Network access selection in heterogeneous wireless networks

In heterogeneous wireless networks (HWNs), both single-homed and multi-homed terminals are supported to provide connectivity to users. A multiservice single-homed multi-mode terminal can support multiple types of services, such as voice call, file download and video streaming simultaneously on any one of the available radio access technologies (RATs) such as Wireless Local Area Network (WLAN), and Long Term Evolution (LTE). Consequently, a single-homed multi-mode terminal having multiple on-going calls may need to perform a vertical handover from one RAT to another. One of the major issues in HWNs is how to select the most suitable RAT for multiple handoff calls, and the selection of a suitable RAT for multiple-calls from a single-homed multi-mode terminal in HWNs is a group decision problem. This is because a single-homed multi-mode terminal can connect to only one RAT at a time, and therefore multiple handoff calls from the terminal have to be handed over to the same RAT. In making group decision for multiple-calls, the quality of service (QoS) requirements for individual calls needs to be considered. Thus, the RAT that most satisfies the QoS requirements of individual calls is selected as the most suitable RAT for the multiple-calls. Whereas most research efforts in HWNs have concentrated on developing vertical handoff decision schemes for a single call from a multi-mode terminal, not much has been reported in the literature on RAT-selection for multiple-calls from a single-homed multi-mode terminal in next generation wireless networks (NGWNs). In addition, not much has been done to investigate the sensitivity of RAT-selection criteria for multiple-calls in NGWNs. Therefore, this dissertation addresses these issues by focusing on following two main aspects: (1) comparative analysis of four candidate multi-criteria group decision-making (MCGDM) schemes that could be adapted for making RAT-selection decisions for multiple-calls, and (2) development of a new RAT-selection scheme named the consensus RAT-selection model. In comparative analysis of the candidate RAT-selection schemes, four MCGDM schemes namely: distance to the ideal alternative-group decision making (DIA-GDM), multiplicative exponent weighting-group decision making (MEW-GDM), simply additive weighting-group decision making (SAW-GDM), technique for order preference by similarity to Ideal solution-group decision making (TOPSIS-GDM) are considered. The performance of the multiple-calls RAT-selection schemes is evaluated using the MATLAB simulation tool. The results show that DIA-GDM and TOPSIS-GDM schemes are more suitable for multiple handoff calls than SAW-GDM and MEW-GDM schemes. This is because they are consistent and less-sensitive in making RAT-selection decision than the other two schemes, with regards to RAT-selection criteria (service price, data rate, security, battery power consumption and network delay) in HWNs. In addition, the newly developed RAT-selection scheme incorporates RAT-consensus level for improving RAT-selection decisions for multiple-calls. Numerical results conducted in MATLAB validate the effectiveness and performance of the newly proposed RAT-selection scheme for multiple-calls in HWNs

Prevalence and associated factors of Plasmodium falciparum and soil transmitted helminth infections among pregnant women in Osun state, Nigeria

Background: Plasmodium falciparum and soil transmitted helminth (STHs) infection are widespread in sub-Sahara Africa, where co-infection is also common. This study assessed the prevalence of these infections and their risk factors among pregnant women in Osogbo, Nigeria.Methods: A total of 200 pregnant women attending the antenatal clinic were recruited. Plasmodium falciparum was detected using thick and thin film methods, while formol ether concentration method was used for STHs detection. A questionnaire was used to investigate the possible risk factors associated with acquisition of malaria and helminth infections.Results: The prevalence of P. falciparum, STHs and their co-infection was 29.5%, 12% and 5% respectively. P. falciparum, STHs and P. falciparum + STHs co-infection was significantly higher in primigravidae (52.5% vs 58.3% vs 80%) than in secongravidae (18.6% vs 25.0% vs 20%) and multigravidae (28.8% vs 16.7% vs 0%) (p=0.02). Prevalence associated factors identified for P. falciparum was age (p=0.0001) while gravidity (p=0.02) was identified for P. falciparum + STHs co-infection.Conclusion: High prevalence of P. falciparum and helminth infections was observed among the pregnant women with primigravidae being the most susceptible to co-infection. There is an urgent need to implement an effective malaria and STHs preventive method for this high risk population.Keywords: P.falciparum, STHs, Co-infection, pregnant women, Nigeria

Prevalence of Plasmodium falciparum Parasitaemia and Its Correlation with Haematological Parameters among HIV-Positive Individuals in Nigeria

Malaria and HIV are the two most important health challenges of our time. Haematologic abnormalities are features in Plasmodium falciparum infection, and anaemia is a well-known outcome. The prevalence and haematological impact of P. falciparum parasitaemia were determined among HIV-infected individuals in Nigeria. Parasite detection was carried out using microscopy and Polymerase Chain Reaction (PCR). Haemoglobin concentration was determined using an automated machine while CD4+ Tcells count was analyzed using flow cytometer. Thirty-seven (18.5%) out of the 200 HIV individuals enrolled had malaria parasites detected in their blood. All the positive cases were detected by PCR while only 20 (10%) were detected by thick blood microscopy. The mean haemoglobin concentration and packed cell volume (PCV) of HIV individuals with malaria parasitaemia were lower compared to those without malaria parasitaemia but the difference was not statistically significant. Also no significant difference was observed in malaria positivity in respect to sex and mean CD4+ cell count. The study highlights the effects of P. falciparum parasitaemia on the haematologic and immune components of HIV individuals

Prevalence of Plasmodium falciparum

Malaria and HIV are the two most important health challenges of our time. Haematologic abnormalities are features in Plasmodium falciparum infection, and anaemia is a well-known outcome. The prevalence and haematological impact of P. falciparum parasitaemia were determined among HIV-infected individuals in Nigeria. Parasite detection was carried out using microscopy and Polymerase Chain Reaction (PCR). Haemoglobin concentration was determined using an automated machine while CD4+ T-cells count was analyzed using flow cytometer. Thirty-seven (18.5%) out of the 200 HIV individuals enrolled had malaria parasites detected in their blood. All the positive cases were detected by PCR while only 20 (10%) were detected by thick blood microscopy. The mean haemoglobin concentration and packed cell volume (PCV) of HIV individuals with malaria parasitaemia were lower compared to those without malaria parasitaemia but the difference was not statistically significant. Also no significant difference was observed in malaria positivity in respect to sex and mean CD4+ cell count. The study highlights the effects of P. falciparum parasitaemia on the haematologic and immune components of HIV individuals

Prevalence and associated factors of Plasmodium falciparum and soil transmitted helminth infections among pregnant women in Osun state, Nigeria

Background: Plasmodium falciparum and soil transmitted helminth (STHs) infection are widespread in sub-Sahara Africa, where co-infection is also common. This study assessed the prevalence of these infections and their risk factors among pregnant women in Osogbo, Nigeria. Methods: A total of 200 pregnant women attending the antenatal clinic were recruited. Plasmodium falciparum was detected using thick and thin film methods, while formol ether concentration method was used for STHs detection. A questionnaire was used to investigate the possible risk factors associated with acquisition of malaria and helminth infections. Results: The prevalence of P. falciparum, STHs and their co-infection was 29.5%, 12% and 5% respectively. P. falciparum, STHs and P. falciparum + STHs co-infection was significantly higher in primigravidae (52.5% vs 58.3% vs 80%) than in secongravidae (18.6% vs 25.0% vs 20%) and multigravidae (28.8% vs 16.7% vs 0%) (p=0.02). Prevalence associated factors identified for P. falciparum was age (p=0.0001) while gravidity (p=0.02) was identified for P. falciparum + STHs co-infection. Conclusion: High prevalence of P. falciparum and helminth infections was observed among the pregnant women with primigravidae being the most susceptible to co-infection. There is an urgent need to implement an effective malaria and STHs preventive method for this high risk population

Sesamum indicum diet prevents hyperlipidemia in experimental rats

Cardiovascular diseases and metabolic complications caused by hyperlipidemia are the leading cause of death globally. In this study, the hypolipidemic potency of Sesamum indicum (SI) seeds was investigated. Of the thirty-five (35) male rats used in the study, five (5) were randomly selected for baseline measurements and thirty (30) were fed high fat diet (HFD) for four (4) weeks before random assignment into three (3) groups. The experimental group was treated with 50% SI seed, the positive control group was given a hypolipidemic drug, atorvastatin (5 mg/kg/day) while the untreated group served as the negative control. With SI administration, the dyslipidemia induced by the HFD consumption in the plasma and the investigated body organs was reversed to a comparable degree with that of atorvastatin treatment. Taken together, this study demonstrates the hypolipidemic potency of SI in ameliorating hyperlipidemia and its associated complications, facilitated by the inhibition of HMG-CoA reductase activity

Assessment of Clinical Diagnosis, Microscopy, Rapid Diagnostic Tests, and Polymerase Chain Reaction in the Diagnosis of Plasmodium falciparum in Nigeria

This study compares the performance of clinical diagnosis and three laboratory diagnostic methods (thick film microscopy (TFM), rapid diagnostic test (RDT), and polymerase chain reaction (PCR)) for the diagnosis of Plasmodium falciparum in Nigeria. Using clinical criteria, 217 children were recruited into the study out of which 106 (48.8%) were positive by TFM, 84 (38.7%) by RDT, and 125 (57.6%) by PCR. Using a composite reference method generated from the three diagnostic methods, 71 (32.7%) patients were found to be truly infected and 90 (41.5%) truly uninfected, while 56 (25.8%) were misidentified as infected or noninfected. When each of the 3 diagnostic methods was compared with the composite reference, PCR had sensitivity of 97.3%, specificity of 62.5%, positive predictive value (PPV) of 56.8%, and negative predictive value (NPV) of 97.8%; microscopy had sensitivity of 77.2%, specificity of 72%, PPV of 66.9%, and NPV of 81.1%, while RDT had sensitivity of 62.3%, specificity of 87.4%, PPV of 67.7%, and NPV of 84.5%. PCR test performed best among the three methods followed by TFM and RDT in that order. The result of this study shows that clinical diagnosis cannot be relied upon for accurate diagnosis of P. falciparum in endemic areas