Huix-Rotllant M.,CNRS Molecular Chemistry Department |
Natarajan B.,CNRS Molecular Chemistry Department |
Natarajan B.,CEA Grenoble |
Ipatov A.,CNRS Molecular Chemistry Department |
And 4 more authors.
Physical Chemistry Chemical Physics | Year: 2010
Under the usual assumption of noninteracting v-representability, density-functional theory (DFT) together with time-dependent DFT (TDDFT) provide a formally exact single-reference method suitable for the theoretical description of the electronic excited-states of large molecules, and hence for the description of excited-state potential energy surfaces important for photochemistry. The quality of this single-reference description is limited in practice by the need to use approximate exchange-correlation functionals. In particular it is far from clear how well approximations used in contemporary practical TDDFT calculations can describe funnel regions such as avoided crossings and conical intersections. These regions typically involve biradical-like structures associated with bond breaking and conventional wisdom would seem to suggest the need to introduce explicit double excitation character to describe these structures. Although this is lacking in ordinary spin-preserving (SP) TDDFT, it is present to some extent in spin-flip (SF) TDDFT. We report our tests of Wang-Ziegler noncollinear SF-TDDFT within the Tamm-Dancoff approximation for describing the avoided crossing in the C 2v CC ring-opening reaction of oxirane and for describing the conical intersection relevant for the more physical asymmetric CO ring-opening reaction of oxirane. Comparisons are made with complete active space self-consistent field and quantum Monte Carlo benchmark results from two previous papers on the subject [J. Chem. Phys., 2007, 127, 164111; ibid129, 2008, 124108]. While the avoided crossing in the C2v pathway is found to be reasonably well described, the method was found to be only partially successful for the conical intersection (CX) associated with the physically more important asymmetric pathway. The origin of the difficulties preventing the noncollinear SF-TDDFT method from giving a completely satisfactory description of the CX was traced back to the inability of SF-TDDFT based upon a single triplet reference state to correlate all potentially relevant configurations involving not just two but three nearly degenerate orbitals (n, σCO, and). This article is also the first report of our implementation of SF-TDDFT within the deMon2k program. © the Owner Societies 2010.
Kagunyu A.F.,Kenya Agricultural and Livestock Research Organization |
Wanjohi J.G.,Catholic University of Eastern Africa
Pastoralism | Year: 2015
This study took place in Isiolo County in northern Kenya among the Borana community, whose major economic activity is livestock production. The County is characterized by droughts which have increased in frequency and severity. This study sought to investigate the availability of camel drought feeds in the study site, guided by two specific objectives: to establish the existence of supplementary feeds used by the Borana community for camels during the drought periods and to establish the distribution of the supplementary feeds. Data was collected through secondary sources, semi-structured interviews, focus group discussions and direct observation. The study findings indicate that the Borana pastoralists use Euphorbia tirucalli to feed their camels during the drought periods. They also revealed that the plant was sparsely distributed in the study site and most of the feeds were purchased from neighbouring agro-pastoralists at affordable prices. E. tirucalli plays a very important role in saving the lives of camels during drought periods. Therefore, this study recommends that pastoralists in Isiolo County need to be encouraged to plant E. tirucalli in their farms. The Borana pastoralists need to be trained on appropriate methods of harvesting and propagating the plant. © 2015, Kagunyu and Wanjohi.
Kwanza J.K.,Jomo Kenyatta University of Agriculture and Technology |
Balakiyema J.A.,Catholic University of Eastern Africa
Journal of Fusion Energy | Year: 2012
The steady two-dimensional magnetohydrodynamic free convective laminar flow of an electrically conducting, viscous and incompressible fluid with finite electrical conductivity past an infinite heated vertical porous plate has been investigated. The coupled ordinary differential equations governing the velocity, the temperature and induced magnetic field distributions are solved analytically. The effects of Prandtl number (P r), Grashof number (Gr), magnetic field parameter (M), and suction parameter (V̄0) on the flow field are analysed using graphs. The study reveals that the increase of the Prandtl number (Pr) and the suction velocity (V̄0) lead to a decrease in the temperature, velocity and the induced magnetic field in the boundary layer region whereas increase in Grashof number and magnetic field parameter lead to increased induced magnetic field. © Springer Science+Business Media, LLC 2011.
Milugo T.K.,University of Nairobi |
Omosa L.K.,University of Nairobi |
Ochanda J.O.,University of Nairobi |
Owuor B.O.,Catholic University of Eastern Africa |
And 3 more authors.
BMC Complementary and Alternative Medicine | Year: 2013
Background: The Quinine tree (Rauvolfia caffra) is used as a medicinal plant among traditional communities in many countries to manage tumors and other diseases associated with oxidative stress. To validate indigenous knowledge and possibly position this herb for technology uptake and utilization, we established the level of antioxidant activity in R. caffra, and probed for the presence of associated phytochemicals.Methods: Antioxidant activity was determined on 1,1-diphenyl-2-picrylhydrazyl (DPPH) while major phytochemicals were identified by multiple tests on methanol fractions.Results: R. caffra showed promise as a cure, with antioxidant activity comparable to the commercially used drug quercetin (R. caffra = 79.7% ±1.9; quercetin = 82.6% ± 2.0). However, we found two phytochemicals with possible antagonistic effect: co-occurrence of alkaloids and saponins significantly reduced antioxidant activity (alkaloids only = 63%; alkaloids plus saponins = 15%; steroids, terpenoids and cardiac glycosides = 82%), thus alkaloids and saponins should be exclusive to each other in drug formulations.Conclusions: Antagonistic relationship among phytochemicals would affect the efficacy of crude extracts as used in traditional medicine. Unlike in herbal medicine, use of modern biotechnology in extraction, purification and design of optimal combinations will ensure efficient drug formulations with optimum bioactivity and minimum toxicity. Metabolic pathway engineering under a controlled environment may optimize availability of desired compounds. © 2013 Milugo et al.; licensee BioMed Central Ltd.
Kagunyu A.W.,Kenya Agricultural Research Institute |
Wanjohi J.,Catholic University of Eastern Africa
Pastoralism | Year: 2014
This study took place in Isiolo County of semi-arid northern Kenya among Borana pastoralists. Current scientific evidence indicates that climate variability is threatening reliance on cattle. This study aimed to understand whether the Borana community would let go their cattle culture and embrace camel production. The results showed that the Borana have changed their preference from cattle to camel rearing. Constraints identified as affecting camel production included the following: diseases, raiding and competition from other livestock. There is need to employ animal health workers to bail out the pastoralists from threats of livestock diseases, and to promote peace in the region. © 2014, Kagunyu and Wanjohi; licensee Springer.
Ogeng'O D.N.,Catholic University of Eastern Africa |
Obimbo M.M.,University of Nairobi |
Ogeng'O J.A.,University of Nairobi
Acta Paediatrica, International Journal of Paediatrics | Year: 2011
Aim: To determine the mean menarcheal age among urban primary school girls in Kenya. Subjects and methods: A structured questionnaire was administered to 820 primary grade 6-8 girls aged between 12 and 17 years in five public primary schools, Langata division of Nairobi West district, Nairobi Kenya. The girls came from low and middle socioeconomic status residences. Declared menarcheal age by recall to the nearest month was recorded. Data were analysed using SPSS version 15.0 for windows. The results are presented using tables and bar charts. Results: The mean menarcheal age was 12.5 ± 2.8 years with peak at 12-14 years. A substantial number of girls (10.8%) attained menarche before the age of 11 years, with 2% of them attaining it before 10 years. None attained menarche before nine or after 16 years. Of those who attained early menarche, 64.3% were from middle while only 35.7% came from low socioeconomic status residence, respectively. Conclusion: Mean menarcheal age of 12.5 years is lower than previously reported with over 10% of the girls attaining menarche by 11 years. Early commencement of reproductive health education and follow-up for complications of early menarche is recommended. © 2011 The Author(s)/Acta Pædiatrica © 2011 Foundation Acta Pædiatrica.
Gakuubi M.M.,Catholic University of Eastern Africa |
Wanzala W.,Catholic University of Eastern Africa |
Wanzala W.,University of Nairobi
Journal of Ethnobiology and Ethnomedicine | Year: 2012
Background: Up till now, nomadic communities in Africa have been the primary focus of ethnoveterinary research. Although mainly arable and/or mixed arable/pastoral farmers, Ameru of central Kenya are known to have a rich history of ethnoveterinary knowledge. Their collective and accumulative ethnoveterinary knowledge (EVK) is likely to be just as rich and worth documenting. The aim of the study was to document and analyse the ethnoveterinary knowledge of the Ameru.Methods: Non-alienating, dialogic, participatory action research (PAR) and participatory rural appraisal (PRA) approaches involving 21 women and men aged between 50 and 79 years old were utilized. A combination of snowball and purposive sampling methods were used to select 21 key respondents. The methods comprised a set of triangulation approach needed in EVK for non-experimental validation of ethnoknowledge of the Ameru.Results: A total of 48 plant species distributed in 26 families were documented with details of diseases/ill-health conditions, parts of plants used and form of preparation and administration methods applied to different animal groups. Of these families, Fabaceae had the highest number of species (16.67%), followed by Solanaceae (12.5%), Asteraceae and Euphorbiacea (each comprising 8.33%), Lamiaceae (6.25%), Apocynaceae and Boraginaceae (each comprising 4.17%), while the rest of the 19 families, each was represented by a single plant species. About 30 livestock diseases/ill-health conditions were described, each treated by at least one of the 48 plant species. Most prevalent diseases/ill-health conditions included: - anaplasmosis, diarrhea, East Coast fever, pneumonia, helminthiasis, general weakness and skin diseases involving wounds caused by ectoparasites.Conclusion: The study showed that there was a rich knowledge and ethnopractices for traditional animal healthcare amongst the Ameru. This study therefore provides some groundwork for elucidating the efficacy of some of these plants, plant products and ethnopractices in managing livestock health as further research may lead to discovery of useful ethnopharmaceutical agents applicable in livestock industry. © 2012 Gakuubi and Wanzala; licensee BioMed Central Ltd.
Mwenda A.N.,Wageningen University |
Bregt A.K.,Wageningen University |
Ligtenberg A.,Wageningen University |
Kibutu T.N.,Catholic University of Eastern Africa
Impact Assessment and Project Appraisal | Year: 2012
The objective of this study was to document trends in public participation within environmental impact assessment (EIA) in Kenya, using a Consultation and Public Participation Index (CPPI) developed for the analysis of EIA Study Reports submitted to the Environment Authority between 2002 and 2010. Results indicated that public participation remained relatively low, with the highest score of 1.65 in 2010, out of a possible score of 5. Scores for individual dimensions within the index fluctuated during the study period, with participation methods and type of participants scoring the highest, following increased emphasis by the Environment Authority on the conducting and reporting of public participation. This was followed by venue, notification and language used, in that order, which were often not reported, and, when reported, choices per dimension were limited. This is the first time this index has been used, yet it serves as a good starting point to evaluate public participation within EIA. © 2012 Copyright IAIA.
Makori E.O.,Catholic University of Eastern Africa
Electronic Library | Year: 2013
Purpose - The purpose of this paper is to investigate the adoption of radio frequency identification (RFID) technology in handling and supporting information services and activities in Kenyan university libraries. Design/methodology/approach - The study utilized a survey research design to collect data, ideas, opinions, views and suggestions from the respondents drawn from various university libraries in Kenya. Collecting data and getting in-depth information from the respondents was done using a web-based structured questionnaire, document analysis and participant observation. Findings - The findings from the study show that few university libraries in Kenya are using radio frequency identification technology to handle and support information services and activities. The study also found various problems hindering the adoption of the technology, such as a lack of information communication technology (ICT) policies, lack of a business approach, limited market opportunities, lack of lobbying or negotiating skills, inadequate funding and budgeting, and lack of ICT competencies and skills. The study recommends that library ICT professionals, information professionals and other stakeholders should make tireless efforts to implement and use RFID technology with the view to building, strengthening, improving and supporting information work and activities in university libraries. Research limitations/implications - The study involved RFID technology, a relatively new and emerging innovation in university library and information systems, especially in the Kenyan context. The study also involved university libraries in Kenya that provide and support the fundamental functions of their respective universities. Practical implications - Fundamentally, library ICT professionals, information professionals and other stakeholders need to take appropriate measures to address issues affecting the use of RFID solutions. There is a need to empower university libraries and information professionals with the right mix of ICT knowledge and skills necessary in the modern information environment. Social implications - Across the world, university libraries are increasingly adopting and implementing RFID solutions in order to handle and support information work and activities. Of critical importance to the discussion is the extent to which university libraries in Kenya are using this technology to handle and support information work and activities effectively and efficiently. Proper management of library operations and services is necessary in university library and information systems. Originality/value - The focus of the study was to assess the extent to which university libraries in Kenya are adopting and using RFID systems in information work and activities. This research is useful in providing a point of reference for university libraries and information professionals, increasingly going for similar solutions in Kenya and Africa in general. © Emerald Group Publishing Limited.
Kifle T.,University of Queensland |
Desta I.H.,Catholic University of Eastern Africa
International Journal of Public Health | Year: 2012
Objectives: This paper explores the association of body mass index (BMI) with socioeconomic and demographic factors using data from the 6th wave of the Household, Income and Labour Dynamics in Australia (HILDA) Survey. Methods: This study applies a stereotype logit model (SLM) to assess 10,875 individuals on the relationship between BMI and socioeconomic and demographic indicators. Results: Aggregate results from the SLM show a positive (and concave) association between age and higher BMI. Further, males are more likely than females to have higher BMI. Higher BMI is positively associated with long-term health problems, reduced prosperity, being married, and being born in Australia and negatively associated with possessing a diploma or above. Conclusions: Results show that there is a positive and concave relationship between age and higher BMI. Further, males tend to have higher BMI as compared to females. Higher BMI is also positively related to long-term health problems, reduced prosperity, being married and being born in Australia. Negative association with BMI is observed on those possessing a diploma and above. © 2011 Swiss School of Public Health.