The reproductive characteristics of mudskipper Periophthalmus barbarus (linnaeus 1760) (teleostei, Gobiidae) in the estuarine swamps of the Imo river, Nigeria

Between December 2007 and September 2008, aspects of the reproductive characteristics of the mudskipper Periophtalmus barbarus were studied using samples (n = 1802) obtained from the Imo River estuary. The overall sex ratio was not different from unity but analysis of ontogenic variation showed that males dominated in 5, 8, 10 and 11 cm total length size classes, while females were preponderant in the 6, 7 and 9 cm total length size class. The number of males was not higher than the number of females during the dry and wet seasons. The smallest mudskipper with incipient gonad was 8.0 cm total length. The median size at maturity was 8.9 cm total length. From the patterns of monthly variation in mean gonado-somatic index (GSI), it was concluded that the species breeds yearround, with at least, one major peak (August to December) and one minor peak (May) in a year. Length-weight allometric relationship for pooled data was W = 17.8 L2.60 with a dry season b value of 2.64 and a wet season b value of 2.55. The monthly variation in mean hepatosomatic index (HSI) showed that the pattern of variation in mean HSI was a reverse of that of the mean GSI. The implication of this is that the species draws down on the energy reserves in the liver for the recrudescence of the gonad. A trade-off was apparent in the body’s use of resources for gonadalrecrudescence. Consequently when the mean hepatosomanic index was low, mean gonad somatic index was high. A major peak of GSI occurred from August to December while a minor peak occurred in May

Agricultural Co-Operatives and Training of Male and Female Farmers on Improved Rice (Oryza sativa) Production Techniques in Ini Local Government Area, Akwa Ibom State, Nigeria

This study assessed the extent to which agricultural cooperatives carryout the training of male and female farmers on improved rice (Oryza sativa) production techniques in Ini Local Government Area of Akwa Ibom state, Nigeria using research questions for 2,500 (male and female) rice farmer cooperative members in the study Area. Data analysis for 1600 completed questionnaire collected revealed that male and female farmers were not efficiently trained by agricultural cooperatives on improved rice production techniques. Moreso, there were no significant difference on the extent of carrying out the training of male and female farmers by agricultural cooperatives on improved rice production techniques in Ini Local Government Area. It is recommended among others that Agricultural cooperatives should organize periodic training sessions for rice farmers through the use of facilities and demonstration in the farm. The Government, through The Ministry of Agriculture should encourage and support agricultural cooperatives by providing materials and adequate funding to enable them perform their primary assignment creditably

Farmers’ perception and Knowledge need for adoption of new cultivars of cassava in Igabi Local Government Area (LGA), Kaduna State.

The study examined farmers’ perception and knowledge need for adoption new varieties of cassava in Igabi LGA, Kaduna State. The purpose of the research was to;( 1) ascertain how cassava farmers in the area perceive the new varieties of cassava vis-a-vis the technologies required for its propagation, and (2) the relationship between the existing and recommended knowledge of cassava cultivation in the area. Seventy six respondents used for the study were selected by random sampling while focus group discussion and interview schedule were employed to gather data. Data were analyzed by mean score analysis. The result of the analysis shows that majority (36.8%) were between 30- 39 years, 89% married and 34.2% had secondary education while 50% had regular extension contact. However, out of five (5) main recommended production technologies, only two- planting methods (51.3%) and weeding interval (56.6%) were in line with farmers’ previous experience or knowledge. Farmers perceived the new cassava cultivars as beneficial through its high yielding capacity (3.3*), fast maturity (3.1) and disease resistance (2.5) among others, while capital and marketing (3.2 apiece), farm size (3.0) were among the perceived constraints to adoption of the new cultivars. The study recommended among others formation of cooperative society to aid farming activities in the area. Keywords: awareness, benefit, constraints, knowledge of planting cassava, perception

Comparison of seismic processing and interpretation tradeoffs between Kirchoff and finite-difference migrations, using poststack migrated data in the west Niger Delta, Nigeria

ABSTRACT The Kirchoff and Finite-Difference migrations were carried out on seismic data from the western part of the Niger Delta of Nigeria. The survey for the acquisition of the data was oriented southwest-north-east, at an angle of 45.4490 o . The KIRCH and FXMIG seismic migration programs were used to process and display the seismic sections. The sections were interpreted for diffractions, faults, and structures. It was observed that the dipping structures were incorrectly positioned downdip from the true reflection point. Prior to migration, the dipping structures were steeper and longer. For both Kirchoff and Finite-Difference migrations, there was proper imaging of the dipping structures. The structures were accurately moved updip and diffractions collapsed. The faulting pattern is a growth fault system as is generally the case in the Niger Delta basin. The reflectors became shorter, anticlines more clearly defined, and reflection events terminating at fault planes. Finite-Difference migration is preferred because it is faster, handles velocity variation and noise better, and events appearance is sufficiently distinctive for the interpreter to find traps, seals and reservoirs

Off mass shell dual amplitude with Mandelstam analyticity

A model for the $Q^2$-dependent dual amplitude with Mandelstam analyticity (DAMA) is proposed. The modified DAMA (M-DAMA) preserves all the attractive properties of DAMA, such as its pole structure and Regge asymptotics, and leads to a generalized dual amplitude $A(s,t,Q^2)$. This generalized amplitude can be checked in the known kinematical limits, i.e. it should reduce to the ordinary dual amplitude on mass shell, and to the nuclear structure function when $t=0$. In such a way we complete a unified "two-dimensionally dual" picture of strong interaction. By comparing the structure function $F_2$, resulting from M-DAMA, with phenomenological parameterizations, we fix the $Q^2$-dependence in M-DAMA. In all studied regions, i.e. in the large and low $x$ limits as well as in the resonance region, the results of M-DAMA are in qualitative agreement with the experiment.Comment: 20 pages, 3 figures; to appear in Phys.Atom.Nuc

Total photoproduction cross-section at very high energy

In this paper we apply to photoproduction total cross-section a model we have proposed for purely hadronic processes and which is based on QCD mini-jets and soft gluon re-summation. We compare the predictions of our model with the HERA data as well as with other models. For cosmic rays, our model predicts substantially higher cross-sections at TeV energies than models based on factorization but lower than models based on mini-jets alone, without soft gluons. We discuss the origin of this difference.Comment: 13 pages, 9 figures. Accepted for publication in EPJC. Changes concern added references, clarifications of the Soft Gluon Resummation method used in the paper, and other changes requested by the Journal referee which do not change the results of the original versio