Homogeneous transit timing analyses of ten exoplanet systems

We study the transit timings of 10 exoplanets in order to investigate potential transit timing variations in them. We model their available ground-based light curves, some presented here and others taken from the literature, and homogeneously measure the mid-transit times. We statistically compare our results with published values and find that the measurement errors agree. However, in terms of recovering the possible frequencies, homogeneous sets can be found to be more useful, of which no statistically relevant example has been found for the planets in our study. We corrected the ephemeris information of all 10 planets we studied and provide these most precise light elements as references for future transit observations with space-borne and ground-based instruments. We found no evidence for secular or periodic changes in the orbital periods of the planets in our sample, including the ultra-short period WASP-103 b, whose orbit is expected to decay on an observable time-scale. Therefore, we derive the lower limits for the reduced tidal quality factors (Q(*)') for the host stars based on best-fitting quadratic functions to their timing data. We also present a global model of all available data for WASP-74 b, which has a Gaia parallax-based distance value similar to 25 per cent larger than the published value

Perceptions of students and teachers participating in a science festival regarding science and scientists

Background: Numerous studies have been conducted to identify students’ perceptions of science and scientists since the 1950s. Those studies have revealed that students have stereotypical perceptions, on which teachers may have a significant effect. It is, therefore, essential to determine both teachers’ and students’ perceptions. Purpose: The aim of this study is to investigate students’ and teachers’ perceptions of science and scientists. Sample: The sample for the study consisted of 85 students and 47 teachers who participated in a science festival. Design and methods: The study is based on a descriptive survey model. Data were collected using the Draw-A-Scientist Test (DAST) and Word Association Test (WAT), and analyzed using content analysis. Results: Participants’ drawings focused on scientists’ physical characteristics, type of activity, working environment and the materials used while conducting experiments. A scientist was often depicted as a man in a lab coat with strange hair and eyeglasses and using laboratory materials. Teachers made more detailed drawings of scientists’ working style and environment and more detailed associations with the nature of science, ways of acquiring scientific knowledge and scientific process. Unlike teachers, students emphasized space-related concepts both in their drawings and word associations. Conclusion: This study shows that both teachers and students possess various stereotypical perceptions of scientists aligned with the previous studies. However, the number of scientists drawn as happy and female is higher than the previous studies, which is a promising finding. Moreover, students’ drawings consisting symbols or alternative images that evoked space in particular is one of the several aspects which differentiate this study from most studies. This study also shows that using drawings and word association tests together provides a richer understanding of people’s views of science and scientists than using only one measurement tool. © 2020, © 2020 Informa UK Limited, trading as Taylor & Francis Group

1H, 13C, and 15N resonance assignment of a 179 residue fragment of hepatitis C virus non-structural protein 5A

Non-structural protein 5A (NS5A) plays an important role in the life cycle of hepatitis C virus. This proline-rich phosphoprotein is organized into three domains. Besides its role in virus replication and virus assembly, NS5A is involved in a variety of cellular regulation processes. Recent studies on domain 2 and 3 revealed that both belong to the class of intrinsically disordered proteins as they adopt a natively unfolded state. In particular, domain 2 together with its vicinal regions is responsible for NS5A's multiple interactions with other proteins necessary for virus persistence. The low chemical shift dispersion observed for instrinsically disordered proteins presents a challenge for NMR spectroscopy. Here we report sequential resonance assignment of a 179-residue fragment of NS5A, comprising the entire domain 2, using a set of sensitivity and resolution optimized 3D correlation experiments, as well as amino-acid-type editing in (1)H-(15)N correlation spectra. Our assignment reveals the presence of several segments with high propensity to form α-helical structure that may be of importance to the function of this protein fragment as a versatile interaction platform

Looking for timing variations in the transits of 16 exoplanets

We update the ephemerides of 16 transiting exoplanets using our ground-based observations, new TESS data, and previously published observations including those of amateur astronomers. All these light curves were modeled by making use of a set of quantitative criteria with the exofast code to obtain mid-transit times. We searched for statistically significant secular and/or periodic trends in the mid-transit times. We found that the timing data are well modeled by a linear ephemeris for all systems except for XO-2 b, for which we detect an orbital decay with the rate of -12.95 ± 1.85 ms/yr that can be confirmed with future observations. We also detect a hint of potential periodic variations in the TTV data of HAT-P-13 b which also requires confirmation with further precise observations