The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

The Science Performance of JWST as Characterized in Commissioning

This paper characterizes the actual science performance of the James Webb Space Telescope (JWST), as determined from the six month commissioning period. We summarize the performance of the spacecraft, telescope, science instruments, and ground system, with an emphasis on differences from pre-launch expectations. Commissioning has made clear that JWST is fully capable of achieving the discoveries for which it was built. Moreover, almost across the board, the science performance of JWST is better than expected; in most cases, JWST will go deeper faster than expected. The telescope and instrument suite have demonstrated the sensitivity, stability, image quality, and spectral range that are necessary to transform our understanding of the cosmos through observations spanning from near-earth asteroids to the most distant galaxies.Comment: 5th version as accepted to PASP; 31 pages, 18 figures; https://iopscience.iop.org/article/10.1088/1538-3873/acb29

Tracking racial integration in South African schools

Paper presented at the Comparative International Education Society Conference: " Beyond Dichotomies, Stanford University, USA, 22-26 Marc

Tracking racial desegregation in South African schools

The purpose of this paper is to examine what the national Education Management Information Statistics database is able to tell us about the racial desegregation of schools and to compare this with findings from qualitative research.Examining challenges in the data and using simple statistical technique to analyse a dataset for 2001, the paper shows that overall patterns appear to confirm the findings of qualitatie research that there has been more movement from and integration of African learners ito schools previously defined as Indian and Coloured; that schools previously defined as white remain largely so and that the statistics for the Western Cape on race provide an interesting contrast with other provinces. The article shows how diverse the picture is provincialy and raises questions about race-based statistics and what they can and cannot tell us about the role of schools in changing broader racial and class identities.

Isolation of cellulose nanofibers from Oryza sativa residues via tempo mediated oxidation

Cellulose nanocrystals (CNCs) or cellulose nanofibers (CNFs) with different morphologies, chemical, mechanical and physical properties can be obtained when microcrystalline cellulose is subjected to enzymatic, chemical or mechanical treatment. With the aim of utilizing cellulose nanofibrils (CNFs) from Oryza sativa, we isolated microcrystalline cellulose using the Kraft process, followed by successive fiber fibrillation using mechanical grinding, then (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPO) mediated oxidation. Analysis of pulp fibers obtained after each treatment step revealed that fiber properties such as length, crystallinity and crystal size changed when the pulp was subjected to mechanical grinding, ultrasonication and TEMPO mediated oxidation. The degree of crystallinity of the fibers increased while crystal size and fiber length decreased after each treatment. TEMPO mediated oxidation led to a decrease in fiber length and an increase in degree of crystallinity of the fibers as compared to mechanical treatment and ultrasonication. It further introduced carboxyl functional groups (COOH) on the surface of the fibrils, which implies that the nanofibers obtained in this study could be further functionalized. Hence, TEMPO mediated oxidation offers the possibility of further chemical functionalization of cellulose nanofibers isolated from agricultural residues

Allergic rhinitis in medical students at the University of the Free State

Background: Allergic rhinitis, the most common form of chronic rhinitis, can adversely affect quality of life. The prevalence of allergic rhinitis in adolescents in South Africa has been estimated to be 38.5%, but there is a paucity of data from African countries on allergic rhinitis.Aim: The aim of this study was to determine the prevalence of allergic rhinitis in medical students in the Faculty of Health Science at the University of the Free State (UFS). Information was acquired on the effects that the condition had on participants with regard to symptoms, quality of life, disease management and treatment.Methods: A cross-sectional study design was used. A self-administered anonymous questionnaire was distributed to all medical students registered with the Faculty of Health Sciences at UFS in 2016. The estimated population was 706 students.Results: The response rate was 62.6%. The prevalence of allergic rhinitis was 39.1%. The most common symptoms were rhinorrhoea (64.8%), repeated sneezing (64.3%) and nasal obstruction (58.5%). Symptoms were at their worst during August to October. Antihistamines had been used by 82.4% of participants to treat their symptoms in the previous 12 months, while 28.8% had used an intranasal steroid spray.Conclusion: The prevalence of allergic rhinitis in medical students at UFS was 39.1%. Rhinorrhoea, sneezing and nasal obstruction were the most frequent and bothersome symptoms

Allergic rhinitis in medical students at the University of the Free State

Background: Allergic rhinitis, the most common form of chronic rhinitis, can adversely affect quality of life. The prevalence of allergic rhinitis in adolescents in South Africa has been estimated to be 38.5%, but there is a paucity of data from African countries on allergic rhinitis.Aim: The aim of this study was to determine the prevalence of allergic rhinitis in medical students in the Faculty of Health Science at the University of the Free State (UFS). Information was acquired on the effects that the condition had on participants with regard to symptoms, quality of life, disease management and treatment.Methods: A cross-sectional study design was used. A self-administered anonymous questionnaire was distributed to all medical students registered with the Faculty of Health Sciences at UFS in 2016. The estimated population was 706 students.Results: The response rate was 62.6%. The prevalence of allergic rhinitis was 39.1%. The most common symptoms were rhinorrhoea (64.8%), repeated sneezing (64.3%) and nasal obstruction (58.5%). Symptoms were at their worst during August to October. Antihistamines had been used by 82.4% of participants to treat their symptoms in the previous 12 months, while 28.8% had used an intranasal steroid spray.Conclusion: The prevalence of allergic rhinitis in medical students at UFS was 39.1%. Rhinorrhoea, sneezing and nasal obstruction were the most frequent and bothersome symptoms

School desegregation trends in Gauteng Province

This study utilized 2003 to 2006 school enrollment data from the Gauteng Department of Education (GDE) to examine school desegregation trends and interracial exposure among learners from different race groups. Descriptive analyses revealed findings consistent with the literature wherein a majority of schools served mainly homogeneous populations. African and White learners experienced limited or no opportunity for interracial contact at school level, whereas Coloured learners experienced moderate levels of interracial contact. The exception was the Indian learner group whose migration from schools formerly reserved for Indian learners into schools formerly reserved for White learners as well as independent schools contributed to increased diversity albeit in a relatively small group of schools. New schools are emerging as a preferred destination for African learners.http://www.informaworld.com/RAERgv201