Design and Linearization of Energy Efficiency Power Amplifier in Nonlinear OFDM Transmitter for LTE-5G Applications. Simulation and measurements of energy efficiency power amplifier in the presence of nonlinear OFDM transmitter system and digital predistortion based on Hammerstein-Wiener method

This research work has made an effort to understand a novel line of radio frequency power amplifiers (RFPAs) that address initiatives for efficiency enhancement and linearity compensation to harmonize the fifth generation (5G) campaign. The objective is to enhance the performance of an orthogonal frequency division multiplexing-long term evolution (OFDM-LTE) transmitter by reducing the nonlinear distortion of the RFPA. The first part of this work explores the design and implementation of 15.5 W class AB RF power amplifier, adopting a balanced technique to stimulate efficiency enhancement and redeeming exhibition of excessive power in the transmitter. Consequently, this work goes beyond improving efficiency over a linear RF power amplifier design; in which a comprehensive investigation on the fundamental and harmonic components of class F RF power amplifier using a load-pull approach to realise an optimum load impedance and the matching network is presented. The frequency bandwidth for both amplifiers was allocated to operate in the 2.620-2.690 GHz of mobile LTE applications. The second part explores the development of the behavioural model for the class AB power amplifier. A particular novel, Hammerstein-Wiener based model is proposed to describe the dynamic nonlinear behaviour of the power amplifier. The RF power amplifier nonlinear distortion is approximated using a new linear parameter approximation approach. The first and second-order Hammerstein-Wiener using the Normalised Least Mean Square Error (NLMSE) algorithm is used with the aim of easing the complexity of filtering process during linear memory cancellation. Moreover, an enhanced adaptive Wiener model is proposed to explore the nonlinear memory effect in the system. The proposed approach is able to balance between convergence speed and high-level accuracy when compared with behavioural modelling algorithms that are more complex in computation. Finally, the adaptive predistorter technique is implemented and verified in the OFDM transceiver test-bed. The results were compared against the computed one from MATLAB simulation for OFDM and 5G modulation transmitters. The results have confirmed the reliability of the model and the effectiveness of the proposed predistorter.Fundacão para a Ciência e a Tecnologia, Portugal, under European Union’s Horizon 2020 research and innovation programme ... grant agreement H2020-MSCA-ITN- 2016 SECRET-722424 I also acknowledge the role of the National Space Research and Development Agency (NASRDA) Sokoto State Government Petroleum Technology Trust Fund (PTDF

Workflow for building and calibrating 3D pre-injection and 4D geomechanics modelling to assess caprock and fault integrity for geologic CO2 storage

Carbon capture and storage (CCS) has been established as a viable technology for the mitigation of climate change caused mainly by anthropogenic greenhouse gas emissions into the atmosphere. Ever since the publication of the special report on CCS by the Intergovernmental Panel on Climate Change in 2005, there has been an increased research and development in all areas of CCS. Some of these research involves use of numerical methods and models for optimizing storage and ensuring effective long term containment. In this paper, we propose a workflow for building and calibrating 3D preinjection and 4D geomechanics modelling to assess caprock and fault integrity for geologic carbon dioxide storage. The workflow presented here describes a seamless end -to-end process which combines a transparent flow of data with an easy-to-use graphical user interface. The workflow can conduct 3D static and 4D flow-, pressure-, and temperature-coupled calculations for rock deformations, failure and stresses. In highly heterogeneous and complex models, the workflow is capable of modelling multiple hundred faults, and multiple thousand discrete fractures. It allows the geological model, despite its high degree of complexity to be maintained throughout the geomechanical analyses process

Design of Radiation Pattern-Reconfigurable 60-GHz Antenna for 5G Applications

noReconfigurable beam steering using circular disc microstrip patch antenna with a ring slotis proposed. The overall dimension of the antenna is 5.4×5.4 mm2 printed on a 0.504 mm thick, Rogers RT5870 substrate with relative permittivity 2.3 and loss tangent 0.0012. The designed antenna operates at the expected 5G frequency band 60 GHz with a central coaxial probe feed. TwoNMOS switches are configured to generate three different beam patterns. Activating each switch individually results in a near 70 degree shift in the main beam direction, whereas the frequency characteristics are unchanged. The power gains are between 3.9 dB and 4.8dB for the three states of switches configurations. Simulated results in terms of return loss, peak gains and radiation pattern are presented and show a reasonable agreement at the expected 60 GHz bandfor 5G applications.The published journal webpage is no longer available

Performance Indices and Physiological Changes in Pearl Guinea Fowls (Numida Meleagris) Supplemented with Molasses Through Drinking Water

. The study was aimed at evaluating the performance indices and physiologic changes in pearl Guinea fowls (Numida meleagris) supplemented with molasses through drinking water. A total of thirty-two (n=32) day-old pearl Guinea fowls raised to 12-week-old were used for the study. The fowls were randomly allocated to two groups (control and experimental) of 16 fowls each, with each having two replicates. Experimental fowls were given 5 mL molasses per litre of drinking water for 8 weeks, while control fowls were given only drinking water. Performance indices which include: feed consumption, water intake and percentage weight gain were measured. Rectal temperature was measured and blood samples were collected to evaluate the changes in haematological parameters, serum triiodothyronine (T3) and thyroxine (T4) concentrations. Results revealed that the molasses-treated fowls had significantly (P<0.05) higher percentage weight gain, blood total protein, packed cell volume and mean corpuscular volume compared to control. However, the feed consumptionwas significantly lower (P<0.05) in the molasses-treated fowls compared to control. In both groups, rectal temperature increased significantly (P<0.05) during the afternoon hours and was lower (P<0.05) in molasses-treated fowls than control during the evening hours. There was no significant difference in other haematological parameters, serum glucose, T4 and T3 betweengroups. In conclusion, molasses supplementation decreased feed consumption, improved body weight gain and enhanced nutritional status and erythropoiesis in Guinea fowls

Alcohol Use and its Associated Factors among Residents of an Urban Community in Plateau State Nigeria

Background:According to the World Health Organization (WHO), alcohol use contributes about 2.3 million deaths globally and accounts for 3.8% of global mortality. Nigeria ranks as the leading country in alcohol consumption in Africa. In view of this, this study was conducted to assess the level of alcohol use and its associated factors among residents of an urban community in Plateau state, Nigeria.Methodology: A cross sectional study carried outnbsp among 212 adult residents of AngwanRukuba community of Jos North Local Government Area of Plateau Statenbsp using quantitative method of data collection.nbsp Epi info statistical software version 7.0 was used for data analysis with adjusted odds ratio and 95% confidence intervalused in the study while a p-value of le 0.05 was considered statistically significant.Result: The average age of the respondents in this study was 28.2plusmn10.4 years with majority being 30 years and below. More of the respondents 142(60.8%) were current consumers of alcoholic drinks with harmful level of alcohol intake found to be 32.0%.Sex, quantity of drinks adjudged as normal in one sitting and age of onset of alcohol use were found to significantly predict harmful intake of alcohol containing drinks in the study.Conclusion: A relatively high level of alcohol use was found in this study with a corresponding level of harmful use. Sex, age of onset of alcohol use and quantity of drinks adjudged as normal in a sitting were significant contributors to harmful alcohol use.nbs

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

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Primary caregivers of the mentally ill experience more burden: A comparative study of mental versus physical illness

Background: Caring for patients with chronic illnesses whether mental or physical imposes a burden on caregivers. Schizophrenia and Type 2 Diabetes Mellitus (DM) are both chronic illnesses which require long term care, though they differ in pathophysiologic concepts. Planning strategies for improving the quality of life of caregivers of these patients will require that clinicians answer the pertinent question of who experiences more burden.Objective: This study assessed and compared the burden of care in caregivers of patients with schizophrenia and Type 2 DM, determined caregiver and patient characteristics that predict burden in both groups.Design: Cross-sectional study.Setting: Endocrinology and Psychiatry outpatient clinics of the University of Ilorin Teaching Hospital, Ilorin, Nigeria.Participants: One hundred patients with schizophrenia and 100 patients with Type 2 DM, along with their primary caregivers.Outcome measures: Caregiver burden was assessed using the ZBI. Results: Caregivers of schizophrenia patients experienced significantly higher burden than caregivers of Type 2 DM (p=0.025). Predictors of burden in schizophrenia patients’ caregivers were caregiver age (OR=2.088), being a lone caregiver (OR=1.39), perceiving caregiving as problematic (OR=6.194), GHQ-12 scores of caregiver (OR=7.46) as well as the presence of psychopathology (OR=2.61). The predictors of burden in Type 2 DM patients’ caregivers were caregiver gender (OR=4.049) presence of physical complications (OR=1.547). Conclusion: Caregivers of patients with schizophrenia were found to experience significantly higher levels of burden and psychological distress and this is important in planning care strategies for this group of patients

Green flexible RF for 5G

No5th Generation mobile networks (5G) and mobile communications technologies beyond 2020 will need to be energy aware so as to support services that are likely to be intelligent and bandwidth hungry, as well as to support multi-mode operation (LTE, LTE+, HSDPA, 3G among others) in a HetNet environment. This imposes stringent design requirements on the RF transceiver, a key consumer of power in networks today. This chapter will investigate the key RF subsystems forming part of the 5G RF transceiver, where energy efficiency and full radio flexibility are at the forefront of system design. In particular, we target advanced designs on antenna systems, RF power amplifiers and the challenges facing cross-talk in MIMO architectures