2-Dimensional position error bias analysis of an angle of arrival based target locating system

An angle of arrival (AOA) based locating system determines the location of an emitting target using its emission detected at spatially deployed ground station (GS) with an angulation algorithm. The position estimation (PE) accuracy of the system depends on several factors one of which is the approach to the development of the angulation algorithm. For passive target locating, the closed-form angulation algorithm is used and has been known to introduce bias in the PE process. In this paper, a bias analysis of the closed-form angulation algorithm is carried out to determine its percentage in the overall position mean square error (MSE). The analysis is carried out using a three-GS triangular configuration at some randomly selected unmanned aerial vehicle (UAV) drone locations. Monte Carlo simulation result based on 200 realizations shows that the bias error introduced by the angulation algorithm in the overall position MSE is about 64%. With the knowledge of the bias percentage, the actual locations of the UAV drones within the AOA-based locating system coverage can be determined

Value Relevance of Accounting Information: Empirical Evidence from Listed Conglomerate Firms in Nigeria

In recent years, internal and external investors have lost confidence in Nigeria due to insecurity, energy (power), economic instability, and governance. Although the government is trying to overcome the menace, there are still unresolved issues in the aspect of the challenges above, which affect value relevance and accounting information in ensuring the perpetual existence of companies in Nigeria. As such, the study examined the value relevance of accounting information of listed conglomerate companies in Nigeria. The study population comprises six companies: UAC Nigeria Plc, Chellarams Plc, SCOA Nigeria Plc, John Holt Plc, Transnational Corporation of Nigeria Plc, and Custodian Investment Plc. The data was extracted from their annual report and accounts. Descriptive statistics correlation regression was conducted in the study. The result shows that return on share price has a significant negative relationship with dividend per share. The study recommends that standards comply in reporting and disclosing all accounting information in the published financial statement to maintain value relevance and attract more investors

A survey of opportunistic infections in HIV seropositive patients attending major hospitals of Kebbi state, Nigeria

A survey was conducted to determine the prevalence of HIV/AIDS related opportunistic infections from the patients attending the five major Hospitals in Kebbi State , which included Federal Medical Center (FMC), Birnin Kebbi, Sir Yahaya Memorial Hospital (SYMH), Birnin Kebbi, General Hospital, Argungu (GHA), General Hospital , Yauri (GHY) and General Hospital , Zuru (GHZ). The screening for the HIV/AID was done using the Genic II HIV-1/HIV – 2 Test and the screening for opportunistic infections was done using thin and thick blood films, direct wet mount, formal ether concentration technique and modified Ziehl – Neelsen (ZN) technique. Microbial Pathogens were isolated through culture and identified through gram staining and biochemical tests. Out of the 1950 patients screened for HIV/AIDS infection, 606 (31.6%) were positive. Higher prevalence 195 (32.2%) was from FMC and the lowest from GHY 90 (15%). The result revealed that 374 (61.7%) of HIV/AIDS positive patients were also positive to one or more opportunistic infections. In this respect, higher prevalence of 32.3% was observed from FMC and the lowest was observed from SYMH with 13.9%. The result of the study also revealed the presence of malarial (Plasmodium) parasites with prevalence of (75.9%).The Federal Medical Centre (FMC) had the highest prevalence of 29.5%, SYMH, 21.7%, GHA, 17.2%, GHY, 16.1 and lastly GHZ with 15.4%. There is therefore the need for urgent positive control programme of HIV and HIV related opportunistic infections. Keywords: Survey, opportunistic infections, HIV Sero positive, Kebbi State

An Investigative Study on Impact of Frequency Dynamics in Load Modeling

Load modeling plays a significant impact in assessing power system stability margin, control, and protection. Frequency in the power system is desired to be kept constant, but in a real sense, it is not constant as loads continually change with time. In much literature, frequency dynamics are ignored in the formulation of load models for the basic assumption that it does not affect the models.  In this paper, the composite load model was formulated with Voltage-Frequency Dependency (V-FD) on real and reactive powers and applied to estimate the load model. 2- Area network 4- machines Kundur test network was used for testing the developed model.  The model was trained with measurements from a low voltage distribution network supplying the Electrical Engineering department at Ahmadu Bello University, Zaria. Both training and testing data were captured under normal system operation (dynamics). To evaluate the V-FD model performance, Voltage-Dependent (VD) model was examined on the same measured data. The work makes use of the Feed Forward Neural Network (FFNN) as a nonlinear estimator. Results obtained indicate that including frequency dynamics in modeling active power reduces the accuracy of the model. While in modeling reactive power the model performance improves. Hence, it can be said that including frequency dynamics in load modeling depends on the intended application of the model

Management of Unilateral Suppurative Mastitis in A Four-year-old Red

Nigerian Veterinary Journal, Vol. 32(3): 2011; 246 - 24

Preliminary field survey on Mycobacterium bovis infection in cattle herds using caudal fold intradermal tuberculin test in two Northeastern States of Nigeria

Aim: A survey was conducted to determine the prevalence of bovine tuberculosis (bTB) in two states of Northeastern Nigeria, namely Bauchi and Gombe States, between February 2010 and November 2014 using caudal fold tuberculin (CFT) skin test. Materials and Methods: A total of 5489 cattle were screened using single CFT in Bauchi and Gombe States. Of the 5489 cattle, 2116 cattle were from 189 herds in five testing areas in Bauchi State and 3373 cattle in 217 herds from five testing areas from Gombe State. Results: On the basis of the CFT, herd prevalence obtained was 56.08% in Bauchi and 55.29% in Gombe State, while the individual animal prevalence was 10.96% in Bauchi and 13.73% obtained in Gombe State. The prevalence based on the testing areas in Bauchi State, Alamari had the highest prevalence with 19.4 % and Disina the lowest with 9.0 %, while in Gombe State, Wakaltu had the highest prevalence with 20.9 % and Poshereng the lowest with 8.0 %. Cows were more likely to have tuberculosis lesions than bulls (p=0.0035) in Bauchi State, but there was no significant difference in Gombe State (p=0.166). However, a statistically significant association (p<0.05) was observed among the cattle age groups with cattle ≥4 years having higher odds for tuberculin reactivity compared to those below the age of 4 years in Bauchi State only. Conclusion: There is the need to strengthen routine meat inspection and public health awareness programs on the zoonotic nature of bTB among the abattoir workers and the herdsmen

Enhancement of Voltage Stability with Unified Power Flow Controller Considering Loadability Analysis

Voltage stability is an important issue in planning and operation of electric power system during both normal and under contingency conditions. This paper presents line voltage stability index (LVSI) for transmission lines voltage stability assessment and evaluation. The system stability under maximum loading and contingency conditions are analyzed using optimal power flow analysis. FACTS device is considered for a real-time control and a dynamic reactive power compensation of the system. Voltage source-based power injection model of unified power flow controller (UPFC) is used for the minimization of voltage deviation and losses on the network. Optimal location and sizing of UPFC is carried out using grey wolf optimization (GWO) technique in order to identify an optimal location where the FACTS device will be installed. UPFC device has proven to increase the line transmittable power, controls the voltage magnitude at the buses as well as enhancing the stability and security of the power system. The various conditions and scenarios used to test the efficacy of this model for system stability and security under contingency conditions are demonstrated on standard IEEE 14-bus test system

Load-ability Analysis during Contingency with Unified Power Flow Controller Using Grey Wolf Optimization Technique

Voltage stability enhancement with optimal placement of a unified power flow controller considering load-ability analysis is investigated in this paper. It is essential, because when voltage instability is left unattended, it leads to voltage collapse and, consequently, in a partial or total blackout of the whole network resulting from cascading effect. The optimization process is achieved by increasing the percentage load demand index to the maximum load-ability and under single contingency. This method will be of great benefits to bulk dispatcher of power to plan ahead of how to wheel and deliver power to the end-users during both normal and contingency conditions at the least cost and time. A grey wolf optimization technique is utilised to find the optimal location and sizing of UPFC on the network. The line’s voltage stability and load margin are then evaluated with and without UPFC under different loading conditions using optimal power flow technique. The approach’s effectiveness is carried out on 31-bus, 330kV Nigeria National Grid (NNG) based on two scenarios: load-ability analysis under maximum loading of the network and load-ability analysis under single contingency. The results show that power can be transmitted to meet the growing energy demand over an existing network during normal and contingency conditions without violating voltage stability by making use of the proposed method in this pape

GREY WOLF OPTIMIZER BASED OPTIMAL PLACEMENT OF MULTIPLE FACTS DEVICES IN THE TRANSMISSION SYSTEM UNDER DYNAMIC LOADING SYSTEM

The application of grey wolf optimization technique for multiple FACTS placement is presented in this paper for the reduction of total system losses and minimization of voltage deviation via optimal placement of Flexible AC Transmission System (FACTS) device. Grey wolf optimization (GWO) technique is inspired by social hierarchy and hunting behaviour of wolves and offers a right balance between exploration and exploitation during the search for global optimal. Series-shunt FACTS device; unified power flow controller (UPFC) is considered as a formidable device that can provides an alternative option for the flexible controllability and improvement of power transfer capability of a transmission lines. The analyses were conducted by increasing the number of UPFC in the network in order to evaluate the optimal number of FACTS devices that would give the least loss under maximum loading and contingency conditions. The efficacy of this proposed technique is demonstrated on 31-bus, 330 kV Nigeria National Grid (NNG) using MATLAB environment. The results show that optimal placement of FACTS device along with optimization technique provides a promising solution to the high power loss and voltage deviation bedevilling Nigeria National Grid

Factors associated with abnormal glomerular filtration rate among HIV-positive children at the University of Maiduguri Teaching Hospital, Maiduguri, Nigeria

Background: Renal disease is commonly encountered in patients with HIV infection. The estimated glomerular filtration rate (eGFR) provides a good assessment of the renal function and is widely used in screening populations that are at risk of renal dysfunction. We determined the prevalence of abnormal eGFR among HIV-positive children and factors associated with it.Methods: In a cross-sectional study, children aged 15 years and below were recruited through systematic random sampling from the Paediatrics Infectious Disease Clinic of the University of Maiduguri Teaching Hospital until the desired sample size of 250 was reached. Clinical and laboratory information was obtained from the patient records and used for clinical staging and immunological classification. Serum creatinine was measured using Jaffe’s reaction and eGFR calculated using the Schwartz formula. The data obtained were analysed using SPSS version 16.Results: A total of 157 (62.8%) children were on antiretroviral therapy (HAART) for periods ranging from 1 to 168 months (mean duration 66.1 ± 46.5 months). Ninety-three (37.2%) children had advanced disease representing WHO clinical stages 3 and 4, whereas 103 (41.2%) had advanced or severe immunosuppression. The mean eGFR of the study population was 102 ± 41 mL/min/1.73 m2. Fifty-two children (20.1%) had low eGFR (&lt;2 SD below the mean eGFR for age and sex) and 6 (2.4%) had high eGFR (&gt;2 SD above the mean eGFR for age and sex). A total of 23 (9.2%) children had moderate to severe renal impairment, defined as eGFR &lt;60 mL/min/1.73 m2. Age, sex, socio-economic status, mode of transmission as well as history of HAART usage were not significantly associated with abnormal eGFR. However, relatively shorter duration of treatment with HAART, as well as advanced clinical or immunological stage were all significantly associated with abnormal eGFR.Conclusion: Renal dysfunction is common among children with HIV disease in Maiduguri with over a third of those affected having moderate to severe renal dysfunction. Abnormal renal function is more frequent among children with advanced clinical and immunological disease. We recommend the regular determination of eGFR and early initiation of HAART in all children with HIV disease