1,162 research outputs found

    Junior Secondary School Pupils' Perception of the Relevance of Environmental Issues: Implications for Science Educators

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    This study focuses on how the Ghanaian youth would want to associate with some environmental matters regarding science and technology learning using the Relevance of Science Education (ROSE) survey questionnaire; and is also aimed at providing implications for science educators. The results reported in this study are an extract from the author's thesis and also from Ghanaian data which are aspects of much larger ROSE data collected from about 40 countries. The study involved a sample of 1027 Junior Secondary School (JSS) 3 or ninth graders (551 boys and 476 girls) drawn from all the 12 districts in the Central Region of Ghana. The study draws on only one of the themes covered by the ROSE instrument and pupils were asked to indicate the extent to which they agree with 18 statements on a 4-point Likert-type scale which goes from ‘Disagree' to ‘Agree'. The responses were analysed using SPSS and Excel. Descriptive statistics was conducted on the data and an independent sample 2-tailed t-test was used to explore the statistical significance of the differences in the items' mean at p ≤ 0.05. On the average, the results suggest that the majority of pupils in the sample, irrespective of the gender shared almost similar sentiments towards environmental protection issues and to a large extent, placed the same items on top as well as at the bottom of their priorities. An interesting aspect of pupils' concerns for the environment was their optimism about the future of the globe. The study suggests the need for science educators to consider pupils' views when teaching environmental related issues. African Journal of Educational Studies in Mathematics and Sciences Vol. 5 2007: pp. 87-9

    Energy efficient lighting in the residences of staff of the University of Education, Winneba

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    It is estimated that 15% of electric power production is used for lighting consumption in Ghana. This figure is likely to increase as the country develops. There is no doubt therefore, that improving the energy efficiency of lighting in Ghana could have a great impact on Ghana's energy consumption, and subsequently, on the economy. The study is to investigate the level to which energy-efficient lighting systems are being used in some selected bungalows at the University of Education, Winneba, in Ghana. Forty bungalows were selected for the survey. A questionnaire was used to ascertain information on compact fluorescent lamp (CFL) as an energy-efficient lighting system. The results of the study show that even though academics in the university have received information about the use of CFLs as a way of saving energy, very few show interest in their use. It is inferred that lamp prices could be a more important influence on consumer's choice of efficient lamp than the cost of electricity. Market barriers, such as cost of and fundamental problems with the use of CFLs are discussed along with appropriate remedies. African Journal of Educational Studies in Mathematics and Sciences Vol. 2(2) 2004: 31-3

    Orphan G protein-coupled receptors MrgA1 and MrgC11 are distinctively activated by RF-amide-related peptides through the G{alpha}q/11 pathway

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    MrgA1 and MrgC11 belong to a recently identified family of orphan G-protein coupled receptors, called mrgs (mas-related genes). They are only expressed in a specific subset of sensory neurons that are known to detect painful stimuli. However, the precise physiological function of Mrg receptors and their underlying mechanisms of signal transduction are not known. We therefore have screened a series of neuropeptides against human embryonic kidney (HEK) 293 cells that stably express either MrgA1 or MrgC11 to identify ligands and/or agonists. MrgA1- or MrgC11-specific agonists stimulated dose-dependent increases in intracellular free Ca2+ in a pertussis toxin-insensitive manner, but failed to alter basal or forskolin-stimulated levels of intracellular cAMP. Furthermore, studies using embryonic fibroblasts derived from various G{alpha} protein knockout mice demonstrated that both the MrgA1 and MrgC11 receptors are coupled to the G{alpha}q/11 signaling pathway. Screening of neuropeptides identified surrogate agonists, most of these peptides included a common C-terminal -RF(Y)G or -RF(Y) amide motif. Structure-function studies suggest that endogenous ligands of Mrg receptors are likely to be RF(Y)G and/or RF(Y) amide-related peptides and that postprocessing of these peptides may serve to determine Mrg receptor-ligand specificity. The differences in ligand specificity also suggest functional diversity amongst the Mrg receptors

    Progress on stochastic background search codes for LIGO

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    One of the types of signals for which the LIGO interferometric gravitational wave detectors will search is a stochastic background of gravitational radiation. We review the technique of searching for a background using the optimally-filtered cross-correlation statistic, and describe the state of plans to perform such cross-correlations between the two LIGO interferometers as well as between LIGO and other gravitational-wave detectors, in particular the preparation of software to perform such data analysis.Comment: 7 pages, 1 encapsulated PostScript figure, uses IOP class files, submitted to the proceedings of the 4th Amaldi meeting (which will be published in Classical and Quantum Gravity

    Winter wheat roots grow twice as deep as spring wheat roots, is this important for N uptake and N leaching losses?

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    Cropping systems comprising winter catch crops followed by spring wheat could reduce N leaching risks compared to traditional winter wheat systems in humid climates. We studied the soil mineral N (Ninorg) and root growth of winter- and spring wheat to 2.5 m depth during three years. Root depth of winter wheat (2.2 m) was twice that of spring wheat, and this was related to much lower amounts of Ninorg in the 1 to 2.5 m layer after winter wheat (81 kg Ninorg ha-1 less). When growing winter catch crops before spring wheat, N content in the 1 to 2.5 m layer after spring wheat was not different from that after winter wheat. The results suggest that by virtue of its deep rooting, winter wheat may not lead to high levels of leaching as it is often assumed in humid climates. Deep soil and root measurements (below 1 m) in this experiment were essential to answer the questions we posed

    De-Trending Time Series for Astronomical Variability Surveys

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    We present a de-trending algorithm for the removal of trends in time series. Trends in time series could be caused by various systematic and random noise sources such as cloud passages, changes of airmass, telescope vibration or CCD noise. Those trends undermine the intrinsic signals of stars and should be removed. We determine the trends from subsets of stars that are highly correlated among themselves. These subsets are selected based on a hierarchical tree clustering algorithm. A bottom-up merging algorithm based on the departure from normal distribution in the correlation is developed to identify subsets, which we call clusters. After identification of clusters, we determine a trend per cluster by weighted sum of normalized light-curves. We then use quadratic programming to de-trend all individual light-curves based on these determined trends. Experimental results with synthetic light-curves containing artificial trends and events are presented. Results from other de-trending methods are also compared. The developed algorithm can be applied to time series for trend removal in both narrow and wide field astronomy.Comment: Revised version according to the referee's second revie

    Breast cancer risk reduction:is it feasible to initiate a randomised controlled trial of a lifestyle intervention programme (ActWell) within a national breast screening programme?

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    BackgroundBreast cancer is the most commonly diagnosed cancer and the second cause of cancer deaths amongst women in the UK. The incidence of the disease is increasing and is highest in women from least deprived areas. It is estimated that around 42% of the disease in post-menopausal women could be prevented by increased physical activity and reductions in alcohol intake and body fatness. Breast cancer control endeavours focus on national screening programmes but these do not include communications or interventions for risk reductionThis study aimed to assess the feasibility of delivery, indicative effects and acceptability of a lifestyle intervention programme initiated within the NHS Scottish Breast Screening Programme (NHSSBSP).MethodsA 1:1 randomised controlled trial (RCT) of the 3 month ActWell programme (focussing on body weight, physical activity and alcohol) versus usual care conducted in two NHSSBSP sites between June 2013 and January 2014. Feasibility assessments included recruitment, retention, and fidelity to protocol. Indicative outcomes were measured at baseline and 3 month follow-up (body weight, waist circumference, eating and alcohol habits and physical activity. At study end, a questionnaire assessed participant satisfaction and qualitative interviews elicited women¿s, coaches and radiographers¿ experiences. Statistical analysis used Chi squared tests for comparisons in proportions and paired t tests for comparisons of means. Linear regression analyses were performed, adjusted for baseline values, with group allocation as a fixed effectResultsA pre-set recruitment target of 80 women was achieved within 12 weeks and 65 (81%) participants (29 intervention, 36 control) completed 3 month assessments. Mean age was 58¿±¿5.6 years, mean BMI was 29.2¿±¿7.0 kg/m2 and many (44%) reported a family history of breast cancer.The primary analysis (baseline body weight adjusted) showed a significant between group difference favouring the intervention group of 2.04 kg (95%CI ¿3.24 kg to ¿0.85 kg). Significant, favourable between group differences were also detected for BMI, waist circumference, physical activity and sitting time. Women rated the programme highly and 70% said they would recommend it to others.ConclusionsRecruitment, retention, indicative results and participant acceptability support the development of a definitive RCT to measure long term effects.Trial registrationThe trial was registered with Current Controlled Trials (ISRCTN56223933)

    Expression Pattern of Immunoproteasome Subunits in Human Thymus

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    The expression pattern of immunoproteasomes in human thymus has not been analyzed but may have important consequences during thymic selection. Here we examined the expression patterns of immunoproteasome subunits in fetal and adult thymic tissues by immunohistochemistry and found that all three subunits are expressed in both cortical and medullary stromal cells. These data suggest that thymic selection in human can be affected by peptide repertoires generated by immunoproteasomes

    Suppression of ferromagnetic ordering in doped manganites: Effects of the superexchange interaction

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    From a Monte Carlo study of the ferromagnetic Kondo lattice model for doped manganites, including the antiferromagnetic superexchange interaction (JAFJ_{AF}), we found that the ferromagnetic ordering was suppressed as JAFJ_{AF} increased. The ferromagnetic transition temperature TcT_c, as obtained from a mean field fit to the calculated susceptibilities, was found to decrease monotonically with increasing JAFJ_{AF}. Further, the suppression in TcT_c scales with the bandwidth narrowing induced by the antiferromagnetic frustration originating from JAFJ_{AF}. From these results, we propose that the change in the superexchange interaction strength between the t2gt_{2g} electrons of the Mn ions is one of the mechanisms responsible for the suppression in TcT_c observed in manganites of the type (La0.7y_{0.7-y}Pry_{y})Ca0.3_{0.3}MnO3_3.Comment: 5 pages, 6 figures. To appear in PR
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