On The Estimation of Parameters of Thick Current Shell Model of Equatorial Electrojet Using Optimisation Method

Equatorial electrojet, an intense current flowing eastward in the low latitude ionosphere within the narrow region flanking the dip equator, is a major phenomenon of interest in geomagnetic field studies. For the first time the five parameters required to fully describe the Onwumechili\'s composite thick current shell model format of equatorial electrojet have been evaluated from a single autonomous set of ground data at solar minimum. The non-linear model was applied to four data points, each with a pair of simultaneously measured horizontal H and vertical Z variation field components. The resultant system of eight non-linear equations with five unknown model parameters were subjected to non-linear least square optimisation method taking advantage of the robust Levenberg-Madquart optimisation subroutine of licensed MATLAB 6.0 version. The thick current shell format model parameters estimated for Indian sector are shown to be within the appropriate limits and in excellent agreement with literature and physical expectation. Keywords: Equatorial electrojet; Numerical models; Optimisation Journal of Science & Technology (Ghana) Vol. 28 (3) 2008: pp. 1-

Structural Characterization of Lithium Doped Nzp Na1-xLixZr(PO4)3(x=0.00-0.75)

Sodium zirconium phosphate (NZP) of composition Na1-xLixZr2(PO4)3 (x=0.0-0.75) have been synthesized using solid state reaction, with a view to minimizing the ZrO2 second phase normally present .The compositions have been characterized by XRD and SEM for phase composition, lattice parameters and density. No ZrO2 second phase was detected in some of the compositions, rather NasZr(PO4)3 and the density showed a systematic decrease with increase of Li. All The compositions belong to the rhombohedral crystal system and were indexed based on hexagonal lattice structure. The density of the composition x=0.00 as calculated from the XRD data is 3.02g/cm3.The grain sizes of the compositions are in the range 1-2&#956m, 2-5&#956m, 3-7 &#956m and 2&#956m for x=0,0.25,0.5 and 0.75, respectively. Keywords: solid state synthesis, NZP, XR

External electric field effect on electron transport in carbon nanotubes

Electronic transport properties of carbon nanotubes are studied theoretically in the presence of external electric field E(t) by using the Boltzmann's transport with constant relaxation time. An analytical expression for the current densities of the nanotubes are obtained. It is observed that the current density-electric field characteristics of the CNs exhibit total self-induced transparency and absolute negative conductivityComment: 5 pages, 2 figure

Serospatial epidemiology of zoonotic Coxiella burnetii in a cross section of cattle and small ruminants in northern Nigeria

The persistent and highly transmissible Coxiella burnetii is a neglected infection that negatively affects reproductive parameters of livestock. It is also of zoonotic importance and has been reported to cause devastating human infections globally. Domestic ruminants represent the most frequent source of human infection. Data from Nigeria are very few and outdated. There is a significant gap in up-to-date information on the exposure, spatial distribution and risk factors of infection of this important disease. The exposure to C. burnetii was determined using sensitive serological assays in cattle and small ruminants. A total of 538 animals made up of 268 cattle and 270 small ruminants were sampled from three northern Nigerian states. The proportion of cattle sampled that were seropositive from the study locations were: Kwara 14/90 (15.6%; 95% CI: 8.8–24.7); Plateau 10/106 (9.43%; 95% CI: 4.6–16.7) and Borno 4/72 (5.56%; 95% CI: 1.5–13.6) states. Lower seroprevalence was recorded among the small ruminants sampled, with positives recorded from sheep and goat sampled from only Kwara state 6/184 (3.3%; 95% CI: 1.2–7.0); while none of the small ruminants sampled from Plateau were seropositive. The results of the bivariate analysis showed that none of the tested independent variables (village, age group, sex, breed of cattle, presence of ticks, reproductive status, and management system) were statistically significant factors associated with seropositivity of cattle for antibodies to C. burnetii. Stakeholders involved in animal husbandry should be duly educated on proper disposal of birth products as well as bodily fluids in order to reduce environmental contamination, persistence and human infection

Meningococcus serogroup C clonal complex ST-10217 outbreak in Zamfara State, Northern Nigeria.

After the successful roll out of MenAfriVac, Nigeria has experienced sequential meningitis outbreaks attributed to meningococcus serogroup C (NmC). Zamfara State in North-western Nigeria recently was at the epicentre of the largest NmC outbreak in the 21st Century with 7,140 suspected meningitis cases and 553 deaths reported between December 2016 and May 2017. The overall attack rate was 155 per 100,000 population and children 5-14 years accounted for 47% (3,369/7,140) of suspected cases. The case fatality rate (CFR) among children 5-9 years was 10%, double that reported among adults ≥ 30 years (5%). NmC and pneumococcus accounted for 94% (172/184) and 5% (9/184) of the laboratory-confirmed cases, respectively. The sequenced NmC belonged to the ST-10217 clonal complex (CC). All serotyped pneumococci were PCV10 serotypes. The emergence of NmC ST-10217 CC outbreaks threatens the public health gains made by MenAfriVac, which calls for an urgent strategic action against meningitis outbreaks

Women’s mass media exposure and maternal health awareness in Ota, Nigeria

Maternal health has been an issue of priority to nations across the globe for years now. This study sought to: identify the sources of maternal health awareness; examine means of obtaining maternal health information; determine the frequency of mass media exposure; and analyse the influence of mass media exposure on maternal health awareness among the female residents. The Agendasetting theory and the descriptive (survey) research design, using the questionnaire as the research instrument, were utilized in this study. For this study, the purposive and haphazard sampling techniques were used. The internet (49%) was the topmost source of maternal health awareness; adverts/campaigns (30.6%) were the most common means of obtaining maternal health information; once in a month [27.6%] was the exposure frequency of most participants to the mass media while the least exposure frequency was once in two weeks [5.1%]. It was discovered that mass media exposure had a significant influence on maternal health awareness