100 research outputs found
Investigating groundwater pollution at an open dumpsite using 2D geoelectrical resistivity imaging and vertical electrical sounding
Geoelectrical resistivity survey has been conducted within the Kurata dump site in
Ota, south-western Nigeria. This present study focuses on the use of 2D resistivity imaging and
Vertical Electrical Sounding to delineate conductive leachate point and degree of movement
within the subsurface for conceivable groundwater pollution. The 2D resistivity survey was
carried out using the ABEM Terrameter (SAS 1000/4000) System with multiple-gradient array
electrode configuration. The Vertical Electrical Sounding was conducted using the
schlumberger electrode configuration. One 2-D imaging profile of length 100m and one
Vertical Electrical Sounding of length 200m were acquired on the established traverse. The
resistivity data was inverted utilizing RES2DINV and WinResist to obtain the inverse model
resistivity distribution. The 2D inverse resistivity models of the subsurface showed that the
study site has a multi-layered aquifer system, four geoelectrical layers were inferred from the
resistivity imaging and they are lateritic clay, clayey sand, sandy clay and coarse sand units.
There is one aquifer system about 13 m which is highly polluted. The unpolluted aquifer
system is localized around 19 m with inverted resistivity range 498Ωm – 685Ωm in the
traverse. Also there might be conceivable sullying of deep groundwater system in the long term
if appropriate moderation procedures are not thought about at the area
Geophysical Imaging of Archaeological Materials at Iyekere, Ile-Ife Southwestern Nigeria
Non-invasive geophysical methods are increasingly being used in archaeological studies. In this study, magnetic and electrical resistivity tomography geophysical techniques were integrated to locate subsurface archaeological materials. The survey consists of four parallel and three perpendicular profiles with station interval of 0.5 m for both magnetic and electrical resistivity tomography. Wenner array with electrode spacing ranging from 0.5 – 3.0 m was used to collect the electrical resistivity data. The results show that high total magnetic intensity anomalies correspond to high inverse model resistivities. The regions with high magnetic and resistivity anomalies were thought to be locations of archaeological materials; the corresponding depths to these materials were inferred from the resulting geophysical images. Test units conducted at the regions of high total magnetic intensity and inverse model resistivity yield archaeological materials including burnt pipes (Tuyere), iron slag, iron smelting, and pottery fragments at approximate depths inferred from the geophysical images. Keywords: Archaeogeophysics, Artefacts, ERT, Magnetic methods, 2D imagin
NEWS for Africa: adaptation and reliability of a built environment questionnaire for physical activity in seven African countries
Perceived crime and traffic safety is related to physical activity among adults in Nigeria
Background: Neighborhood safety is inconsistently related to physical activity, but is seldom studied in developing countries. This study examined associations between perceived neighborhood safety and physical activity among Nigerian adults.
Methods: In a cross-sectional study, accelerometer-based physical activity (MVPA), reported walking, perceived crime and traffic safety were measured in 219 Nigerian adults. Logistic regression analysis was conducted, and the odds ratio for meeting health guidelines for MVPA and walking was calculated in relation to four safety variables, after adjustment for potential confounders.
Results: Sufficient MVPA was related to more perception of safety from traffic to walk (OR = 2.28, CI = 1.13-6.25) and more safety from crime at night (OR = 1.68, CI = 1.07-3.64), but with less perception of safety from crime during the day to walk (OR = 0.34, CI = 0.06- 0.91). More crime safety during the day and night were associated with more walking.
Conclusions: Perceived safety from crime and traffic were associated with physical activity among Nigerian adults. These findings provide preliminary evidence on the need to provide safe traffic and crime environments that will make it easier and more likely for African adults to be physically active
Association between perceived built environmental attributes and physical activity among adults in South Africa
Background: To investigate the association between perceived environmental attributes and leisure-time and transport-related physical activity. Methods: This was a cross-sectional survey involving 671 South Africans aged ?35 years from urban and rural settings. International Physical Activity Questionnaire and Neighbourhood Walkability Scale were used to collect data. Multivariable logistic regressions were used to investigate the associations. Results: Significant urban vs. rural differences were apparent in the distribution of most attributes of neighborhood environment. After adjusting for gender, age, setting and relevant interaction terms, proximity to local stores was significantly associated with leisure-time physical activity (OR: 4.26; 95% CI, 1.00-18.08); while proximity to transit stops (2.44; 1.48-4.02), pleasant scenery (1.93; 1.07-3.46), sidewalks (2.36; 1.25-4.44), shade from trees (2.14; 1.19-3.85), traffic (2.17; 91.21-3.91) and well-lit streets (2.01; 1.04-3.89) were significantly associated with walking for leisure. Four-way intersections (4.54; 1.54-13.43), pleasant scenery (3.84; 1.35-10.99), traffic (0.28; 0.09-0.89), sidewalks (3.75; 1.06-13.27) and crosswalks were associated with transport related physical activity. Proximity to transit stops (2.12; 1.17-3.84) and well maintained sidewalks (2.69; 2.20-10.02) were significantly associated with total physical activity. Significant interactions by setting were apparent in some of the associations. Conclusion: Some, but not all attributes of a neighborhood environment were significantly associated in expected directions with the three physical activity domains in this mixed urban and rural population. This study highlights the need for policy strategies aimed at improving or maintaining these perceived environmental attributes to promote physical activity.IS
Thermal Adaptation of Dihydrofolate Reductase from the Moderate ThermophileGeobacillus stearothermophilus
The thermal melting temperature of dihydrofolate reductase from Geobacillus stearothermophilus (BsDHFR) is 30 °C higher than that of its homologue from the psychrophile Moritella profunda. Additional proline residues in the loop regions of BsDHFR have been proposed to enhance the thermostability of BsDHFR, but site-directed mutagenesis studies reveal that these proline residues contribute only minimally. Instead, the high thermal stability of BsDHFR is partly due to removal of water-accessible thermolabile residues such as glutamine and methionine, which are prone to hydrolysis or oxidation at high temperatures. The extra thermostability of BsDHFR can be obtained by ligand binding, or in the presence of salts or cosolvents such as glycerol and sucrose. The sum of all these incremental factors allows BsDHFR to function efficiently in the natural habitat of G. stearothermophilus, which is characterized by temperatures that can reach 75 °C
Work-related musculoskeletal disorders among Nigerian Physiotherapists
<p>Abstract</p> <p>Background</p> <p>Physiotherapists are known to be prone to Work- related musculoskeletal disorders (WRMDs) but its prevalence among physiotherapists in Nigeria has not been reported. This study investigated the prevalence and work factors of WRMDs among physiotherapists in Nigeria.</p> <p>Methods</p> <p>A cross- sectional survey was administered to physiotherapists in different parts of Nigeria using a 2- part questionnaire with items adopted from questionnaires used for similar studies around the world. Two hundred and seventeen copies of the questionnaire were distributed for self administration but 126 physiotherapists returned completed surveys for a 58.1% response. The data were analyzed using SPPS version 10 at alpha level of 0.05. Descriptive statistics of frequency and percentages and inferential statistics of <it>x</it><sup>2 </sup>were used as appropriate for data analysis.</p> <p>Results</p> <p>Reported 12- month prevalence of WRMDs among Nigerian physiotherapists was 91.3%. Prevalence of WRMDs was significantly higher in female physiotherapists (p = 0.007) and those with lower body mass index (p = 0.045). The low back (69.8%) was the most commonly affected body part, followed by the neck (34.1%). Fifty percent of the physiotherapists first experienced their WRMDs within five years of graduation and the highest prevalence (61.7%) was found among physiotherapists younger than 30 years. Treating large number of patients in a day was cited by most (83.5%) of the respondents as the most important work factor for their WRMDs. The most commonly adopted coping strategy identified was for the therapists to modify their position and/or the patient's position (64.3%). Majority of the respondents (87.0%) did not leave the profession but 62.6% changed and/or modified their treatment because of their WRMDs.</p> <p>Conclusion</p> <p>The prevalence of WRMDs among physiotherapists in Nigeria is higher than most values reported for their counterparts around the world. The coping strategies and work factors of WRMDs among Nigerian physiotherapists are mostly similar to those of their counterparts elsewhere.</p
Loop Interactions during Catalysis by Dihydrofolate Reductase fromMoritella profunda
Dihydrofolate reductase (DHFR) is often used as a model system to
study the relation between protein dynamics and catalysis. We have studied a
number of variants of the cold-adapted DHFR from Moritella profunda
(MpDHFR), in which the catalytically important M20 and FG loops have been
altered, and present a comparison with the corresponding variants of the wellstudied
DHFR from Escherichia coli (EcDHFR). Mutations in the M20 loop do not
affect the actual chemical step of transfer of hydride from reduced nicotinamide
adenine dinucleotide phosphate to the substrate 7,8-dihydrofolate in the catalytic
cycle in either enzyme; they affect the steady state turnover rate in EcDHFR but
not in MpDHFR. Mutations in the FG loop also have different effects on catalysis
by the two DHFRs. Despite the two enzymes most likely sharing a common catalytic cycle at pH 7, motions of these loops,
known to be important for progression through the catalytic cycle in EcDHFR, appear not to play a significant role in MpDHFR
Prevalence and socio-demographic correlates of physical activity levels among South African adults in Cape Town and Mount Frere communities in 2008-2009
BACKGROUND: Physical activity has been linked to reduced risk of various cardiometabolic disease, cancer, and
premature mortality. We investigated the prevalence and socio-demographic correlates of physical activity
among adults in urban and rural communities in South Africa. METHODS: This was a cross-sectional survey
comprising 1733 adults aged ?35 years from the Cape Town (urban) and Mount Frere (rural) sites of the
Prospective Urban Rural Epidemiology study. Physical activity was assessed using the validated International
Physical Activity Questionnaire. Multinomial logistic regressions were used to relate physical activity with
socio-demographic characteristics.
RESULTS: Overall, 74% of participants engaged in moderate-to-vigorous physical activity. In the adjusted regression
models, women were 34% less likely to engage in vigorous physical activity (OR =0.66, 95%-CI = 0.47-0.93). Physical
activity decreased with age, varied with marital status, education and occupation, always in differential ways
between urban and rural participants (all interactions p ? 0.047). For instance, in urban settings, those with
secondary education were more likely to engage in moderate physical activity (OR = 2.06, 95%-CI = 1.08-3.92)
than those with tertiary education. Single people were more likely to engage in high physical activity (OR = 2.10,
95%-CI = 1.03-4.28) than divorced. Overall, skilled participants were more likely to engage in vigorous physical
activity (OR = 2.07, 95%-CI = 1.41-3.05) driven by significant effect in rural area (OR = 2.70, 95%-CI = 1.51-4.83).
Urban participants were more likely to engage in moderate physical activity (OR = 1.67, 95%-CI = 1.31-2.13)
than rural participants.
CONCLUSIONS: To prevent chronic diseases among South Africans, attention should be paid to specific policies
and interventions aimed at promoting PA among young adults in rural and urban setting, and across the
social-economic diversity
Neighbourhood ethnic density effects on behavioural and cognitive problems among young racial/ethnic minority children in the US and England: a cross-national comparison
Studies on adult racial/ethnic minority populations show that the increased concentration of racial/ethnic minorities in a neighbourhood—a so-called ethnic density effect—is associated with improved health of racial/ethnic minority residents when adjusting for area deprivation. However, this literature has focused mainly on adult populations, individual racial/ethnic groups, and single countries, with no studies focusing on children of different racial/ethnic groups or comparing across nations. This study aims to compare neighbourhood ethnic density effects on young children’s cognitive and behavioural outcomes in the US and in England. We used data from two nationally representative birth cohort studies, the US Early Childhood Longitudinal Study-Birth Cohort and the UK Millennium Cohort Study, to estimate the association between own ethnic density and behavioural and cognitive development at 5 years of age. Findings show substantial heterogeneity in ethnic density effects on child outcomes within and between the two countries, suggesting that ethnic density effects may reflect the wider social and economic context. We argue that researchers should take area deprivation into account when estimating ethnic density effects and when developing policy initiatives targeted at strengthening and improving the health and development of racial and ethnic minority children
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