The role of teleconnections and solar activity on the discharge of tropical river systems within the Niger basin.

The behavior of tropical river systems is driven by some internal and external factors. Understanding the role of these external forces, such as large-scale oscillations, on river discharge will provide insight into their dynamic complexities and modelling. In this study, the role of teleconnection patterns and solar activity on river discharges within the Niger basin was considered using both linear (correlation) and nonlinear (multifractal and joint recurrence analysis) statistical approaches. Correlation analysis suggests the existence of a linear relationship between tropical teleconnection patterns in the Atlantic and Pacific oceans with river discharge in the Niger basin. Nonlinear relationships were investigated using multifractal formalism and joint recurrence quantification analysis. A strong nonlinear relationship was observed between the teleconnection patterns and river discharge in Diola while other stations (Koulikoro, Ansongo, Niamey, Mopti, Kirango) showed no such relationship. The observation at Diola is attributed to its location (coastal) among other things. The multifractal strengths were found in the range of 0.58-2.86, suggesting fractal correlations between the parameters. There was no conclusive evidence of a linear and nonlinear relationship between solar activity and tropical river discharge within the Niger basin.

An assessment of flood event along Lower Niger using Sentinel-1 imagery.

Flood incidence, especially in global south countries, is one of the most challenging natural disasters in the light of changing climates, especially in Africa. This is because African countries have a large sub-section of vulnerable people who either live within flood-prone areas or depend on flood-prone areas for their means of livelihood such as we have in Nigeria. Recent flood disasters in Nigeria have been of major concern to people, communities, and institutions. Several studies have been conducted on flood events and their impacts in Nigeria. However, most of these studies are on public perception, flood modeling (rainfall-runoff), and the provision of binary maps with few studies engaging in the use of satellite observations, especially the use of Synthetic Aperture Radar, SAR, to enhance flood early warning designs, especially in Sub-Saharan Africa. This study is aimed at assessing the 2018 flood event in Lokoja, Kogi State, Nigeria, using the Sentinel-1 imagery. The study confirmed that a total of 69 buildings out of 611 buildings were affected by the flood disaster with about 24,902 people displaced by this singular flood event. The study shows that backscattering from microwave sensors provides very useful information for highlighting inundated areas that could prove useful in forecasting, monitoring, and precision-based flood early warning designs before, during, and after flood events.

Land use/land cover change and land surface temperature of Ibadan and environs, Nigeria.

Rapid urbanization is having a considerable impact on various aspects of living, thereby altering the biophysical environment. This study adopted the use of remote sensing technique and geographical information system (GIS) to analyse the relationship between changing land use/land cover and land surface temperature in a rapidly urbanizing tropical city of Ibadan between 1984 and 2019. Landsat series TM, ETM+, and OLI satellite imageries of Ibadan region city for 1984, 2002, and 2019, respectively, were obtained from the US Geological Survey (USGS) Landsat series of Earth Observation satellites accessible on the Google earth engine (GEE) platform. Supervised classification was done using a random forest (RF) machine learning classifier in the GEE platform. Surface emissivity maps were obtained from the normalized difference vegetation index (NDVI) thresholds method and land cover information. The surface emissivity based on NDVI classes was used to retrieve land surface temperature (LST). The results showed an increase in urban cover from 341.72 km2 in 1984 to 520.58 km2 in 2019 with an average increase in land surface temperature from 17 °C to 38 °C, respectively. Temperature sampling in the north-south and west-east transect revealed that highly urbanized areas located at the city centre of Ibadan have the highest LST of about 38 °C. It dissipates to about 19 °C at the suburb that is less built up. A significant negative relationship exists between the health condition of vegetation (NDVI) and LST with a correlation coefficient of r = - 0.95. The study confirms the potential application of GIS and remote sensing for detecting urban growth as well as relates growth impact to LST, thereby suggesting that fitting strategies will be important for the sustainable management of the urban areas.

Early warning systems development for agricultural drought assessment in Nigeria.

The existing drought monitoring mechanisms in the sub-Saharan Africa region mostly depend on the conventional methods of drought monitoring. These methods have limitations based on timeliness, objectivity, reliability, and adequacy. This study aims to identify the spread and frequency of drought in Nigeria using Remote Sensing/Geographic Information Systems techniques to determine the areas that are at risk of drought events within the country. The study further develops a web-GIS application platform that provides drought early warning signals. Monthly NOAA-AVHRR Pathfinder NDVI images of 1 km by 1 km spatial resolution and MODIS with a spatial resolution of 500 m by 500 m were used in this study together with rainfall data from 25 synoptic stations covering 32 years. The spatio-temporal variation of drought showed that drought occurred at different times of the year in all parts of the country with the highest drought risk in the north-eastern parts. The map view showed that the high drought risk covered 5.98% (55,312 km2) of the country's landmass, while low drought risk covered 42.4% (391,881 km2) and very low drought risk areas 51.5% (476,578 km2). Results revealed that a strong relationship exists between annual rainfall and season-integrated NDVI (r2 = 0.6). Based on the spatio-temporal distribution and frequency of droughts in Nigeria, drought monitoring using remote sensing techniques of VCI and NDVI could play an invaluable role in food security and drought preparedness. The map view from the web-based drought monitoring system, developed in this study, is accessible through localhost.

Association Between Weather Parameters and SARS-CoV-2 Confirmed Cases in Two South African Cities.

Several approaches have been used in the race against time to mitigate the spread and impact of COVID-19. In this study, we investigated the role of temperature, relative humidity, and particulate matter in the spread of COVID-19 cases within two densely populated cities of South Africa-Pretoria and Cape Town. The role of different levels of COVID-19 restrictions in the air pollution levels, obtained from the Purple Air Network, of the two cities were also considered. Our results suggest that 26.73% and 43.66% reduction in PM2.5 levels were observed in Cape Town and Pretoria respectively for no lockdown (Level 0) to the strictest lockdown level (Level 5). Furthermore, our results showed a significant relationship between particulate matter and COVID-19 in the two cities. Particulate matter was found to be a good predictor, based on the significance of causality test, of COVID-19 cases in Pretoria with a lag of 7 days and more. This suggests that the effect of particulate matter on the number of cases can be felt after 7 days and beyond in Pretoria.

Early geography of the coronavirus disease outbreak in Nigeria.

An understanding of the COVID-19 spread is growing around the world, yet little is known of Africa. This paper explores the time-space geographies of COVID-19 infection focusing on Africa and Nigeria especially. We appraise the global-to-local situation of confirmed cases, deaths and recoveries as well as measures engaged in response to the pandemic. Findings reveal that South Africa accounts for 40% of the total confirmed cases in Africa, followed by Egypt (18%), Nigeria (6.8%), Ghana (4.6%) and Algeria (3.6). Our study shows a significant relationship between population density and COVID-19 cases in Nigeria (R2 = 0.76; y = 2.43x - 268.7). This expression suggests that high population densities catalyze the spread of COVID-19. While Nigeria has only recorded about 25,964 cases as at the time of writing, the country is struggling to match pressures from rising cases as a result of existing disparities in health care systems.

Geographical trend analysis of COVID-19 pandemic onset in Africa.

Little has been documented in literature concerning the manner of occurrence and spread of COVID-19 in Africa. Understanding the geographic nature of the corona virus pandemic may offer critical response signals for Africa. This paper employed analysis of variance (ANOVA) to show that significant variations exist among African countries', particularly total population as well as those using basic drinking water services, gross national income, expenditure on health, number of physicians and air transport passengers. Although we have only considered the number of confirmed corona virus infections noting that the fatality may be too early to discuss, we have relied on data from the European Centre for Disease Prevention and Control (ECDC) to establish a significant association between international mobility based on average annual air passenger carried (r â€‹= â€‹0.6) which also successfully predicted (R 2 â€‹= â€‹0.501) the number of COVID-19 cases reported in each country along with the population density (R 2 â€‹= â€‹0.418). We also detected that COVID-19 cases report y geometrically increased daily x (R 2 â€‹= â€‹0.860) with a 2nd order polynomial equation in the form of y â€‹= â€‹0.3993 â€‹× â€‹2-8.7569 x and a clustered spatial pattern with a nearest neighbour ratio of 0.025 significant at 0.05 α-level. African countries have responded to the pandemic in different ways including partial lockdown, closure of borders and airports as well as providing test centres. We concluded that 40% of Africa are categorized as emerging hot spots while responses differ significantly across regions.

FACTORS ASSOCIATED WITH HIV INFECTION AMONG CLIENTS ACCESSING HIV COUNSELING AND TESTING SERVICES IN A SECONDARY REFERRAL HOSPITAL IN LAGOS, NIGERIA.

BACKGROUND: HIV counselling and testing (HCT) provides an opportunity for people to learn more about the human immune deficiency virus (HIV). This study assessed the knowledge of, and factors associated with, HIV infections among clients assessing HCT services referral hospital in Lagos, Nigeria. MATERIALS AND METHODS: Retrospective review of records of clients who assessed HCT services at Mainland Hospital Lagos, Nigeria, between July 1, 2016, and December 31, 2017, was done. Multivariate analysis was done to identify the factors associated with HIV infection and knowledge of HIV. RESULTS: A total of 4273 clients were screened for HIV within the study period. The mean age of clients was 38.5±14.4. Male: Female ratio was 1:0.87. The prevalence of HIV infection was 19%. Factors associated with HIV infection were: age above 24 years, being female (AOR 1.6 95% CI 1.4-2.0, p<0.001), previous marriage (divorced, widowed, separated) (AOR 2.3 95% CI 1.7- 3.3, p<0.001) and poor knowledge of HIV (AOR 2.9 95% CI 2.2-3.6, p<0.001). Males were 15 times more likely to have good knowledge of HIV than females (AOR 14.5 95% CI 10.5- 20.0, p<0.001). In addition, the clients who were single (AOR 3.6 95% CI 2.4-5.4, p<0.001) and married (AOR 3.9 95% CI 2.9-5.3, p<0.001) were four times more likely to have good knowledge of HIV than clients who were previously married. CONCLUSION: More proactive measures are required to educate the public, especially women who were previously married, on HIV transmission and prevention.

PREDICTORS OF UPTAKE OF A POTENTIAL COVID-19 VACCINE AMONG NIGERIAN ADULTS

BackgroundThe Coronavirus diseases (COVID-19) pandemic is not abating and there is no approved treatment yet. The development of vaccines is hoped to help in addressing this disease outbreak. However, in the face of anti-vaccines uprise, it is important to understand the factors that may influence the uptake of COVID-19 vaccines as this will influence how successful the fight against COVID-19 will be in the long term. MethodsA cross-sectional study among 776 adult Nigerians (age [≥]18 years) was conducted in the 36 States of Nigeria and the Capital City with online questionnaire. The questionnaire consisted of 5 sections: socio-demographic characteristics of respondents, respondents knowledge of COVID-19, respondents risk perception of COVID-19, vaccination history of respondents, and willingness to receive COVID-19 vaccine. Descriptive analysis of variables was done and multivariate analysis using logistic regression was carried out to determine the predictors of uptake of a potential COVID-19 vaccine. The level of significance was predetermined at a p-value < 0.05. Data analysis was done with SPSS version 21. ResultsMost of the respondents were male (58.1%). Most participants were willing to take a potential COVID-19 vaccine (58.2%), while 19.2% would not take it with 22.6% indecisive. 53.5% would prefer a single dose COVID-19 vaccine. For vaccine uptake, being male (p= 0.002) and the perception that "vaccines are good" (p< 0.001) were the positive predictor of uptake of a potential COVID-19 vaccine. ConclusionMost Nigerians were willing to take a potential COVID-19 vaccine with the male gender and perception that "vaccines are good" being positive predictors. There is a need for public enlightenment aim at encouraging those that are indecisive or averse to receiving COVID-19 vaccines.