On the fuzzy nature of constructed algebraic structure

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A Comparative Study on Bias Regression Methods in the Presence of Multicollinearity Based on Gamma and Chi Square Distributions

The aim of this study is to compare some regression methods in the presence of multicollinearity problem. This problem makes the estimated regression coefficients by least squares method to be conditional upon the correlated predictor variables in the model. It is also a condition in a set of regression data that have two or more regressors which are redundant and have the same information. Therefore, some regression methods that handle with multicollinearity such as partial least square regression (PLSR), ridge regression (RR) and lasso regression (LR) had reported. In this paper, the methods were compared using simulated data that follows gamma and chi square distributions with P=4 and 10, and n=60 and 90. All results were compared with each other through Mean Square Log Error (MSLE), Mean Absolute Error (MAE) and R2 of their estimated values for different methods. The results show that when P=4 and n=60 RR is better methods with gamma distribution, but with chi square distribution PLRS is better methods. Also, when P=4 and n=90, RR shows better results with gamma distribution but with chi square distribution all methods have equal predictive ability. However, at P=10 and n=60 RR performed better with both gamma and chi square distributions while RR shows better results at both gamma and chi square distributions when P=10 and n=90. Keywords: Multicollinearity, Partial Least Square Regression, Ridge Regression, Principal Component Regressio

Multi-elemental analysis of some Nigerian mineral rocks for a comparative assay of gamma shielding with concrete using winxcom

Analysis of chemical composition and concentration of three Nigerian minerals have been carried out with the research reactor (GHARR-1) at Ghana Atomic energy commission Kwabenya Accra, in order to analyze their gamma photon shielding prospects using WINXCOM software. The physical densities of Serpentinite rock from Katsina/ Zamfara state, Hematite rock from Kogi state and Barite from Benue states of Nigeria were measured, and their moisture content analyzed with the Am-Be neutron source irradiation facility at Centre for Energy Research and Training (CERT) A.B.U. in Nigeria Qualitative and quantitative evaluation of gamma ray spectra of the residual radio nuclides of the rock samples were performed using the SPAN 5.0 software. The result of the chemical composition was observed to have a good elemental correlation with the well known neutron shields (concrete), but indicative of a better substitute to ordinary concrete when, in addition, the moisture retention capabilities, refractive properties and, most importantly, their densities are taken into account. The knowledge of the elemental composition is a requirement for calculating the shielding characteristics using WINXCOM. For an increase in photon energy by a factor of 0.21keV the mass attenuation in Serpentinite decreased by 2.0cm2/g; Hematite had a decrease of 5.0cm2/g; Barite also decreased by 5cm2/g while concrete had its mass attenuated by only 1.3cm2/g. Keywords: Transmission, Reflection, Mineral rock, Thermal neutrons, Fast neutrons, Moistur

Determinants for hospitalization in " low-risk" community acquired pneumonia

BACKGROUND: A variable decision in managing community acquired pneumonia (CAP) is the initial site of care; in-patient versus outpatient. These variations persist despite comprehensive practice guidelines. Patients with a Pneumonia Severity Index (PSI) score lower than seventy have low risk for complications and outpatient antibiotic management is recommended in this group. These patients are generally below the age of fifty years, non-nursing home residents, HIV negative and have no major cardiac, hepatic, renal or malignant diseases. METHODS: A retrospective analysis of 296 low-risk CAP patients evaluated within a year one period at St. Agnes Hospital, Baltimore, Maryland was undertaken. All patients were assigned a PSI score. 208 (70%) were evaluated and discharged from the emergency department (E.D.) to complete outpatient antibiotic therapy, while 88 (30%) were hospitalized. Patients were sub-stratified into classes I-V according to PSI. A comparison of demographic, clinical, social and financial parameters was made between the E.D. discharged and hospitalized groups. RESULTS: Statistically significant differences in favor of the hospitalized group were noted for female gender (CI: 1.46-5.89, p= 0.0018), African Americans (CI: 0.31-0.73, p= 0.004), insurance coverage (CI: 0.19-0.63, p= 0.0034), temperature (CI: 0.04-0.09, p= 0.0001) and pulse rate (CI: 0.03-0.14, p= 0.0001). No statistically significant differences were observed between the two groups for altered mental status, hypotension, tachypnea, laboratory/radiological parameters and social indicators (p>0.05). The average length of stay for in-patients was 3.5 days at about eight time's higher cost than outpatient management. There was no difference in mortality or treatment failures between the two groups. The documentation rate and justifications for hospitalizing low risk CAP patients by admitting physicians was less than optimal. CONCLUSIONS: High fever, tachycardia, female gender, African- American race and medical insurance coverage are determinants for hospitalization among low risk CAP patients in our study. The average length of stay for in-patients was 3.5 days (3 to 5 days). The cost of in-patient care was about eight times higher than outpatient management. This study supports the recommendation of using the PSI for E.D evaluation of patients in appropriate social settings

Neutron spectrum parameters in two irradiation channels of the Nigeria research reactor-1 (nirr-1) for use in k0-naa

For the utilization of the NIRR-1 to include the k0-standardization method, the following neutron spectrum parameters in one inner and one outer irradiation channels were determined using the “Cd-ratio for multi-monitor method”: The thermal to epithermal flux ratio, f, and the epithermal flux shape factor, α. These parameters determined in the inner irradiation channel A1,are: α = - 0.046 ± 0.005 and f = 18.4 ± 0.34 and for the outer irradiation channel A2 α = + 0.024 ± 0.002 and f = 49.5 ± 0.96. The results compare well with reported values obtained from other reactor facilities with similar core configuration such as the Slowpoke and Miniature Neutron Source Reactor facilities available in literature

Determination of neutron-induced activation cross sections using nirr-1

Thermal Activation cross-sections for the (n, γ) reaction were experimentally measured using NIRR-1 facilities. The irradiated target isotopes were 71Ga, 109Ag, 55Mn 94Zr; 96Zr; 238U, 74Se, 75As and 48Ca. In order to obtain reliable activation cross sections, careful attention was paid to neutron irradiation and to the measurement of induced activity. The values obtained for the ten (n, γ) reactions were compared against the comprehensive evaluated values listed in Mughabghab, (2003) and other evaluated data libraries. The values were found to compare well with values evaluated by Mughabghab and those from other libraries

Measurement of Radon Concentration in Water Sources around Ririwai Artisanal Tin Mine Kano State, Nigeria

In this work liquid scintillation analysis was used to measure the concentration of 222Rn in three sources of water around Ririwai Artisanal Tin mine. The annual effective dose due to 222Rn concentration in surface water source and Domestic water were also determined. The result shows that the tailing bearing water has the highest 222Rn concentration of 3.04±0.14 Bq/L followed by surface water source with 222Rn concentration of 2.51±0.13 Bq/L while the Domestic water has the lowest 222Rn concentration of 2.23±0.11 Bq/L. The results also indicated that the annual effective dose due to the 222Rn concentration is higher in surface water with 13.05±0.55 mSv/year than in Domestic water with 11.11 ± 0.44mSv/year. The mean 222Rn concentration obtained in this work is lower than 10.00Bq/L recommended by WHO and UNSCEAR. Also in this study the annual effective dose obtained is lower than the maximum permissible of 0.1mSv/year recommended by UNSCEAR. Keywords: Radionuclide, activity concentration and annual effective dos

Investigation on the Effects of Addition of Binder and Particle Size on the High Calorific Value of Solid Biofuel Briquettes

The effects of biomass particle size and addition of binder on the high calorific values (HCVs) of five (5) selected biomass briquettes is studied. Analyses of the experimental results show that finely grinded particles (about 1.75mm and 2.00mm) had low calorific values as the grinding resulted in a loss of some heat and made the sample vulnerable to air oxidation.Addition of gum Arabic binder greatly inceases the high calorific value of all samples followed by starch and top-glue binder tend to decerease the HCVs for the range of biomass tested in the order 25.3201> 23.2985>20.0023 respectively.Thus indicating gum Arabic and starch improves the caloric value while top glue and polyvinyl Chloride (PVC) decreases the calorific value of the samples. An extensive investigation on the PVC dissolved in Toluene compound(organic) as chemical binder was observed to decrease the calorific values of all the briquette samples except those made of coconut shell and rice husk. Keywords: Biomass, Biofuel, Binder, Briquette, High heating valu

Analysis of activity concentrations due to natural radionuclides in the fish of Kainji Lake

A study was conducted for natural radioactivity of some fish samples from Kainji Lake, situated between latitudes 9~' 50' - 10~' 57' North and longitudes 4~'25'-4~'45' East, New Bussa, Niger state, Nigeria, using gamma spectroscopy method with Nal(TI) detector. Radioactivity a phenomenon that leads to production of radiations, and radiation is known to trigger or induce cancer. The fish are analyzed to estimate the radioactivity (activity) concentrations due to natural radionuclides (Radium 222(226Ra), Thorium 232(232Th) and Potassium 40 (40K). The obtained result shows that the activity concentration for (226Ra), in all the fish samples collected ranges from 16.06 ~c 0.44 Bqkg-1 to 67.39 ~c 12.34 Bqkg-1 with an average value of 37.22 ~c 4.31 Bqkg-1. That of 232Th, ranges from 42.66 ~c 0.81 Bqkg-1 to 200.6 ~c 10.66 Bqkg-1 and the average value stands at 94.82 ~c 3.82 Bqkg-1. The activity concentration for 40K, ranges between 243.3 ~c 1.56 Bqkg-1 to 384.98 ~c 11.97 Bqkg-1 and the average is 618.2 ~c 26.81 Bqkg-1. This indicated that average daily intake due to natural activity from the fish is valued at 0.999 Bq/day, 2.545Bq/day and 10.31 Bq/day for 226Ra, 232Th and 40K respectively. This shows a promising result, since the activity concentration values for most of the fish are within the acceptable limits. However location Upstream02 (9~'51'.285~AN, 4~'35'.533~AE) and Upstream07 (9~'51'.285~AN, 4~'35'.533~AE) fish, became outliers with significant values of 1 13.10~kSvy-1 and 121.68~kSvy-1 effective dose. This could be attributed to variation in geological formations in the lake as well as the feeding habits of these fish. The work shows that consumers of fish from Kainji Lake have no risk of radioactivity ingestion, even though no amount of radiation is assumed to be totally safe