Assessment of multipath and shadowing effects on UHF band in built-up environments

Ultra-high frequency (UHF) bands are radio frequencies in the range of 300 MHz and 3 GHz. These bands are used for television broadcasting, mobile cellular systems, Wi-Fi, satellite communications and many others. Effective communication link in the UHF band requires direct line of sight between the transmitters and receivers. However, this is not always the case in built-up areas where diverse obstacles such as large buildings, trees, moving objects and hills are present along the communication path. These obstacles result in signal degradation as a result of shadowing (blockages) and multi-path, which are two major causes of signal losses. Path loss models are used in predicting signal losses but, the accuracy of these models depend on the fitness between the model's predictions and measured loses. In this work, the multi-path and shadowing effects on signal impairment were investigated through the use of empirical and semi-empirical path loss models analysis in built-up environments. Electromagnetic field strength measurements were conducted using four television transmitters at UHF bands along four major routes of Osun State, Nigeria. Experimental and simulation results indicated that the empirical models provide a better fit than the semi-empirical models. It was also found that the poor performance of the Knife Edge Model which is a semi-empirical model was traced to the bases of its formulation, which assumed point like knife edge for all obstacles on the path of radio propagation. The work therefore recommends that network planners employ empirical models found suitable for their kind of terrain when faced with coverage planning and optimization.Keywords: Path loss models, Radio propagation,  Terrain feature

Spontaneous subcutaneous emphysema in a male toddler in a health facility in Nasarawa state: A case report

Background: Spontaneous subcutaneous emphysema (SSE) is a clinical condition in which air escapes into the subcutaneous tissues. It is a rare complication of childhood pneumonia and often occurs with pneumothorax and/or pneumomediastinum. Although the sight of a child with SSE could be frightening, it is mostly benign requiring in most cases supportive care. We report a case of SSE complicating pneumonia in an 18-month-old toddler that was managed conservatively.Case Report: An 18-months-old toddler was admitted with a 5-day history of progressive swelling of the face, scalp, upper limbs, and trunk. He was referred from a peripheral hospital where he was admitted for 5 days with pneumonia and had received antibiotics, intravenous fluid, and oxygen therapy. Clinical evaluation revealed extensive subcutaneous emphysema and right-sided pneumothorax. Antibiotics were optimized and the patient was provided supportive care and monitored for 7 days with complete resolution of the emphysema.Conclusion: SSE could complicate childhood pneumonia but it has a benign course. Effective treatment of underlying pneumonia alongside supportive care will achieve complete resolution

Numerical study of effect of design and physical parameters on a PEM fuel cell performance

Paper presented at the 8th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Mauritius, 11-13 July, 2011.A proton exchange membrane (PEM) fuel cell is one of the widely researched fuel cell systems due to its low temperature operation, high power density, fast start-up, system robustness and low emission characteristics. A three-dimensional numerical computation of the effect of design parameters (geometry and flow orientation) and physical parameters (gas diffusion layer porosity) on PEM fuel cell performance was carried out. The continuity, momentum, energy and species conservation equations describing the flow and species transport of the gas mixture in the coupled gas channels and the electrodes were numerically solved using a computational fluid dynamics code. This paper investigated how channel geometries (width and depth), flow orientation and gas diffusion layer (GDL) porosity affect performance and species distribution in a typical fuel cell system. The study also incorporated pressure drop characteristics in the flow channel. The numerical results computed agree well with experimental data in the literature.mp201

Fatal case of newborn Lassa fever virus infection mimicking late onset neonatal sepsis: a case report from northern Nigeria

BACKGROUND: Lassa fever is a zoonotic viral infection endemic to the West Africa countries. It is highly fatal during pregnancy and as such reports of neonatal onset Lassa fever infections are rare in scientific literature. We report a fatal case of Lassa fever in a 26-day-old neonate mimicking the diagnosis of late-onset neonatal sepsis. CASE PRESENTATION: The patient is a 26-day-old neonate who was admitted with a day history of fever, poor feeding, pre-auricular lymphadenopathy and sudden parental death. He was initially evaluated for late onset neonatal sepsis. He later developed abnormal bleeding and multiple convulsions while on admission, prompting the need to evaluate for Lassa fever using reverse transcription polymerase chain reaction (RT-PCR). He died 31 h into admission and RT-PCR result was positive for Lassa fever. CONCLUSIONS: Neonatal Lassa fever infection is highly fatal and can mimic neonatal sepsis. High index of suspicion is needed particularly for atypical presentations of neonatal sepsis in Lassa fever endemic areas

Impact of cooling channel geometry on thermal management and performance of a proton exchange membrane fuel cell

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.Proton exchange membrane fuel cell has many distinctive features that made it an attractive alternative clean energy source, including low start-up, high power density, high efficiency, portability and remote applications. Commercial application of this energy source had been greatly hindered by series of technical issues ranging from inadequate water and heat management, intolerance to impurities such as CO, slow electrochemical kinetics at electrodes, and relatively high cost. An approach to stem the thermal build-up within the fuel cell structure that could lead to degradation of the system components is by integrating cooling channels as part of flow structure of the PEM fuel cell system. In this study, a numerical investigation was carried out to investigate the impact of cooling channel geometry in combination with temperature dependent operating parameters on thermal management and overall performance of a PEM fuel cell system. The evaluation is performed using a CFD code based on a finite volume approach. The systems net power and polarization curves are presented as a function of the system temperature, operating parameters and geometry. In addition, the parameters studied were optimized using a mathematical optimization code integrated with the commercial computational fluid dynamics code.dc201

Modeling and optimization of reactant gas transport in a PEM fuel cell with a transverse pin fin insert in channel flow

A proton exchange membrane (PEM) fuel cell has many distinctive features which make it an attractive alternative clean energy source. Some of those features are low start-up, high power density, high efficiency and remote applications. In the present study, a numerical investigation was conducted to analyse the flow field and reactant gas distribution in a PEM fuel cell channel with transversely inserted pin fins in the channel flow aimed at improving reactant gas distribution. A fin configuration of small hydraulic diameter was employed to minimise the additional pressure drop. The influence of the pin fin parameters, the flow Reynolds number, the gas diffusion layer (GDL) porosity on the reactant gas transport and the pressure drop across the channel length were explored. The parameters examined were optimized using a mathematical optimization code integrated with a commercial computational fluid dynamics code. The results obtained indicate that a pin fin insert in the channel flow considerably improves fuel cell performance and that optimal pin fin geometries exist for minimized pressure drop along the fuel channel for the fuel cell model considered. The results obtained provide a novel approach for improving the design of fuel cells for optimal performance.The University of Pretoria, NRF, TESP, EEDSM Hub, CSIR, and the Solar Hub of the University of Pretoria and Stellenbosch University.http://www.elsevier.com/locate/heai201

Trend and Epidemiology of Tetanus in Nasarawa State, Nigeria: A Five Years Review

Background: Tetanus is a vaccine preventable, non-communicable disease known as lockjaw and characterized by muscle spasm. It is a forgotten disease in the developed world but remained an infection of public health importance in the developing countries. This study aimed to determine the trend in its epidemiology and outcome in Nasarawa state. Subjects and Method: A retrospective study using secondary data from the medical records of three selected health facilities, one each across the three senatorial zones of the state. All those who had tetanus were included while those with incomplete records, 5 were excluded. Data analysis was done using a statistical package for social sciences version 23. The dependent variable was the outcome of tetanus while the independent variables were incubation period, onset period, type of tetanus, risk factors, vaccination history, and manifestations of tetanus. Results: The subject consists of 53.8% males and single with age (Mean=15; SD=6.90). Four and 17 days were the shortest and longest incubation periods while one and six days were the shortest and longest onset periods respectively. A total of 24 (93.3%) patients had generalized tetanus. Nail puncture, road traffic accidents, and umbilical infection were the commonest sources of post-neonatal and neonatal tetanus in this study. Spasm is the commonest manifestation, present in 19 (73.1%) of the study population. This is closely followed by trismus in 57.7% of the cases. About half have a positive vaccination history. This study found case fatality of 7.7%. Conclusion: Generalized tetanus was the commonest type seen in this study, while nail puncture, road traffic accident and umbilical infection were the most common sources of infection. Although, more than half of the study subjects received immunization to prevent tetanus, the case fatality in this study was in one in twelve sufferers. Keywords: Epidemiology, review, tetanus, trend. Correspondence: Bello Surajudeen Oyeleke. Department of Paediatrics Dalhatu Araf Specialist Hospital. Shendam Road, PMB 07, Lafia, Nasarawa State. Email: [email protected]. Mobile: +2347064641540

Factors Affecting Uptake and Utilization of Insecticide Treated Net Among Women of Reproductive Age (15 – 49 years) Group Attending Antenatal Clinics in Nasarawa State Nigeria

Background: Vector control is the main path to preventing and reducing malaria transmission. The ownership and use of Insecticide-Treated Nets (ITNs) is the core vector control method and a proven intervention for the control and elimination of malaria in several malaria-endemic countries. This study determined the factors affecting the uptake and utilization of ITN by women in their reproductive age group in Nasarawa State Nigeria. Methods: A descriptive cross sectional study among women of reproductive age group (15 – 49 years) attending Ante Natal Clinic at the Dalhatu Araf Specialist Hospital Lafia, General Hospital Akwanga and Medical Centre Mararaba Gurku in Nasarawa State Nigeria. An interviewer administered questionnaire was used after obtaining an informed consent. Ethical approval was gotten from the state research ethics committee. Data analysis was done using SPSS version 23.0. Results: The mean age of this study population was 27.9 ± 10.6 years. Of the total number of 772 participants in this study, a larger chunk of 707 (91.6%) have heard of insecticide treated net. In addition, most 538 (69.7%) participants said healthcare workers emphasizes the use of insecticide treated net during their antenatal care visits. More than half of the participants, 432 (56.0%) owned an ITN at home. Utilization of insecticide treated nets showed that, 451 (58.4%) sleeps under an insecticide treated net, with 334 (74.1%) of these sleeping under it daily. Reasons for not using ITN for some were; due to heat 137 (30.4%), due to smell 83 (18.3%) and others for no good reason 86 (19.1%) respectively. Beliefs about usefulness of ITN showed 320 (71.0%) felt it is very good and useful in preventing malaria. Conclusions: Most participants are aware of ITN. More than half owned (56%) and sleeps (58.4%) under the ITN. About 71% believed ITN is useful in preventing mosquito bites and malaria. Reasons for declining using ITN among some were due to the ITN’s heat and smell. While more than two-third felt ITN is useful in preventing mosquito bites and malaria. Keywords: Factors, Insecticide Treated Nets, Uptake, Utilization. DOI: 10.7176/JHMN/92-06 Publication date:August 31st 202

A Randomized Trial to Compare the Safety, Tolerability, and Effectiveness of 3 Antimalarial Regimens for the Prevention of Malaria in Nigerian Patients With Sickle Cell Disease.

BACKGROUND: Malaria prophylaxis is recommended for persons with sickle cell disease (SCD), but the value of this has been questioned. The aim of this study was to find out whether intermittent preventive treatment (IPT) with a fixed-dose combination of mefloquine-artesunate (MQAS) or sulfadoxine-pyrimethamine plus amodiaquine (SPAQ) was more effective than daily proguanil for malaria prevention in subjects with SCD. METHODS: Patients with SCD were randomized to receive daily treatment with proguanil or IPT with either MQAS or SPAQ once every 2 months at routine clinic visits. Patients were followed up for 14 months. FINDINGS: A total of 270 patients with SCD were studied, with 90 in each group. Adherence to the IPT regimens was excellent, but 57% of patients took <75% of their daily doses of proguanil. IPT was well tolerated; the most common side effects were vomiting and abdominal pain. Protective efficacy against malaria, compared with daily proguanil, was 61% (95% confidence interval, 3%-84%) for MQAS and 36% (40%-70%) for SPAQ. There were fewer outpatient illness episodes in children who received IPT than those who received proguanil. CONCLUSIONS: IPT with MQAS administered to patients with SCD during routine clinic visits was well tolerated and more effective in preventing malaria than daily prophylaxis with proguanil. CLINICAL TRIALS REGISTRATION: NCT01319448 and ISRCTN46158146

aetiology and outcome of community acquired pneumonia at a tertiary hospital in Lafia Nigeria.

Background: Pneumonia is the commonest and the most severe form of the lower respiratory tract infection. With increasing needs and dwindling resources, the knowledge of the burden of disease in an area will be critical to health-care planning, resource mobilization and allocation of same. This study seeks to identify the pathogens responsible for this devastating childhood disease so as to guide choice of anti-microbial and as such preventing the development of resistance and wasteful spending.Methods: This was a descriptive cross sectional study of children aged < 18 years admitted with the diagnosis of Pneumonia at a tertiary health facility in Lafia North-central Nigeria from the 1st of January to the 31st of December 2019. We obtained relevant data using a standard pre-tested study proforma and analyzed using SPSS v.20.0Results: Community acquired pneumonia accounted for 11.3% of the overall admissions and most of the children (94.3%) were below age five. Pneumonia accounted for 19.6% of the overall mortality with a case fatality of 15.6%. Blood culture was positive in 33.1% of cases while Klebsiella sp. and Staphylococcus aureus were responsible for two-third (69.8%) of the pathogens isolated. Sensitivities were more to the Quinolones and the Aminoglycosides, while resistances were more to the Penicillin (Ampicillin and Amoxicilin).Conclusion: Community acquired pneumonia remains a common cause of under five morbidity and mortality with a positive blood culture in a third of cases.  Klebsiella sp and Staphylococcus aureus were the leading pathogenic cause of pneumonia in this study. The Quinolones in addition to the aminoglycosides should be considered as the first line antibiotics in management of childhood pneumonia