Se realizó una investigación sobre el efecto que tienen algunas actividades humanas en la susceptibilidad magnética y la susceptibilidad dependiente de la frecuencia: el estudio se realizó en Jalingo, estado de Taraba, Nigeria, en la superficie del suelo de una zona comercial, un estacionamiento de autos y una zona escolar. El objetivo fue evaluar la variación de la susceptibilidad magnética con distintos tipos de uso de la tierra y detectar los puntos más contaminados utilizando los parámetros de proxy magnéticos. Con ello se evaluó la contribución de superparamagnéticas (SP), del tamaño de un grano, a

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The rapid increase in vehicular activities in the past two centuries contributes vastly to air pollution levels. In as much as Social interactions and economic growth are well enhanced by vehicular transportation in many developing countries, it is unfortunate that exhausts from vehicles contribute immensely to ambient air quality especially in the urban areas. The concentrations of carbon monoxides (CO) and carbon dioxide (CO2) emissions in selected roadsides in Jalingo have been assessed. Four roads were used as sample locations where the concentration of CO2 and CO were measured using an air quality meter for four weeks. The mean concentration of CO2 and CO obtained were respectively as follows: 542.25 ppm and 7.49 ppm for the roadblock, 540.05 ppm and 5.55 ppm for Hammaruwa way, 598.81 ppm and 17.42 ppm for market road, and 463.80 ppm and 1.08 ppm for Nigerian Labour Congress (NLC) road (control). Based on the acceptable limit of CO2 (600 ppm), the Roadblock road, Hammaruwa way, and the NLC/control road are safe. Only the market road had value that exceeded the acceptable limit, and it may be attributed to high vehicular activities on the roadsides. Therefore, more alternative roads should be constructed in other to minimize traffic congestion and also, the use of nose masks should be encouraged. For the CO, all the sites are safe because they fall within the acceptable level of CO (1-70 ppm).

The ability of the soil to regulate heat energy is important for plant growth, soil texture and strength. Many agricultural soils are acidic in nature which tends to limit plant growth and microbial activity. Aside from agricultural lime, wood ash is used to amend physical and physicochemical properties of the soil. To maintain the soil hydraulic and physicochemical properties and to increase plant yield, it is important to know the physicochemical and physical properties of the ash used. The physiochemical and physical properties vary across various plant species. Ash samples from seven different plants were used for this study. The Horiba metre was used to measure the electrical conductivity, pH, Total Dissolved Solid (TDS) and salinity of the samples, while the Lees Disc apparatus was used to measure the thermal conductivity of the samples. The study revealed that moringa olieferra ash has the highest salinity, TDS and Electrical conductivity, while azadichta indica and tiobroma cacoa have least pH. Also, Kyah seleelygalisis and azadichta indica had the highest and lowest thermal conductivity respectively.

<p>According to the principle of general covariance, the laws of physics are the same in all reference frames. The controversial theory of the Varying Speed of Light (VSL) contradicts the principle of general covariance. Fortunately the VLS theory explains some crucial issues in cosmology such as Lorentz variance, biometric theories, locally Lorentz variance, cosmological constant problem, horizon<em> </em>and flatness<em> </em>problems. Also, recent astronomical observations from quasar show that the fine structural constant depends on redshift and therefore, varies with cosmological time. In other to harness this fascinating and published knowledge, two models where used in this work.  1. Cosmology with variables c; here the Friedmann-Robertson-Walker (FRW) is used in the Einstein field equation with variable c and Λ terms to obtain the scale factor, which shows the continuous exponential expansion of the universe. 2. Variation of the speed of light as a function of the scale factor of the universe; here we obtained: a good approximation to estimate the current age of the universe. The scale factor of the universe depends its content given by the equation of state parameter ω. We obtained the deceleration parameter in terms of the Hubble parameter. We arrived at a conclusion that the universe was decelerating at ω = 1, accelerating at ω = 1/3 and the Hubble parameter diverges at the beginning and end of the universe.</p>