Posttraumatic Growth after the Fukushima Nuclear Disaster: Examination of Free Descriptions among Fukushima Residents Who Lived in the Evacuation Area

We examined the differences in the posttraumatic growth (PTG) free descriptions from clusters of Fukushima residents (evacuation and non-evacuation zones) who experienced the Great East Japan Earthquake, and the relationship between “recovery from radiation anxiety” and the PTG-free description classification in these regions. A mail survey was conducted in August 2016 among Fukushima residents aged 20–79 years for free descriptions of their PTG. Participants were then divided into the “no anxiety,” “recovered from anxiety,” and “unrecovered from anxiety” groups based on their “recovery from radiation anxiety.” Data from 786 responses were analyzed. The PTG-free descriptions were classified into eight categories. Among those who lived in the evacuation zone versus those in the non-evacuation zone, “relating to others” (non-evacuation zone: 11.9% vs. evacuation zone: 18.4%) and “appreciation of life” (non-evacuation zone: 2.7% vs. evacuation zone: 9.8%) were significantly higher, and “increased awareness of disaster prevention” (non-evacuation zone: 20.4% vs. evacuation zone: 8.0%) was significantly lower. In the evacuation zone, “renewed recognition of nuclear issues” was significantly lower than the expected value in the no anxiety group (3.1%) and significantly higher than the expected value in the recovered group (22.9%). Further studies are needed to build support measures and potentially aid in preparing for future disasters.

To Become or Not to Become Tumorigenic: Subventricular Zone Versus Hippocampal Neural Stem Cells

Neural stem cells (NSCs) persist in the adult mammalian brain in two neurogenic regions: the subventricular zone lining the lateral ventricles and the dentate gyrus of the hippocampus. Compelling evidence suggests that NSCs of the subventricular zone could be the cell type of origin of glioblastoma, the most devastating brain tumor. Studies in glioblastoma patients revealed that NSCs of the tumor-free subventricular zone, harbor cancer-driver mutations that were found in the tumor cells but were not present in normal cortical tissue. Endogenous mutagenesis can also take place in hippocampal NSCs. However, to date, no conclusive studies have linked hippocampal mutations with glioblastoma development. In addition, glioblastoma cells often invade or are closely located to the subventricular zone, whereas they do not tend to infiltrate into the hippocampus. In this review we will analyze possible causes by which subventricular zone NSCs might be more susceptible to malignant transformation than their hippocampal counterparts. Cellular and molecular differences between the two neurogenic niches, as well as genotypic and phenotypic characteristics of their respective NSCs will be discussed regarding why the cell type originating glioblastoma brain tumors has been linked mainly to subventricular zone, but not to hippocampal NSCs.

Erosion of an exoplanetary atmosphere caused by stellar winds

Aims. We present a formalism for a first-order estimation of the magnetosphere radius of exoplanets orbiting stars in the range from 0.08 to 1.3 M⊙. With this radius, we estimate the atmospheric surface that is not protected from stellar winds. We have analyzed this unprotected surface for the most extreme environment for exoplanets: GKM-type and very low-mass stars at the two limits of the habitable zone. The estimated unprotected surface makes it possible to define a likelihood for an exoplanet to retain its atmosphere. This function can be incorporated into the new habitability index SEPHI. Methods. Using different formulations in the literature in addition to stellar and exoplanet physical characteristics, we estimated the stellar magnetic induction, the main characteristics of the stellar wind, and the different star-planet interaction regions (sub- and super-Alfvénic, sub- and supersonic). With this information, we can estimate the radius of the exoplanet magnetopause and thus the exoplanet unprotected surface. Results. We have conducted a study of the auroral aperture angles for Earth-like exoplanets orbiting the habitable zone of its star, and found different behaviors depending on whether the star is in rotational saturated or unsaturated regimes, with angles of aperture of the auroral ring above or below 36°, respectively, and with different slopes for the linear relation between the auroral aperture angle at the inner edge of the habitable zone versus the difference between auroral aperture angles at the two boundaries of the habitable zone. When the planet is tidally locked, the unprotected angle increases dramatically to values higher than 40° with a low likelihood of keeping its atmosphere. When the impact of stellar wind is produced in the sub-Alfvénic regime, the likelihood of keeping the atmosphere is almost zero for exoplanets orbiting very close to their star, regardless of whether they are saturated or not.