Insights on the Sun birth environment in the context of star-cluster formation in hub-filament systems

Cylindrical molecular filaments are observed to be the main sites of Sun-like star formation, while massive stars form in dense hubs, at the junction of multiple filaments. The role of hub-filament configurations has not been discussed yet in relation to the birth environment of the solar system and to infer the origin of isotopic ratios of Short-Lived Radionuclides (SLR, such as $^{26}$Al) of Calcium-Aluminum-rich Inclusions (CAIs) observed in meteorites. In this work, we present simple analytical estimates of the impact of stellar feedback on the young solar system forming along a filament of a hub-filament system. We find that the host filament can shield the young solar system from the stellar feedback, both during the formation and evolution of stars (stellar outflow, wind, and radiation) and at the end of their life (supernovae). We show that the young solar system formed along a dense filament can be enriched with supernova ejecta (e.g., $^{26}$Al) during the formation timescale of CAIs. We also propose that the streamers recently observed around protostars may be channeling the SLR-rich material onto the young solar system. We conclude that considering hub-filament configurations as the birth environment of the Sun is important when deriving theoretical models explaining the observed properties of the solar system.Comment: Accepted for publication in The Astrophysical Journal Letter

Examination of scales measuring reactance traits

The pnrpose of this study was to find the most valid and reliable scale measuring reactance traits.This study dealt with the threat of anti-attitudinal persuasion. Subjects were 150 nniversity str~de~lwtsh o were eligible for this experiment, and they were randomly assigned to high and low threat conditions. The procedures of the experiment were as follows: (1) pre-measurement of dependent variables, (2) measurement of reactance traits, (3) manipulation of the threat variable and presentation of a persuasive message, (4) post-mcilsurement of dependent variables. To measure reactance traits, three kinds of reactance scales were used: I-Iong's Psychological Reactance Scale (Hong's Scale: 14 items), Merz's Questionnaire for the Measurement of Psychological Reactance (Merz's Scale: IS items), and Merz's Scale revised by Imajo (Merz-Imajo's Scale: 28 items). The General Psychological Reactance Scale (General Scale: 42 items), which consisted of all items contained in the three scales, was also examined. Results showed that reactance traits measured by the General Scale had the most main effects and interactio~l effects with the threat variable of the fonr scales. Thus, it was concluded that the General Scale had the greatest validity and reliability of the four scales. The General Scale consisted of four-factors with 23 items (4 items from the Hong's Scale, 10 items from the Merz's Scale, and 9 items from the Merz-Imajo's Scale)

Chromosome aberrations in normal human fibroblasts analyzed in G0/G1 and G2/M phases after exposure in G0 to radiation with different linear energy transfer (LET).

We have studied the induction of chromosome aberrations in human fibroblasts exposed in G0/G1 to X-rays or heavy ions to study the influence of G1 cell cycle arrest. Confluent normal fibroblasts were exposed to X-rays or accelerated particles with different LET values and chromosome aberrations were investigated in the first G0/G1 and G2//M phase. The particles used here were 490MeV/nucleon Si, 500MeV/nucleon Fe, and 200MeV/nucleon Fe ions. Cells were subcultured 24h after exposure and premature chromosome condensation (PCC) was performed by fusion-induced method for analysis of G0/G1 cells, and chemically-induced method for analysis of G2 and metaphase cells. Chromosome damage was assessed in chromosomes 1 and 3 using whole chromosome fluorescence in situ hybridization (FISH). Cell cycle was analyzed by flow cytometry at different incubation times following subculture. After irradiation with 2Gy of high-LET particles, the yields of chromosome aberrations and fragments were significantly higher in G0/G1 phase than in G2/M phase, whereas similar yields of damage were measured in both phases after exposure to X-rays. In contrast, the yield of misrepair, assessed by the number of color junctions, was similar in the G0/G1 and G2/M phases after exposure to either X-rays or high-LET particles. The yields of chromosome aberrations, fragments, and color junctions in both the G0/G1 and the G2/M phases, increased with LET up to 200keV/μm, then decreased for 440keV/μm Fe particles. A good correlation was found between chromosome aberrations in both G0/G1 and G2/M cells and survival fractions after 2Gy of different LET radiations, although the slopes were steeper for the G0/G1 cells. Flow cytometry analysis indicated that high-LET particles induce more non cycling G0/G1 cells within 48h of subculture than X-rays, suggesting that chromosome aberrations scored at the G2/M phase may not accurately describe the true radiation effect