Showing papers by "University of Nigeria, Nsukka published in 1973"

Effects of Defoliation and Topping on Semi-Upright Cowpeas [ Vigna Unguiculata (L.) Walp.] in a Humid Tropical Environment

Abstract: The yield of cowpeas could be increased by judicious defoliation of the older leaves or by topping the growing apices at the onset of flowering. Limited defoliation at the pre-flowering stage did not reduce the yield of beans significantly but severe defoliation at any stage prior to maturity drastically reduced yield. Satisfactory yields of cowpea could be obtained by maintaining only about one-half to two-thirds of the potential leaf-area of the plants, suggesting that a reduction in the number and area of leaves, coupled with a better display of the fewer remaining leaves, could make cowpeas more productive than hitherto.

Ecology of the variegated grasshopper, zonocerus variegatus, (orthoptera: acridoidea, pyrgomorphidae) on the nsukka plateau, nigeria

Abstract: A study of the local population of the variegated grasshopper, Z. variegatus on the Nsukka Plateau, Nigeria, has shown that there are two populations, the dry season and the wet season populations, whose life-histories overlap. The average span of life, from nymph to adult of the individuals of either population is 9–10 months, while development from nymph to reproductive maturity in either form is 4–5 months. For the dry season population, nymphs appear in October, young adults by March–April, and by August the last remnants of this population die out. The wet season individuals appear first as nymphs by about February, as young adults by June, and die out by about December. In general, egg pods remain in the soil for 5–6 months (April–October), and for 4–5 months (October–February) for the dry season and wet season individuals respectively, before hatching. The shorter period spent in the soil by the eggs of the wet season individuals appears to be due to the fact of delay of oviposition in the mature females by the extreme wetness of the soil when reproductive maturity is attained. In the laboratory, attempts to mate reproductively mature and copulating adults from either seasonal population with each other, were not successful. The phenology of the dry season population is the same, whether reared in the laboratory or in the field. The growth characteristics of these grasshoppers conform to Dyar's rule. However, while growth as indicated by increases in mean body length is linear, growth as indicated by weight measurements shows a two-phase relationship, the divergence appearing at the IV instar. Resume ECOLOGIE DE ZONOCERUS VARIEGATUS (ORTHOPTERA: ACRIDOIDEA, PYRGOMORPHIDAE) SUR LE PLATEAU NSUKKA, NIGERIA. Une etude de la population locale de Z. variegatus sur le Plateau Nsukka au Nigeria, a montre qu'il y a en fait coexistence de deux populations distinctes, dont les cycles biologiques se chevauchent, l'une correspondant a la saison seche et l'autre a la saison humide. La longeviTE moyenne des individus (vie larvaire + vie imaginale) dans l'une ou l'autre de ces populations est de 9 a 10 mois, le developpement, depuis la larve jusqu'a la maturiTE sexuelle, etant de 4 a 5 mois. Pour la population de la saison seche, les larves apparaissent en octobre, les jeunes adultes en mars—avril, et les derniers survivants s'observent jusqu'en aout. Les larves des individus de la saison humide apparaissent courant fevrier, leurs jeunes adultes en juin, et la population s'eteint en decembre. En general les coques ovigeres n'eclosent qu'apres un sejour dans le sol de 5 a 6 mois (avril a octobre) pour la population de la saison seche, et de 4 a 5 mois (octobre a fevrier) pour la population de la saison humide. Le fait que le temps d'incubations dans le sol soit plus court pour les œufs deposes par les individus de la saison humide serait du a ce que, lorsque ces femelles auront atteint leur maturiTE, l'extreme humidiTE du sol ne permettra pas la ponte qui se trouvera ainsi retardee. Les tentatives faites en laboratoire, pour croiser entre eux des adultes genitalement murs provenant de chacune de ces 2 populations, ont echoue. La phenologie de la population de la saison seche reste la meme, que celle-ci soit elevee an laboratoire ou dans la nature. Les caracTEristiques de la croissance de ces OrthopTEres sont conformes a la regle de Dyar. Toutefois, tandis que cette croissance est lineaire quand on la mesure d'apres la longueur du corps, on y releve deux phases si l'on se refere au poids des individus, la divergence se manifestant a partir du 4e stade larvaire.

Nigerian Population Studies: A Partial Bibliography of Periodical Literature. 1950-1970

Abstract: Nigeria with a population of 56 million people* is the largest country in Black Africa. This rapid population growth is a post-war phenomenon which has been accentuated by improved medical and health services. Population explosion as it is now known in demographic literature, poses some socio-economic problems. A close relationship exists between population dynamics and economic development. When population grows faster than the available and developed natural resources as in Nigeria, per capita income is bound to fall and low standard of living will be the result. On the other hand, high rates of population growth and especially high fertility growth;. will produce problems other than those of investment and employment. The problem lies with age structure, and with a preponderance of children. This broad-based population structure costs the Nigerian government a lot to maintain. With the introduction of planned programs of economic and social development, it becomes imperative that population studies be actively undertaken in our universities and institutes. This will enable planning authorities to prepare meaningful national development plans. When inaccurate information or political intrigues enter into census taking, results are bound to be grossly inaccurate and any development based on that, is likely to fail. The effect may even be more disastrous and can rock the very political foundation as nearly happened in Nigeria after the 1962 census ruse. Population growth further leads to urbanization. Before World War II, Nigeria's population was growing at the rate of 1.8% per annum with population movement being mainly rural-to-rural and migration was also seasonal and temporary. Since 1963 there hasbeen an upsurge of urban population growth with an overall rate of the country's population at 2.8% per annum. Many of the towns, especially Lagos, are witnessing a sort of urban revolution. The rate of growth in Lagos has been particularly high being estimated at 5.5% per annum. There is now a marked internal movement from rural-to-urban. With industries, commerce, and centers of administration located to few towns, people tend to move to these places in order to secure employment. The result has been the occurrence of social ills connected with urbanization.

Fertilizer applications and the organic matter status in the agege experimental field in Nigeria

Abstract: The influence of 14 years application of mineral fertilizers on the organic carbon content of the Agege sandy soil was appraised. The fertilizer treatments in comparison to unfertilized plots led to higher as well as lower organic carbon. The sole applications of N. P, and K were compared, while N alone increased the organic carbon content of the soil, P alone tended to decrease it, but K alone especially decreased the soil organic carbon. Increased P application, however, could compensate this decrease, whereas increased K-accelerated the decrease. NP and NK combinations showed similar trends to decrease the organic carbon but this decrease was more with NK than NP. But PK fertilizer combinations in contrast to the effect of each of these nutrients alone influenced the organic carbon positively, whereby higher P contents showed again favourable effects than higher K. The fertilizer combinations of the three nutrients (NPK) showed in comparison to unfertilized variants not much higher carbon contents. The complete fertilizer decreased the organic carbon as against unfertilized variants. It was therefore concluded that not always and everywhere can harmonious fertilizer lead to higher organic carbon in the soil, this depends on the type of soil and kinds of cations available in the soil concerned.

Case for special schools for the distributive trades in Africa

Abstract: Fifty or more years ago much of Nigeria and other African countries still lacked the rudiments of a lively business in the modern sense of the word. This was mainly because there were much less goods and services to dispose of, much less purchasing power, much less serviceable means of transport for handling the meagre surpluses than are available today. However, there existed centres of aboriginal economic organization which also, even in a rudimentary way, achieved the circulation of goods. For instance, relevant information is available which indicates that even where barter prevailed, extrafamilial and intertribal exchanges were to be found, while what might be termed protomarkets, where particular kinds of goods were bartered at particular times, existed. From the point of view of the functional common denominator, exchange, therefore, proofs abound which falsify the concept that separates different levels of “the market” or of “marketing” and concentrates attention only on the “modern” aspect. This is to say that what existed in Africa in this regard was, and to some extent is, the first end of a continuum whose other end is the modern market. In many cases, a movement toward the middle of this continuum and even to the modern end is today observable in nearly every country in Africa. Thus, in truth, the difference is not in kind but rather in degree. What I am trying to emphasize is that the trading instinct is strong in many Africans.

Inverse Compton x-ray generation in QSS and the distance problem

Abstract: Earlier expressions (Okoye, Mon. Not. R. Astr. Soc.; 160: 339 (1972)) for the inverse Compton x-ray emission expected from nearby radio galaxies are generalized to include sources at cosmological distances. The theoretical results are applied to QSS under the assumption that their redshifts are indicators of distance. It is shown that if the cosmological interpretation of the QSS redshifts is correct, the x-ray luminosities of some selected QSS must have been greater at earlier epochs and the expected Compton x-ray fluxes greater than the corresponding values for a local hypothesis'' model. The importance of the present results, in terms of the problem of the QSS redshifts, is that they suggest a real possibility of distinguishing observationally between the local and cosmological models of QSS by increasing the sensitivities of current X- ray telescopes by one or two orders of magnitude. (auth)

First africain regional conference

Abstract: A conference with more than no registered participants (and many auditors) and at which 13 nations were represented is clearly successful; and it is particularly gratifying that nearly half of the participants are working in Nigeria, and can therefore form a nucleus for a local, professional association.

The origin of unitarity and duality in the Nakanishi amplitude

Abstract: The model of strong interaction proposed by VENEZIANO (I) explains many of the strong-interaction phenomena successfully, in a narrow-resonance approximation, such as l inearly rising trajectories, exchange degeneracy, crossing, correct Regge behaviour, etc. However, the Veneziano model violates uni tar i ty , a proper ty which is very fundamental in physics. To overcome the uni tar i ty violation, recently dual models with Mandelstam analytic i ty have been proposed (2). During such a s tudy of dual ampli tudes with Mandelstam analyt ic i ty , TAHA (a) has shown tha t the Nakanishi scattering ampli tude (4) is a very successful model when crossing, Regge behaviour, Mandelstam analyt ic i ty , (~ dual i ty in a generalized sense ,), etc. are concerned, in this let ter , we point out the origin of un i ta r i ty in the Nakanishi scattering ampli tude and show tha t the Nakanishi scattering ampli tude can be expanded in continuous Veneziano terms. The unsubtrac ted form of the Nakanishi scattering ampli tude for two.part icle scattering is given by