Trade-Off between Steady-State Broadband Noise Levels and Time of Exposure for Zero Noise-Induced Hearing Loss

In this work expressions for damage risk criteria and trade-off between the sound pressure levels and times of exposure for zero noise-induced hearing loss were derived. The expression for the damage risk criteria was used to compute the criteria risk values at octave frequencies between 250Hz and 8000Hz for males and females. The expression for the trade-off was used to compute the maximum times of exposure for sound pressure levels from 65 dBA to 112 dBA. This trade-off between noise sound pressure levels and corresponding times of exposure obtained from this work were obtained from the damage risk criteria which were determined from empirical values. Results show that workers should not be exposed to noise levels that are more than 112 for more than one second if the workers’ hearing is to be conserved. The expression supports the Equal Energy Hypothesis (EEH) and the 3dBA exchange rate. Key Words: Trade-Off, Hearing Loss, Noise Levels, Broadband Noise, Induced noise

Noisiness and Perceived Noise Levels in Some Food Processing Industries in Jos

Measurement of noise sound pressure levels in food processing industries, a social survey to determine the extent to which the workers were disturbed by the noise in the same industries, in Jos, were carried out. In all the industries, only one had equivalent continuous noise level below 85dBA. The results of the physical measurements showed that the noise was predominantly broad-band, continuous and steady state. Noisiness and perceived noise levels were obtained from the results of the physical measurements. The result showed that perceived noise levels were not more than 2dB higher than their corresponding equivalent continuous noise levels implying that the human ear perceives noise (2 dB maximally) higher than that measured by a sound level meter on A-weighting scale. For noise levels at 90dB and above small increase would result to higher noisiness increase. However, noise level and perceived noise level have continuous and steady dependence at all values. The correlation coefficient for noise rating and perceived noise level ?1=0.8599, and the correlation coefficient for noise annoyance and perceived noise levels ?1=0.8892,  both showing strong positive correlations between objective and subjective assessment of noise. Keywords: Noisiness, perceived noise level, annoyance, noise rating

Comparative Study on Luminal Diameter, Blood Flow Velocity and Intima Media Thickness of Carotid Arteries in Obese and Non- Obese Humans

Studies leading to the determination of the onset of atherosclerosis, a major parameter in cardiovascular diseases has dominated the academic community concerned with heart diseases. This study is aimed at investigating the difference in blood flow velocities, lumen diameters and intima-media thickness of the carotid arteries of over-weight/obese and non-obese human subjects. Doppler ultrasound measurements of the carotid arteries was performed in 50 adults, aged between 18-76 years old. The Body Mass Index (BMI), Waist to Height Ratio (WHtR) of the subjects were calculated from their weight, height and waist measurements. Results show significant differences between group 1 (normal weight) and group 2 (over-weight/obese): luminal diameters on the right (RLD) and left (LLD), intima media thickness on the right (RIMT) and left (LIMT) of the carotid arteries were significantly larger in group 2 than in group 1; peak systolic velocities on the right (RPSV) and the left (LPSV) of the carotid arteries were significantly lower in group 2 than in group 1, while the end diastolic velocities on the right (REDV) and left (LEDV) were significantly larger in group 2 than in group 1. In the over-weight/obese subjects, the increased RLD, LLD, RIMT, LIMT, RPSV, LPSV and high REDV and LEDV points at the early stage of atherosclerosis. These effects mean that over-weight and obesity increase the chances of atherosclerosis and stroke. Keywords: Atherosclerosis, luminal diameter, obese, carotid artery, intima media thickness

Determination of Boundary Values of Body Mass Index (BMI) for Cardiometabolic Risk Using Waist-To-Height Ratio (WHTR) for a Cross-Section of Adult Nigerian Population in Jos, Nigeria

The measurements of body mass and height to determine the Body Mass Index (BMI) in order to classify individuals whether they are normal, pre-obese or obese may not be sufficient as a primary screening tool for Cardio-metabolic risk assessment. However, it has been established that the Waist-to-Height Ratio (WHtR) will be of greater advantage over BMI in such risk assessments. It is widely assumed that mostly the individuals who are pre-obese and obese will be at risk for Cardio-metabolic diseases based on the BMI classification. But this may not be true as some individuals who are placed on normal category in BMI are found to be at risk based on the WHtR values which are greater than 0.5.Hence there is need to determine the boundary value of BMI for Cardio-metabolic risk using WHtR. This study concludes that for a cross-section of 200 (both male and female) adult Nigerian population of ages 20-67 years in Jos, Nigeria, the boundary value for Cardio-metabolic risk to be 24.45 Kg/m2. It was also found that the males are at a higher risk for Cardio-metabolic diseases than their female counterparts in this study population. And these boundary values fall within the normal category (18.50 – 24.99 Kg/m2 ) of BMI, suggesting that individuals of normal body mass can also be at risk for Cardio-metabolic diseases, in addition to pre-obese and obese categories on BMI classification Keywords: Body Mass Index, Waist-to-Height Ratio, Cardio-metabolic risk, boundary value

Average Sound Absorption per Person at Octave Band Frequencies Between 125Hz And 4000Hz in an Enclosure

The audience constitutes the major sound absorbent materials in most church auditoria and, non-inclusion of the sound absorbed by the audience in the determination of the optimum reverberation time from the design stage accounts for the problem of poor sound quality in such church auditoria. To address this problem, this research was carried out to provide designers with data on sound absorption by an individual at some octave band frequencies important for understanding speech. The work utilized the Sabine’s formula for Reverberation Time to determine the sound absorption per person at Octave band frequencies of 125Hz, 250Hz, 500Hz, 1000Hz, 2000Hz and 4000Hz.  Data which included the volume, sitting capacity of persons and reverberation time of eight (8) churches were obtained when the churches were occupied and when unoccupied.  These data gave the calculated average sound absorption per person of 0.29, 0.43, 0.51, 0.68, 0.71 and 0.73 at these octave band frequencies respectively, all showing that the average sound absorption by an individual increases with frequency within this octave band frequency range. Key Words: Reverberation Time, Sound Absorption, Octave Band Frequency

Relationship between Adult Liver and Spleen Sizes from Sonographic Measurements with Body Mass Index (BMI) in a Nigerian Cross-Section Population in Jos

The Liver and the Spleen are two of the main body organs are normally examined among others in all abdominal   ultrasound scans. The correlation between the sizes of these two body organs with Height, Weight, Age and Body Mass Index (BMI) have been investigated with ultrasonic measurements of 50 normal scan data of a cross-section of Nigerian population in Jos. It was found that the liver span significantly correlated with body weight (r = 0.369, p < 0.01) and BMI (r = 0.351, p < 0.05) while the Splenic length significantly correlated with only BMI (r = 0.333, p < 0.05). The age range of the subjects was from 16 –70 years with mean age of 32.98 ± 12.20 years while the mean BMI was 23.16 ± 3.84 kg/m2. The mean Liver span and Splenic length were found to be 13.46 ± 1.14 cm and 9.79 ± 0.96 cm respectively. The Liver/Spleen Ratio was computed to be approximately 1.4 for the adult Nigerian population in Jos. There were no significant difference in both the Liver span and the Splenic length between the males and the females but males have larger Liver span and Splenic length compared to females. Linear Regression relationships between Liver span and splenic length with BMI as well as between Liver span and Splenic length were established. Keywords: Liver Span, Splenic Length, Body Mass Index, (BMI), Liver/Spleen Ratio

B-Mode Doppler Ultrasound Blood Flow Velocity Measurements for the Determination of the Intima Media Thickness in the Human Carotid Artery

Excess mortality associated with cardiovascular diseases and stroke is linked to atherosclerosis which in turn, is related to the intima-media thickness (IMT). An increase in IMT in the common carotid artery (CCA) is therefore commonly used as a marker of atherosclerosis. The purpose of this study was to investigate the relationship between blood flow velocity and IMT in the CCA which is also an indicator of atherosclerosis in the carotid bifurcation. Fifty (50) apparently healthy volunteers (25 males and 25 females) whose ages ranged between 19 and 75 years were considered for carotid ultrasound scanning in Jos University Teaching Hospital (JUTH). IMT, Peak Systolic and End Diastolic blood velocities of the right and left Common Carotid Arteries (CCA) were measured by means of a Doppler Ultrasound Machine Type LOGIQ 5 EXPERT at 6MHz frequency with an insonation angle of 600 by a single trained sonologist. Quantitative variables were analyzed with the IBM SPSS. Results show that the Right Peak Systolic Velocity (RPSV) and the Left Peak Systolic Velocity (LPSV) of blood in the CCA correlate negatively with the Right Intima Media Thickness (RIMT). The LPSV of blood shows a negative correlation with the Left Intima Media thickness (LIMT) but the RPSV has no significant correlation with the LIMT. The RIMT and the LIMT show a strong positive correlation with age but no significant correlation with sex, Right End Diastolic Velocity (REDV) and Left End Diastolic Velocity (LEDV). The RPSV and REDV also show a negative and positive correlation with age respectively, but the LPSV and LEDV show no significant relationship with age. We therefore conclude that the RPSV and LPSV of blood in the CCA is correlated to the degree of atherosclerosis in the carotid bifurcations more than the REDV and LEDV. The degree of atherosclerosis increases with advancing in age because of the strong positive correlation between IMT and age. Keywords: Intima-Media Thickness, Common Carotid Artery, Atherosclerosis.

Body Mass Index (BMI) and Waist to Height Ratio (WHTR) for Prediction of Cardiovascular Diseases: Women at Higher Risk than Men in Jos

The problem of cardiac arrest and stroke in humans leading to paralysis or death are known to relate to the risk for certain diseases such as heart disease, high blood pressure, type II diabetes, gallstone, breathing problems and certain cancers.  The risk for such diseases in turn, is correlated to the Body Mass Index (BMI) and Waist to Height Ratio (WHtR) which are strong indicators of visceral/abdominal fat which accumulates around the internal organs affecting the heart, liver and kidneys. However, it is not known whether these major risk factors are higher in males or females. In this work, the weights, heights and waists of 50 volunteers (25 males and 25 females) were carried out on people whose ages ranged between 19 and 75 years with the aid of a weighing balance and a measuring tape. Results show that the Body Mass Indices (BMI) of males ranged between 18.29 and 30.70kg/m2 while that of females ranged between 19.05 and 39.11kg/m2. Waist to Height Ratios for males ranged between 0.4331 and 0.6954 while that for females ranged between 0.4310 and 0.7746. The 2-tailed......

Sound Pressure Level, Power Level, Noisiness and Perceived Noise Level of some commonly used Generators in Pankshin Metropolis of Plateau State, Nigeria

In this work, sound pressure levels of some generators in Pankshin town of Plateau State, Nigeria were measured. The sound power levels, noisiness, perceived noise levels of generators and people’s attitude towards the noise were obtained. The sound pressure levels of the different generators were carried out using sound level meter type SL 4010 EUROLAB. The measured sound pressure levels range between 76dBA and 98dBA. The sound power levels range between 87dBA and 109dBA. The values of noisiness were in the range of 14noy and 60noy.The perceived noise levels (PNdB) were in the range of 78dBA to 99dBA. The generator sound was rated to range between moderately noisy and noisy whereas the annoyance rating ranges between slight annoyance and very much annoyance. The correlation coefficient for the generator noise and the noise rating was ?1=0.589 whereas the correlation coefficient for generator noise sound pressure levels and annoyance rating by respondents was ?1=0.729, both implying that the higher the noise level, the higher the noise rating and the higher the annoyance. Keywords: Sound pressure level, sound power level, noisiness, perceived noise level, annoyance

Human Age Estimation: Use of Doppler Ultrasound Blood Velocity Measurement in the Human Carotid Artery

Assessment of a living person’s age has gained prominence due to its numerous applicability: suspected criminals with no reliable records of identification where verifying age is essential for determining legal and/or financial responsibility; adults from developing nations with no reliable certificates or documents and falsification of age in order to merit appointments or participate in sporting events are a few to mention. In this work, the Peak Systolic Velocity (PSV) and End Diastolic Velocity (EDV) on the right and left Common Carotid Arteries were measured with the LOGIQ 5 EXPERT Ultrasound Machine using the technique of Doppler Ultrasound Velocity Measurement of blood flow in the carotid arteries of 50 volunteers (25 males and 25 females) whose blood pressures were taken. Use of The IBM SPSS shows that the Right Peak Systolic Velocity and Left End Diastolic Velocity were unrelated to the blood pressure for the hypertensive, pre-hypertensive and.......