Morphology of F-region vertical E×B drifts in the African sector using ionosonde measurements

F-region vertical velocities are derived from the ground-based ionosonde data for Ibadan (7.4°N, 3.9°E; dip 6°S: an equatorial station in the African zone), to study the general characteristics of electrodynamics of equatorial ionosphere, such as their variation with season, solar cycle, and magnetic activity at different local time sectors. The results show profound seasonal and geomagnetic effects. Except for equinoctial period, there is an excellent consistency in the magnitudes (nearly 20 m/s) and patterns of upward daytime F-region drifts at low and high solar activity periods. Evening F-region exhibits strong motion with absolute mean value for quiet-time (15 m/s) greater than on disturbed-time (10 m/s). The average downward quiet midnight-early morning hours sector value is well below than 10 m/s. The evening reversal time is earliest and latest during solstitial periods. Prereversal peak is season dependent and varies strongly with magnetic activity. We show that prereversal peak, daytime, and nighttime maximum drifts saturate at particular values of F10.7 cm solar radio flux index, effects not noticed with corresponding sunspot number. Our observations confirm several previous results from other equatorial sites utilizing different experimental techniques

Antihyperglycaemic and hypolipidemic effect of methanol extracts of Ageratum conyzoides L (Asteraceae) in normal and diabetic rats

Purpose: To investigate the antihyperglycaemic and hypolipidemic potential of the methanol extracts of leaf, stem and root of Ageratum conyzoides in streptozotocin (STZ)-induced diabetic rats.Methods: The extract of each of the plant part was obtained by extraction in methanol. A total of 60 male Wistar albino rats (30 induced with diabetes and 30 normoglycaemic) were assigned into diabetic and normoglycaemic groups of 6 rats each. Methanol extracts of leaf, stem and root of Ageratum conyzoides were administered orally at a dose of 100 mg/kg to the rats for a period of 14 days, with glibenclamide as the standard drug (1 mg/kg). Fasting blood glucose and lipid profile were determined to ascertain the antihyperglycaemic and hypolipidemic activities of the different parts of the plant.Results: Ageratum conyzoides significantly (p < 0.05) reduced fasting blood glucose (FBG) levels in diabetic rats by 38.71 ± 19.41 % (leaf), 25.64 ± 20.53 % (stem), and 34.76 ± 18.03 % (root) on day 14 of the treatment, compared with untreated diabetic rats where FBG increased by 11.33±8.91 %. Total cholesterol (leaf, 119.10 ± 8.12 mg/dl; stem, 109.28 ± 8.13 mg/dl) and triglycerides (leaf, 61.71 ± 9.37 mg/dl; stem, 72.45 ± 3.39 mg/dl) levels were also significantly (p < 0.05) lowered in diabetic rats. Low density lipoprotein cholesterol (leaf, 77.21 ± 8.12 mg/dl; stem, 64.76 ± 8.04 mg/dl; root, 79.08 ± 10.61mg/dl) levels were significantly (p < 0.05) lowered in all treated diabetic groups compared with the untreated diabetic rats (103.19 ± 6.08 mg/dl).Conclusion: The results from this study indicate that Ageratum conyzoides has hypoglycaemic and hypolipidemic properties in rats, and this probably justifies its reported use in the traditional management of diabetes mellitus.Keywords: Ageratum conyzoides, Diabetes mellitus, Antihyperglycaemic, Hypolipidemi

Antidiabetic Botanicals and their Potential Benefits in the Management of Diabetes Mellitus

Book ChapterPlease refer to full text

Anti-Diabetic Effects of Nigerian Indigenous Plant Foods/Diets

Book ChapterPlease refer to full tex

Histopatologia de frangos de corte alimentados com dietas suplementadas com óleo essencial de Prosopis africana (mesquita africana)

This study was carried out to investigate the hepatic histopathology of broiler chickens fed diets supplemented with Prosopis africana (African mesquite) essential oil (PRSO). 300, 1-day old broiler chicks were randomly distributed into six treatments with 5 replicates consisting of 10 birds each. Birds in diet 1 (D1) was fed basal diet supplemented with 0 % PRSO, D2: basal diet with 1.0 g/kg-1 oxytetracycline, D3, D4, D5 and D6 were fed basal diet supplemented with PRSO at 200 mg, 400 mg, 600 mg and 800 mg/kg-1 respectively. The experiment lasted for 56 days and a completely randomized design was adopted. Phyto-constituents of PRSO revealed the presence of tannins (201.21 mg/g-1), flavonoids (677.83 mg/g-1), alkaloids (405.90 mg/g-1), saponins (75.62 mg/g-1), phenols (508.28 mg/g-1), phytates (20.10 mg/g-1) and oxalates (5.26 mg/g-1). Hepatic histopathology showed that tissues from D1, D3, D4, D5 and D6 showed no signs of any damage; the central vein, blood portal vessels showed no congestion. Mild hepatocellular damage was recorded among liver of birds in D2. It can be concluded that Prosopis africana essential oil are among the key alternative solutions to antibiotics because they contain bioactive compounds that are safe, effective and performs multiple biological functions in the body of animals.Este estudio se llevó a cabo para investigar la histopatología hepática de pollos de engorde alimentados con dietas suplementadas con aceite esencial de Prosopis africana (mosquita africana) (PRSO). Se asignaron al azar 300 pollos de engorde de un día de edad a seis tratamientos con 5 repeticiones de 10 aves cada una. Las aves en la dieta 1 (D1) recibieron dieta basal suplementada con 0% de PRSO, D2: dieta basal con 1,0 g/kg-1 de oxitetraciclina, D3, D4, D5 y D6 recibieron dieta basal suplementada con 200 mg de PRSO, 400 mg, 600 mg y 800 mg/kg-1, respectivamente. El experimento tuvo una duración de 56 días y se adoptó un diseño completamente al azar. Los fitoconstituyentes PRSO revelaron la presencia de taninos (201,21 mg/g-1), flavonoides (677,83 mg/g-1), alcaloides (405,90 mg/g-1), saponinas (75,62 mg/g-1), fenoles (508,28 mg /g-1), fitatos (20,10 mg/g-1) y oxalatos (5,26 mg/g-1). La histopatología hepática mostró que los tejidos de D1, D3, D4, D5 y D6 no presentaban signos de daño; la vena central, los vasos sanguíneos porta no mostraron congestión. Se registró daño hepatocelular leve entre los hígados de aves de corral en D2. Se puede concluir que el aceite esencial de Prosopis africana se encuentra entre las principales soluciones alternativas a los antibióticos debido a que contiene compuestos bioactivos que son seguros, efectivos y realizan múltiples funciones biológicas en el organismo de los animales.Este estudo foi realizado para investigar a histopatologia hepática de frangos de corte alimentados com dietas suplementadas com óleo essencial de Prosopis africana (mesquita africana) (PRSO). 300 pintos de corte de 1 dia de idade foram distribuídos aleatoriamente em seis tratamentos com 5 repetições de 10 aves cada. Aves na dieta 1 (D1) receberam dieta basal suplementada com 0 % de PRSO, D2: dieta basal com 1,0 g/kg-1 de oxitetraciclina, D3, D4, D5 e D6 receberam dieta basal suplementada com PRSO a 200 mg, 400 mg, 600 mg e 800 mg/kg-1, respectivamente. O experimento teve duração de 56 dias e foi adotado o delineamento inteiramente casualizado. Os fitoconstituintes do PRSO revelaram a presença de taninos (201,21 mg/g-1), flavonoides (677,83 mg/g-1), alcaloides (405,90 mg/g-1), saponinas (75,62 mg/g-1), fenóis (508,28 mg/g-1), fitatos (20,10 mg/g-1) e oxalatos (5,26 mg/g-1). A histopatologia hepática mostrou que os tecidos de D1, D3, D4, D5 e D6 não apresentavam sinais de danos; a veia central, os vasos sanguíneos portais não apresentaram congestão. Danos hepatocelulares leves foram registrados entre fígados de aves em D2. Pode-se concluir que o óleo essencial de Prosopis africana está entre as principais soluções alternativas aos antibióticos porque contém compostos bioativos que são seguros, eficazes e desempenham múltiplas funções biológicas no corpo dos animais

DETERMINATION OF AFLATOXIN LEVELS IN COMMERCIAL POULTRY FEEDS SOLD IN SOME PARTS OF SOUTHWESTERN NIGERIA

Aflatoxin contamination of animal feeds is common and widely spread especially in the tropics due to        ubiquity of the producing fungi. This study was carried out to identify and quantify common moulds and        aflatoxin levels in commercial poultry feeds sold in four states of South Western, Nigeria. Twenty sam-        ples of poultry feeds, 5 from each state (Lagos, Ogun, Osun and Oyo) were bought from retailers. The        feed   samples   were   analysed   microbiologically   for   moulds   and   total   aflatoxins   using   Enzyme-linked                                                                              4            4         Immunosorbent   Assay   (ELISA).   Mould   count   ranged   between   1  x   10 and   8   x   10 cfu/g.   Common        moulds   isolated   were   Aspergillus   flavus,   A.  parasiticus,  A.   terreus,   A.  niger,  A.  oryzae,  Rhizopus        oryzae,  and Penicillium notatum.  Total aflatoxin levels ranged between 13.5 and 270 ug/kg. Maize        was the main ingredient in all feeds examined. This study highlights the need for routine surveillance.         Feed millers are encouraged to add fungal growth inhibitors or toxin binders to their feeds.&nbsp

One-minute rain rate distribution in Nigeria derived from TRMM satellite data

Data from the Tropical Rainfall Measuring Mission (TRMM) satellite sensors, the Microwave Imager (TMI, 3A12 V6) and other satellite sources (3B43 V6) have been used to derive the thunderstorm ratio â, total rain accumulation M, and 1-min rainfall rates, R1min, for 37 stations in Nigeria, for 0.001–1% of an average year, for the period 1998–2006. Results of the rain accumulations from the TRMM satellite (1998–2006) were compared with the data collected from 14 ground stations in Nigeria for the period 1991–2000. The two data sets are reasonably positively correlated, with correlation coefficients varying from 0.64 to 0.99. Deduced 1-min rainfall rates compared fairly well with the previous ground data of Ajayi and Ezekpo (1988. Development of climatic maps of rainfall rate and attenuation for microwave applications in Nigeria. The Nigerian Engineering 23(4), 13–30) with correlation coefficients varying from 0.17 to 0.97 in all 37 stations. The agreement was much better when compared with the International Telecommunications Union Radio communication Study group 3 digital maps with correlation coefficients varying from 0.84 to 0.98 in 23 locations; however there were negative correlation coefficient (of 0.2 in 7 stations) in the Middle Belt and a weak positive coefficient (of 0.09 in 6 stations) in the South South. Regionally the inferred mean annual 1-min rainfall rates are the highest in the South-East region with values between 111 and 125 mm/h throughout the 9 years, followed by the South-South region (105–124 mm/h). The lowest rainfall rate and rainfall accumulation occur in the North-West region (60–86 mm/h) followed, in ascending order, by the North-East (66–95 mm/h) region, the Middle-Belt region (76–102 mm/h) and the South-West region (77–110 mm/h). The present results were also compared with 9 tropical stations around the world and there was positive correlation between the results. The present results will be very useful for satellite rain attenuation modeling in the tropics and subtropical stations around the world. It is useful to note that one country, particularly one as large as Nigeria, can have significant variations in its rainfall characteristics for a variety of reasons, and this is borne out by the results presented

Impairment of radio wave signal by rainfall on fixed satellite service on earth–space path at 37 stations in Nigeria

This study investigates the effect of rainfall on horizontally polarized radio waves for fixed satellite service at Ku, Ka and V bands for links to the recently launched Nigeria Communication Satellite one (NigComSat-1), for annual time availabilities of 99–99.99% in an average year for 37 stations in Nigeria. The results obtained at Ku-band downlink shows that 99.99% availability is possible in all the 37-stations in Nigeria. At Ka-band downlink the results also show that only 99.9% availability is practicable in all the 37 stations in Nigeria. At V-band downlink, 99.99% availability is also not possible in all the 37 stations in Nigeria. An availability level of 99.9% is only practicable in the North–West (NW) and North–East (NE) regions, where the attenuation is between 14 and 17.9 dB. Total fade out of signals during rainfall are probable in the South–South (SS), South–East (SE), South–West (SW) and Middle–Belt (MB) regions at 99.9% availability

A PRISMA-driven systematic mapping study on system assurance weakeners

Context: An assurance case is a structured hierarchy of claims aiming at demonstrating that a given mission-critical system supports specific requirements (e.g., safety, security, privacy). The presence of assurance weakeners (i.e., assurance deficits, logical fallacies) in assurance cases reflects insufficient evidence, knowledge, or gaps in reasoning. These weakeners can undermine confidence in assurance arguments, potentially hindering the verification of mission-critical system capabilities. Objectives: As a stepping stone for future research on assurance weakeners, we aim to initiate the first comprehensive systematic mapping study on this subject. Methods: We followed the well-established PRISMA 2020 and SEGRESS guidelines to conduct our systematic mapping study. We searched for primary studies in five digital libraries and focused on the 2012-2023 publication year range. Our selection criteria focused on studies addressing assurance weakeners at the modeling level, resulting in the inclusion of 39 primary studies in our systematic review. Results: Our systematic mapping study reports a taxonomy (map) that provides a uniform categorization of assurance weakeners and approaches proposed to manage them at the modeling level. Conclusion: Our study findings suggest that the SACM (Structured Assurance Case Metamodel) -- a standard specified by the OMG (Object Management Group) -- may be the best specification to capture structured arguments and reason about their potential assurance weakeners

Accelerating Rural Growth Through Collective Action: Groups\u27 Activities and Determinants of Participation in Southwestern Nigeria

This study was conducted to investigate the types of activities promoted by cooperative groups and the determinants of participation intensity of members in cooperative activities in southwestern Nigeria. A multistage sampling approach was used to select 326 cooperators (45 groups). Data collected were analyzed using descriptive statistics, difference of means test, and Tobit regression.Cooperative groups engaged in farm and off-farm activities such as arable crop production, fish farming, agricultural products processing, and produce marketing, among others. Farm input procurements and access to market information (74 percent), cooperative credits and thrift (53 percent), social networking (37 percent), multipurpose commercial activities (21.6 percent), and political influence (17 percent) were given as reasons for interest and participation in groups\u27 activities. Income realized by cooperators was significantly and consistently higher than income of non-cooperators who engaged in the same economic activity. Participation intensity was influenced by gender, farm size cultivated, and the social status of members