scholarly journals Meteorological parameter anomalies and anomalous radio propagation over Nigeria

2020 ◽  
Vol 9 (1) ◽  
pp. 34-50
Author(s):  
I. Emmanuel ◽  
K.D. Adedayo ◽  
B. Adeyemi ◽  
O.S. Ojo

Distribution and variation of anomalous radio propagation, temperature and relative humidity anomalies were obtained and analyzed using six years (2010-2015) Era interim data. Seasonal spatial distribution of refractivity gradient and its components were analyzed. The result showed that about 90% of wet component contributed to the variation of refractivity gradient. Highest range of refractivity gradients and its wet components were obtained during the wet season. The result of correlation between ducting occurrence and temperature showed strong negative correlation except in Lagos where positive correlation of 3% was observed. However, positive correlation which ranges between 39% and 70% exist between duct occurrence and relative humidity except in Lagos in Nigeria. Refractivity gradients, relative humidity anomaly and temperature experience a monthly variation. These variations can be attributed to the seasonal movement of inter-tropical discontinuity (ITD) across Nigeria. Keywords: anomalous, anomaly, correlation, ITD

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Gang Lin ◽  
Jingying Fu ◽  
Dong Jiang ◽  
Jianhua Wang ◽  
Qiao Wang ◽  
...  

Epidemiological studies around the world have reported that fine particulate matter (PM2.5) is closely associated with human health. The distribution of PM2.5concentrations is influenced by multiple geographic and socioeconomic factors. Using a remote-sensing-derived PM2.5dataset, this paper explores the relationship between PM2.5concentrations and meteorological parameters and their spatial variance in China for the period 2001–2010. The spatial variations of the relationships between the annual average PM2.5, the annual average precipitation (AAP), and the annual average temperature (AAT) were evaluated using the Geographically Weighted Regression (GWR) model. The results indicated that PM2.5had a strong and stable correlation with meteorological parameters. In particular, PM2.5had a negative correlation with precipitation and a positive correlation with temperature. In addition, the relationship between the variables changed over space, and the strong negative correlation between PM2.5and the AAP mainly appeared in the warm temperate semihumid region and northern subtropical humid region in 2001 and 2010, with some localized differences. The strong positive correlation between the PM2.5and the AAT mainly occurred in the mid-temperate semiarid region, the humid, semihumid, and semiarid warm temperate regions, and the northern subtropical humid region in 2001 and 2010.


2018 ◽  
Vol 15 (2) ◽  
pp. 207-214
Author(s):  
I Hossain ◽  
MMH Khan ◽  
SMH Jahan

The study was conducted to know the reproductive performance of spiralling whitefly on guava. Number of colony, eggs, 1st instar, 2nd instar, 3rd instar and 4th instar nymphs per five leaves ranged from 6 to 15, 8 to 32, 0 to 44, 0 to 22, 0 to 45 and 0 to 28, respectively. Maximum number of adults and nymphs were found in the month of January. Highest longevity of Aleurodicus dispersus (21.5 days) was recorded in adult while the lowest was in 2nd instar nymph (6.4 days). The number of colony/leaf and number of 3rd and 4th instar nymphs of A. dispersus had significant positive correlation with minimum and maximum temperature while non-significant positive correlation is observed between the number of egg/colony, the number 1st and 2nd instar nymphs with minimum and maximum temperature. A. dispersus showed nonsignificant positive correlation with minimum and maximum relative humidity regarding number of colony/leaf, 2nd instar nymph while nonsignificant negative correlation with 4th instar nymph.SAARC J. Agri., 15(2): 207-214 (2017)


2020 ◽  
pp. 126-126
Author(s):  
Milovan Stojanovic ◽  
Marina Deljanin-Ilic ◽  
Stevan Ilic ◽  
Dejan Petrovic ◽  
Bojan Ilic

Background / Aim. Well-organized cardiovascular rehabilitation (CVR) reduces cardiovascular burden by influencing cardiovascular risk factors, improving the quality of life and reducing mortality and hospital readmission. However, its effects on hemodynamic status are largely unknown. The aim of our study was to evaluate the influence of three-week CVR program on hemodynamic status and to investigate if there is a correlation between physical strain tolerance and hemodynamic parameters measured by impedance cardiography (ICG) before and after CVR program in patients with coronary artery disease. Methods. Fifty-two patients attended a three-week CVR program. At the beginning and at the end of rehabilitation program laboratory tests, exercise stress tests (EST) and ICG measurements were taken. Results. Patients showed better strain tolerance on the second exercise stress test (EST2) by achieving higher strain level (Z=2,315; p=0,021) and longer duration of test (Z=2,305; p=0,021). There was a strong positive correlation between the level of EST2 and cardiac output (CO) (r=0,538; p<0,001) and stroke volume (SV) (r=0,380; p=0,017) on the second ICG (ICG2). Also, there was a strong negative correlation between EST2 level and systemic vascular resistance (SVR) (r=-0,472; p=0,002) and SVR index (SSVRI) (r=-0,407; p=0,010) on ICG2. There was a strong positive correlation between EST2 duration and CO (r=0.517; p=0.001) as well as between EST2 duration and SV (r=0.340; p=0.034), and a strong negative correlation between EST2 duration and SVR (r=-0.504; p=0.001) as well as between EST2 duration and SVRI (r=-0.448; p=0.004), according to ICG2. Conclusion. Our study showed that a well-designed CVR program can lead to better physical strain tolerance. Furthermore, CVR led to a significant positive correlation between EST and cardiac output as well as between EST and stroke volume measured by ICG. On the other hand, there was a significant negative correlation between EST and vascular related parameters according to ICG at the end of the CVR program.


2019 ◽  
Vol 1 (2) ◽  
pp. 1
Author(s):  
Hasby Ghoni Asiddiqi ◽  
Agatha Sih Piranti ◽  
Erwin Ardli Riyanto

Phytoplankton is the primary producer whose existence depends not only on the nutrient. The eastern part of Segara Anakan waters experienced changes where the decline in quality which received input from organic and inorganic wastes and residential, industrial and factory wastes of Holcim and Pertamina factories. The purpose of this research is to study the water quality and to study the relationship between water quality and abundance of phytoplankton at the eastern part of Segara Anakan. The result showed that Water quality in Segara Anakan waters in the eastern part of Cilacap consists of several parameters that beyond the quality standards according to the Keputusan Menteri Lingkungan Hidup No. 51 of 2004 such as pH, Nitrate, Ammonia, Phosphate, and TSS. Water temperature is a physical factor which has a strong negative correlation with the abundance of phytoplankton, followed by TSS as a physical factor which has a positive correlation. The chemical factor which has a positive correlation with abundance are TDS, Nitrite and pH, followed by Phosphate, Salinity, Ammonia, and Nitrate which has a negative correlation with the abundance of phytoplankton. Key Words: Environmental factor, phytoplankton, Segara Anakan, Spatial variation, temporal variation.


2019 ◽  
Vol 16 (2) ◽  
pp. 73-82
Author(s):  
MMH Khan

The research was carried out to know the abundance and damage severity of mealybug on sarupkathi variety of guava and to evaluate the efficacy of jet powder and Fighter 2.5EC for suppressing populations of mealybug during January to October 2014. Results revealed that the highest number of guava mealybug was observed on middle leaf (42/leaf) while the lowest number was on lower leaf (13/leaf). The highest percent leaf area covered by mealybug was found on middle leaf (78%) while the lowest was on fruit (18%). Maximum temperature and relative humidity had a positive correlation on the mealybug population while the rainfall showed a negative correlation. The highest percent mortality was observed in T2 treatment (Jet powder applied @ 5.0 g L-1 of water) at 24 HAT (hours after treatment) (86.05%) and 48 HAT (93.83%), respectively. At 72 HAT, the highest percent mortality was observed T3 treatment (Jet powder applied @ 7.5 g L-1 of water). In case of insecticidal control, the highest percent mortality was observed in T2 (100%) and T3 (100%) treatments, respectively followed by T1 (98.03%) at 24 HAT. Similar trends were also observed among all treatments at 48 HAT and 72 HAT, respectively. No significant differences were found among three doses of Fighter 2.5EC. The lowest percent mortality of mealybug population was found in T4 (Water spray forcibly) at 24 HAT, 48 HAT and 72 HAT, respectively. No mortality was recorded in untreated control at different HAT in both application of soap solution and insecticides. SAARC J. Agri., 16(2): 73-82 (2018)


2020 ◽  
Vol 3 (3) ◽  
pp. 315-328
Author(s):  
Herbert Mapira Tendayi ◽  
Jerome Ndayisenga ◽  
Solange Nyiramahirwe ◽  
Jacqueline Mukanshuti ◽  
Valens Karenzi ◽  
...  

Background Infertility remains a highly prevalent global condition in the second decade of the new millennium. Reproductive hormones determine sperm quality as they initiate and maintain spermatogenesis. Hormonal imbalance can cause abnormal sperm quality that can be treated by hormonal replacement therapy. Objective To assess the relationship between sperm quality and male reproductive hormones among male partners with fertility complications attending CHUB. Methods The study was a descriptive cross-sectional, and a convenient sampling strategy was used to recruit subjects at CHUB. Sixty-two male subjects with fertility complications provided both semen and blood sample to analyze sperm quality and reproductive hormones. Descriptive statistics were used to analyze data. Results Both FSH and LH showed a strong negative correlation with sperm count which is more profound with FSH (r= -0.722) than LH (r= -0.545). Testosterone showed a strong positive correlation with sperm count (r= 0.712). FSH and LH showed a negative correlation with sperm motility which is more profound in FSH (r= -0.312) than LH (r= -0.302). Testosterone also showed a positive correlation with sperm motility (r= 0.360). Conclusion Our study found a correlation between sperm quality and male reproductive hormones. We further suggest other studies to investigate predictive power of male reproductive hormones. Rwanda J Med Health Sci 2020;3(3):315-328


2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Endeshaw Lake

In this paper we access the effects of two atmospheric variables (temperature and relative humidity) on two important pollutants in the atmosphere (Nitrogen oxides (NOx) and carbon monoxide (CO)) by using one year (2016) data of Addis Ababa. Temperature has impact on atmospheric mixing and cause for the reduction of NOx as temperature increases. There are positive correlation between temperature and CO concentration from January to April with (R2 = 0.69), negative correlation from May to August with (R2 = 0.92) and no correlation for the remaining months. NOx and CO have moderate positive and negative correlation with relative humidity during the months January-April (R2 = 0.294 for NOx and R2 = 0291 for CO) and in the months May-August are R2 = 0.97 and R2 = 0.15 for NOx and CO respectively. But there are no clear correlation between the NOx and CO with relative humidity from September-December. NOx concentrations during wet season was almost about twice that of the dry season, but no such difference was observed in the case of CO. The seasonal average air temperature in wet season is relatively lower than dry season. NOx exhibited positive and CO negative seasonal correlations with relative humidity.


2017 ◽  
Vol 15 (1) ◽  
pp. 13-21
Author(s):  
MMH Khan ◽  
S Talukder

In order to study the influence of weather factors on the abundance and population dynamics of Spodoptera litura F. and Pieris brassicae L. on cabbage, a field experiment was conducted. Larval population of S. litura ranged from 0.56 to 1.57 larvae/plant during 8 January to 12 February 2014 crop season while the highest peak was on 5 February 2014 (1.57 larvae/plant) at 29.5 0C temperature. In case of Pieris brassicae, larval population ranged from 0.58 to1.98 larvae/plant and the highest peak of P. brassicae was also on 5 February. The highest peak was on 5 February 2014 at 96% and 38% relative humidity of both maximum and minimum categories and the highest peak of P. brassicae was on 5 February. There was a strong positive correlation (r = 0.824 and r = 0.920) between population of Spodoptera litura and temperature (maximum and minimum). On the other hand, there was a negative correlation (r = -0.439) between population of S. litura and maximum relative humidity and a strong negative correlation (r = - 0.716) between population of S. litura and minimum relative humidity. The population of Pieris brassicae was positively correlated (r = 0.899 and r = 0.956) with maximum and minimum temperatures. There was a negative correlation (r = -0.443) between population of P. brassicae and maximum relative humidity and a strong negative correlation (r = - 0.645) between population of P. brassicae and minimum relative humidity.SAARC J. Agri., 15(1): 13-21 (2017)


2016 ◽  
Vol 12 (2) ◽  
pp. 91-98 ◽  
Author(s):  
E. Birch ◽  
A. Carter ◽  
J. Boyd

Research examining kinematic parameters of the canine athlete is markedly behind equivalent human and equine research. With increasing participation and popularity, canine sports science needs to bridge this gap with comparable equine research. The aim of this study was to examine changes to specific kinematic parameters as hurdle height increases. Twenty border collies and border collie crosses were analysed jumping over a single hurdle at increasing heights, starting with a pole on the floor and increasing to a maximum height of 65 cm. Length of trajectory and jump speed were analysed, alongside apparent (without the use of markers) neck, lumbar spine and shoulder angles using Dartfish software. For each dog, the percentage of the hurdle height in relation to their height at the dorsal aspect of the scapula (withers) was used to normalise the dogs evenly. Overall jump speed decreased as percentage height increased (P<0.001), with a strong negative correlation between the two (r=-0.815). Length of trajectory significantly increased with percentage height (P<0.001) with a strong positive correlation between the two (r=0.740). However, length of trajectory decreased when a dog jumped ≥126% of its height to the withers. This is supported by a significantly more flexed apparent neck angle upon landing at this percentage height (P<0.001). Apparent lumbar spine angles showed greater dorsal extension upon landing as percentage height increased (P<0.001). Apparent shoulder angles become significantly more flexed as percentage height increased during the suspension phase of the jump (P<0.001). These results suggest that dogs significantly alter their jump kinematics as hurdle height increases.


2016 ◽  
Vol 56 (3) ◽  
pp. 541 ◽  
Author(s):  
J. Dijkstra ◽  
S. van Gastelen ◽  
E. C. Antunes-Fernandes ◽  
D. Warner ◽  
B. Hatew ◽  
...  

We quantified relationships between methane production and milk fatty acid (FA) profile in dairy cattle fed grass- or grass silage-based diets, and determined whether recent prediction equations for methane, based on a wide variety of diets, are applicable to grass- and grass silage-based diets. Data from three studies were used, encompassing four grass herbage and 14 grass silage treatments and 132 individual cow observations. Methane production was measured using respiration chambers and milk fatty acids (FAs) analysed using gas chromatography. The proportion of grass or grass silage (dry matter (DM) basis) was 0.80 ± 0.037. Methane yield averaged 22.3 ± 2.10 g/kg DM intake (DMI) and 14.2 ± 2.90 g/kg fat- and protein-corrected milk (FPCM). Mixed model univariate regression including a random study effect on intercept was applied to predict methane yield, with individual milk FA concentrations (g/100 g FA) as fixed effects. Of the 42 milk FAs identified, no single FA had a strong positive correlation (r; strong correlation defined as |r| ≥ 0.50) with methane yield (g/kg DMI), and cis-12 C18:1 and cis-9,12,15 C18:3 had a strong negative correlation with methane yield (g/kg DMI). C14:0 iso, C15:0, C15:0 iso, C15:0 anteiso, C16:0, C20:0, cis-11,14 C20:2, cis-5,8,11,14 C20:4, C22:0, cis-7,10,13,16,19 C22:5 and C24:0 had a strong positive correlation with methane yield (g/kg FPCM), and trans-15+cis-11 C18:1, cis-9 C18:1, and cis-11 C20:1 had a strong negative correlation with methane yield (g/kg FPCM). Observed methane yield was compared with methane yield predicted by the equations of van Lingen et al. (2014; Journal of Dairy Science 97, 7115–7132). These equations did not accurately predict methane yield as grams per kilogram DMI (concordance correlation coefficient (CCC) = 0.13) or as grams per kilogram FPCM (CCC = 0.22), in particular related to large differences in standard deviation between predicted and observed values. In conclusion, quantitative relationships between milk FA profile and methane yield in cattle fed grass- or grass silage-based diets differ from those determined for other types of diets.


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