Book review: Where research begins: choosing a research project that matters to you (and the world) by Thomas S. Mullaney and Christopher Rea

In Where Research Begins: Choosing a Research Project that Matters to You (and the World), Thomas S. Mullaney and Christopher Rea offer a new guide to deciding on your research topic and formulating your research questions to develop a project that really matters. This easy-to-follow, innovative and empowering book may help to make the next search for research questions easier than expected, writes Jingying Wang. Where Research Begins: Choosing a Research Project that Matters to You (and the World). Thomas S. Mullaney and Christopher Rea. University of Chicago Press. 2022

Dry Stone Wall Relics as a Part of Cultural Landscapes: A Case Study from the Foot of Mt. Hira Region in Japan

[EN] Shishigaki (wild boar defense walls), as a part of cultural landscapes in Japan, currently faces serious deterioration. The research aims to identify the characteristics of Shishigaki walls in eight villages located at the foot of Mt. Hira and propose conservation strategies. Interpretation of historical documents and cadastral maps, interviews, and measurement surveys were conducted. As a result, about 4,3 km of Shish-igaki relics are confirmed, of a total length up to12,7 km built in the 18th to 19th century. Shishigaki walls were built by local households collaboratively with different drystone masonry techniques. Based on the field surveys, it was found that although up to 91% of Shishigaki walls located within the village territories were demolished, only half of Shishigaki walls in the forest were deconstructed. Loss of functionality as protection fences with the change of land use is considered as the main reason for the demolition of Shish-igaki walls. It is suggested that Shishigaki relics in the forest could be integrated into existing hiking routes and promoted through collaborative map-making with local residents. The authors contest that heritage interpretation rooted in local historical studies and conservation with community involvement could be adopted in the promotion of cultural landscapes worldwide.This research was supported by the Research Institute for Humanity and Nature Eco-DRR Project (14200103).Ochiai, C.; Wang, J. (2022). Dry Stone Wall Relics as a Part of Cultural Landscapes: A Case Study from the Foot of Mt. Hira Region in Japan. Editorial Universitat Politècnica de València. 417-424. https://doi.org/10.4995/HERITAGE2022.2022.1513741742

Revealing A Head-on Major Merger in the Nearby NGC 6338 Group with Chandra and VLA observations

By analyzing the Chandra archival data of the nearby NGC 6338 galaxy group, we identify two X-ray bright clumps (N-clump and S-clump) within the central 100 kpc, and detect an arc-like X-ray brightness discontinuity at the south boundary of the N-clump, which is defined as a cold front with a gas flow Mach number of M<0.8. Furthermore, at the north-east boundary of the S-clump (dominated by galaxy NGC 6338) another X-ray edge is detected that corresponds to a weaker cold front. Therefore, the two clumps are approaching each other approximately from opposite directions, and the group is undergoing a head-on collision that is in a stage of pre-core passage. This merger scenario is also supported by the study of the line-of-sight velocity distribution of the group member galaxies. The merger mass ratio is about 1:1.8 as estimated from the central gas temperature of the two clumps, which suggests the merger is most likely to be a major merger. We also analyze the VLA 1.4 and 4.9 GHz radio data, but we do not detect any extended radio emission that is associated with the merger.Comment: Accepted by Ap

The Application of Continuous Wavelet Transform Based Foreground Subtraction Method in 21 cm Sky Surveys

We propose a continuous wavelet transform based non-parametric foreground subtraction method for the detection of redshifted 21 cm signal from the epoch of reionization. This method works based on the assumption that the foreground spectra are smooth in frequency domain, while the 21 cm signal spectrum is full of saw-tooth-like structures, thus their characteristic scales are significantly different. We can distinguish them in the wavelet coefficient space easily and perform the foreground subtraction. Compared with the traditional spectral fitting based method, our method is more tolerant to complex foregrounds. Furthermore, we also find that when the instrument has uncorrected response error, our method can also work significantly better than the spectral fitting based method. Our method can obtain similar results with the Wp smoothing method, which is also a non-parametric method, but our method consumes much less computing time.Comment: Accepted by Ap

Chandra Observation of a Weak Shock in the Galaxy Cluster A2556

Based on a 21.5 ks \chandra\ observation of A2556, we identify an edge on the surface brightness profile (SBP) at about 160$h_{71}^{-1}$ kpc northeast of the cluster center, and it corresponds to a shock front whose Mach number $\mathcal{M}$ is calculated to be $1.25_{-0.03}^{+0.02}$. No prominent substructure, such as sub-cluster, is found in either optical or X-ray band that can be associated with the edge, suggesting that the conventional super-sonic motion mechanism may not work in this case. As an alternative solution, we propose that the nonlinear steepening of acoustic wave, which is induced by the turbulence of the ICM at the core of the cluster, can be used to explain the origin of the shock front. Although nonlinear steepening weak shock is expected to occur frequently in clusters, why it is rarely observed still remains a question that requires further investigation, including both deeper X-ray observation and extensive theoretical studies.Comment: 15 pages, 4 figures, accepted by Ap

Aging-associated Alteration in the Cardiac MIF-AMPK Cascade in Response to Ischemic Stress

An important role for a macrophage migration inhibitory factor (MIF)-AMP-activated protein kinase (AMPK) signaling pathway in ameliorating myocardial damage following ischemia/reperfusion has been described. An aging-associated reduction in AMPK activity may be associated with a decline in the ability of cardiac cells to activate the MIF-AMPK cascade, thereby resulting in reduced tolerance to ischemic insults. To test this hypothesis, _in vivo_ regional ischemia was induced by occlusion of the left anterior descending (LAD) coronary artery in young (4-6 months) and aged (24-26 months) mice. The ischemic AMPK activation response was impaired in aged hearts compared to young ones (p&#x3c;0.01). Notably, cardiac MIF expression in aged hearts was lower than in young hearts (p&#x3c;0.01). Dual staining data clearly demonstrated larger infarct size in aged hearts following ischemia and reperfusion compared to young hearts (p&#x3c;0.05). Ischemia-induced AMPK activation in MIF knock out (MIF KO) hearts was blunted, leading to greater contractile dysfunction of MIF KO cardiomyocytes during hypoxia than that of wild type (WT) cardiomyocytes. Finally exogenous recombinant MIF significantly reversed the contractile dysfunction of aged cardiomyocytes in response to hypoxia. We conclude that an aging-associated reduction in ischemic AMPK activation contributes to ischemic intolerance in aged hearts