Open Access Opinion Article

An Opinion Regarding Equivalence Testing for Evaluating Measurement Agreement

Manolis Adamakis

Journal of Scientific Research and Reports, Page 1-4
DOI: 10.9734/jsrr/2019/v24i530163

The novel statistical approach ‘equivalence testing’ has been proposed in order to statistically examine agreement between different physical activity measures. By using this method, researchers argued that it is possible to determine whether a method is significantly equivalent to another method. Recently, equivalence testing was supported with the use of 90% confidence interval, obtained from a mixed ANOVA, which I believe is a more robust approach. This paper further discusses the use of this method in comparison to a more well-established statistical analysis (i.e. mixed design ANOVA), as well as various limitations and arbitrary assumptions in order to perform this analysis. The paper concludes with some remarks and considerations for future use in similar approaches.

Open Access Original Research Article

Annual Effective Dose and Lifetime Cancer Risks Due to Natural Radioactivity in Hand –Dug Well Water of Tai Rivers State, Nigeria

C. P. Ononugbo, N. N. Ndodo

Journal of Scientific Research and Reports, Page 1-10
DOI: 10.9734/jsrr/2019/v24i530164

The presence of radionuclide in water poses a number of health hazards, especially when the radionuclide is deposited in the human body through drinking water. The aim of this study was to evaluate natural radioactivity and its associated health risk in hand dug well water of Tai Local Government Area of Rivers State, Nigeria by means of gamma spectroscopy techniques and radiation models. The well water was collected from five selected coastal communities of Tai and chemically treated by adding nitric acid and then pre-concentrated further by evaporating to certain levels and kept in marineli beaker properly sealed for 28 days, after which was counted with NaI(Ti) detector. The mean values of specific activity concentration of 40K, 226Ra and 228Ra(232Th) were  25.90, 19.21 and 18.50 Bql-1 respectively. The annual effective doses for different age categories were estimated taking into consideration the ingested dose conversion factors as well as their yearly average water consumption. The average annual effective dose estimated for infants, children, teenagers and adult population were 0.115, 0.027, 0.071 and 0.013 Svy-1 respectively. The annual effective dose due to ingestion of the sampled water were above the recommended values by WHO, IAEA and UNSCEAR for the age brackets. The paper presents the overview of the techniques used and the summary of the findings. The result of this study gives the radiological baseline data for effective monitoring of the study area.

Open Access Original Research Article

Pesticide Residue Levels in Soil, Water, Kales and Tomatoes in Ewaso Narok Wetland, Laikipia, County, Kenya

Peter Ngolo, Mildred Nawiri, Alex Machocho, Helida Oyieke

Journal of Scientific Research and Reports, Page 1-11
DOI: 10.9734/jsrr/2019/v24i530165

Soil, water, kales and tomatoes from Ewaso Narok wetland were collected during wet and dry seasons and analyzed for 15 pesticide residues. Multi-residues method (QuEChERS EN) was used for sample preparation and Liquid chromatography-tandem mass spectrometry (LC-MS/MS) used for analysis. The soil was highly contaminated compared to water, kales and tomatoes. Banned (Aldicarb, azinphos methyl) and restricted (diazinon, chlorpyrifos and fenpropathrin) pesticide residues were detected in sample matrices in different concentrations. Residues levels that exceeded the European Union (EU) maximum residues limit (MRLs) were found in kales (triadimefon, cyproconazole I and II, fenpropathrin), tomatoes (cyproconazole I and II, fenpropathrin and spiroxamine) and water (aldicarb). All the pesticide residues concentrations were within the recommended levels of the World Health Organization (WHO) and Agricultural Food Organization (FAO). Residue levels were significantly high in the upstream and midstream during wet and dry seasons. Temperatures, conductivity (EC), pH, salinity, total dissolved solids (TDS) and dissolved oxygen (DO) were measured to assess soil/water quality. All the physicochemical parameters were within the recommended levels. Though most residue levels were below the EU-MRLs, MCLs and within the toxicological levels (LD50), the negative effects of the long term exposure to the wetland biodiversity and human health are real and should not be ignored. Farmers need to embrace Good Agricultural Practices (GAP) in order to reduce over-reliance on pesticide use in the wetland.

Open Access Original Research Article

Transient Stability Improvement on Jos – Gombe 330kV Line Using Static Var Compensator

Joseph F. Udo, Maruf A. Aminu

Journal of Scientific Research and Reports, Page 1-7
DOI: 10.9734/jsrr/2019/v24i530166

In this paper, the result of a study carried out to determine the impact of static VAr compensator on voltage profiles and reactive power flow in the Nigerian 330kV transmission grid network is presented. The research seeks to mitigate the challenge of high reactive power on Jos – Gombe 330kV single circuit transmission line. The high reactive power is produced in that axis as a result of low industrial demand in the North-Eastern region of Nigeria which results in low-inductive loading of the long transmission line that spans from Jos to Gombe and its extension to Yola, Damaturu and Maiduguri. The study also performed optimal placement of the static VAr compensator in the area where it can influence the voltage at the static VAr compensator device connection point by controlling the reactive power flow through the grid. This was accomplished by modeling the existing 330kV Nigerian network in DIgSILENT PowerFactory. The result is an improved power stability on the line between Jos and Gombe. The voltage tolerance with the approved Nigerian Grid Code and compliance was ensured. Also, the static VAr compensator was proposed over reactors due to the fact that it is dynamically switched.

Open Access Original Research Article

Evaluation of the Trend of CD4 Cell Count Over Time in Case of HIV/AIDS Patients under ART Follow-up

Kabtamu Tolosie Gergiso, Markos Abiso Erango

Journal of Scientific Research and Reports, Page 1-8
DOI: 10.9734/jsrr/2019/v24i530167

Background: Globally 36.7 million people living with HIV, 1.8 million new HIV infection, and 1 million AIDS-related deaths in 2016.Patient mortality was high during the first 6 months after therapy for all patient subgroups and exceeded 40 per 100 patient years among patients who started treatment at low CD4 count. The aim this study was to evaluate the trend of CD4 cell count over time and to determine the progress of patient characteristics measured at baseline on CD4 cell count of HIV-infected patients who were under ART treatment in Arba Minch Hospital. 

Methods: This study was retrospective follow up study using data extracted from medical records, patient interviews, and laboratory work-up. The study was employed among 550 adult patients that were selected by simple random sampling. The continuous outcome variable CD4 cell count has measured at months 0, 6, 12, 18, and 24. Longitudinal data analysis were used because the set of measurements on one patient tend to be correlated, measurements on the same patient close in time tend to be more highly correlated than measurements far apart in time, and the variability of longitudinal data often changes with time and the data handled through linear mixed effect models.

Result: The fitted result of the linear mixed model showed that linear visit time effect and the baseline characteristics education status, condom, tobacco, degree of Disclosure, and weight effects had significant effect on CD4 measurements. Also, the interaction age with linear visit time effect had significant effect on the evolution of CD4 cell count. However, no significant difference between sex, WHO stage, and marital status groups.

Conclusion: This study find that the CD4 cell count of HIV/AIDS patients is significantly determined by the visit time, education status, condom, tobacco, degree of Disclosure, and weight effects of patients.