Enhancing first year chemistry student’s participation in practical chemistry course

In this study, enhancing student’s participation in practical analytical chemistry course at Haramaya University with various reasons was conducted. The data were collected from I year chemistry undergraduate students of class size 56 of which 23 were females and 33 were males. The class was arranged in to two groups for laboratory class and the experiment was conducted once per week in analytical laboratory. The research used mainly three kinds of data collection techniques namely questionnaire and laboratory report and demonstration result to gather the required qualitative and quantitative data for improving the participation of first year chemistry students. From the result, it was found that students were interested towards the practical analytical courses on the basis of condition such as, necessity of the chemistry with life, their participation in the laboratory, getting experience from the laboratory and performing the experiment in group. The results of the study support the notion that, students were more interested to a group work rather than individual work since they share idea, read their manual before coming to laboratory which contributed to their own participation in learning practical chemistry courses. The research has also shown that student’s activity through experimental demonstration in group increases student’s participations in the laboratory effectively by achieving better results than using laboratory report writing methods. The findings also revealed that some of the causes of students’ negative attitudes towards learning practical Chemistry were mainly due to problems in preparing a flow chart for the experiments by themselves and lack of exposure to well-equipped laboratory for conducting demonstrations. In view of the findings and conclusions drawn in the study, Chemistry laboratories should be adequately equipped to ensure a smooth running of the practical classes and students should be encouraged to participate on practical chemistry courses and appropriate motivation should be given so that they will develop positive attitude towards the practical sessions

On modeling and measuring viscoelasticity with dynamic Atomic Force Microscopy

The interaction between a rapidly oscillating atomic force microscope tip and a soft material surface is described using both elastic and viscous forces with a moving surface model. We derive the simplest form of this model, motivating it as a way to capture the impact dynamics of the tip and sample with an interaction consisting of two components: interfacial or surface force, and bulk or volumetric force. Analytic solutions to the piece-wise linear model identify characteristic time constants, providing a physical explanation of the hysteresis observed in the measured dynamic force quadrature curves. Numerical simulation is used to fit the model to experimental data and excellent agreement is found with a variety of different samples. The model parameters form a dimensionless impact-rheology factor, giving a quantitative physical number to characterize a viscoelastic surface that does not depend on the tip shape or cantilever frequency.Comment: 13 pages, 7 figure

Renormalization of four-quark operators, effective theory, and the role of evanescent operators

We present, in the context of dimensional regularization, a prescription to renormalize Feynman diagrams with an arbitrary number of external fermions. This prescription, which is based on the original t'Hooft-Veltman proposal to keep external particles in four dimensions, is particularly useful to define the 'renormalization' (in the context of effective Lagrangian) of physical four-quark operators without introducing any evanescent operator. The results obtained for $b\rightarrow s$ processes agree with those from the so-called naive prescription, but disagree with the ones with the introduction of evanescent operators in a renormalization group analysis. We also present an explicit two loop calculation of the mixing of the evanescent operators with the physical dimension five operators for the same processes. Particular attention is paid to the unboundedness nature of such mixing and how a formal finite transformation is effected to decouple. The inevitable mass dependence of one of these schemes in the literature is pointed out as the cause for the difference mentioned.Comment: 39 pages plain TeX and 10 Postscript figures available upon request, McGill/ 94-14 and UM-TH-94-2

In vivo efficacy of artemether-lumefantrine against uncomplicated Plasmodium falciparum malaria in Central Ethiopia

<p>Abstract</p> <p>Background</p> <p><it>In vivo </it>efficacy assessments of the first-line treatments for <it>Plasmodium falciparum </it>malaria are essential for ensuring effective case management. In Ethiopia, artemether-lumefantrine (AL) has been the first-line treatment for uncomplicated <it>P. falciparum </it>malaria since 2004.</p> <p>Methods</p> <p>Between October and November 2009, we conducted a 42-day, single arm, open label study of AL for <it>P. falciparum </it>in individuals >6 months of age at two sites in Oromia State, Ethiopia. Eligible patients who had documented <it>P. falciparum </it>mono-infection were enrolled and followed according to the standard 2009 World Health Organization <it>in vivo </it>drug efficacy monitoring protocol. The primary and secondary endpoints were PCR uncorrected and corrected cure rates, as measured by adequate clinical and parasitological response on days 28 and 42, respectively.</p> <p>Results</p> <p>Of 4426 patients tested, 120 with confirmed falciparum malaria were enrolled and treated with AL. Follow-up was completed for 112 patients at day 28 and 104 patients at day 42. There was one late parasitological failure, which was classified as undetermined after genotyping. Uncorrected cure rates at both day 28 and 42 for the per protocol analysis were 99.1% (95% CI 95.1-100.0); corrected cure rates at both day 28 and 42 were 100.0%. Uncorrected cure rates at day 28 and 42 for the intention to treat analysis were 93.3% (95% CI 87.2-97.1) and 86.6% (95% CI 79.1-92.1), respectively, while the corrected cure rates at day 28 and 42 were 94.1% (95% CI 88.2-97.6) and 87.3% (95% CI 79.9-92.7), respectively. Using survival analysis, the unadjusted cure rate was 99.1% and 100.0% adjusted by genotyping for day 28 and 42, respectively. Eight <it>P. falciparum </it>patients (6.7%) presented with <it>Plasmodium vivax </it>infection during follow-up and were excluded from the per protocol analysis. Only one patient had persistent parasitaemia at day 3. No serious adverse events were reported, with cough and nausea/vomiting being the most common adverse events.</p> <p>Conclusions</p> <p>AL remains a highly effective and well-tolerated treatment for uncomplicated falciparum malaria in the study setting after several years of universal access to AL. A high rate of parasitaemia with <it>P. vivax </it>possibly from relapse or new infection was observed.</p> <p>Trial Registration</p> <p><a href="http://www.clinicaltrials.gov/ct2/show/NCT01052584">NCT01052584</a></p

Predictors of unintended pregnancy in Kersa, Eastern Ethiopia, 2010

<p>Abstract</p> <p>Background</p> <p>In Ethiopia, little is known about pregnancy among rural women. Proper maternal health care depends on clear understanding of the reproductive health situation. The objective of this study was to identify predictors of unintended pregnancy in rural eastern Ethiopia.</p> <p>Methodology</p> <p>This study was part of pregnancy surveillance at Kersa Demographic Surveillance and Health Research Center, East Ethiopia. Pregnant women were assessed whether their current pregnancy was intended or not. Data were collected by lay interviewers using uniform questionnaire. Odds Ratio, with 95% confidence interval using multiple and multinomial logistic regression were calculated to detect level of significance.</p> <p>Results</p> <p>Unintended pregnancy was reported by 27.9% (578/2072) of the study subjects. Out of which, 440 were mistimed and 138 were not wanted. Unintended pregnancy was associated with family wealth status (OR 1.47; 95% CI 1.14, 1.90), high parity (7 +) (OR 5.18; 95% CI 3.31, 8.12), and a longer estimated time to walk to the nearest health care facility (OR 2.24; 95% CI: 1.49, 3.39).</p> <p>In the multinomial regression, women from poor family reported that their pregnancy was mistimed (OR 1.69; 95% CI 1.27, 2.25). The longer estimated time (80 + minutes) to walk to the nearest health care facility influenced the occurrence of mistimed pregnancy (OR 2.58; 95% CI: 1.65, 4.02). High parity (7+) showed a strong association to mistimed and unwanted pregnancies (OR 3.11; 95% CI 1.87, 5.12) and (OR 14.34; 95% CI 5.72, 35.98), respectively.</p> <p>Conclusions</p> <p>The economy of the family, parity, and walking distance to the nearest health care institution are strong predictors of unintended pregnancy. In order to reduce the high rate of unintended pregnancy Efforts to reach rural women with family planning services should be strengthened.</p