Factors Affecting Use of Practical Work in Teaching and Learning Physics: Assessment of Six Secondary Schools in Kigali City, Rwanda

Nowadays there is a global change in teaching and learning methods. Methods that support learners’ participation and construction of their own knowledge have been emphasized in all academic activities. Science theories are mastered in practices in teaching and learning activities. Teaching and learning through practical work is among methods that undoubtedly facilitate knowledge transfer and skills acquisition in teaching and learning events. The present study examined the real factors affecting the use of practical work in teaching and learning sciences, particularly physics in secondary schools located in Kigali city/Rwanda. The participants in this study were physics teachers, learners, directors of studies and headmasters from public and government-assisted schools. Qualitative and quantitative data were collected using questionnaires, interviews and observations. The findings indicated that lack of training and policy governing the use of practical work coupled with inadequate resources and facilities hindered the use of practical work in the teaching and learning of physics in secondary schools. The study recommended that in-service teacher training prioritizing the use of practical work in teaching and learning should be initiated and sustained, assessment of practical skills should be required for qualification and used formatively in all levels, Government Funds for education should be allocated to build, equip, and sustain laboratories in schools, also practical physics should be allocated on the school timetable and regular supervision should be carried out in the classroom to ensure effective implementation of practical work. Conversely, putting into practice practical work in teaching and learning actively engages learners in the creation of their understanding and be familiar with the everyday phenomenon that learners observe and experience around them

Properties of green valley galaxies in relation to their selection criteria

The distribution of galaxies has been studied to show the difference between the blue cloud and red sequence and to define the green valley region. However, there are still many open questions regarding the importance of the green valley for understanding the morphological transformation and evolution of galaxies, how galaxies change from late-type to early-type and the role of AGN in galaxy formation and evolution scenario. The work focused on studying in more details the properties of green valley galaxies by testing the six most used selection criteria, differences between them, and how they may affect the main results and conclusions. The main findings are that, by selecting the green valley galaxies using different criteria, we are selecting different types of galaxies in terms of their stellar masses, sSFR, SFR, spectroscopic classification and morphological properties, where the difference was more significant for colour criteria than for sSFR and SFR vs. stellar-mass criteria.Comment: Proceedings paper of the IAU symposium "Nuclear Activity in Galaxies Across Cosmic Time" (Ethiopia) accepted to be published under the Cambridge University Press, eds. M. Povic, P. Marziani, J. Masegosa, H. Netzer, S. H. Negu, and S. B. Tessem

Modelling the Multifrequency SED of AGN Candidates among the Unidentied EGRET and Fermi Gamma-Ray Sources

Of the 271 sources in the 3rd EGRET catalogue, 131 were reported as unidentied, i.e. not associated with any particular class of point source in the sky. Since the largest fraction of the EGRET sources were extragalactic, a sample of 13 extragalactic unidentied sources have been selected for multi-wavelength follow-up studies. Five of the selected EGRET sources coincide with gamma-ray flux enhancements seen in the Fermi-LAT data after one year of operation. In this article, we report the multi-wavelength properties of, among others, the 5 sources detected by Fermi-LAT from our sample of high galactic latitude unidentied EGRET sources. Recent spectroscopic observations with the Southern African Large Telescope (SALT) conrmed one of the unidentied EGRET sources as a possible Seyfert 2 galaxy, or alternatively, a narrow line radio galaxy. The detected gamma-ray emission (Eγ > 30 MeV) of the 5 coinciding EGRET/Fermi-LAT sources are tted with external Compton and Synchrotron Self Compton (SSC) models to investigate the energetics required to produce the EGRET/Fermi gamma-ray flux. In all the models the inclination angle of the jet with respect to the observer is jet 60, between those of Seyfert 1 and Seyfert 2/radio galaxies. These results confirm the possibility of Seyfert and radio galaxies sources are constituting a new class of gamma-ray source in the energy range Eγ > 30 MeV

Impact of Project -based Learning on Students' Critical Thinking Skills in Kinematics in Mbale District, Uganda

This study explored the influence of project-based learning (PBL) on students’ critical thinking skills. The participants were fifty 10th-grade students from a purposively selected school in Mbale District, Eastern Uganda. Participants were randomly distributed to the experimental and control groups using cluster sampling. A mixed-method research approach was adopted. The pretest-posttest non-equivalent quasi-experimental design was used. The experimental group used the PBL approach while the control group followed the conventional approach. A kinematics survey test with eight essay questions and focus group interview prompts were data collection tools. The questions were open-ended to adequately measure students' critical thinking skills in kinematics. The survey test was validated by experts and piloted (α=0.88). Data was analyzed using independent samples t-tests and effect size. Though both groups' mean scores increased, the independent sample t-test (t(50)=12.22, df.=48, p=0.00) revealed that students from the treatment group exhibited proficiency in critical thinking skills relative to their counterparts from the control group. Therefore, this study recommends that science educators should adopt PBL to improve students’ life and career skills

Properties of X-ray detected far-IR AGN in the green valley

In this study, we analysed active galactic nuclei in the "green valley" by comparing active and non-active galaxies using data from the COSMOS field. We found that most of our X-ray detected active galactic nuclei with far-infrared emission have star formation rates higher than the ones of normal galaxies of the same stellar mass range.Comment: Proceedings paper of the IAU symposium "Nuclear Activity in Galaxies Across Cosmic Time" (Ethiopia) accepted to be published under the Cambridge University Press, eds. M. Povic, P. Marziani, J. Masegosa, H. Netzer, S. H. Negu, and S. B. Tessem

The [OIII] profiles of far-infrared active and non-active optically-selected green valley galaxies

We present a study of the $\rm{[OIII]\lambda\,5007}$ line profile in a sub-sample of 8 active galactic nuclei (AGN) and 6 non-AGN in the optically-selected green valley at $\rm{z\,<\,0.5}$ using long-slit spectroscopic observations with the 11 m Southern African Large Telescope. Gaussian decomposition of the line profile was performed to study its different components. We observe that the AGN profile is more complex than the non-AGN one. In particular, in most AGN (5/8) we detect a blue wing of the line. We derive the FWHM velocities of the wing and systemic component, and find that AGN show higher FWHM velocity than non-AGN in their core component. We also find that the AGN show blue wings with a median velocity width of approximately 600 $\rm{km\,s^{-1}}$, and a velocity offset from the core component in the range -90 to -350 $\rm{km\,s^{-1}}$, in contrast to the non-AGN galaxies, where we do not detect blue wings in any of their $\rm{[OIII]\lambda\,5007}$ line profiles. Using spatial information in our spectra, we show that at least three of the outflow candidate galaxies have centrally driven gas outflows extending across the whole galaxy. Moreover, these are also the galaxies which are located on the main sequence of star formation, raising the possibility that the AGN in our sample are influencing SF of their host galaxies (such as positive feedback). This is in agreement with our previous work where we studied SF, morphology, and stellar population properties of a sample of green valley AGN and non-AGN galaxies.Comment: 15 pages, 6 figures, accepted for publication in Ap

Development in Astronomy and Space Science in Africa

The development of astronomy and space science in Africa has grown significantly over the past few years. These advancements make the United Nations Sustainable Development Goals more achievable, and open up the possibility of new beneficial collaborations.Comment: Paper published in Nature Astronomy. Figures 1 and 2 are included in the published version, that can be seen at https://rdcu.be/2oE

THE SEARCH FOR BLAZARS AMONG THE UNIDENTIFIED EGRET gamma-RAY SOURCES

In this paper we report the results of a multi-wavelength follow-up study of selected flat spectrum extragalactic radio-optical counterparts within the error boxes of 13 unidentified EGRET sources. Two of these previously unidentified counterparts have been selected for optical photometric and spectroscopic follow-up studies. Spectroscopic observations made with the 4.1m SOAR telescope at Cerro Pachón, Chile, showed that the spectra of the optical counterparts of 3EG J0821−5814 (PKS J0820−5705) and 3EG J0706−3837 (PMN J0710−3835) correspond to a flat spectrum radio quasar (FSRQ) and LINER-Seyfert I galaxy respectively. Optical photometry of these sources, performed with the 1.0m telescope at Sutherland (South-Africa) shows noticeable intranight variability for PKS J0820−5705, as well as a 5 sigma variation of the mean brightness in the R-filter over a timescale of three nights. Significant variability has been detected in the B-band for PMN J0710−3835 as well. The gamma-ray spectral indices of all 13 candidates range between 2–3, correlating well with the BL Lacs and FSRQs detected with Fermi-LAT in the first 11 months of operation