Stimulation Modelling of the Effect of Internal Migration on Urbanization in Rivers State, Nigeria

Internal migration is defined as “a movement of people from one area of a country (especially one local government area) to another area of the same country for the purpose or with the effect of establishing a new residence” either temporarily or permanently, is a complex and multidimensional process. In this study we are expected to determine the impact of internal migration in Port Harcourt city and Bori town respectively and to show the effect of the variation of some parameters that affect the growth of Port Harcourt city, through Simplified Assumptions and Mathematical Formulations. The internal migration of effective working population from Port Harcourt city to Bori town is lesser than that of Bori town to Port Harcourt city due to lesser jobs and social infrastructural facilities in Bori than Port Harcourt. Method of Analysis used is a non-linear ordinary differential equation of order 45 which otherwise is called O.D.E 45(Matlab ODE 45). It is evident from the results of the study that the variation of the rate of internal migration can produce either a positive or a negative effect on the population growth patterns of the two interacting population predictions

Shaking table tests of lightly RC walls: Numerical simulations

International audienceIn the framework of the European consortium ECOLEADER, a seismic research project has been performed on specimens tested on a shaking table. The specimens were representative of reinforced concrete buildings with bearing walls. The mock-up studied in particular in this article is composed of two parallel walls linked with a perpendicular one that has openings. The walls are reinforced according to the current design practice in France with a small amount of reinforcement. Two kinds of finite element simulations have been performed: a refined one using a detailed 3D description of the specimen and a simplified one, based on multifiber beams. The comparison between the experimental and numerical results not only demonstrates the accuracy of the time-history analysis models, but also allows obtaining more detailed information about the behavior of the specimen for more complex seismic excitations. It is shown that both models are able to describe quantitatively the global and qualitatively the local behavior of the structure. The simplified model is furthermore used to investigate the behavior of the specimen under a 3D earthquake loading

Numerical modelling for earthquake engineering: the case of lightly RC structural walls

Different types of numerical models exist to describe the non‐linear behaviour of reinforced concrete structures. Based on the level of discretization they are often classified as refined or simplified ones. The efficiency of two simplified models using beam elements and damage mechanics in describing the global and local behaviour of lightly reinforced concrete structural walls subjected to seismic loadings is investigated in this paper. The first model uses an implicit and the second an explicit numerical scheme. For each case, the results of the CAMUS 2000 experimental programme are used to validate the approaches

Effect of COVID-19 lockdown on reproductive activity in Rivers state

Background: Reproductive activity is an important biological process that always take place between married and unmarried couples across the globe. The study was carried out to evaluate the effect of COVID-19 on reproductive activity during and post-lockdown in Rivers state. The aim of the study was to evaluate the effect of COVID-19 on reproductive activity during and post-lockdown in Rivers state.Methods: A well-structured questionnaire containing demographics and effect of COVID-19 on reproductive activity were administered to participants. Each participant had one questionnaire to fill appropriately and independently after instructions were given to them by the researchers.Results: The study revealed that 57.58% (57/99) of the participants were between the ages 16-20, 58.82% (60/102) were single and 99.03% (102/103) of the participants (women) have unprotected sexual intercourse during COVID-19 lockdown. 99.03% (102/103) the participants engaged in unprotected sex because the pharmacist’s stores were closed. The study also shows that 43.69% (103) have the urge for sex due to inactivity and 76.60% (102) of the participants got pregnant and 96.25% (77/80) of the pregnancy were not planned. 51.29% (41/80) of the participants aborted the pregnancy and 92.68% (38/41) 0f the women who got pregnant did not attend antenatal clinic.Conclusions: A total number of 103 respondents participated in the research. 76.6% of the population got pregnant during the lockdown for different reasons and most of the participants were singles and did not plan for the pregnancy.

Analyzing the Environmental Impacts and Potential Health Challenges Resulting From Artisanal Gold Mining in Shango Area of Minna, North-Central, Nigeria

The environmental impact and potential health challenges resulting from artisanal mining in Shango area of Minna, North Central Nigeria was put into perspective. The methodology adopted for the research includes field work and laboratory analysis. Results of field observation reveal that mining activity resulted in physical environmental impact such as land degradation, destruction of vegetation, erosion of soils and degrading water quality. Results from the laboratory analyses show that soils are contaminated with elements such as Cu (27.7ppm), Cd (0.6 ppm), Hg (0.62 ppm) and Ag (0.35 ppm) and generally show high status when compared to published standard for upper continental crust. While, Zn (14.8ppm), Ni (7.17ppm), Mn (207ppm), Pb (0.58ppm), As (0.4ppm), Co (0.55ppm), Mo (0.16ppm), and Zr (129.8ppm) are rated low in line with the published standard; other determined elements such as Cr (37.8ppm), Fe (31.1ppm) and Au (0.2ppm) are high. These elements can easily be absorbed by plants and subsequently accumulate in their tissues. When such plants are eventually eaten by man, it may lead to different health problems such as slow growth rate, liver and kidney problem. High concentration of these elements in plant tissues may causes different problems

Effects of Englerina drummondii Balle ex Polhill and Wiens leaves extract on selected female rat organs’ weights

Background: Herbal medicine are patronized by several people across the globe This herbal medicine is routinely use and are more accessible and available. This study aimed to investigate the effects of Englerina drummondii Balle ex Polhill and Wiens leaves on rat organs (thyroid gland, kidneys, ovary and fallopian tubes) weights in female rats. Methods: 20 female rats were selected randomly into 4 groups with 5 rats per group. Group 1 received 5 ml/kg of water, group 2 received extract 100 mg/kg, group 3 received extract 200 mg/kg, and group 4 received extract 400 mg/kg. Administration of extract was done for 28 days. Results: The study revealed significance decreased in the weight of the left ovary organ when extract of medium dose (200 mg/kg) and high dose (400 mg/kg) was administered, as compared to control. The result also shows decrease in the organs weight of the thyroid gland, left kidney, right and left fallopian tubes extract of low, medium and high dose were administered. The right kidney shows increase when low dose extract was given but decrease when both low and medium dose of extract was given. However, this decrease is not significance and could be due to dose or time dependent. Statistical analysis was done using statistical package for the social sciences (SPSS) version 23 and p<0.05 was significant. Conclusions: There was significance decreased in the weight of the left ovary organ when extract of medium dose (200 mg/kg) and high dose (400 mg/kg) was administered. Also, there is decrease in other organs weight when low, medium and high dose was given but not significance

Mapping subnational HIV mortality in six Latin American countries with incomplete vital registration systems

Background: Human immunodeficiency virus (HIV) remains a public health priority in Latin America. While the burden of HIV is historically concentrated in urban areas and high-risk groups, subnational estimates that cover multiple countries and years are missing. This paucity is partially due to incomplete vital registration (VR) systems and statistical challenges related to estimating mortality rates in areas with low numbers of HIV deaths. In this analysis, we address this gap and provide novel estimates of the HIV mortality rate and the number of HIV deaths by age group, sex, and municipality in Brazil, Colombia, Costa Rica, Ecuador, Guatemala, and Mexico. Methods: We performed an ecological study using VR data ranging from 2000 to 2017, dependent on individual country data availability. We modeled HIV mortality using a Bayesian spatially explicit mixed-effects regression model that incorporates prior information on VR completeness. We calibrated our results to the Global Burden of Disease Study 2017. Results: All countries displayed over a 40-fold difference in HIV mortality between municipalities with the highest and lowest age-standardized HIV mortality rate in the last year of study for men, and over a 20-fold difference for women. Despite decreases in national HIV mortality in all countries—apart from Ecuador—across the period of study, we found broad variation in relative changes in HIV mortality at the municipality level and increasing relative inequality over time in all countries. In all six countries included in this analysis, 50% or more HIV deaths were concentrated in fewer than 10% of municipalities in the latest year of study. In addition, national age patterns reflected shifts in mortality to older age groups—the median age group among decedents ranged from 30 to 45 years of age at the municipality level in Brazil, Colombia, and Mexico in 2017. Conclusions: Our subnational estimates of HIV mortality revealed significant spatial variation and diverging local trends in HIV mortality over time and by age. This analysis provides a framework for incorporating data and uncertainty from incomplete VR systems and can help guide more geographically precise public health intervention to support HIV-related care and reduce HIV-related deaths

Experimental characterization and modeling of energy dissipation in reinforced concrete beams subjected to cyclic loading

The way of modeling the damping phenomenon in nonlinear time history analysis is still an opened question and remains a motivating challenge in the scientific community. The well-known approach lies in considering non-physical viscous forces that are proportional to the velocity field. A damping matrix must be defined and its identification is not based on physical considerations. This study aims at exploring the possibility of identifying a local constitutive model in order to account for damping in a natural way. To reach this objective, an experimental campaign based on reinforced concrete beams subjected to reverse three-point bending tests is presented. These results allow identifying in an accurate way the hysteretic scheme used to take into account the hysteretic phenomenon. In particular, an ad hoc hysteretic scheme is shown to be consistent in terms of energy dissipation. Numerical free vibration tests are then carried out in order to demonstrate that the use of a viscous damping can be avoided if the local constitutive concrete model accounting for hysteretic phenomenon is accurately identified