The Merging of a Coronal Dimming and the Southern Polar Coronal Hole

We report on the merging between the southern polar coronal hole and an adjacent coronal dimming induced by a coronal mass ejection on 2022 March 18, resulting in the merged region persisting for at least 72 hr. We use remote sensing data from multiple co-observing spacecraft to understand the physical processes during this merging event. The evolution of the merger is examined using Extreme-UltraViolet (EUV) images obtained from the Atmospheric Imaging Assembly on board the Solar Dynamic Observatory and Extreme Ultraviolet Imager, which is on board the Solar Orbiter spacecraft. The plasma dynamics are quantified using spectroscopic data obtained from the EUV Imaging Spectrometer on board Hinode. The photospheric magnetograms from the Helioseismic and Magnetic Imager are used to derive the magnetic field properties. To our knowledge, this work is the first spectroscopical analysis of the merging of two open-field structures. We find that the coronal hole and the coronal dimming become indistinguishable after the merging. The upflow speeds inside the coronal dimming become more similar to that of a coronal hole, with a mixture of plasma upflows and downflows observable after the merging. The brightening of the bright points and the appearance of coronal jets inside the merged region further imply ongoing reconnection processes. We propose that component reconnection between the coronal hole and coronal dimming fields plays an important role during this merging event because the footpoint switching resulting from the reconnection allows the coronal dimming to intrude onto the boundary of the southern polar coronal hole

Understanding the Relationship between Solar Coronal Abundances and F10.7 cm Radio Emission

Sun-as-a-star coronal plasma composition, derived from full-Sun spectra, and the F10.7 radio flux (2.8 GHz) have been shown to be highly correlated (r = 0.88) during solar cycle 24. However, this correlation becomes nonlinear during increased solar magnetic activity. Here we use cotemporal, high spatial resolution, multiwavelength images of the Sun to investigate the underlying causes of the nonlinearity between coronal composition (FIP bias) and F10.7 solar index correlation. Using the Karl G. Jansky Very Large Array, Hinode/EIS (EUV Imaging Spectrometer), and the Solar Dynamics Observatory, we observed a small active region, AR 12759, throughout the solar atmosphere from the photosphere to the corona. The results of this study show that the magnetic field strength (flux density) in active regions plays an important role in the variability of coronal abundances, and it is likely the main contributing factor to this nonlinearity during increased solar activity. Coronal abundances above cool sunspots are lower than in dispersed magnetic plage regions. Strong magnetic concentrations are associated with stronger F10.7 cm gyroresonance emission. Considering that as the solar cycle moves from minimum to maximum, the sizes of sunspots and their field strength increase with the gyroresonance component, the distinctly different tendencies of radio emission and coronal abundances in the vicinity of sunspots is the likely cause of saturation of Sun-as-a-star coronal abundances during solar maximum, while the F10.7 index remains well correlated with the sunspot number and other magnetic field proxies

Slow Solar Wind Connection Science during Solar Orbiter’s First Close Perihelion Passage

The Slow Solar Wind Connection Solar Orbiter Observing Plan (Slow Wind SOOP) was developed to utilize the extensive suite of remote-sensing and in situ instruments on board the ESA/NASA Solar Orbiter mission to answer significant outstanding questions regarding the origin and formation of the slow solar wind. The Slow Wind SOOP was designed to link remote-sensing and in situ measurements of slow wind originating at open–closed magnetic field boundaries. The SOOP ran just prior to Solar Orbiter’s first close perihelion passage during two remote-sensing windows (RSW1 and RSW2) between 2022 March 3–6 and 2022 March 17–22, while Solar Orbiter was at respective heliocentric distances of 0.55–0.51 and 0.38–0.34 au from the Sun. Coordinated observation campaigns were also conducted by Hinode and IRIS. The magnetic connectivity tool was used, along with low-latency in situ data and full-disk remote-sensing observations, to guide the target pointing of Solar Orbiter. Solar Orbiter targeted an active region complex during RSW1, the boundary of a coronal hole, and the periphery of a decayed active region during RSW2. Postobservation analysis using the magnetic connectivity tool, along with in situ measurements from MAG and SWA/PAS, showed that slow solar wind originating from two out of three of the target regions arrived at the spacecraft with velocities between ∼210 and 600 km s−1. The Slow Wind SOOP, despite presenting many challenges, was very successful, providing a blueprint for planning future observation campaigns that rely on the magnetic connectivity of Solar Orbiter

Implications of methodological differences in measuring the rates of exclusive breastfeeding in Nepal: findings from literature review and cohort study

BACKGROUND: Correct measurement and continuous monitoring of exclusive breastfeeding are essential to promote exclusive breastfeeding. Measuring exclusive breastfeeding is a complex issue as rates can vary according to the definition, measurement period, questions asked, and infant's age. This article reviewed the methodology of reporting exclusive breastfeeding in Nepal, and compared exclusive breastfeeding rates using data from a cohort study undertaken in western Nepal. METHODS: A literature review was first conducted on studies published during 2000-2014. In our cohort study, 735 mother-infant pairs were recruited within the first month postpartum and followed up during the fourth and sixth months. RESULTS: The majority of studies in Nepal, including national surveys, used the World Health Organization (WHO) recommended definition (only breastmilk with the exception of medicine and vitamin syrup), and the most common measurement period was a 24-h recall. Our data demonstrated that the exclusive breastfeeding rate during the sixth month was 8.9% using the recall-since-birth method but was 18.7% using the 24-h recall method. Substantial differences in rates were also found during the first (66.3% vs 83.9%) and fourth months (39.2% vs 61.1%). CONCLUSION: We found that recent studies reporting exclusive breastfeeding in Nepal varied considerably in methodology. The most commonly used measurement, the 24-h recall, leads to over-estimation of the prevalence of exclusive breastfeeding when compared to the recall-since-birth method. A common standard of reporting exclusive breastfeeding is clearly needed for evidence-based decision making

Proceedings of The HKIE Geotechnical Division 43rd Annual Seminar: Towards a Smart-Green-Resilient Geo-Future for World-class City

This seminar proceedings contain articles on the various research ideas of the academic community and practitioners presented at The HKIE Geotechnical Division 43rd Annual Seminar (GDAS2023). This seminarprovides a platform for policymakers, practitioners, and academia to share their insights and brainstorm ideas with a view to seizing future opportunities and shaping the new future of Hong Kong. GDAS2023 was organized by the Geotechnical Division, The Hong Kong Institution of Engineers on 19th May 2023. Seminar Title: The HKIE Geotechnical Division 43rd Annual SeminarSeminar Acronym: GDAS2023Seminar Date: 19 May 2023Seminar Location:  Hong KongSeminar Organizers: Geotechnical Division, The Hong Kong Institution of Engineers Link to the GDAS2021 Proceedings: Proceedings of The HKIE Geotechnical Division 41st Annual Seminar Link to the GDAS2022 Proceedings: Proceedings of The HKIE Geotechnical Division 42nd Annual Semina