A prototype parabolic trough solar concentrators for steam production

In this work, the potential for a solar-thermal concentrator to produce steam has been studied. Three parabolic trough solar concentrators (PTSCs) of dimensions: -aperture width of 1.2 m, Collector length of 5.8 m and aperture area of 6.95 m2 were investigated. The absorber pipe was a copper tube which carried water as the heat transfer fluid, were designed, fabricated, characterized and their efficiencies compared when closed and when open. The PTSCs´ were made of appropriate materials and were manually tracked. They were designed with principal focus at 0.4 m so that the receiver heat loss is minimized by covering the collectors with glass which was 0.0025 m in thickness. The concentration ratio of the solar concentrators was 128. The concentrator testing was carried out for each of the concentrators. The maximum temperature of steam obtained was 248.3oC while average temperature of steam was produced was 150oC. When closed their efficiencies were: Aluminium sheet reflector PTSC; 55.52 %, Car solar reflector PTSC; 54.65 % and Aluminium foil reflector PTSC; 51.29 %. The open solar concentrator efficiencies were 32.38 %, 34.45 % and 27.74 % respectively. The efficiency of car solar reflector when open was higher than for aluminium sheet since it was less prone to thermal degradation when exposed to weather elements. The results obtained show that production of power using the sun flux is a viable undertaking. The concentrators can be used to provide power to remote areas which are far away from the power transmission gridlines. This will make power readily available to the marginalized rural people. Improvement of the tracking system and optical efficiency can improve the efficiencies of the fabricated concentrator systemsKeywords: Parabolic trough concentrator, solar-thermal, transmittance absorptance product, thermal and optical efficienc

An investigation of the utility scale wind energy for north‐eastern Kenya region

In the present study, the wind energy potential for Garissa (0°28S, 39°38'E) and Marsabit (2° 19N, 37° 58'E), both rural towns in  north-eastern Kenya have been statistically analyzed on a 6-year  measured hourly time series wind speed data. The probability distribution parameters are derived the time series data and the distributional  parameters are identified and fitted annually on the basis of Weibull model. Garissas average wind speeds were found to range between 2.5 and 3.5 m/s giving power densities of between 74 and 190 W/m2 at a height of 50 m. The yearly value of Weibulls shape parameter k ranged from 1.26 to 1.38, whilst the values of the scale parameter c ranged between 2.92 and 3.90 m/s. In the case of Marsabit average wind speeds greater than 11 m/s are prevalent. The available power density at a height of 50 m is between 1776 and 2202 W/m2 which is in the wind class range of 7 and 8. Values of Weibull parameters k and c ranged between 2.5-3.05 and 11.86-12.97 m/s, respectively. From the analysis, the Marsabit site was found suitable for grid connected power generation while the Garissa site was found suitable for non]grid uses such as water pumping and battery charging.Key words: Wind speed, power law, Weibull parameters, wind class, wind rose, energy potentia

Farmers\u27 Screening of Indigenous Fodder Trees and Shrubs in Kenya

The lack of fodder quantity and quality is a constraint for small scale livestock production systems in central Kenya which are intensive or are rapidly becoming so. This study examined farmers’ knowledge about indigenous fodder trees and shrubs (IFTS) which are fed to livestock. The study consisted of a formal survey in three agroecological zones with mean annual rainfall varying from 750 to 1400 mm. Farmers rated IFTS for different qualities, which were analysed by Chi square. Differences of ratings among species for these qualities were significant (p\u3c0.05). The most promising species for the sub-humid zone, in terms of what farmers want to plant and in terms of preliminary nutritive analysis, were: Tithonia diversifolia, Commiphora zimmermanii, Ficus spp. and Trema orientalis. The species that show promise for the same reasons, in the semi-arid zones, are: Crotalaria goodiiformis, Aspilia mossambicensis, Indigofera lupatana, T. diversifolia, Grewia tembensis and Acacia ataxacantha

Cooperative Learning Method and Development of Pre-School Children’s Competences Acquisition in Mathematical Concepts in Kirinyaga County, Kenya

The research from which this paper is derived explored the effect of cooperative learning method on development of pre-schoolers’ competences in mathematical concepts. 20 pre-school teachers on their regular teaching in their pre-schools were observed teaching their 639 Pre-primary Two learners. The purpose of this study was to establish the difference between the mean score index of pre-school learners taught by a teacher who facilitates learning using the Cooperative Learning Method (CLM) and those taught by a teacher who does not. Data was collected through the use of observation schedule and teacher questionnaire. Each of the twenty pre-school teachers was observed by the researcher while facilitating mathematical concepts’ competences during number work lessons. A documentary analysis guide was used to access the pre-school teachers’ schemes of work and lesson plans to establish their level of preparation in line with CLM. Descriptive and inferential statistics were used to analyse the collected data and guided by the themes arising from the objective of the study the key findings were arrived at. The various levels of the teachers’ facilitation of CLM were tied to the pre-school leaners’ performance in the mathematical concepts competences achievement test. The findings emerging showed that those learners who were taught using CLM achieved higher mean score indices than those who were not. The implication here is that the use of CLM improves pre-school learners’ levels of achievement, indicating that it is a more effective method of teaching. Teachers’ facilitation of CLM seemed to have a significant positive influence on the learners’ Mathematical Concepts Competences Acquisition. These features were; availability of groupings and teacher preparedness, level of provision of learning resources, level of coordination, level of interaction, time taken in CLM activities. This implies that CLM imparts the required mathematical concepts competences better than traditional instructional methods. The study recommends that the Ministry of Education should develop programmes and policies that provide regular in-service training, in which CLM training forms a key part of the agenda and to refresh the mathematical concepts competences instructional skills of pre-school teachers. Keywords: Competences; Cooperative Learning Method; Mathematical Concepts DOI: 10.7176/JEP/12-32-05 Publication date: November 30th 202

Anti-Inflammatory and Anti-Diarrhoeal Activities of a Steroidal Indoxyl

The anti-inflammatory and antidiarrhoeal activities of 3β-Hydroxy-16, 17-seco-16-nor-5-androsten-15-(2-indoxyliden)-17-oic acid (I) are reported. After intraperitoneal administration, compound (I) gave an ED50 of 9.5 mg/kg using the carrageenan induced rat paw oedema anti-inflammatory assay method. Indomethacin had an ED50 of 5.8 mg/kg in this assay. Compound (I) and indomethacin caused comparable and dose-dependent varying degrees of delay in diarrhoea and also significantly reduced net colonic water flux into the colon of rats induced by castor oil. Key words: Steroidal Indoxyl, Anti-Inflammatory, Antidiarrhoeal. East and Central African Journal of Pharmaceutical Sciences Vol.6(2) 2003: 26-2

Successful pregnancy outcome following laparoscopic myomectomy: case report

Laparoscopic myomectomy is now widely used as an alternative to laparotomy in the management of symptomatic uterine fibroids. The advantages of this minimal access approach outweigh those of the open techniques. The pregnancy outcomes between the two methods have been studied and are comparable, but there still exists a lot of scepticism locally concerning this. It is against this background that we present a 31 year old nulliparous lady who had a two year history of primary infertility secondary to multiple uterine fibroids, the largest being fundal and measuring 6.6cm. She underwent a successful laparoscopic myomectomy in November, 2006 and conceived spontaneously in February 2007. Her antenatal follow up was uneventful. She delivered a live male, 2,650 grams by Caesarean section in October, 2007 and had an unremarkable peuperium. With the availability of proper equipment, instruments, and adequately developing skills, laparoscopic myomectomy is feasible locally and with proper patient selection could result in favourable outcome as it is elsewhere

Adherence to ministry of health guidelines in management of severe pre-eclampsia/eclampsia in Pumwani maternity hospital, Kenya

Background: Guidelines have shown to impact positively on the management of medical conditions. The impact of these guidelines has not been evaluated for severe preeclampsia and eclampsia in Kenya.Objective: To evaluate the level of adherence to Kenya Ministry of Health (MOH) guidelines in the management of severe pre-eclampsia and eclampsia at PumwaniMaternity Hospital, Kenya.Design: A cross sectionalSetting: Pumwani Maternity Hospital, Kenya.Subjects: Records of women managed for severe pre-eclampsia and eclampsia, deliveredbetween 2010 and 2013.Results: The overall adherence to guidelines was 31.4%. Adherence to specific parameters: history taking and examination, investigations, fetomaternal monitoring, use of recommended guidelines and post-partum guidelines was 67.8%, 13.9%, 26.1%, 29.5% and 20% respectively.Conclusions: Adherence to Kenya Ministry of Health (MOH) guidelines in management of severe pre-eclampsia and eclampsia in Pumwani Maternity Hospital is poor. Studies on the reasons for poor adherence and implementation need to be carried out

Coping with perceived abusive supervision: the role of paranoia

Two studies (a cross-sectional survey of 90 U.K. workers and an experiment with 100 U.K. workers) examined the cognitive and behavioral effects of abusive supervision. Both studies confirmed the hypothesis that workers who experience abusive supervision show paranoia and that makes them more prone to a type of cognitive error called the "sinister attribution error." This is where workers misattribute innocent workplace events such as tripping over something or hearing colleagues laughing to malevolent motives such as wanting to harm or mock them. Study 1 also showed that abusive supervision is associated with lower well-being. Perceived organizational support buffers these effects, and this is associated with workers making fewer sinister attribution errors, thereby protecting well-being. Study 2 explored the role of contextual cues by exposing workers to images of abusive supervision. This increased their paranoia and contributed to workers making sinister attribution errors when they were asked to interpret workplace events. Moreover, depending on the types of contextual cues, workers were more likely to express the intention of workplace deviance after thinking about past experiences of abusive supervision. We recommend that corporate ethical responsibilities include training managers and workers about the negative cognitive and mental health effects of abusive supervision

Coping with perceived abusive supervision in the workplace: the role of paranoia

Two studies (a cross-sectional survey of 90 UK workers and an experiment with 100 UK workers) examined the cognitive and behavioral effects of abusive supervision. Both studies confirmed the hypothesis that workers who experience abusive supervision show paranoia and this makes them more prone to a type of cognitive error called the “sinister attribution error”. This is where workers misattribute innocent workplace events such as tripping over something or hearing colleagues laughing to malevolent motives such as wanting to harm or mock them. Study 1 also showed that abusive supervision is associated with lower wellbeing. Perceived organizational support buffers these effects, and this is associated with workers making less sinister attribution errors, thereby protecting wellbeing. Study 2 explored the role of contextual cues by exposing workers to images of abusive supervision. This increased their paranoia and contributed to workers making sinister attribution errors when they were asked to interpret workplace events. Moreover, depending on the types of contextual cues, workers were more likely to express intentions of workplace deviance after thinking about past experiences of abusive supervision. We recommend that corporate ethical responsibilities include training managers and workers about the negative cognitive and mental health effects of abusive supervision

Changes in transmission of Enterovirus D68 (EV-D68) in England inferred from seroprevalence data.

The factors leading to the global emergence of Enterovirus D68 (EV-D68) in 2014 as a cause of acute flaccid myelitis (AFM) in children are unknown. To investigate potential changes in virus transmissibility or population susceptibility, we measured the seroprevalence of EV-D68-specific neutralising antibodies in serum samples collected in England in 2006, 2011, and 2017. Using catalytic mathematical models, we estimate an approximately 50% increase in the annual probability of infection over the 10-year study period, coinciding with the emergence of clade B around 2009. Despite such increase in transmission, seroprevalence data suggest that the virus was already widely circulating before the AFM outbreaks and the increase of infections by age cannot explain the observed number of AFM cases. Therefore, the acquisition of or an increase in neuropathogenicity would be additionally required to explain the emergence of outbreaks of AFM. Our results provide evidence that changes in enterovirus phenotypes cause major changes in disease epidemiology