nine percent of the EPEC strins were resistant to gentamicin compared to 37% in the non-EPEC group. No correlation was observed between administration of gentamicin and percentage of resistant strains isolated. None of the nine neonates receiving gentamicin died during the outbreak. Gentamicin resistance was observed in E.coli strains from six out of these nine neonates. Five out of fourteen neonates who received other antimicrobials, or no antibiotic at all, died.

Key words: Enteropathogenic Escherichia Coli; antimicrobial resistance;

This study examined the RWH using the run tests, Ljung-Box statistics, and the unit root tests. The data covered the period starting January 1994 to June 2007 for the daily closing prices of the Ksh/UD dollar spot rate. The main finding of this study is that the RWH is strongly rejected at the 5% significance level. The results indicate that the rejections are due to autocorrelation in currency returns. The exchange rate tends to appreciate most of the time over the sample period. Therefore failure of the EMH could be due to exchange rate undershooting and overshooting phenomena. The unit root tests showed that the exchange rate data is non-stationary while returns are stationary. Therefore the evidence strongly suggested that the foreign exchange market is not efficient.

Farmers of the Sagana irrigation project, Kenya, have identified fluctuating and low prices for their agricultural produce as their main constraint. This paper reports results from a study carried out to identify an alternative cropping system that could be used to optimize their returns by harvesting their crops when the market price is highest. The study shows that there is a complex interaction of factors affecting the selection of a cropping system: climatic, water requirements, marketing and farmer preferences. It also illustrates how proper planning of the cropping calendar can reduce irrigation water requirements and maximize project benefits.

Despite availability of tea growing technologies to all Kenya tea farmers, green leaf production in smallholder sub-sector remains low. Tea in Kenya is grown in the East of the Rift Valley and the West of the Rift Valley regions. It is assumed that tea farms behave according to a certain decision rule termed as profit maximization. The objective of this study was to estimate the profit function for tea farms in the two regions and to compare/test the relative economic efficiency between them. A profit function model was fitted on 212 smallholder farms. The dependent variable was gross margin per farm per year. The independent variables were: number of tea bushes per farm per year, cost of fertilizer (Kshs.) per hectare per year, labour wage rate (Kshs.) per man-day in each farm and a dummy variable where D=1 for east Rift and D=0 for west Rift. The results depicted that the coefficients of the number of bushes, fertilizer cost/ha/year and labour wage rate/man-day were all positive and significant at 1 percent level. It had been hypothesized that there is no efficiency difference between East of the Rift Valley and West of the Rift Valley in tea production. Hence the coefficient of the region dummy would be zero. The results rejected the hypothesis of equal efficiency between the two regions at 10 percent level. Further more, the positive sign of the dummy variable indicates that East Rift Valley tea farms are more economic efficient, at all observed prices of the variable inputs given the distribution of the fixed factors of production. It is concluded that East Rift Valley is more successful in responding to the set of prices it faces (Price efficiency) and /or has higher quantities of fixed factors of production including entrepreneurship (technical efficiency).

It is proposed that the direct analgesic effect of morphine becomes attenuated over the course of successive administrations of the narcotic by a conditioned, compensatory, hyperalgesic response elicited by the administration procedure, the net result being analgesic tolerance. Using the "hot plate" analgesia assessment situation with rats, this conditioning view of tolerance is supported by several findings: (a) It is necessary to have reliable environmental cues predicting the systemic effects of morphine if tolerance is to be observed, (b) a hyperalgesic conditioned response may be observed in morphine-tolerant subjects when drug administration cues are followed by a placebo, and (c) merely by repeatedly presenting environmental cues previously associated with morphine (but now presented with a placebo), morphine tolerance can be extinguished.

The 2015/2016 El Niño has been classified as one of the three most severe on record. El Niño teleconnections are commonly associated with droughts in southern Africa and high precipitation in eastern Africa. Despite their relatively frequent occurrence, evidence for their hydrological effects and impacts beyond agriculture is limited. We examine the hydrological response and impact pathways of the 2015/2016 El Niño in eastern and southern Africa, focusing on Botswana, Kenya, and Zambia. We use in situ and remotely sensed time series of precipitation, river flow, and lake levels complemented by qualitative insights from interviews with key organizations in each country about awareness, impacts, and responses. Our results show that drought conditions prevailed in large parts of southern Africa, reducing runoff and contributing to unusually low lake levels in Botswana and Zambia. Key informants characterized this El Niño through record high temperatures and water supply disruption in Botswana and through hydroelectric load shedding in Zambia. Warnings of flood risk in Kenya were pronounced, but the El Niño teleconnection did not materialize as expected in 2015/2016. Extreme precipitation was limited and caused localized impacts. The hydrological impacts in southern Africa were severe and complex, strongly exacerbated by dry antecedent conditions, recent changes in exposure and sensitivity and management decisions. Improved understanding of hydrological responses and the complexity of differing impact pathways can support design of more adaptive, region‐specific management strategies.

FDP aldolase was found to be present in the cell-free extracts of Rhizobium leguminosarum, Rhizobium phaseoli, Rhizobium trifolii, Rhizobium meliloti, Rhizobium lupini, Rhizobium japonicum and Rhizobium species from Arachis hypogaea and Sesbania cannabina. The enzyme in 3 representative species has optimal activity at pH 8.4 in 0.2M veronal buffer. The enzyme activity was completely lost by treatment at 60 degrees C for 15 min. The Km values were in the range from 2.38 to 4.55 X 10(-6)M FDP. Metal chelating agents inhibited enzyme activity, but monovalent or bivalent metal ions failed to stimulate the activity. Bivalent metal ions in general were rather inhibitory.