412 research outputs found
Real-time PCR quantitative assessment of hepatitis A virus, rotaviruses and enteroviruses in the Tyume River located in the Eastern Cape Province, South Africa
We applied real-time RT-PCR (reverse transcription-polymerase chain reaction) to assess the incidence of hepatitis A virus, rotaviruses and enteroviruses in the Tyume River, an important water resource in the impoverished Eastern Cape Province of South Africa. Detection of noroviruses was done using conventional semi-nested RT-PCR. Water samples were collected once monthly from 6 sampling sites over a 12-month period starting in August 2010 and ending in July 2011. Hepatitis A virus was detected in 13% of the samples in concentrations ranging between 1.67×103 genome copies/ℓ and 1.64×104 genome copies/ℓ while rotaviruses were detected in 4% of the samples with concentrations ranging from 9×101 genome copies/ℓ to 5.64×103 genome copies/ℓ. Enteroviruses were not detected in any of the samples, while noroviruses were detected in 4% of the samples. All hepatitis A and rotaviruses positive samples were from the upstream sections of Tyume River while noroviruses were detected in samples from downstream sections only. Statistical analysis showed that occurrence of the viruses in Tyume River was sporadic. Risk analysis showed that hepatitis A virus posed greater risk than rotaviruses for both recreational and domestic water uses. Because of the low infectious dose of enteric viruses, the detection of even low concentrations of hepatitis A virus, rotaviruses and noroviruses in surface water poses a significant risk to public health.Keywords: Hepatitis A virus, rotaviruses, noroviruses, TaqMan real-time PCR, reverse transcription, Tyume River, public healt
In vitro evaluation of the interactions between acetone extracts of Garcinia kola seeds and some antibiotics
The effect of combinations of the acetone extract of Garcinia kola seeds and six first-line antibiotics was investigated by means of fractional inhibitory concentration (FIC) indices as well as by the use oftime kill assays. Using the FIC indices, synergistic interactions were observed largely against gram positive organisms (FIC indices of 0.52 - 0.875) with combinations against gram negatives yieldinglargely antagonistic interactions (FIC indices of 2.0 to 5.0). The time kill assay detected synergy against both gram negative and gram positive organisms with a ≥ 1000 times (≥ 3Log10) potentiation of thebactericidal activity of tetracycline and chloramphenicol (against E. coli ATCC8739 and K. pneumoniae ATCC10031) as well as amoxycillin and penicillin G against Staphylococcus aureus ATCC 6538.Combinations involving erythromycin and ciprofloxacin consistently gave antagonistic or indifferent interactions. We conclude that the acetone extract of G. kola can be a potential source of broad spectrum antibiotics resistance modifying compounds
The challenges of overcoming antibiotic resistance: Plant extracts as potential sources of antimicrobial and resistance modifying agents
The problem of antibiotic resistance, which has limited the use of cheap and old antibiotics, has necessitated the need for a continued search for new antimicrobial compounds. Understanding the mechanisms of resistance is important in the development of strategies to solving the problem. Active efflux of drugs, alteration of target sites and enzymatic degradations are the strategies by which pathogenic bacteria acquire or develop intrinsic resistance to antibiotics. Multi-drug resistance (MDR)pumps, capable of recognizing and expelling a variety of structurally unrelated compounds from the bacterial cell and conferring resistance to a wide range of antibiotics have since been characterized inmany gram positive and gram negative pathogens like Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and, more recently, in mycobacteria. The ability of some chemical compounds (called MDR inhibitors or resistance modifying agents) to modify the resistance phenotype in bacteria by working synergistically with antibiotics in vitro has since been observed. The search for such compounds which can be combined with antibiotics in the treatment of drug resistant infectionsmay be an alternative to overcoming the problem of resistance in bacteria. Crude extracts of medicinal plants stand out as veritable sources of potential resistance modifying agents and the Africanbiosphere promises to be a potential source of such compounds owing to its rich plant species diversity
The Random Walk Theory And Stock Prices: Evidence From Johannesburg Stock Exchange
In this paper, we test the Johannesburg Stock Exchange market for the existence of the random walk hypothesis using monthly time series of the All Share Index (ALSI) covering the period 2000 – 2011. Traditional methods, such as unit root tests and autocorrelation test, were employed first and they all confirmed that during the period under consideration, the JSE price index followed the random walk process. In addition, the ARIMA model was constructed and it was found that the ARIMA (1, 1, 1) was the model that most excellently fitted the data in question. Furthermore, residual tests were performed to determine whether the residuals of the estimated equation followed a random walk process in the series.  The authors found that the ALSI resembles a series that follow random walk hypothesis with strong evidence of a wide variance between forecasted and actual values, indicating little or no forecasting strength in the series. To further validate the findings in this research, the variance ratio test was conducted under heteroscedasticity and resulted in non-rejection of the random walk hypothesis. It was concluded that since the returns follow the random walk hypothesis, it can be said that JSE, in terms of efficiency, is on the weak form level and therefore opportunities of making excess returns based on out-performing the market is ruled out and is merely a game of chance
Assessing the impact of livestock trampling on soil compaction on Intunjambili wetland Matopo
Extending the Shelf Life of Fresh Marula (Sclerocarya birrea) Juice by Altering Its Physico-Chemical Parameters
CHALLENGES OF INCLUSIVE SCHOOLING ON ACADEMIC PERFORMANCE OF STUDENTS WITH VISUAL IMPAIRMENT AT MUNALI BOY’S SECONDARY SCHOOL, ZAMBIA
This manuscript is about challenges of inclusive education on academic performance of students with visual impairment at Munali Boy’s Secondary School. The objectives of the study were to find out the attitude of teachers and sighted students towards the inclusion of students with visual impairment into regular classes. It also sought to examine the academic performance of performance of students with visual impairment in inclusive settings. It further wanted to establish subjects in which students with visual impairment face difficulties. A descriptive survey design was adopted in which 42 participants were purposively selected. The study revealed that, although teachers and sighted students have a fair understanding of inclusive schooling, they give positive attention to students with visual impairment. It also revealed that students with visual impairment face academic challenges at Munali Boys’ which include teachers’ inability to use embossed teaching and learning aids during lesson, lack of individualised attention, mobility challenges, and their pace of teaching does not support the learning of students with visual impairment. The study established that although, inclusive education is fully accepted at Munali Boy’s Secondary School, students with visual impairment are not included in mathematics and sciences related subjects.
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Evaluation of a seed storage facility in relation to preserving seed moisture, vigour and germination
The performance of a solar energy-assisted seed storage room was evaluated through an ordinary 22-m3 room that was retrofitted with a solar collector, inlets and chimney. The structure was made of a solar collector to heat the ambient air before entering the chimney. The chimney circulated the air inside the structure and inlets. To compare the performance of the modified storage room, a room with a similar capacity and without the retrofitted components (control storage room) was used. Twelve 8 kg bags of maize were stored in each storage room for a period of three months. Samples were taken every two weeks to determine germination rate, moisture content and seed vigour. The temperature and relative humidity (RH) was measured during storage. The RH in the control storage was significantly higher (P≤0.05) (60.6 ± 5.87%) than in the modified storage (40.1 ± 3.21%) during the day. However, at night, the RH in the control storage room was significantly lower (P≤0.05) (58.5 ± 7.32%) than in the modified storage (63.7 ± 6.28%). The RH in the modified storage room increased from 40.1% during the day to 63.7% at night. The RH in the control storage room decreased slightly from 60.6% to 58.5% during the day and night. The seed moisture content in the modified storage facility was significantly lower (P≤0.05) (12.6 ± 0.21%) than in the control storage room (13.3 ± 0.52%). The moisture content in the modified storage room decreased from 12.6% to 12.4%, whereas in the control room, moisture content increased from 12.6% to 13.8% in three months. The seed germination rate obtained after three months of storage in the modified storage room was significantly higher (P≤0.05) (98.5 ± 0.85%) than in the control storage room (96.8 ± 1.49%).The seed igour obtained in the modified storage room was significantly higher (93.6 ± 0.35%) than in the control room (91.7 ± 2.08%) (P≤0.05). Seed stored in the control storage lost vigour at a faster rate, compared to the seeds stored in the modified storage room. Therefore, the modified naturally-ventilated seed storage room maintained seed quality better than the control storage room
Determining the burden of fungal infections in Zimbabwe.
Zimbabwe currently faces several healthcare challenges, most notably HIV and associated infections including tuberculosis (TB), malaria and recently outbreaks of cholera, typhoid fever and COVID-19. Fungal infections, which are also a major public health threat, receive considerably less attention. Consequently, there is dearth of data regarding the burden of fungal diseases in the country. We estimated the burden of fungal diseases in Zimbabwe based on published literature and 'at-risk' populations (HIV/AIDS patients, survivors of pulmonary TB, cancer, chronic obstructive pulmonary disease, asthma and patients receiving critical care) using previously described methods. Where there was no data for Zimbabwe, regional, or international data was used. Our study revealed that approximately 14.9% of Zimbabweans suffer from fungal infections annually, with 80% having tinea capitis. The annual incidence of cryptococcal meningitis and Pneumocystis jirovecii pneumonia in HIV/AIDS were estimated at 41/100,000 and 63/100,000, respectively. The estimated prevalence of recurrent vulvovaginal candidiasis (RVVC) was 2,739/100,000. The estimated burden of fungal diseases in Zimbabwe is high in comparison to other African countries, highlighting the urgent need for increased awareness and surveillance to improve diagnosis and management
Discrimination of tomato plants (solanum lycopersicum) grown under anaerobic baffled reactor effluent, nitrified urine concentrate and commercial hydroponic fertilizer regimes using multi-source satellite data
We evaluate the detection and discriminative strength of three different satellite spectral settings, namely, HyspIRI, the forthcoming
Landsat 9 and Sentinel 2-MSI, in mapping tomato (Solanum lycopersicum) plants grown under hydroponic system using humanexcreta
derived materials (HEDM), namely, anaerobic baffled reactor (ABR) effluent and nitrified urine concentrate (NUC) and
commercial hydroponic fertilizer mix (CHFM) as nutrient sources. Partial least squares – discriminant analysis (PLS-DA) and
discriminant analysis (DA) were applied to discriminate tomatoes grown under these different nutrient sources. Results of this
study showed that spectral settings of HyspIRI sensor can better discriminate tomatoes grown under different fertilizer regimes
when compared to Landsat 9 OLI and Sentinel-2 MSI spectral configurations. For instance, based on DA algorithm, HyspIRI
exhibited high overall accuracy of 0.99 and a kappa statistic of 0.99 whereas Landsat OLI and Sentinel-2 MSI exhibited over
accuracies of 0.94 and 0.95 as well as kappa statistics of 0.79 and 0.85, respectively. Further, the performance of DA was
significantly different (α = 0.05) from that of PLS-DA based on the MaNemar tests. Overall, the performance of HyspIRI, Landsat
9 OLI-2 and Sentinel-2 MSI data seem to bring new opportunities for crop monitoring at farm scale
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