Classical r-matrices via semidualisation

We study the interplay between double cross sum decompositions of a given Lie algebra and classical r-matrices for its semidual. For a class of Lie algebras which can be obtained by a process of generalised complexification we derive an expression for classical r-matrices of the semidual Lie bialgebra in terms of the data which determines the decomposition of the original Lie algebra. Applied to the local isometry Lie algebras arising in three-dimensional gravity, decomposition and semidualisation yields the main class of non-trivial r-matrices for the Euclidean and Poincare group in three dimensions. In addition, the construction links the r-matrices with the Bianchi classification of three dimensional real Lie algebras.Comment: 21 pages, 1 figure, typos correcte

Classical r-matrices for the generalised Chern-Simons formulation of 3d gravity

We study the conditions for classical r-matrices to be compatible with the generalised Chern-Simons action for 3d gravity. Compatibility means solving the classical Yang-Baxter equations with a prescribed symmetric part for each of the real Lie algebras and bilinear pairings arising in the generalised Chern-Simons action. We give a new construction of r-matrices via a generalised complexification and derive a non-linear set of matrix equations determining the most general compatible r-matrix. We exhibit new families of solutions and show that they contain known solutions for special parameter valuesComment: 20 pages, minor corrections and comments added in v

Kitaev lattice model for bicrossproduct Hopf algebras and tensor network representation

Kitaev's lattice models are usually defined as representations of the Drinfeld quantum double. We propose a new version based on Majid's bicrossproduct quantum group. Given a Hopf algebra $H$, we show that a triangulated oriented surface defines a representation of the bicrossproduct quantum group $H^{\text{cop}}\blacktriangleright\!\!\!\triangleleft H$. Even though the bicrossproduct has a more complicated and entangled coproduct, the construction of this new model is relatively natural as it relies on the use of the covariant Hopf algebra actions. We obtain an exactly solvable Hamiltonian for the model and provide a definition of the ground state in terms of a tensor network representation.Comment: 34 page

Leadership: The Missing Variable in the Economic Development of Sub-Saharan Africa

Contemporary economic theories, modernization and dependency, have overlooked the fact that the development process depends on the interaction of social factors. Specifically, the theories have ignored the role of leadership in analyzing economic development. This dissertation seeks to incorporate the importance of leadership into the analysis of development. It argues that sub-Saharan African countries have not developed economically because leaders in the region have been less than successful in establishing a culture conducive to industrialization. African leaders have failed to establish the high moral and scientific cultures necessary to promote economic progress. In place of those cultural attributes, the leaders have fostered corrupt and authoritarian political cultures that undermine the general economic development of their societies. This dissertation offers a detailed paired comparison of the colonial and postcolonial experience of Ghana and Botswana. The two countries constitute an effective comparison because they were once colonies of Great Britain and have similar resource endowments. Since independence. Botswana has achieved greater social and economic progress because its leaders have established a high moral culture. Ghana, on the other hand, has experienced stagnation, and in some respects actual decline, in its standards of living due to its leaders\u27 inability to establish a high moral culture. Despite differences in standards of living, neither country has achieved diversified industrialization due to a lack of a scientific culture. The inability to establish high moral and scientific cultures is partially due to the colonial experience and the political philosophy of Senghorianism. Direct colonial rule in Ghana replaced the traditional leadership of the country that had shown a greater political commitment to the general public. In contrast, the colonial protectorate in Botswana recognized traditional leaders as autonomous authorities without undermining their legitimacy. Botswana\u27s leadership continuity preserved the government\u27s moral obligation to the general public. The lack of socio-scientific culture in both countries is due, to a considerable extent, to the influence of Senghorian philosophy on post-colonial leaders. Senghorianism argues that analytical scientific thinking reflects the dichotomous European culture and contrasts with the holistic African intuitive mode of knowing. The adherence to this philosophy by sub-Saharan African leaders has inhibited the emergence of a scientific culture that would promote industrialization and economic development

Rapid field multiplication of plantains using benzyl adenine or coconut water-treated split corms

An appropriate inexpensive technique for rapid field multiplication of local false and true horn plantain cultivars, Apantu and Asamienu, has been developed by injecting 6 or 8 ml boiled and filtered coconut water from fully ripe dried fruit or 4 ml 10-2 M benzyl adenine on 3 consecutive alternate days at the base of over 35 cm tall split corm-derived suckers, and sprouting the split corms of the treated suckers in moist sawdust, 3 weeks after the injection treatments. Up to 1,000 suckers can be generated from one Apantu sucker in a year, and 3,375 suckers from one Asamienu sucker in 18 months with the coconut water treatment. The cost of 25 ml coconut water required to treat one sucker is insignificant compared with the multiplication ratios derived from the treated suckers.Une technique appropriee et moins chere pour la multiplication rapide sur Ie terrain de deux varietes locales de plantain Apantu (une corne fausse) et Asamienu (une come veritable) a ete obtenue par injection de 6 ou 8 ml du jus de noix de coco mur sec apres L' ebullition et la filtration ou de 4 ml 10-2 M benzyle adenine pour trois jours. Consecutifs alternes a la base de surgeons-derives de bulbes divises d'une taille au-dessus de 35 cm, et germant les bulbes divises de surgeons traites en sciure de bois moullee, trois semaines apres les traitements d'injection. Jusqu'a 1000 surgeons pourraient etre produits d'un surgeon d' Apantu dans un an et 3,375 d'un surgeon d' Asamienu en 18 mois avec Ie traitement du jus de noix de coco. Le cout de 25 ml du jus de coco exige pour traiter un surgeon est insignificant compare avec les proportions de multiplication obtenues de surgeons traites. Ghana Journal of Agricultural Science Vol. 39 (2) 2006: pp. 189-20

The germination of colanuts (Cola nitida Ventenant) Schott and Endlicher

Factors affecting colanut (Cola nitida Ventenant) Schott and Endlicher, germination have been investigated. The storage of colanuts enhances germination of the nuts. Within 8 weeks white colanuts germinated faster than red or pink nuts. Some varieties of C. nitida show superior germination characteristics than others. Although greening of stored colanuts stimulates early radicle emergence, subsequent plumule emergence was not affected by greening. Nut size did not affect gennination. Potassium nitrate, sodium nitrite, hydroxylamine, ammonium chloride and potassium cyanide did not show any consistent effect on the germination of colanuts stored for 4 weeks

Molecular marker screening of tomato, (solanum lycopersicum L.) Germplasm for root-knot nematodes (Meloidogyne species) resistance

Tomato is one of the crops in which genetic resistance has specially been effective against root-knot nematodes. In this study, molecular screening was done on some tomato germplasm to detect markers for the gene that confers resistance (Mi) with specific primer (Mi23/F//Mi23/R). The cultivars; VFNT, FLA 505-BL 1172, 2641A, “Adwoa Deede” and Terminator FI showed the marker for the homozygous resistant genotypes (Mi/Mi). The cultivars, Tima and 2644A showed both markers, corresponding to heterozygous resistant genotypes (Mi/mi). Twenty one (21) of the cultivars did not show any of the markers presumably due to non-specificity at the primer-binding sites. Five (5) heterozygous individuals were determined out of 6 resistant cultivars following the Hardy-Weinberg principle in population genetics.Keywords: Germplasm, Meloidogyne incognita, molecular marker, resistance, Solanum lycopersicum

Bismuth Sulfide Nanoflowers for Detection of X-rays in the Mammographic Energy Range

Nambiar, S., Osei, E. K., & Yeow, J. T. W. (2015). Bismuth Sulfide Nanoflowers for Detection of X-rays in the Mammographic Energy Range. Scientific Reports, 5, 9440. DOI: 10.1038/srep09440The increased use of diagnostic x-rays, especially in the field of medical radiology, has necessitated a significant demand for high resolution, real-time radiation detectors. In this regard, the photoresponse of bismuth sulfide (Bi2S3), an n-type semiconducting metal chalcogenide, to low energy x-rays has been investigated in this study. In recent years, several types of nanomaterials of Bi2S3 have been widely studied for optoelectronic and thermoelectric applications. However, photoresponse of Bi2S3 nanomaterials for dosimetric applications has not yet been reported. The photosensitivity of Bi2S3 with nanoscale “flower-like” structures was characterized under x-ray tube-potentials typically used in mammographic procedures. Both dark current and photocurrent were measured under varying x-ray doses, field sizes, and bias voltages for each of the tube potentials – 20, 23, 26 and 30 kV. Results show that the Bi2S3 nanoflowers instantaneously responded to even minor changes in the dose delivered. The photoresponse was found to be relatively high (few nA) at bias voltage as low as +1 V, and fairly repeatable for both short and long exposures to mammographic x-rays with minimal or no loss in sensitivity. The overall dose-sensitivity of the Bi2S3 nanoflowers was found to be similar to that of a micro-ionization chamber.This project was funded by the Waterloo Institute for Nanotechnology (University of Waterloo, Canada) as part of a collaboration program with Prof. C.N.R. Rao's laboratory at the Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR, Bangalore, India)

Hydrogeological evaluation of geological formations in Ashanti Region, Ghana

The success of groundwater exploitation in an area largely depends on prior knowledge of existing hydrogeological parameters such as borehole yield, overburden thickness, depth of boreholes, static water level, specific capacity and the quality of water. This study, therefore, employed Geographical Information System to assess some of these hydrogeological parameters in the Ashanti Region using the ordinary kriging interpolation method. Data on 2,788 drilled boreholes in the region were used and the assessment focused on the various geological formations in the region that comprised the Birimian, Granitoids, Tarkwaian and Voltaian formations. The study results indicate that the Birimian formation is generally within medium to high yielding potential zones (30 – 60 l/min or higher) with a high drilling success rate of 91% and average borehole depth of 53 m. The Granitoids are, mostly, within the low yielding zone (< 30 l/min) with isolated high yielding boreholes and have average borehole depth and drilling success rate of 50 m and 72 % respectively. The Tarkwaian formation, on other hand, is within the medium yield zone with a drilling success rate of 80 % whilst the Voltaian formation is mainly classified to fall within low yield zone with about 60% success rate although significant high yield zones occur within the sandstone formation underlying its westernmost part in the region. Groundwater in the region is generally potable except in a few locations within the Birimian and ranitoids,where there are problems with levels of iron, nitrate, manganese and pH. Keywords: Groundwater; Hydrogeological parameters; Geological formations; Geographical Information System; Ashanti Regio

Appraisal of some methods of weed control during initial establishment of cocoa in a semi-deciduous forest zone of Ghana

In appraising the effects of the quantum and quality of weed control required in establishment of young cocoa, six manual methods of controlling weeds were compared with chemical weed control at two stations of the Cocoa Research Institute of Ghana. Growth of cocoa seedlings after 2 years in the field was superior (P < 0.05) in plots which were clean-weeded two or four times per year or treated with paraquat four times per year than when plots were slashed two or four times per year. There was strong evidence to suggest that treatments which ensured a weed-free environment to the cocoa over a long period were favourable to girth increments in the seedlings. Death of seedlings during establishment was generally lower in plots which were either clean-weeded or treated with paraquat. Labour requirement for controlling weeds with paraquat was considerably lower than that required for the other treatments. Considering the equipment and chemical input, paraquat application was expensive compared to high slashing with or without clean-line weeding two times a year, or clean weeding two times a year; but by virtue of its efficacy, it is recommended for cocoa establishment. En évaluant les effets du quatum et de la qualité de désherbage exigé dans la culture de jeune cacao, six méthodes de désherbage manuel étaient comparées avec le désherbage chimique à deux stations de l'Institut de Recherche en cacao du Ghana. La croissance de semis de cacao, après deux années, dans le champ était supérieure (P £ 0.05 ) dans les lots qui étaient complètement désherbés 2 ou 4 fois/an ou traités avec le paraquat 4 fois/an que dans les lots qui étaient entaillés 2 ou 4 fois/an. Il y avait de nombreuses preuves qui laissent penser que les traitements qui assuraient un environnement sans mauvaise herbe pour le cacao sur une longue période étaient favorables aux augmentations de circonférence des semis. La mort de semis pendant la culture était dans l'ensemble plus faible dans les lots, qui étaient soit complètement désherbés soit traités avec le paraquat. L'exigence de main-d'oeuvre pour maîtriser les mauvaises herbes avec le paraquat était considérablement plus faible que celle exigée pour les autres traitements. En ce qui concerne les matériels et les intrants chimiques, l'application de paraquat était chère que les entailles élevées avec ou sans le désherbage complet en ligne deux fois par an ou le désherbage complet deux fois par an mais en vertu de son efficacité il est recommandé pour la culture de cacao. Ghana Journal of Agricultural Science Vol. 40 (1) 2007: pp. 67-7